Pcom 23 GHz Conversion Info

This Page Last Modified on October 30,2010

This is a temporary collection of drawings, parts lists, etc. to aid in the ongoing
attempt to document modification of Pcom 23 GHz units for amateur 24 GHz use.
It is expected that a complete set of modification instructions will be produced soon by
members of the SBMS. Meanwhile as some modification components are developed,
here is info from SMBS contributors. Most drawings are in Adobe Acrobat format.

Pcom "High Side LO" Modification to 24 GHz. Status Report by Kerry
Banke, N6IZW. Revised info on Mods to Pcom Synthesizer. Describes
module-by-module changes and results of this recent effort. DC-DC Power Supply
Mods, 2-3 GHz U/D Converter external wiring mods, power control and
distribution circuits. Clarified Tx and Rx module power wiring connections (5/2/07)
Added photos of antenna and assembled/modified ODU (12/3/2009) .
Added Mod notes from Steve Miller, W6QIW. (10/30/2010)

Block Diagram of Pcom "Low-Side LO" Mods by Sam, K6VLM. From SBMS
Feb 2003 Newsletter by WA6QYR and WB6DTA; redrawn for web by W6OYJ.
This mod is for the low side LO version of the 23 Ghz Pcom units. This version
of the mods uses only the vco buffer amp and multiplier parts of the Pcom
synthesizer module and does not use the original Pcom synthesizer or the
boot-up Pic Processor and "small board". In Adobe Acrobat Format. (Rev A. 3/7/03)

DC Wiring Diagram of K6VLM Pcom Mods. (Removed 2/18/03). Changes are
currently being worked out.

2-3 GHz U/D Converter to 432 MHz. (Revised 3/31/03). Also known as the "Mixer Board" and designed by Sam, K6VLM. This up/down converter converts from a first i.f. frequency in the 2208 to 3072 MHz range to a 2nd i.f. of 432 MHz and vice-versa. The required LO input is 2640 MHz. This converter became an SBMS kit project to support the modification of the Pcom 23 GHz ODUs to 24 GHz amateur frequencies.

First I.F. Filters between 2-3 GHz U/D Converter and Tx and Rx Modules. 3072 MHZ and 2208 MHZ I.F. Filters by Sam, K6VLM. (Adobe Acrobat Format) from SBMS Newsletter for March 2002), ( 5/25/02); 2208 MHz Evanescent waveguide filter in 5/8 inch hobby brass tubing by Ed, W6OYJ, (Adobe Acrobat Format),(4/22/03). Tunable evanescent waveguide filter in hobby brass tubing covers 2000-3300 MHz, by Ed Munn, W6OYJ. (4/28/03)

Qualcomm DRO Synthesizer Mods to operate at 2640 MHz. By Chuck Houghton,
WB6IGP. (Adobe Acrobat Format).This older Qualcomm Synthesizer has a pc board
shape and size similar to the "Texas" Synthesizer, but uses a Motorola MC145152P
Synthesizer IC instead of the Qualcomm Q3036. It is also recognizable by the
rectangular metal shield and cover, 1.8 by 1.3 inches, over the VCO and RF
components. The mod involves adding a solder blob to the DRO Puck (See Photo) in
the RF shielded section, and cutting and grounding a few synthesizer pins.
(From SBMS Newsletter for February 2002). (corrected here 5/30/02)

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