[Moon-Net] Which 432 Mhz feed for a 4.5M dish in combo with 23cm Septum feed

Edward R Cole kl7uw at acsalaska.net
Tue Nov 29 18:02:33 CET 2016


Guy,

Back when I was still considering running 
dual-band 432/1296, I was thinking to duplicate VK3UM's dish feed:
http://www.vk3um.com/VK3UM%20Dual%20Feed.html

I am using a W2IMU feed on 1296 same as Doug so 
his was a good design for me even though my 4.9m 
dish is half the size of his.  I suspect you can 
use using a septum feed for 1296 in the center of 
a dual-dipole, dual-pol 432 feed.

You would not have the ideal polarity matching of 
a rotable 432 feed, but one could use a dual-pol 
receiver like the IQ+ to do adaptive-pol on Rx. 
That was the direction I was considering.  But 
concerns of the extra feed blockage for operating 
1296 plus expense of adding a custom-built 
dual-Rx transverter ($800+), two preamps/relay 
matrix ($400-500), and 1kW amplifier ($1200+) 
plus the feed dissuaded me from doing 432, so 
just installed the 1296 W2IMU horn.
http://www.kl7uw.com/W2IMU_Feed_001.jpg

73, Ed - KL7UW

At 07:25 AM 11/29/2016, ON4AOI_PDA wrote:
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>Hi dish guru’s ,
>
>After lot of reading , vk3um-sm6fhz-ok1dfc-kl6m 
>to name a few I don’t know what will be the best choice anymore.
>I have a 4.5M (15ft) dish F/d = 0.45 
>(unassembled) from RFHAMDESIGN since January 
>waiting to get on a lift crane system ( NEKO 400A)
>First intention was for 23cm only with a septum 
>feed 



 but my 4 x 38 elem M2 on 432Mhz are a big pain in the 
.
>When its dry they work FB even for single yagi 
>stations like TO2EME - PJ7/PE1L - E44CM but asap 
>that it rains or even when humidity gets high
>SWR goes up dramatically and kicks out my AMP.
>I am for now the only ON qrv on 432Mhz but limited to weather conditions.
>Depending on the specs from the 4.5M dish the 
>gain will be equal to the 4 stack except that I 
>will have the benefit of switching H-V ,
>With a motor even all in between.
>
>Will it be possible (with min of losses) to have 
>both 23cm (septum feed ) and 70cm mounted together ?
>
>If YES what feed do I need to build or buy for 70cm to have both H and V
>If NO what will be my best option for a 4.5M - F/d = 0.45 dish ?
>
>
>73 Guy ON4AOI – OT7K
>
>
>
>
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73, Ed - KL7UW
http://www.kl7uw.com
     "Kits made by KL7UW"
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