Re: Horn for 3.4GHz


Raymond Brooks
 

For Sheet mica look at microwave oven spears.

 

 

From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of KENT BRITAIN
Sent: 22 June 2021 13:09
To: UKMicrowaves@groups.io; UKMicrowaves@groups.io
Subject: Re: [UKMicrowaves] Horn for 3.4GHz

 

Hi Colin

 

I usually put the window between the horn and the WG Transition.    Much smaller piece and it's out of the weather.

I like to use a sheet of Mica, but that's for X-Band and higher.  Hard to find Mica sheet big enough for 9cm but the bits for the larger power transistors is OK for WG16.  Also the Teflon Tape used in plumbing works well.  But again a pretty big piece for 9 cm but the standard tape works well at 3 cm and higher.   73 Kent

 

On Tuesday, June 22, 2021, 05:57:25 AM CDT, Colin Ranson <g8lbs@...> wrote:

 

 

Yes please. Ideas for thin 10GHz transparent materials for weather proofing horns, feeds etc. Milk bottle material sounds good and is plentiful !

 

Colin de G8LBS.

 

Sent from Mail for Windows 10

 

From: Andy G4JNT
Sent: 22 June 2021 08:40
To: UK Microwaves groups.io
Subject: Re: [UKMicrowaves] Horn for 3.4GHz

 

I use the old software written by G8AGN decades ago for horn design, updated for 32 bit OS and now with graphical output including a cutting template.

Here are my values for a 12.1 dBi gain Horn (Why, ever, specify gains in dBd ??????)

 

 

 

Andy

 

 

 

On Tue, 22 Jun 2021 at 08:28, Gareth G4XAT via groups.io <g4xat=ntlworld.com@groups.io> wrote:

My local repeater GB3JV (DATV) (Petts Wood SE London) is pretty much LOS to me at home, so rather than tie up my Titanium PLL LNB I picked up a NOS Nortel DRO commercial unit. As it needs some form of weather protection I thought I might as well add some gain too. Using this software https://www.raytechx.com/antenna-calc I then designed a 3-D printed 10dBd horn, which came out like the picture. Interior surface finish has been improved by flat filing and I will then cover with aluminium tape. 
A couple of questions....
1. It seems very 'wide' compared to horns I've seen on 10GHz stuff - maybe why its 'only' 10dBd.
2. I have some PTFE sheet, would this be suitable as a gasket to keep the weather out of the LNB cavity, if not would HDPE from a milk carton work?
The horn sizes very quickly got very large (longer print time/too big for the printer) if I upped the target gain figure. I was surprised by this...not like adding a couple of elements to a yagi....
Comments welcome...
Gareth

 


--
Raymond G8KPS

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