[Elecraft] Rhombic antenna "gain"

[David Olean]

Hi Wes,

You forgot to mention that Chris VK5MC was only running 150 watts 
output. His pattern dropped off drastically as the moon exited his 
window. When I built my humongous 144 MHz array in 1979/80, I figured 
that my window with VK5MC would be a bit wider with the added gain from 
the 24 yagi array.  It hardly varied at all! He just got louder when I 
could hear him. I might have picked up one minute.  Great fun thinking 
about those times! Thanks.

To make this Elecraft related, I wish I had a K3 for my EME receiver 
instead of the Collins 75A4 that I was using back then. The APF would be 
fantastic on CW EME. It would have saved me a lot of time modifying the 
A4 to make it better!!  I replaced the 6BA7 mixers with 6DJ8s. I took 
out an IF can and dropped in an R-390A 2.0 kHz mechanical filter. I had 
to add a 2N4416 FET to account for the added loss in the filter. The 
last big mod was to add another Collins 300 Hz crystal filter in the CW 
fillter position. I jury rigged it underneath the chassis on a bracket. 
I still have the 75A4 and did a cap replacement last winter. It had not 
been fired up since about 1992. It needed work. After it was all working 
fine again, I checked MDS  (-138 dBm) and close in dynamic range at 2 
kHz. I saw 92 dB which is not too shabby and in a different league than 
a stock A4. Still it is a good 10 dB below the K3.

Dave K1WHS

On 9/14/2019 12:09 PM, Wes wrote:
> I completed my 2-meter WAC by working VK5MC on December 3, 1982. Chris 
> was using a rhombic, IIRC, 50 wavelengths on a leg and more-or-less 
> fixed on his rising moon.  I believe with some ropes he could "steer" 
> one end to get a few minutes more on another couple of days a month of 
> use.  Otherwise it was a pretty short window.  Modern Yagi designs 
> blow these away.
>
> Wes  N7WS
>
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