10Ghz Penny Feed

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g7wiz
Posts: 4
Joined: Tue Sep 17, 2013 11:28 am

10Ghz Penny Feed

Post by g7wiz » Tue Sep 17, 2013 11:40 am

Hi I was wondering if anyone could confirm the polarity of a "penny feed" 10Ghz dish antenna. I have managed to work GB3GG at 10.2Km using the PW exe dish but had expected to use the dish with the narrow ends of the waveguide pointing left/right but was unsuccessful. However changing the antenna to the opposite direction I did manage to get a p4/p5 in. The dish was very twitchy with a few degrees between in and out. GB3GG is Horizontal. John G0ATW suggested that the penny feed might be circular??? Can anyone shed any light on this please?

Rich
G7WIZ

KenW6HHC
Posts: 302
Joined: Mon Jun 01, 2009 4:20 pm

Re: 10Ghz Penny Feed

Post by KenW6HHC » Tue Sep 17, 2013 2:12 pm

Hi Rich G7WIZ,

Your question intrigued me since I had never heard of a "penny feed" on an antenna before.
A quick search on Google led me to a chapter inside the online Microwave Antenna Book by Paul Wade W1GHZ

An on-line URL is http://www.qsl.net/n1bwt/chap6-7.pdf

Look in section 6.7.2 for the write-up on the G4ALN "penny feed". W1GHZ has some interesting results and observations.

Hope this helps. I have contacted W1GHZ with questions by e-mail before, and he was quite responsive.

73...de Ken W6HHC

G1LWX
Posts: 49
Joined: Sun Mar 27, 2011 11:10 pm

Re: 10Ghz Penny Feed

Post by G1LWX » Tue Sep 17, 2013 2:41 pm

Hi
The polarity of wave guide is Vertical for Horizontal
Horizontal for Vertical .
If you look at the transition to waveguide, the launch probe is the polarity .
ATV is horizontal polarization so the waveguide should be vertical.

Mike

g7wiz
Posts: 4
Joined: Tue Sep 17, 2013 11:28 am

Re: 10Ghz Penny Feed

Post by g7wiz » Tue Sep 17, 2013 4:47 pm

Hi mike and Ken,

Thanks both for you replies....

Just to clarify in my own mind, at the penny feed end the slots facing left and right would be horizontal, and the slots facing up and down would be vertical. In the attached picture, it would be horizontal as indicated by the yellow lines, and if rotated 90 degrees to the blue line it would be vertical. I hope that's correct as the orientation shown is what worked last night!

Rich

G7WIZ
Attachments
resized penny feed.jpg
resized penny feed.jpg (661.44 KiB) Viewed 4171 times

G1LWX
Posts: 49
Joined: Sun Mar 27, 2011 11:10 pm

Re: 10Ghz Penny Feed

Post by G1LWX » Tue Sep 17, 2013 7:07 pm

Yes the picture is correct .

73's Mike

g8gtz
Posts: 1195
Joined: Wed Apr 07, 2010 6:26 pm

Re: 10Ghz Penny Feed

Post by g8gtz » Sun Sep 29, 2013 11:56 am

I'll still got my original PW Exe dish and penny feed in the shed as well...

If you bring it along to CAT13 at Finningley and you can get the gain measured on antennae range on Sunday - perhaps I'll drag my out and see if it still works...

73

Noel - G8GTZ

g7wiz
Posts: 4
Joined: Tue Sep 17, 2013 11:28 am

Re: 10Ghz Penny Feed

Post by g7wiz » Tue Oct 01, 2013 2:23 am

g8gtz wrote:I'll still got my original PW Exe dish and penny feed in the shed as well...

If you bring it along to CAT13 at Finningley and you can get the gain measured on antennae range on Sunday - perhaps I'll drag my out and see if it still works...

73

Noel - G8GTZ

Hi Noel, sure will do! I'm looking forward to finningley, I've never been before!!!

73's

Rich

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