Re: 10GHz Feedhorn 60cm offset dish, looking for

Neil Smith G4DBN

Motivations were:

1) I have a load of Rexolite 1422 that I need to use up

2) Inherently waterproof and spider-resistant.

3) Small enough to fit alongside a similar model on 5.7 GHz with 2 degrees of dish nod to swap bands

It isn't going to be any better than a well-designed W2IMU or Pickett-Potter or corrugated-choke horn in terms of sidelobe suppression, but it is reasonably easy to control sidelobes and set a decent edge taper.

I'll make half a dozen and see how they look on a rotary mount, and then see what sort of sun noise I get when compared with a known horn.


On 09/03/2021 20:53, Colin Ranson wrote:

Looks nice Neil – yo a star !  as my brummy missus would say.  I don’t think I can get away with anything bigger than a Zone 2 elliptical – my house is stating to look like the Mothership in Battlestar Galactica !


73’s    Colin.


Sent from Mail for Windows 10


From: Neil Smith G4DBN
Sent: 09 March 2021 19:18
Subject: Re: [UKMicrowaves] 10GHz Feedhorn 60cm offset dish, looking for


I'm making some lensed dielspike horns with a collar to fit a 40mm feedhorn clamp on an offset dish, they have an aluminium body with an SMA connector and a truncated conical Rexolite 1422 lens similar to the ones designed by HB9PZK for QO-100.  The cone angle is calculated to give a 12dB edge taper on a typical 80cm offset dish

They are sealed units and designed to be left out in the rain. I haven't tried doing them with an N connector mainly on cost grounds, but it should be feasible to use an N connector with a reduced SMA base in exactly the same unit, so long as it has a 4.06 mm PTFE sleeve.  You could probably modify any SMA-equipped transition to use one of these N types (perhaps from someone cheaper than H&S!)

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