432 MHz Loop Feed,

VLNAs & Cavity filter


Final information after first sharp start of use in DUBUS EME contest 2010. 

Here you can see log from contest and EME activity when was feed first time use:   LOG of EME DUBUS activity 22.nd - 25th of April 2010
Sun noise: SFU 71 - Sun noise 18,6dB
Smallest station worked with this setup is IT9CJC
November 2011 - upgrade of polarity rotor

Previous used old fashion Hirschman rotor collapsed and I have developed new system for exchanging V to H polarity. More details above.

Feed mounted in the feed point in V pol. position

Feed mounted in the feed point in H pol. position

Feed completed with rotor Hirschman

Rear side of feed

Front side of feed

SWR diagram of feed installed in the feed point of 10m dish. 

Click on picture to max. resolution

Feed mounted in the dish for Sun noise test

March 2010

Aluminum body and out for connection to the box

Front of feed -34dB SWR open space

PVC water proof box

SPINER relay and first LNA 0,35 dB N/F

Box and relay "SPINER"

Cavity 5 stage filter + second LNA

All parts in box before final painting of feed and wiring

January 2010
In cooperation with Petr OK1FAQ - OK7FA (well know operator of OK1KKD as 144 MHz EME station) we are now working on final version of 432 MHz feed. On following pictures you can see which type of connectors we have choice and also some mechanical parts of 50 ohm conduct to the feed loop.

May 2009 - prototype

Due to terrible problems with interference on 432 MHz I was looking for any reliable solution. In First step I made a feed which is compiling feeds designed by CT1DMK and his ring feed for deep dish with V/H switch, DL4MEA feed-ring for 23cm and OM6AA Dual feed ring for 23 and 13cm. I am expecting very similar parameters like Rasto OM6AA has already modeled for 23 and 13cm. That is mean good efficiency, very good illumination in vertical and horizontal axe and very simple building system. On following pictures you can see how looks first prototype of this feed and will follow very soon with new VLNA designed in cooperation with Jan DL9KR wit transistor TC2384. ( Jan TNX very much for your comments and experience) Jan DL9KR has already build LNA with this transistor and reached good parameters. Second stage LNA I am using LNA with ATF 54143 described here. Whole system I would like to test in DUBUS EME 432 MHz contest immediately when WX permit to work outside of house.

Here you can see feed. Diameter only 420mm, dipole ring diameter 212 mm. Very small and compact dish feed. Rim is 90mm high from bottom of feed. Three PTFE pillars are keeping right distance of loop over bottom of feed. Distance is 86mm. Fourth pillar is 50 ohm guider ended by N connector in this prototype. In original I am expecting to use 7/16" Spiner connector. Then is following Spiner 7/16" high power switch relay, VLNA - Filter and second LNA. All documentation will be available here. Measured SWR in open space -34 dB. I will follow design of CT1DMK with tuning screw and tested possible SWR up to -40 dB easy.

Back side of feed with N connector. You can see also 4 small holes where will be screwed special part for connection to rotator and giving possibility turn between V to H polarization.

And this is as looks the feed. In final version I am expecting to use also special PVC covering over whole feed and painting with special paint recommended as a anti corrosion protection on Aluminum and Copper.

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