[amsat-bb] S-band patch.

John Hackett archie.hackett at hotmail.com
Wed Feb 27 10:12:58 PST 2008

       I can assure you the patch *IS* correct. 

The photo is taken from the rear, what you are seeing in the photo is the 'rear' of the reflector and the back end of the gold SMA connector.

The radiator - (hidden by the larger reflector, in the photo) - is connected to the pip of the SMA connector and is mounted 3mm  'above' the reflector. 

The radiator is 'cut' for 2401Mhz and is made from silver plated brass sheet ...  bas is the reflector.

I think what may have fooled you is ...

1) Not realising you were looking at the rear of the patch.
2) The fact that my reflector is square, not round.

The G3RUH design uses a round reflector,  the K3OE uses square.

As far as I can assertain there is no practical difference between the designs.

73 John.   <la2qaa at amsat.org> 

73 John.

From: sv1bsx at yahoo.gr
To: la2qaa at amsat.org
Subject: Re: [eu-amsat] S-band test gear.
Date: Wed, 27 Feb 2008 15:03:14 +0200

 Hi John,
 I read your post but I am afraid that, your 
PATCH  is not correct. Sorry if I am wrong, but due to non-clear photo I 
can see
on the Left-UP part of photo ONLY 
the "drive element" of Patch (the square-piece with cut-corners )  without 
the "circular piece" behind of drive-element which acts as 
As I see also in your photo, the chassis-connector is 
mounted on this square piece and not to the 
circular reflector.
  If that is not my... illusion, that is not a 
correct Patch. I send you a clear photo to take a view how is the
complete Patch by viewing that from the front-side. 

73, Mak

  ----- Original Message ----- 
  John Hackett 
  To: allan_gm1sxx at hotmail.com 
  Cc: sv1bsx at yahoo.gr ; amsat-bb at amsat.org ; Eu-amsat at yahoogroups.com 
  Sent: Wednesday, February 27, 2008 1:22 
  Subject: [eu-amsat] S-band test 

  NORWAY.          February 

Based on SV1BSX's comments about receiving a *THUNDERING* signal 
  from AO-51's S-band transmitter on a patch antenna 'without' a reflector - I 
  decided to chuck together a few components to see if somebody as 'thick' as 
  LA2QAA could manage it.

The attached pic is the ... 'fruits of LA2QAA's 

Starting at the top right we have a silver covered brass plate 
  2.4Ghz patch antenna (note the real gold SMA connector, folks) mounted 3mm 
  over a (ditto) groundplane, via a short length of high quality (fell off the 
  back of a North Sea Oil industry lorry) coax  feeding the input of a 2.4G 
  70 70cm converter ... the output of which goes to the IC-E91 dual mode 
  handheld and a pair of 'cans' ... (headphones, to you!).

To the right 
  of the IC-E91 is a Nokia N70 mobile phone - (not shown in this pic because I 
  was using it to take the picture) - with the 'SATme' tracking software .... 
  which is very !! useful for tracking S-mode signals from LEO birds with the 
  'slight' doppler thus received.

The phone also contains a compas as 
  well as GPS software so there's no excuse for ... 'but I can't find north' ... 
  (not always easy in 3 feet of snow, null visibility and cloudy conditions) ... 
  and there's *NEVER* a brownie or a girl guide around when you want one. 

S-band signals in those conditions? ... you'd be surprised - we don't 
  all live in satellite friendly climes you know.

Mak (SV1BSX) is right. 
  A 60cm dish is overkill for AO-51 mode-S ... though of course, there are! 
  those that think you need a personal 
Jodrell Bank to hear anything above 

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