A Discussion of the History and State-of-the-Art of Microwaving in this Region
By: David E. Laag, WA6OWD (K6OW), Vice President, San Bernardino Microwave Society
April 4, 1994
"OK Chuck, I've copied W6HCC DE WA6EXV DM15. Your signal is pretty good as I was able to copy the entire sequence almost the first time through. Let me set up and transmit back to you now." Phil W6HCC moves a few cables around on the back of his 10' dish and checks the position of the moon through his boresight. "Alright Chuck, I've got thirty two watts coming your way via the moon." Minutes later, the contact is completed with Phil sending Chuck a string of didahdits. Chuck WA6EXV's voice appears on the liaison radio. "Well Phil, congratulations, we've done it! You are my first 10 Ghz EME contact with a California station."PREFACE This most recent success by the two individuals highlighted above is only the tip of the iceberg. California Hams have been making microwaves for almost fifty years now. This paper will present the history of microwaving in this region from the viewpoint of the membership of the San Bernardino Microwave Society (SBMS). It will not however be limited to SBMS activities as there have been many great contributions by Hams affiliated with other organizations or as individuals.
This paper is dedicated to those Radio Amateurs whose foresight, experimentive attitude, competitiveness and borderline insanity have opened the microwave bands to the rest of us. Your Author wishes to point out to the reader the names and call signs of a few individuals who, by their unselfish dedication, have left their achievements as cornerstones for those of us who follow.
(*) This paper is an excerpt from "The History of the San Bernardino Microwave Society", an SBMS historical publication. Sources for non SBMS activities have been credited where applicable.
The top of this list is Donovan "Tommy" Thompson, W6IFE, the father of the "Pola-plexer" and the one key individual who generally got things going in the Southern California Area starting in 1946. Another key figure in this era was Bill Baird, W6VIX, who helped to organize an eager group of individuals into what is now the San Bernardino Microwave Society (SBMS). Also, the dedicated and still contributing "cornerstone" of the SBMS, George F. Tillitson, K6MBL, the father of ROCKLOC and author of many high-tech microwave-related papers.
At this point the list becomes more difficult as there are so many members, past and present, who deserve this recognition. Your Author is forced to choose one figure from the last twenty-five years who, since his arrival at the SBMS, has had the most influence on local Amateur microwaving, and microwaving in general. Chuck Swedblom WA6EXV brought the rest of us from the older technologies like klystrons (they worked, and a lot was accomplished with them and their use paved the way to rapid deployment of newer technologies like Gunnplexers!), first to Gunnplexers, then "Narrowband" and finally PHEMTs and the moon. This paper is dedicated to these individuals who (stealing a quote from Frank WB6CWN) "allowed the rest of us to look great while standing on the shoulders of giants".
Your author's 1957 Webster's New World Dictionary defines microwaves as "extremely short electromagnetic waves - less than ten meters or especially less than one meter in length". Newer versions of this book define them as wavelengths from 50 cm (600 Mhz) to 1 mm (300 Ghz) in wavelength. The SBMS has devoted its activities to 1 Ghz and up. Reluctantly, recent activities on 70 cm (420-450 Mhz), 33 cm (902-928 Mhz), 23 cm (1,240-1,300 Mhz) and 13 cm (2,300-2,450 Mhz) will not be covered here. Activities on these bands are heavily covered in the Amateur Radio magazines and newsletters of VHF/UHF organizations. Recent articles covering the higher microwave bands have been sparse, especially covering activities on 9 cm and up (we need a forum like QSTs now defunct "New Frontier").
This paper will primarily cover the recent activities on the remaining bands from 9 cm (3,300-3500 Mhz) and up as well as the historical activities on all of the microwave bands. Every effort has been made to assure historical correctness of the material contained within this paper. Your Author is solely responsible for errors, omissions and its editorial content. If I have missed something important, it is because of my ignorance and nothing personal should be taken from it.
OUR MICROWAVE ROOTS
One of the most important historical figures in this paper is Donovan "Tommy" Thompson, W6IFE. He was a central figure in Southern California microwave activity from 1947 through 1969. It was his idea, the use of Polarity-Duplexing (The Pola-plexer), that carried Amateur microwaving with klystrons well into the 1970s.
While the first 3 cm contact was made in May of 1946 (James W2JRM and Charles W2JN, 2 miles (3.22 km)), Tommy W6IFE (shortly before returning to California) and W. Kenedy W4HPJ, quickly stretched this record out to 7.65 miles (12.31 km). These early contacts would serve as an indicator as to how successful this band would eventually be. To this date, 3 cm. is by far the most populated of the microwave bands above 13 cm.
Tommy W6IFE is credited with opening the 9 cm band [The ARRL UHF/Microwave Experimenter's Handbook, page 1-8]. Early on, Tommy had to construct both ends of the microwave equipment used on his microwave shots. On June 5, 1947, Tommy is credited with working 186 miles (299.46 km) on 9 cm.
April 25, 1948, Tommy W6IFE is credited with working a 150 mile (241.5 km) record path with W6ET on the 13 cm band.
Tommy's creation, the Pola-plexer, allowed the transmitter carrier to also be used as the receiver local oscillator (LO) source, thus allowing simultaneous transmit and receive (duplex) operation. By rotating the polarity of the received signal 90 degrees, isolation was achieved between the transmitter and the receiver. The whole assembly was (usually) constructed on circular waveguide of a correct diameter for the particular band being worked. One band in particular used an empty steel beer can as the piece of circular waveguide, thus making the material required for this assembly readily available (and is the literal incarnation of the beer can antenna, or "SBMS Beer Can Pola-plexer").
This completed assembly, consisting of klystron LO and receiver mixer (and IF preamplifier) was placed (in most cases) in front of the dish (if a dish was used at all!). Mounting the Pola-plexer directly in front of the dish eliminated feedline losses which were very high at the microwave frequencies used. Even today, this same principle is applied to high performance stations wishing to eliminate every db (we're counting them in tenths or hundredth of a db nowadays) of loss in a system.
In April of 1955, the first meeting of the SBMS was held in Ontario, CA. Ontario is located near the western edge of San Bernardino County from which the name "San Bernardino Microwave Society" comes. The stated purpose of the society is as follows: A nonprofit amateur technical organization dedicated to the advancement of communications above 1000 Mhz. An early roster of the SBMS shows twenty two members.
During the June 1955 VHF Contest, the SBMS made 400 contacts with other stations on bands ranging from 6 m through 9 cm. The effort resulted in a score of 5,365 contest points. Over the years the SBMS participated in many VHF Contests, and more recently has had members finishing at or near the top of the list in the ARRL 10 Ghz Cumulative Contest.
During November of 1955, Bill W6VIX published the first of three articles covering the design and construction of a "Pola-plexer" for 3,300 Mhz (please note the correct spelling of "Pola-plexer" from his hand). Bill's early work had been on 70 cm, where he held several distance records. Bill's first record, made with W6ZRN on July 27, 1947, was for 156 miles (251.16 km). Almost two years later on July 4, 1949, the two teamed up for another 70 cm record of 262 miles (421.82 km).
On June 9, 1956 (three months before your author was even born!), Tommy W6IFE and Bill W6VIX ventured to Point Loma near San Diego and La Cumbre Peak near Santa Barbara. They worked this path on 9 cm for a distance of 190 miles (305.9 km) (is this the first time this was done across this all water path on a microwave band?). Tommy used a four foot dish mounted in the back of his panel truck and Bill used an eight foot dish on a trailer (if you have ever had to move a solid eight foot dish you can appreciate what a task this was!). This path has been used extensively in recent years to extend microwave records on most all of the microwave bands up to 12 mm.
Later this same day, Bill W6VIX also worked W6IHK on 1,215 Mhz. for the same 190 miles (305.9 km). Four hours earlier on this same day, the distance record had been set by K6BAT and W6AXN at 160 miles (257.6 km). Records are made to be broken...
During the June 1957 VHF Contest, the SBMS operated under its early club call of K6OEE. Society members worked 510 stations on the bands from 6 m to 3 cm for a club total of 17,110 points. On June 23, 1957, Dale W6BGK worked Bill W6VIX for a record distance on 3 cm. of 124 Miles (199.64 km).
In September of 1957, the SBMS produced it's first microwave handbook. The package contained sixteen articles of special interest all combined into one package and handed out at the meeting. Additionally, Bill W6VIX and Dale W6BGK wrote and had articles subsequently published in QST. In 1992, George K6MBL used a reproduction of this manual as a handout for a meeting regarding SBMS history. The table of contents read as follows:
1. SBMS Standards
2 . through 4. The Pola-plexer, parts I, II and III
5. Circular Waveguide Chart
6. Voltage Compensated Power Supply
7. Wobulated Tone Multivibrator
8. Simple 9 cm. Transmitter
9. Regenerhet Pola-plexer - Super 2
10. Adjustment of Microwave Communications System
11. Double Dipole Feed on Coaxial Line
12. Focal Point of a Paraboloid
13. Klystron Power Supply for 723A/B, 2K25, 726A (Tube Data)
14. Basic Pola-plexer Using 1/2 Qt. Beer Can (9 cm.)
15. Transducer for Perpendicular Modes in TE1,1 Guide (3 cm.)
16. Predicting Propagation Paths Using Flat Earth Method October 12, 1957, an SBMS record shot was made on 6 cm. by George K6MBL and Bill W6VIX. Bill traveled to Strawberry Peak (6,100 ft/3,788.9 km) in the San Bernardino Mountains San Bernardino, Ca.) and George operated from his home QTH in Pomona. The 34 mile (54.74 km) path produced a QSO lasting over an hour, with a signal report at the Pomona end of 5X9 and 5X8 at Strawberry Peak.
September of 1958 marks a contact between George K6MBL and Vern W6SDE on the newly created "8 cm" band. The FCC had closed 3,300 to 3,500 Mhz to amateur use and replaced it with 3,500 to 3,700 Mhz in a move that would later be reversed.
November 16, 1958 found Ed W6OYJ and Vern W6SDE traveling to the mountain cabin of W6RIS near Crestline, Ca. (north of San Bernardino with an elevation of approx. 5,000 ft/3,106 km) in the San Bernardino Mountains. Vern and Ed both set up on 3,535 Mhz and prepared to work a number of stations in the vast "Inland Empire" spread out in front of them.
Vern worked Bill W6VIX at his home QTH in Ontario for a distance of 25 mi (40.25 km), George K6MBL at his home QTH in Pomona for 32 mi (51.52 km) and Marty K6JDJ/6 on Box Springs Mountain near Riverside for 17 mi (27.37 km). Both Ed and Vern worked Tommy W6IFE "mobile 6" near Lake Elsinore for a distance of 42 mi (67.62 km) for what was a new (club?) record.
The rigs touted "low noise" 30 Mhz preamps using 417A and 6J4 tubes. This trip was marred by severe interference in the 30 Mhz IF strips at the Crestline end because of a 10 m "Sweepstakes" contest station being operated nearby. Additionally, the fall weather in the mountains was beginning to become wintry as Ed reports; "Those who went to the mountains experienced severe winds and frigid temperatures. At the cabin near Crestline, a cup of hot coffee liberally spiked with "microwave antifreeze" froze anyway in about two hours". Ed goes on to report that 2 m was used as liaison although it was not needed for the shot with Tommy.ROCKLOC AND THE 1960s.
In 1960, George K6MBL introduced the principle of "Relative or Crystal Klystron Local Oscillator Control" or "ROCKLOC". This innovative enhancement allowed the klystron LO in the Pola-plexer to be frequency locked to a harmonic of a "reference" highly stable crystal oscillator. A frequency lock (referred to as automatic frequency control or AFC) correction voltage was generated by multiplying the reference oscillator so that it fell near the desired klystron oscillator operating frequency. This crystal oscillator harmonic frequency was then mixed with the klystron frequency to produce an AFC IF frequency of between 20 to 28 Mhz. A tunable AFC IF receiver operating in this range was used to produce an AFC error voltage which in turn was used to control and correct the klystron to the desired frequency. Since the frequency control element of the klystron required high DC correction voltage (between 200 and 500 volts), special interface circuits between the AFC receiver and klystron were required.
On October 14, 1960 George K6MBL tested the first ROCKLOC rig operating on 3,535 Mhz. Six days later on October 20, from his home QTH in Pomona, George worked Tommy W6IFE at his home QTH in Corona. George was ROCKLOCked on 3,535 Mhz, and Tommy, whose rig could AFC lock to George's signal, was therefore locked to 3,565 Mhz.
Early In 1961, George K6MBL presented his ROCKLOC system at an SBMS meeting. The SBMS standardized on the ROCKLOC frequencies of 3,335 and 3,365, anticipating the return of the 9 cm band back to its original 3,300 to 3,500 Mhz. After the band was returned, George and Tommy teamed up for the first contact on the "new band" between their respective homes. This contact occurred on December 22, 1961, between the hours of 2015 and 2145.
On November 4, 1962, George K6MBL, located near Pearblossom on the western edge of the Mojave Desert, established contact with Tommy W6IFE at his home QTH in Corona. This path was accomplished on 9 cm by using "Knife-edge Diffraction" over the ten thousand foot peaks of the Southern San Gabriel Mountains. This contact was made possible by using ROCKLOC at both ends and by using "Pseudo CW" combined with very narrow receiver bandwidths. Pseudo CW was generated by modulating the FM transmitted carrier with a tone whose frequency was carefully controlled to produce a "Bessel Null" at f-zero, causing the carrier to literally "disappear". This occurs because all of the energy is contained in the sidebands at this unique combination of modulation index and modulating frequency [Bessel and the Radio Amateur, SBMS, Researched and Edited by George F. Tillitson, K6MBL]. As the key was depressed to send dots, dashes or a continuous carrier, the modulating tone is removed from the FM carrier, allowing it to return with all of its energy centered around f-zero. The end result in a narrow receiver is that the carrier comes and goes exactly the same as real CW, and can be detected at the far end using a BFO just like real CW.
June 9, 1963 Ed W6OYJ and Don K6VYC traveled to Long Beach to set up on the 10th floor roof garden at the Lafayette Hotel. The event was an operational display for "The First Annual Southern California VHF Jamboree" sponsored by the "Microwave Society of Long Beach, Inc." and held at the hotel. The brochure for the event (actually dating the event as the 14th of June) touted lectures like "The FCC and the Amateur", "Tracking Earth Satellites at Goldstone", "Traveling Wave Tubes for Relay and Satellite Applications", "Varactor Multipliers for Hams" and The Oscar Concept", among others.
Don and Ed used ROCKLOC tuned up for transmitting on 3,335 and receiving on 3,365 Mhz and used W6OYJ/6 as the station call sign. RF output power was 50 mw and was fed into a thirty inch dish. They contacted the following stations: George K6MBL, at his home QTH in Pomona 30.5 miles (49.11 km)away, Vern W6SDE at his home QTH in Ontario 34.2 miles (55.05 km) away and Tommy W6IFE/6 running "microwave mobile" near Olive (at the coastal mouth of the Santa Ana Canyon leading from Orange County to Riverside County) at a distance of 21.1 miles (33.97 km).
In 1964, George K6MBL and Ed W6OYJ both had the capability of operating all bands from 13 Cm. through 3 Cm. The SBMS roster dated April 7, 1967 shows seventeen members including Roy W6DEY, the ARRL SCM.
The 1960s end with the passing of Donovan L. "Tommy" Thompson W6IFE, and the club unanimously agreed to accept his call as the club station call. The San Bernardino Microwave Society still maintains W6IFE as a club call to this day as an ongoing memorial to his achievements as an Amateur microwave pioneer. Bill WA6QYR has stored for posterity Tommy's ROCKLOC system and there is a lot of history in that jam packed six foot relay rack. Maybe someday an SBMS exhibit or museum... [SBMS history to this date is quoted liberally from "A Bit of SBMS History", George F. Tillitson, SBMS Historian, 1994 as well as numerous SBMS historical documents supplied by George K6MBL and Ed W6OYJ]EMERGENCE OF SOLID-STATE HELPS PORTABILITY IN THE 1970s "Barstow Hams Set Mark" read a headline in the Tuesday, July 21, 1970 edition of "The Sun", a San Bernardino County daily newspaper. This story, of course, begins earlier in June as an attempt to extend the 9 and 6 cm distance records. Dick K6HIJ and Marvin W6DSL traveled to Mount Hamilton in the San Francisco Bay Area and operated as K6HIJ/6. The other end of the shot, located at Breckenridge Mountain near Bakersfield, was held down by Ed W6OYJ, John W6NVV, Gordon WA6ZKY and Bill WA6QYR, operating with call signs of W6OYJ/6 on 6 cm and W6IFE/6 on 9 cm.
On the 18th of June, excellent communications was established on 9 cm over the path of 214 miles (344.54 km). This broke an earlier record of 190 miles (305.9 km) established by Tommy W6IFE and Bill W6VIX on July 9, 1956. On this same day, an earlier record of 179 Miles (288.19 km) on 6 cm was broken over this same path. Signals were so strong across the path that 40 db of IF attenuation was added before signals became unreadable! Stations used were running about 100 mw on both bands. A four foot dish was used by Dick K6HIJ at Mount Hamilton and a trailer mounted six foot dish was used by Ed W6OYJ at the Breckenridge Mountain end.
Stop and think for a second. The receiver noise figure from the single ended mixer in the ROCKLOC rig was probably over 10 db! The transmitter power was reported to be 100 mw. Add the wideband FM signal threshold penalty of about 8 db. (over an equivalent narrowband system). In Your Author's opinion, this was a difficult path with the equipment available at that time, but these people worked it easily. The story even gets better, as liaison on 80 m had to be coordinated over the microwave path because no contact could be established on HF!
From January 31 through February 9, 1971, Americans ventured into space to visit the moon, and the SBMS was there! No, they weren't on the moon, but they did receive signals from it. SBMS members Dick K6HIJ, Marvin W6DSL and Bill WA6QYR set up a ROCKLOC system at Dick's house in Barstow, Ca. An eight foot dish was used and the trio reported receiving signals from the Apollo 14 mission.
In July of 1971, Bill WA6QYR at his home QTH in Ridgecrest, Ca, set up his ROCKLOC rig on 2,300 Mhz to again attempt to receive signals from the Moon. Bill combined the same eight foot dish used in the above attempt with his Pola-plexer head for a receive setup. Bill writes in the July SBMS newsletter "Apollo 15 had a perfect launch today, see you at the meeting." His handwritten note at the bottom of the page reads "we heard it!". Bill reported that signals were not strong enough to decode any of the intelligence, but they were received nonetheless.
In 1972 and 1973 the SBMS began a group project to build a 13 cm beacon for OSCAR-7. The proposed beacon was to operate on 2,304.1 Mhz with an output power of 200 mw. Chuck WA6EXV and Gordy WA6ZKY worked together on the RF portion of the project. A crystal oscillator and SRD multiplier with all necessary filtering formed the basis of the beacon. A keyer and controller were built by Dick K6HIJ and Frank W6PBK using radiation hardened CMOS technology.
The assembled unit was placed into a small private aircraft and powered up while being flown from San Diego to Northern California. This flyover test was heard by Ed W6OYJ during its only in-flight operation over North America! The final testing and "space certification" on the beacon was made by NASA and the OSCAR program.
The entire OSCAR-7 package was then assembled and eventually placed into orbit in November of 1974. The beacon became a political football and was never allowed to be operated over the USA and Europe. It was turned on and subsequently received only over Australia and New Zealand.
The technological improvements of this era came from Chuck WA6EXV, who decided to apply solid-state circuitry to the ROCKLOC system. The existing portable ROCKLOC technology required lots of vacuum tube operated devices to make the system work. The power supply requirements to operate such a system in the field virtually assured a motor generator for a power source. He built a solid-state ROCKLOC tray to use with his Pola-plexer.
The first contact made with the solid-state ROCKLOC was on August 24, 1973. Chuck had ROCKLOCked a 9 Watt klystron on 9 cm and used it to communicate with Bill WA6QYR, both in the Ridgecrest area. Bill also built a solid-state ROCKLOC system and successfully used it on 9 cm.
As an innovation in this period, Gordy WA6ZKY spearheaded the use of inexpensive FM entertainment receivers to use in the IF system for ROCKLOC. Chuck and Gordy ran tropo schedules on the band from Ridgecrest to Corona, Ca. over several high mountain ridges. While occasional signals were heard at both ends, a completed two way QSO was never accomplished.
Other stations active on 9 cm. ROCKLOC in this era included Dick K6HIJ, George K6MBL, Gordy WA6ZKY, Frank W6PBK, Bill WA6LMO, Marv W6DSL and Ed W6OYJ. The 9 cm. ROCKLOC activity continued until about 1978 when it was set aside for newer technologies.
By 1975, Ma/Com introduced their 10 Ghz Gunnplexer, which consisted of a Gunn oscillator, ferrite isolator and mixer, self contained into one unit. This configuration is very similar to the SBMS Pola-plexer, with the exception that the transmit and receive signal polarization are the same on the Gunnplexer. Isolation between the transmitter and receiver is supplied by the built in isolator as opposed to the shift in polarization used by the Pola-plexer.
Immediately, Gunnplexers became a hit with Radio Amateurs. All that was needed to make one operate was a power supply which, like in the klystron, controlled the power and operating frequency of the device. Additionally, a receiver IF system was necessary to demodulate the incoming receive signals and to supply an AFC correction voltage back to the Gunn oscillator for frequency control. Articles for construction of the complete Gunnplexer transceiver have appeared in almost all amateur technical publications, and a set of plans for a complete system still appear in the ARRL Radio Amateurs Handbook.
The beauty of these devices is that they can be assembled and operated by amateurs not possessing a microwave lab or exotic test equipment. As time has progressed, several complete systems requiring virtually no assembly have been marketed, bringing such systems within the grasp of all amateurs and thus providing a simple and economical pathway into the microwave portion of the hobby.
In 1977, Chuck WA6EXV adapted ROCKLOC to the Gunnplexer. His circuit was published by Ma/Com in May of that year in an application note to help development of Gunnplexer communications systems. His system, based around the RCA CA-3089 FM IF Amplifier Subsystem, allowed an entire ROCKLOC system to be built into a small package which would fit onto the back of a dish.
The popularity of both Klystron and Gunnplexer based ROCKLOC systems sadly diminished in the late 1970s, mainly due to the simplicity of the use of "wavemeter" frequency control. Stations wishing to control the frequency of gunnplexers used a wavemeter, either permanently mounted in the system or held in front of the antenna, to determine the frequency of operation of the Gunnplexer. While the amount of display error on the wavemeter could allow for frequency errors large enough to prevent two stations from hearing each other, Hams determined to communicate always seemed to get the job done.
Those who are serious about the use of Gunnplexers might want to explore Gunnplexer ROCKLOC. By carefully controlling the frequencies of the Gunnplexers at both ends of a path, one variable is removed when attempting to work long paths or tropo scatter. The operator is then left to concentrate on dish orientation or allowed to wait for favorable path conditions. Additionally, the rigs on each end do not need to be AFC relocked after a deep path fade.
In the spring of 1978, the SBMS installed their 13 cm beacon on Heaps Peak in the San Bernardino Mountains. Chuck WA6EXV built the beacon and antenna and tested them for over a year at his home QTH. The antenna is a five element collinear design with 6.7 dbd gain housed in a Lexan radome, being driven by a transmitter running about three watts. This combination produces an FM modulated CW ID signal of about ten watts ERP on 2.304 Ghz (or thereabouts).
The beacon is quite strong throughout Southern California, and numerous stations have heard and used it through the years. The CW ID has a special message which can be copied and sent to the SBMS for a special QSL card. In the fifteen years that the beacon has been in operation, not one response has been made for the special QSL card.NEW TECHNOLOGIES COME TO FRUITION IN THE 1980s In 1986 Kerry N6IZW and Chuck WB6IGP led the rapid growth of 3 cm microwave activity in the San Diego Area. They hosted several garage workshops and developed simple kits to make low power transceivers by cannibalizing parts from RF burglar alarms bought at swap meets. By the time the 1986 ARRL 10 Ghz Cumulative Contest happened there were over two dozen local amateurs on the band. This group included some of the microwave "Old Timers" in the area such as "Red" Truax W6BLK (now a Silent Key), who installed the first 3 cm beacon on his house near Mount Helix.
Chip N6CA remembers his first wideband contact on the "1.14 Inch" (3 cm) band with Ed W6OYJ and Kerry N6IZW on June 14, 1986. Ed and Kerry were on Mount Soledad in San Diego and Chip was on top of the Palos Verdes Peninsula in Los Angeles. Chip's rig consisted of a 14 mw. Gunnplexer and a sixteen-inch dish.
The Summer of 1986 had Northern California microwavers Bill K6UQH and Art W6RXQ experimenting with "Narrowband" communications [QST September 1986, page 78 "The New Frontier"] using SSB and CW. Using crystal oscillators multiplied to 10 Ghz and power levels of about 0.5 mw and approximately eighteen-inch dishes, they report working paths of up to 110 miles (177.1 km). Power may make a path easier to work because the signal is easier to find, but certainly is not necessary in all cases. This is a case of careful frequency control combined with good operatorsmanship (a new word?) giving fantastic results.
Bill and Art built their systems completely from scratch. Stabilized LO sources with SRD multipliers (Bill wrote the book on this scheme, see the ARRL UHF/Microwave Experimenters Manual), mixers, and even the feeds for the dishes.
September and October of 1986 featured the first ever ARRL 10 Ghz Cumulative Contest [QST, March 1987 issue, pages 87 and 88]. Ed W6OYJ had the honor of starting off a Southern California tradition by winning this inaugural event with a 15 mw rig and Pola-plexer. Wideband rigs of almost every type were the order of the day, although seventeen percent of the participants had narrowband capabilities.
Ed W6OYJ's winning score of 3,763 points coupled with his 40 QSOs, 18 unique call signs and best DX of 171 Km (106.2 mi) was followed closely by Chuck WA6EXV with 3,137/20/6/164(101.86 mi), Kerry N6IZW 3118/26/18/154(95.65 mi) and Bill WA6QYR's 3103/21/8/171(106.21). These gentlemen represented the local microwave community from either the San Diego Microwave Group or the SBMS.
It's interesting how chance plays an important role in our lives. During this time period, Phil W6HCC had begun a research project (which fell through due to loss of funding) using phase-locked klystrons. The spoils, 100 mw-3 cm klystrons, Hewlett Packard power supplies and Dymec synchronizers, were put to use as his first microwave rigs (what a combination for a first rig, Hewlett Packard ROCKLOC!). Setting the system up on 10.00036 Ghz, with circulator and single ended detector, a 60 Mhz high IF, solid state down converter and his Collins 75S1 and 51J4 receivers as the IF receivers, he was ready to communicate.
His son, Myles KA6DZK, took half of the equipment to Mount Davis (or David, take your pick) near Beaumont and Phil took the rest to the San Bernardino Mountains near Crestline. They worked each other using CW, and had S9 plus signals both directions across the path. Encouraged by their newly found microwave success, Phil and Myles decided to try a longer and more challenging path. The next path to conquer was from Mount Davis to Mount Wilson. Again they were successful, this time with a measured 28 db signal to noise ratio! The rigs ran 100 mw of power combined with eighteen and twenty four inch dishes, and motor generators at each end for power.
Phil and Myles accomplishments were made independent of an organized Amateur Radio group. Phil had searched for the SBMS (in San Bernardino, of course!), but they were not to be found. Based upon his recent successes, Phil set out to find "bigger and better" sites. During this quest, he ran into Ed W6OYJ, setting up a narrowband 3 cm station on Mount Pinos. Phil was very interested in Ed's microwave equipment and, best of all, he was an SBMS member.
Now here is where the chance comment made above fits in. Ed had gone to Mount Pinos to set up for a 3 cm distance record attempt. What are the chances of running into somebody from San Diego, 200 Miles from home, a 3 cm microwaver, an SBMS member, on a remote mountain like Mount Pinos? There's a greater energy at work here... Your Author ran into Phil on Heaps Peak, almost two years later, as He and Marilyn were testing converted Ma/Com rigs with Chuck WA6EXV, but that's another story...
The dates were July 18 and 19 of 1987, and Ed W6OYJ was setting the station mentioned above. He was part of a group of microwavers from all over California cooperating to establish a new narrowband 3 cm record. The other participants distributed themselves as follows: Rich WB7ABP west of Redding (CN80) at 6,900 Ft, Glenn N6GN (who spearheaded the project) Ball Rock, Tehema County (CM89), Bruce WB0HLC Mt. Oso (CM97) at 3,300 Ft, Bob W6SFH to Frazier Pk (DM04) and Chuck WA6EXV to Piute Peak (DM04), both over 8,000 Ft.
As is typical for this type of propagation, the group had to wait for an early morning duct to form. At 0530 hours local, a duct had indeed formed and stations began to attempt to work each other. When the smoke had cleared, a new record for 3 cm distance had been set between Bob W6SFH (four foot dish and 300 mw) on Frazier and Glenn N6GN (four foot dish and 250 mw) on Ball Rock. The new record of 414 miles (665.54 km) replaced an earlier record of 296 miles (476.56 km)[QST, November 1987, "The New Frontier", page 58].
The 1987 ARRL 10 Ghz. Cumulative contest [QST, March 1988, pages 80 through 82] was almost a carbon copy of the 1986 version from the viewpoint of leaders. Ed W6OYJ again came in ahead of the pack with 10,536 points from 84 QSOs, 37 call signs and a top distance of 315 Km (195.65 mi). Again Chuck WA6EXV was close on his heels with 10,216/87/19/172(106.83mi) as was Bill WA6QYR with 8,508/65/15/171(106.21mi) and Gordon WB6NOA with 7498/49/25/213(132.23mi). Again the tradition of using wideband equipment in the contest is still very strong along the west coast, but the faint rumblings of narrowband can now be heard...
In 1988, Kerry N6IZW installed a 3 cm "wideband" beacon operating on 10.25 Ghz on Mount Helix in the San Diego Area. Beacons serve a number of needs on the microwave bands. When building feeds for dishes, a reliable signal source like a beacon is used to focus the feed in the dish. When aligning or testing a receiver front end (without a microwave signal generator), the beacon can be used to evaluate relative receiver performance. Perhaps the most common use for a beacon is to determine what frequency your rig is operating on. The universal use for beacons on any frequency band is of course to evaluate propagation characteristics and help to spot band openings or enhanced paths.
On June 06, 1988, Chuck WA6EXV ventured to Bird Springs (DM05xm) and set up his "Narrow Band" transverter. Phil W6HCC packed up his newly phase-locked gunn transmitter and set up on Heaps Peak (DM14kf). Phil's sideband phase noise was so bad that Chuck used it to easily find his signal, even at a distance of over 100 miles (161 km) away! Phil had 65 mw, a thirty inch dish and Chuck had 40 watts and a fourfoot dish!
On August 6, 1988, another 3 cm attempt was made over the San Joaquin Valley of California. This time Rich WB7ABP went to Bonanza King Mountain (CN18qc) at the 8,000 foot level while Bruce WB0HLC went to Frazier Mountain (DM04ms) at a similar elevation. The contact was made with SSB quality signals at 0600 local establishing a new 3 cm record of 479 miles (771.19 km). Rigs used were 700 mw into thirty two inch (WB0HLC) and fourty-eight-inch (WB7ABP) dishes with receive noise figures around 4.5 db [QST, January 1989, "The New Frontier", page 86].
In August and September of 1988, fifty four amateurs entered the ARRL 10 Ghz. Cumulative Contest [QST, March 1989, pages 87 and 88], with one third of these entrants from California. An international station operated from multiple locations in Mexico led the way in points scored as well as generating some real long haul distances. The XE2GBO group (operators N6XQ and WA5LIG) racked up 16,644 points from 61 QSOs, 27 call signs and a best distance of 647 km (401.86 mi). Close behind this year is Chuck WA6EXV with 14,299/121/22/206(127.95mi), Ed W6OYJ with 12,048/85/28/352(218.63mi) and Bill WA6QYR with 9,184/73/15/171(106.21mi).
On July 23, 1989 Jack XE2GXQ set up 9 and 6 cm radios at Guerrero Negro, Mexico (DL37cx). Chip N6CA traveled to the southeast corner of CM94 (CM94xl) north of Santa Barbara and set up similar equipment. They were able to work the 613.4 mile (987.57 km) path on both bands with 5 w transmitters and fourfoot dishes on both ends. This distance produced a North American record on these bands. The rigs that Jack used were then shipped to Hawaii for use in later attempts to work back to the mainland.
Conditions along this over-water path were excellent, and Gary NN6W combined with XE2GFH on the same day to produce a new 3 cm record. Their efforts on wideband netted them the same 613.4 miles (987.57 km). This path would again be exploited for even more distance at 3 cm.
August 19, 1989 marked the first operation on 12 mm for Chip N6CA. His powerful 280 mw wideband rig used a 25 dbi. horn for this first contact with Gary WA6MEM. During this time there were 5 stations with 24 Ghz wideband rigs in use; Chip N6CA, Gary WA6MEM, Jack N6XQ, Alan W6CPL and Gary NN6W. A flurry of 24 Ghz activity followed as this group of stations worked for VUCC, with many of the shots directly from home to home!
The 1989 ARRL 10 Ghz. Cumulative Contest had the following results: Phil, W6HCC won with 10,320 points, 78 QSOs, 17 unique call signs and a best DX of 266 Km (165.21 mi) followed by Chuck WA6EXV, 9,272, 71, 11, 266(165.22mi), Gary NN6W, 8,222, 62, 22, 201(124.84mi) and Bill WA6QYR, 7,912, 67, 17, 266(165.22mi).BANDWIDTHS GET SMALLER AND DISTANCES GET LONGER IN THE 1990S
In the late eighties, the ground rules began to change for Amateur microwave. Once a novelty, narrow band stations began appearing on mountains and paths otherwise unheard of were being worked. Wideband/Narrowband refers loosely to the modulation used and is part of microwave jargon. A wideband station uses FM modulation and associated wider receiver bandwidths for communication. The likes of Pola-plexers, ROCKLOC and Gunnplexers are wideband rigs. Narrowband stations use Single Sideband and CW modulation to narrow the receiver bandwidth and increase the signal to noise ratio on weak signals.
While the advantages of narrowband are obvious, it has one major drawback; frequency stability of the LO chain is extremely important. A frequency differential of 10 khz between two stations working a path might result in a missed contact because of the narrow bandwidths used in SSB and CW receivers. The IF bandwidths used in wideband equipment were very forgiving, and the ability to "AFC Lock" to a distant station took care of frequency instability or drift problems.
For narrowband operation, LO chains with poor FM performance (microphonics, drift, hum, etc.) would make a transmitted signal difficult to copy at the other end or make an otherwise clean transmission difficult to copy. The solution to this problem was the use of ovenized crystal oscillators in narrowband transverters. An ovenized primary frequency source is used to either phase-lock the LO to its correct operating frequency or is multiplied to the LO frequency directly. Unless otherwise noted, all operations described from this point foreword are narrowband.
Then a narrowband miracle occurred! Approximately 125 surplus 10 Ghz Ma/Com T-1 radios became available to Amateur microwavers. These units were transverters, complete with an LO system that allowed the use of 2 meters as the IF! All that needed conversion was the power supply to AC for home use or 12 Volts for mountain top use. They came contained in a weatherproof aluminum housing with a built-in twenty seven inch dish sporting a good performing receiver and a transmitter PA capable of 200 mw of linear operation. They were quickly purchased and a majority of them made it to the airways during the next few years. This is certainly the single most important event leading to the switch in the 1990s from wideband to narrowband.
January 1990 started out hot for 12 mm wideband activity. Armed with their 15 mw gunnplexers, Alan W6CPL worked Jack N6XQ on January 26 for a distance of 108 miles. The important thing about this contact was that again both operators were at their respective homes, Alan in the Baldwin Hills (DM04ta) near the Los Angeles International Airport and Jack (DM12jr) near San Diego).
In May of 1990, Chuck WA6EXV heard his 3 cm echoes off of the moon for the first time. Using his 40 Watts and 10' dish complete with Az-El drive and video camera for optical steering, Chuck easily copied his own echoes. During the summer of 1990, Chip N6CA installed his 3 cm beacon on top of the Palos Verdes Peninsula (DM03ts). The beacon uses a solid state transmitter running 3.5 watts into 100' of EW-90 elliptical wavequide. This in turn feeds a 13 dbi omni directional antenna which saturates the Los Angeles basin. The beacon uses a high-stability oven so its signal can be used as a frequency reference. All 3 cm narrowband operators in this area have used Chip's beacon at one time or another to determine if the receiver in their rig or associated antenna hardware is operating correctly.
The N6CA beacon is heard even out of the Los Angeles area. Your Author has heard the beacon as far north as San Benito Mountain (CM96qi) in Central California. Chip has heard it as far east as Mt. Potosai near Las Vegas, Nevada. Jack N6XQ has the distance record for reception of the beacon, however, with a distance of 489 miles to Guerrero Negro, Mexico (DL37ck).
Additional beacons have appeared in all of the major metropolitan areas, some for 3 cm narrowband and others for wideband. A current list is frequently published in the newsletters of the SBMS as well as other microwave organizations. Some dedicated operators have gone so far as to build their own portable beacons. These units, running from microwatts to milliwatts, supply a weak RF source in areas not covered by fixed beacons.
On September 15, 1990 during the ARRL 10 Ghz Cumulative Contest, a very successful operation occurred. Phil W6HCC and Frank WB6CWN started out up the Owens Valley as rovers. Phil was using his "Mega Rig", 15 watts and a four foot dish while Frank used a converted Ma/Comm unit running 200 mw and a twenty seven inch dish. The two stations would stop, setup, and communicate with stations located on Heaps Peak, Keller Peak and Onyx Peak, all in the San Bernardino Mountain Range. Most of their contacts were non line of site and required a bounce path off of Walts Point in the Southern Sierras. The point production of this trip was astounding for stations working the pair. Phil later dubbed this "The Run" and it has had wide reaching implications for 10 Ghz operations. While the reflective properties of many surfaces at microwave frequencies are well known, the use of bounce-paths by amateurs had been largely overlooked.
Chip N6CA and Jack XE2/N6XQ combined for a best DX of 622 Km. Chuck WA6EXV went on to win the contest, with an astounding score of 22,189 points, 124 QSOs, 17 call signs and a best DX of 365 Km (226.7 mi). The next highest point scorers were Chip N6CA, 14,628, 78, 20, 622(386.34mi), Phil W6HCC, 12,525, 73, 16, 365(226.7mi) and Bill WA6QYR, 12,144, 85, 18, 365(226.7mi) [QST, March 1991, pages 85 and 86].
The San Francisco Bay area brought life to 12 mm narrowband as Bill N6OLD, Bruce KK6TG and Lynn WB7ABP all have rigs running in January of 1991. Their first assault on this band/mode occurs the 27th of this month and has Lynn traveling to English Hill (CM88ni) and Bill near the Hewlett Packard facility in Santa Rosa (CM88pl) for a distance of 12 miles (19.32 km). This may not seem like a long distance but take into account the following: Bill N6OLD, 2 mw, thirty inch dish, bare mixer receiver and Lynn WB7ABP less than 100 mw and a twenty four inch dish.
On February 23 this same team extended their previous distance out to 125 miles (201.25 km)! Bill N6OLD positioned himself on Mount Diablo (CM97bv) and had Bruce KK6TG on Hull Mountain (CM89mm). Bill was running the same rig described above and Bruce was running similar power and antenna size. Rumor has it that these guys now have "more power" and better receivers and are waiting for some of us in Southern California to get on the air and work them!
During 1991, Kerry N6IZW replaced his 3 cm "wideband" Mount Helix beacon with a dual mode "wideband/narrowband" beacon. This new dual mode beacon was installed on Cowles Mountain (DM12lt). The frequencies of operation are 10.250 Ghz. and 10.368,050 Ghz operating with call signs of N6IZW and WB6IGP, respectively August 28, 1991 marks the completion of the first of two worldwide records which will be very difficult to beat. Chip N6CA and Paul KH6HME connected for on 9 cm. for a path of 2,468 miles from Paul's site on the Island of Hawaii (BK29go) to the top of Palos Verdes (DM03ts). The following day, lightning struck twice as the pair again connected, this time on 6 cm over the same path.
In 1991, four microwave stations sport continuous band occupation from 23 cm (more accurately starting with 160M!) through 12 mm. They are Chip N6CA, Alan W6CPL, Dave WA6CGR and Jack N6XQ. Paul Kh6hme has all microwave bands available from DC to 3 cm. The rest and majority of local microwave activity is focused on 3 cm.
During this time period, another project is taken on by Phil W6HCC and Chuck WA6EXV. The two began a grid square hunt on 3 cm. which has grown to large proportions. Originally focused around 6,000 Foot high Heaps Peak (DM14kf), it was later transferred to 8,000 Foot high Keller Peak (DM14le) both near Running Springs, CA. Phil's total of 34 grids combined with Chucks 31 are certainly accomplishments which, like Chip and Paul's Hawaii to mainland shots, will be difficult to overtake. The technological improvements necessary to allow for the preceding accomplishment to be made are as follows. Receivers, largely unchanged up to this point, began to have better noise figures. The commercial availability of economical GASFets with acceptable noise figures at 3 cm allowed for good receiver Low Noise Amplifiers (LNAs) to be built.
Several versions became available, Chuck WA6EXV and Chip N6CA came up with viable local designs and a complete series covering the most of the microwave bands are currently covered in the Radio Amateur's Handbook with kits being marketed by Downeast Microwave.
The quest for better receiver performance continued with the moving of the LNA to the back of the dish. This removed the loss contained in the jumper, either coaxial or flexible waveguide, that ran from the dish to the transverter. This meant that the transmit/receive changeover system also had to be moved to the back of the dish. A typical configuration has a waveguide switch mounted directly to the back end of the feed and the receive LNA connected to the switch with very short jumpers or adapters.
Additionally, more transmit power was becoming available. Chip N6CA built a number of GASFet TX power amplifiers running about 3.5 watts. Concurrently, a number of surplus 11 Ghz, Traveling Wave Tube Amplifiers (TWTAs) became available. These TWTAs operated from -28 Vdc. and produced from 5 to 15 watts of power at 3 cm. The DC primary power source was easily implemented with automobile batteries and these amplifiers were quickly integrated into existing systems. Transmit power began showing up on mountain tops at a rapid rate.
The 1991 ARRL 10 Ghz Cumulative Contest marks a substantial reduction in wideband usage in the Los Angeles Basin. While many of the narrowbanders are still carrying their wideband equipment, it is pressed into service less than ever. One big event occurred for the San Diego Microwave group as five members worked KY7B on Mount Union near Phoenix, Az. The San Diego Group worked the 415 km (257.76 mi) path from Monument Peak, 50 Miles east of San Diego. A large number of thunder storms plagued the path and by midday signals had faded substantially.
The contest had Bill WA6QYR winning with 20,586 points after 124 QSOs, 13 unique call signs (lots of rover points) best DX of 361 Km (224.22 mi). Other leaders were Phil W6HCC, 18,209, 94, 16, 360(223.6mi), Chuck WA6EXV 17,818, 92, 13, 361(224.22mi) and Dave WA6OWD 14,038, 85, 14 and 360(223.6mi).
On November 3, 1991 Frank WB6CWN, Bill WA6QYR and Your Author ventured to Onyx Peak (DM14pe 9,000') near Big Bear Lake, Ca. to work Dave KY7B on Mount Union (DM34tk) in Arizona. Chuck WA6EXV and Phil W6HCC went to Keller Peak in hopes of working Dave KY7B for a new and distant grid square. This was a perfect fall day in Southern California and the microwave activity was just frosting on the cake. At about 10:00 local, 2 meter liaison contact was made, and when 3 cm signals were turned on at the Arizona end, they were heard immediately at Onyx Peak. After the Onyx Peak group completed their contacts, Chuck and Phil took their turn. After a minor struggle, all stations had worked Dave in Arizona, bringing this microwave year to a close.
On May 13, 1992, Chuck WA6EXV made his first 3 cm EME contact. For this, he teamed up with Jim WA7CJO in Phoenix, Az. Chuck became the first successful 3 cm EME station in California and for Jim this was another "feather in his cap" (his first 3 cm EME contact occurred 8-27-88 with WA5VJB). Jim was running 300 watts into a sixteen foot dish while Chuck was using his usual 40 watts into his ten foot dish.
In August and September of 1992, the 7th ARRL 10 Ghz Cumulative Contest was held. New voice for this contest was Robin, WA6CDR, operating his fixed station on Mount Wilson in Southern California. Not only was Robin working other stations, he also spent time to help many others "connect" when frequency difference or path problems made contact completion difficult. His strong signal, keen sense of microwave operation and exceptional CW skills (a seasoned 160 m contester) have allowed him to work all stations within his reach. Frank WB6CWN and Your Author ventured to Piute Springs (DM05tk) near Tehachipi, Ca. on Saturday of the second contest weekend. Stations worked included Ron K6GZA running 15 mw, Jim W6ASL running 200 mw and Bill N6OLD running 10 watts, all located on Loma Prieta Mountain (CM97bc) near San Jose, Ca. Ron's 15 mw was easy CW copy from Loma Prieta Mountain which is 360 km (223.6 mi) from Piute Springs. Frank was running 200 mw into a twenty seven inch dish and Your Author was running 5 watts into a similar size dish. During mid afternoon, a rogue gust of wind knocked over Your Author's dish, which in turn pulled the feedline and entire microwave rig off the tailgate of My 1977 S-10 Blazer spreading everything all over the ground! The dish was bent but everything still worked and was used as is on Sunday.
The last day of the contest had San Diego Microwave Group members Kerry N6IZW and Chuck WB6IGP operating narrowband "microwave mobile". Their run started in San Diego and continued up highways 5 and 405 into Orange County. They worked many stations in the contest as this was a very successful adventure. Bill WA6QYR won the contest in spite of a dead battery and vehicle troubles "off the paved highway" in the desert of the Owens Valley. The results were Bill WA6QYR with 11,533, 65, 16 and 324 km (201.24 mi) with Dave WA6OWD next with 9,805, 56, 17, 364(226.08mi), then Ed W6OYJ with 8,956, 68, 22, 333(206.83mi) and Jack N6XQ with 7,740, 51, 17 and 335(208.07mi).
On September 26, 1992, a forward thinking Amateur Community, representing all current as well as potential microwave users, gathered in Orange County, Ca, for a meeting which would serve to set the stage for microwaving in the future. The goal of the meeting was to develop band plans for the microwave bands not currently covered by such plans. The basis for the new plans built upon established spectrum usage practices as well as to anticipate the future growth of Amateur microwave needs. Issues were discussed from all possible viewpoints with current usage, "technical feasibility" and "inter-user protection" given high consideration.
This coalition of microwave spectrum users spent a very full day identifying current uses as well as organizing the bands for the pending onslaught of new users. The bands covered on that day were 13, 9, 6 and 3 cm. The groups participating in this project were: ARRL, VUAC Dave WA6PMX, VRAC Karl N6BVU, SW Dir. Freed WA6WZO, Asst. SW Dir. Art W6XD, OCCC Races, WSVMS, ATN, VCARC, SCDCC, SBMS and SCRRBA for a total of 21 participants.
By the end of a long day a band plan for each of the bands covered had been arrived at. By mutual agreement of all parties concerned the plans were adopted for use in this region. SCRRBA has in turn adopted this plan for the Southern California area and additionally has forwarded the plan for national review and adoption.
The implications of band planning are obvious. Knowing where a particular activity belongs, and what technical requirements maximize usage of the bands will help potential users get projects on the air allowing for more occupation of these bands. These plans were included in an SBMS paper entitled "The Microwave Spectrum: What can we do with it." [Chuck Swedblom, Senior Member, SBMS, published in the Proceedings of the 38th Annual West Coast VHF/UHF Conference, published by: The ARRL].
In late 1992, the SBMS members began assembling handouts from prior SBMS technical talks to form the basis of an updated microwave manual. This book contains reproductions of historical articles as well a handouts from recent technical talks. The first run went very quickly and from time to time limited reruns are made. 1993 IS A BUMPER CROP YEAR FOR 10 GHZ
1993 will be remembered as a pinnacle year as far as 3 cm is concerned. January 23 was one of those California postcard days and the 3 cm activity for the year began with an attempt to work from Point Reyes just north of the Golden Gate to Surf (CM94qq) on the Pacific Ocean near Point Conception. Jim, W6ASL and Bill N6OLD manned the north end of the path and Dave, WA6CGR, Frank, WB6CWN, Phil, W6HCC and Chuck WA6EXV held down the south end of the path. Your Author ensconced himself on Santa Ynez Peak (DM04ag) with the ability to look both to the north and south. Liaison for this shot was a disaster as most repeater networks covering the gap between north and south were inoperative. Cellular telephones were reluctantly pressed into service and by mid afternoon signals had been heard by the stations at the south end of the path. This path was to wait for another day to be completed. Your Author worked seven stations that day with his low power exciter, .5 watts and a fourfoot dish.
On the evening of the May SBMS meeting, Chip N6CA and Dave WA6CGR commuted to the meeting while communicating on 3 cm. mobile. Both mobiles were equipped with 17 Db. "Winged Slot" antennas and good communications were achieved over some healthy distances. Signals were so good that they could use narrowband FM as the communications mode, thus eliminating most of the effects of doppler shift heard in narrower and more frequency sensitive modes.
On the 15th of May Your Author ventured to Box Springs Mountain (DM13ix) to operate a station commemorating the Riverside Centennial. The station was operated as W6TJ, the Riverside County Amateur Radio Association club call sign. Six stations were worked ranging from San Diego to Santa Barbara. Stations worked could send a QSL card to the Riverside Club and receive a commemorative QSL card back as well as having their card put into a time capsule by the centennial committee. Your author used his .5 watt exciter and fourfoot dish.
Two days later on the 17th of May, Jack N6XQ and Bernardo XE2HWB, came on the air with a 3 cm station on the Isla De Guadalupe, Mexico. They were part of a "DXpedition" which included stations on 6 m through 70 cm, 23 cm and 3 cm, as well as HF (five operators whose main thrust for the trip was an RSGB "IOTA" expedition). The island, 155 miles off of the coast of Baja California, is 350 miles south of Los Angeles and is divided into two extremely rare grid squares, DL08 and DL09.
The group actually arrived two days earlier and operated VHF/UHF from a location which had rolling hills obstructing their path to the north. Conditions over the water were so good that the station, operating as XF1G, was able to work Dave WA6CGR at Point Reyes near San Francisco, almost 700 miles (1,130 km) away! All things considered, Dave and Jack would probably have worked on 3 cm if the local obstruction (rolling hills) at the XF1G location had been overcome. After two days, an opportunity to move the station to a better 3 cm location presented itself. Unfortunately, Dave, with prior commitments, had already left Point Reyes by the time that this move had occurred.
As Jack moved to the better location, a group of 3 cm operators in the Los Angeles and San Diego area awaited his arrival. The propagation conditions were excellent and stations who were able to be on the air (a Monday) had no difficulty in working the Island. Phil W6HCC worked Jack 3 times, first from Keller Peak, then Heaps Peak, then from his house on a bounced path off of the top of Mount San Gorgonio. Frank WB6CWN worked Jack from Saddle Peak and signals were so strong that Frank was able to work him with just an open waveguide. Frank's rig was in the form of a breadboard (a neatly built breadboard!), and was carried on a piece of plywood at the time. Other stations working Jack were Robin WA6CDR, Chip N6CA, Chuck WA6EXV and Dave WA6CGR. Jack reported that all stations were S9 plus at this distance of 350 miles (565 km) plus, with Phil peaking at S-5 on the bounce path!
June 12th marked the first of two unusual maritime operations for the year. Gordon WB6NOA, with horn in hand, proceeded to work from some very rare grids. He navigated his boat to DM02, DM03, CM92 and CM93 and worked quite a number of stations. The rig was a 200 mw transverter used with a horn antenna. Some of the longer paths were difficult to work as the boat would go down into a swell and the water would block signals. When the boat reemerged above the liquid horizon the signals would peak again.
On the eve on the Fourth of July, Frank WB6CWN and Your Author ventured to San Benito Mountain (CM96qi) near Kettleman City in Central California. During the afternoon hours the following stations were worked: Rich, KF6CU located on Mt. Hamilton (CM97ei), Bill, K6UQH in Saratoga (CM87xf), Chip, N6CA on Palos Verdes (DM03ts), Phil W6HCC on Heaps Peak (DM14kf), Bill WA6QYR at Bird Springs (DM05wm), Chuck, WA6EXV in Ridgecrest (DM15dp) and Jim, W6ASL on Mount Diablo (CM97av). All stations were worked with good signals and the N6CA beacon on Palos Verdes was also heard at this site.
On July 11, Chuck WA6EXV took to the water and worked microwave 3 cm from his 21' Bayliner the "Audrey J". Putting the water bound portions of CM94 on the map, Chuck worked a number of stations with his solid state rig running .75 watts into a 15 db gain horn.
On July 18, 1993, an attempt was made to break the standing North American 10 Ghz over-land record of 479 miles. Phil W6HCC and Chuck WA6EXV had been working on the attempt for about three years. A prior attempt in 1991 from Frazier Mountain in Southern Ca. to Mt Ashland near Medford, Or. had ended without any signals being heard across the path. Several things had been learned from this unsuccessful attempt:
1. Mt Ashland was an excellent location to attempt the path from and good operating positions were located.
2. It was obvious that "beacon" stations along the path were necessary to help to determine which portion of the path needed extra help or which elevations to look for the signals at.
3. Better liaison was needed as HF, VHF and UHF SSB had proven difficult at best; 2 meter signals had been heard along the path intermittently and at very weak strengths.
4. Weather patterns needed very close watching. The many variables and incongruities along a lengthy over-land path (compared to the ocean where inversion layers can provide uniform ducts thousands of miles long) are difficult to control. The weather at the south (Frazier Mt.) end of the path was excellent for the three days spent during the attempt but the weather at the north end (MT. Ashland) was quite unstable. A strong on-shore flow was believed to be the major culprit in preventing this path to be worked at that time.
Armed with this information, a schedule was set up for July/August of 1992. The attempt was called off due to a continual stream of weak cold fronts moving into the Northwest United States keeping the weather along the path unsettled.
The dates were set for the 1993 attempt [see QST, March 1994, pages 48 and 49]. Phil W6HCC and Marilyn left for Mt Ashland almost a week early, towing a trailer that was to be used as a support base near Mt. Ashland. 40 m SSB was used by all participants to keep in touch as the northern (Mt Ashland) team traveled. On site arrival of the southern (Frazier Mountain) team was the afternoon of July 16. Chuck WA6EXV learned that his permit for Frazier had been revoked due to a confrontation between another Amateur Radio Club and Forest Service Personnel a few weeks earlier. As a concession, a permit was issued for the top of Mt. Pinos about ten miles to the north.
The group consisting of Chuck WA6EXV, Frank WB6CWN and Dave WA6OWD assembled on Mt. Pinos (DM04kt). Pine trees obscured the horizon to the north but a suitable operating position was found where the three stations had clear shots to Mount Ashland (the three dishes were almost touching at the edges). Phil W6HCC and Marilyn had been at the Mt. Ashland end for several days and had awaited our arrival. Jim W6ASL and Ron K6GZA had gone to Mt Vaca (CM88wj) as an intermediate station 298 mi (479.8 km) from Mt. Pinos. During the early evening hours signals were exchanged between Mt Vaca and Mt Ashland as well as between Mt Vaca and Mt. Pinos. No signals were heard between Mt Ashland and Mt. Pinos.
The stations were all secured for the night. Mountaintopping has the great benefit of overwhelming you with many aspects of nature. The sunrises and sunsets were spectacular, the air was clean and clear and the night skies full of a continuous canopy of planets and stars. Your Author, sleeping on the tailgate of his Chevrolet S-10 Blazer, woke up at about 0200 local after dreaming that rats were crawling over, under and around him. A quick check with a flashlight confirmed that this had been more than a dream! The tailgate was closed to put an end to this all too personal rat-race.
July 17 was spent with continuous attempts along the path starting at 0530 local. Since the Mt. Ashland station was based out of a trailer park adjacent to the mountain, the station had to be set up on the mountain before operation. Phil and Marilyn arrived about an hour before the target start time. Most of the station was mounted in the back of Phil and Marilyn's 4X4 Ford pickup truck but they still had to set up the station peripherals (mount the fourfoot dish and feed, liaison antennas, etc.), all in total darkness! The Mt. Pinos stations were mostly left in place during the nights and required very little predawn assembly.
The rigs used are described below:
WA6EXV: Fourfoot dish with scaler feed, dish mounted waveguide switch and RX low noise amplifier (LNA), transverter with 432 Mhz IF, Traveling Wave Tube Amplifier (TWTA) with 40 watts out. The system operated from a small gasoline generator.
WB6CWN: Fourfoot dish with Ma/Com bent splasher feed, dish mounted transverter with 144 Mhz IF, TWTA with 15 watts switchable to 1 watt solid state and RX LNA. Single battery 12 volt operation. W6HCC: Fourfoot dish with scaler feed, dish mounted waveguide switch and RX LNA, transverter with 144 Mhz IF, 15 watt TWTA. Multiple battery operation with gasoline generator backup.
WA6OWD: Fourfoot dish with Ma/Com bent splasher feed, dish mounted double conversion transverter with 28 Mhz IF, 10 watt TWTA and RX LNA. Multiple battery operation requiring +12 and -24 volts.
Once set up, the operating procedure used had a station at one end transmitting from five to fifteen minutes while the station at the other end received. The stations then reversed roles for the next five to fifteen minutes. By mid afternoon on July 17 the batteries at the Mt. Ashland end were getting low and would need to be recharged during the night. No signals had been heard at either end during the entire day.
The morning of July 18 came quickly and attempts were made again starting at 0530 local. Our spirits diminished as another morning had come without any signals heard between the ends of the path. Robin WA6CDR had traveled during the night and set up on San Benito Mountain about one third of the way to Mt. Ashland from Mt. Pinos. Robin used 425 feet (130 m) of extension cords to get AC power from a near by communications facility. Phil and Robin attempted to communicate between Mt. Ashland and San Benito
Mt. and very weak signals were being heard. From about 0600 to 0800 Phil and Robin watched the path between them and noted a slight improvement in signals as the day progressed. Shortly after 0800 Chuck began the process of cooking breakfast. While he prepared pancakes a strong (20+ over S9) but short burst (about 3 seconds) was heard from the Mt. Ashland end. The burst was long enough for your author to quickly peak his dish on it. Several send-receive sequences went by and Chuck continued to cook pancakes (one at a time, one for Frank, one for Himself and one for Your Author). About 0830, while your author was transmitting towards Mt Ashland (and eating pancakes), Phil's voice came over the liaison radio "I'm hearing your signal, continue to send and I'll see what I can do with it".
Breakfast was cut short and Chuck began sending to Mt. Ashland with his 40 watt "Flamethrower". Although the path was fading from S9 plus to no signal at all, exchanges were made between Chuck and Phil. For some reason Your Author's rig had lost almost all of its high IF gain and no front end noise was present at the IF rig. Both Frank and Chuck were hearing Phil's signal S9 plus while it was a struggle for your author to hear. The contact was finally completed however just as the path began to deteriorate.
The July fireworks continued into the first weekend of the 10 Ghz. contest. On August 21, Frank WB6CWN and your author ventured to Piute Springs (CM96qi) near Tehachipi. Thirty five minutes after the contest began Frank and your author worked Ron, K6GZA at Mount Loma Prieta (CM97bc) near San Jose. Ron was running .4 watts and a three foot dish and signals were S-3 to S-7 along the path. As the day continued the Piute Springs group worked K6UQH at his home QTH in Saratoga (CM87xf, 5 watts and a twenty two inch dish) and Bill N6OLD and Russ K6KLY, both located on Mt. Diablo (CM97av). In all, thirteen stations were worked spanning most of the State of California.
August 22, 1993 was even better than the previous day. Frank WB6CWN ventured to Mount Pinos and worked San Francisco Bay Area stations as well a Jack XE2/N6XQ, well into Mexico. Dave, WA6CGR had been working his way up the coast and spent the night in Santa Maria. He positioned himself on a bluff near Point Sal and was able to work Jack, XE2/N6XQ in Mexico for a new North American record of 1019 km (632 mi) Conditions across the ocean from Mexico to most California Coastal mountain peaks were excellent, and Jack went on to work virtually all stations in the Los Angeles area.
For some reason the only location having difficulty working Jack was Mount Wilson. Robin WA6CDR, finally succeeded in working Jack in (DL27qo) at a distance of 500 miles (804 km). To accomplish this, Robin used an oblique bounce angle off of Catalina Island to complete the path. As this was going on, Dave WA6CGR, was commuting back from Point Sal and working Robin with his microwave mobile on narrowband FM. They both made numerous contacts using this communications mode.
Both weekends found Joe WA6PAZ doing his own unique kind of mountaintopping. In the wideband days, Joe would hike to the top of Mount Baldy and "work the world" across his 360 degree view. To keep up with the changing technology, Joe built a portable narrowband rig which put out about 40 mw and sported dual 17 db gain horn antennas (one for receive and one for transmit as there was no antenna relay for power conservation reasons). From his lofty perches (Mount Baldy, 10,064 ft (3,100 m) and San Gorgonio Mountain, 11,502 feet (3,506 m)). Joe made 36 contacts with a best distance of 455 km (282.6 mi). Not bad for 40 mw and dual horns! The second weekend of the contest again turned out to be just as hot as far as conditions were concerned. Jack XE2/N6XQ again ventured to Mexico and was able to again work a majority of Los Angeles Basin stations.
Your Author spent Saturday afternoon from about 1300 to 1800 local involved in a unique attempt with Ron K6GZA and Jim W6ASL. The two San Francisco stations positioned themselves on Mount Diablo (CM97av) and Your Author was set up on the side of Pacifico Mountain (DM04xj). We were able to exchange weak carriers, too weak to copy CW using normal means (as my TS-440 was in the narrow CW mode). The interesting thing about the signals was that the strength never changed! Bill K6UQH ran a tropo path analysis based on our respective stations. He confirmed that we had indeed discovered what should be a reliable, albeit weak, foreword tropo scatter path. All stations returned the next morning to see if the path had improved, but no such luck. About local noon, the path had increased where we were able to just barely copy CW from each other. At 1241 the contact with K6GZA (which had taken almost an hour) was completed! Shortly after midday the path began to slowly deteriorate and Your Author was unable to copy Jim W6ASL except for occasional short bursts of airplane scatter.
Frank WB6CWN started out Saturday on Santa Ynez Peak near Santa Barbara, again working several Bay Area stations, and finished out Sunday on a mountain top in San Diego. Frank went on to make 41 contacts over 250 km as a total for both weekends! The contest was a dead heat between Frank and Jack, but when the smoke had cleared, Frank had just barely won! Frank and Jack both achieved all time record scores of 27,412, 119, 29, 934 km (580.1 mi) and 27,172, 46, 15, 1,019 km (633 mi) (the record shot with WA6CGR!), respectively. Other high scorers were Dave WA6CGR with 12,972, 76, 181, 1,019(633 mi) and Ed W6OYJ with 12,631, 57, 23, 561(348.5mi)[QST, March 1994, pages 117 and 118].
As our final spotlighted activity, Your Author would like to return to the opening paragraph of this paper. On March 2, 1994, Phil W6HCC at home in Beaumont, Ca, and Chuck WA6EXV at home in Ridgecrest, Ca, completed an almost yearlong quest for a 3 cm EME contact. Phil's station, ten foot dish on a pseudo polar mount, 32 watts of transmitter power and a hot RX LNA (dual stage PHEMT, WA6EXV design) handled the job quite well. This was
Phil's first EME contact! Chuck's system, ten foot dish, 40 watts and a similar RX LNA, had the prior successes on EME outlined earlier in this paper.
As a side note, Your Author was present at Phil's location to observe an EME contact. Just prior to the commencement of Chuck and Phil's QSO, we set up my rig with its fourfoot dish and similar design RX LNA. We observed .4 db s/n ratio on moon noise (Phil had 2.0 db on his system!). We then asked Chuck to give us a transmission and to our amazement, we found his signal, almost right away! It was too weak to copy CW using conventional techniques (bare ears), but was easily identified by tuning the receiver through it. On March 26, Your Author again set up at Phil's QTH for more EME work. Again, before Chuck and Phil ran their tests, we listened to Chuck's signal with my system (described above). This time, Chuck's signal was easily copied without having to tune through it. Chuck then sent a steady string of dashes which were mostly discernible in my system.
Equipment problems and poorer conditions the following night prevented an attempt to copy Chuck's CW message this time around. Recordings were made on both Phil and Your Author's systems for analyzing with DSP equipment.NOT BAD FOR OUR FIRST 40 YEARS - BUT WHAT'S IN STORE NEXT?
In 1995, The San Bernardino Microwave Society begins it's 40th year of existence. We are lucky indeed to have original "franchise" members still active in the group as well as Amateurs "just getting their feet wet".
Additionally, The Society has been blessed, since its inception, with extremely thoughtful, talented and dedicated individuals whose vision of the future of microwaving extends well beyond the visible horizon. The convergence of the energies these fifty plus individuals can only lead to a greater understanding of Amateur Microwave and how it applies to the future Amateur Radio and radio communications, in general.
And what a future it will have. As spectrum of all wavelengths becomes more and more valuable there will surely be a push to the microwave bands for Amateur (and commercial) uses of all types. The form and success of these uses is based upon our experiences of today. These experiences and applications of technologies are what fill the agenda of the SBMS for the next decade of it's service to the Amateur Community.
Jim W6ASL probably has put it best, "We are ready to begin working back yard to back yard, San Francisco Bay Area to Southern California" on 3 cm. While this might seem fanciful on the surface, it has been proven that there are propagation conditions which we do not fully understand or have fully exploited. This feat has been achieved on all of the lower bands up to 13 cm, and as more equipment comes on the air on 9 and 6 cm, additional information about the propagation will be learned.
Additionally, more cutting edge home stations are appearing all the time, like Chuck WA6EXV's computer driven AZ-EL mounted ten foot dish. Other home or fixed stations currently running are Bill K6UQH's home station and Robin WA6CDR's fixed station on Mount Wilson, just to name a few. New, more powerful and strategically located beacons are scheduled to come on line in the near future. Couple this with digital signal processing (a front being heavily explored by many SBMS members) and quieter LNAs and we transcend fanciful all the way to probable. Another front which seems to be heating up is 9, 6 and 3 cm moonbounce. Several SBMS members are already active, and others have been bitten by the bug. The technology is already implemented by most of these stations, and the logistics of putting an eight or ten foot dish on the moon (figuratively speaking) is the only problem waiting to be solved. Other frontiers to cover are the population of the higher bands. As noted earlier, narrowband activity is already occurring in the San Francisco Bay Area in the 12 mm band. As the uses for the higher frequency bands become more commercially viable (like General Motor's millimeter wavelength crash avoidance system proposed for the center of the 4 mm band and being designed as this is written!), spinoff technology will certainly help amateurs to populate these bands. Some fill in activity needs to occur on the 9 and 6 cm bands. While quite active in the ROCKLOC and Pola-plexer days, there are still about the same number of operating stations there today. This is prime spectrum, whether used for weak signal tropo, terrestrial or EME communications, as it combines the best of 13 cm simplicity with 3 cm like propagation characteristics. There are currently no-tune transverter kits available for these bands as well as lots of surplus telephone/satellite hardware so equipment availability and test equipment requirements are certainly not a problem.
Which brings Your Author to this final point. As this is written, there is already a plan in the works for the remaining portions of the 13 cm band to be decimated to create new spectrum for PCS technology. The long term plan is for 200 Mhz of Government spectrum to be reassigned to the private sector. The parts to be taken out of the 13 cm band are only just the beginning of this project. It is almost a given that the rest of the 200 Mhz will come out of other Amateur Bands. As a group, the SBMS is looking at the options available to voice our concern over the loss of any Amateur spectrum, especially in the microwave bands. All Amateurs are encouraged to do the same.
There is no time better than the present to begin a plan to populate as many of the microwave bands as is possible. Do not let the possibility of loss of portions of the bands stop your plans of microwave adventure! While a particular segment of the bands may be lost, a coalition of amateur groups will reorganize the remaining spectrum in a coordinated manner similar to how it exists today. See you on the bands, microwave bands that is! Dave - WA6OWD Moreno Valley, Ca.Acknowledgment: Your Author would like to thank several individuals who helped in supplying materials or checking over the manuscript for historical correctness. George Tillitson K6MBL and Ed Munn W6OYJ were instrumental in supplying historical documentation for the pre 1970 years. Those of you who gave your time and patience to the interview process or sent text to fill gaps from 1970 to the present. Finally Ed Munn W6OYJ, Chuck Swedblom WA6EXV, Bill Burns WA6QYR and Phil Lee W6HCC who read over the preliminary manuscripts and provided general support of the project. My wife Dolores and son Edward who tolerated my many nights in the garage alone with only the computer. I sincerely thank you all as your help changed this project from a "Labor of Love" to a paper that literally "Wrote Itself". Thanks and 73, Dave.
A Footnote: All SBMS members have been told at one time or another "I've heard about you folks for years but never knew how to find you". Let's solve this problem now!
You may reach the SBMS by:Writing: Bill Burns, WA6QYR Corresponding Secretary, SBMS247 Rebel Road, Ridgecrest, CA 93555
Attending:Next SBMS Meeting, 1st Thursday of each month.American Legion Hall, 1024 B Main Street,Corona, CA. Meeting begins at 1900 Hrs. local.
Out of town, state, country memberships welcome.Please write or attend for details.