Stellar Labs 30-2460

The Stellar Labs 30-2460 is a four-element Yagi with folded dipole and integral 75:300Ω balun. The boom length is 1.63 m (64″). The red dot marks the feedpoint.

Modeling Results

I modeled the antenna with the AO 9.67 Antenna Optimizer. Calculated performance is for 28 analysis segments per conductor halfwave. Forward gain includes mismatch and conductor losses. F/R is the ratio of forward power to that of the worst backlobe in the rear half-plane.

Frequency  Impedance    SWR   Mismatch  Conductor   Forward     F/R 
   MHz        ohms             Loss dB   Loss dB   Gain dBd      dB 
    88      130-j94     2.58     0.94      0.01      4.47       8.33
    89      146-j62     2.17     0.63      0.01      4.81      10.38
    90      162-j34     1.88     0.43      0.01      4.98      12.17
    91      178-j10     1.69     0.30      0.01      5.04      13.38
    92      192+j13     1.57     0.22      0.01      5.05      13.94
    93      205+j34     1.50     0.18      0.01      5.04      13.90
    94      218+j55     1.47     0.16      0.01      5.01      13.50
    95      230+j75     1.47     0.16      0.01      4.98      12.93
    96      242+j96     1.51     0.18      0.01      4.95      12.32
    97      256+j115    1.55     0.21      0.01      4.92      11.71
    98      270+j137    1.63     0.26      0.01      4.89      11.15
    99      285+j159    1.72     0.31      0.01      4.86      10.64
   100      301+j181    1.81     0.38      0.01      4.83      10.16
   101      319+j205    1.92     0.45      0.01      4.79       9.72
   102      340+j228    2.03     0.54      0.01      4.76       9.32
   103      366+j251    2.15     0.62      0.01      4.72       8.94
   104      394+j274    2.27     0.71      0.01      4.68       8.61
   105      426+j295    2.39     0.80      0.01      4.65       8.30
   106      464+j313    2.50     0.88      0.01      4.61       8.05
   107      507+j326    2.59     0.95      0.01      4.58       7.84
   108      554+j329    2.67     1.00      0.01      4.58       7.71

Antenna File

Stellar Labs 4-Element Yagi
Free Space Symmetric
98 MHz
7 6063-T832 wires, mm
ab = 46			; DE distance above boom
bb = 37			; DE distance below boom
dep = 629		; element positions
d1p = 1113
d2p = 1630
r = 808			; element half-lengths
de = 705
d1 = 589
d2 = 589
1     0   -r    0      0    r    0    10
1   dep  -de  -bb    dep   de  -bb    10
1   dep  -de   ab    dep   de   ab    10
1   dep  -de   ab    dep  -de  -bb    10
1   dep   de   ab    dep   de  -bb    10
1   d1p  -d1    0    d1p   d1    0    10
1   d2p  -d2    0    d2p   d2    0    10
1 source
Wire 2, center

Modified Antenna

You can improve performance by adding two elements between the driven element and first director. Make them from a single 96″ length of 6063-T5 aluminum angle. Cut a 5115/16″ length and place it 4″ from the driven element. Place the remaining piece 1115/16″ from the driven element. You can further increase forward gain by replacing the ferrite balun with a halfwave coaxial balun.

The blue and green curves include 0.75 dB estimated loss for the stock ferrite balun. The red curve includes the loss for a halfwave coaxial balun.


June 7, 201888108 MHz