Re: [amsat-bb] AO-40 - RX help please...

["Gary \"Joe\" Mayfield" <gary_mayfield@xxxxxxxxxxx>]

Tony,

     I believe you will find virtually every converter out there has more
than enough gain.  Use of an attenuator after the downconverter is a common
practice.  Noise figure and antenna gain are what will make or break you.
There is a wonderful spread sheet at

http://www.g3wdg.free-online.co.uk/ao-40_spreadsheet.htm

that will let you play and learn.  A little extra antenna can help you save
a bunch on downconverter.  Many of us hear quite well with the surplus MMDS
downconverters.

     You should have plenty of uplink..  I have about 35 to 40 Watts into an
8 X 8 element uplink antenna.  It was plenty for AO-13, but is a bit light
for AO-40.

73,
Joe
ka0yos@amsat.org


----- Original Message -----
From: "AA2AE" <aa2ae@optonline.net>
To: <amsat-bb@AMSAT.Org>
Sent: Sunday, July 21, 2002 4:30 AM
Subject: [amsat-bb] AO-40 - RX help please...


> Group
>
> I'm looking for suggestions on which downconverter / antenna I should
> purchase for AO-40. If I'm going to invest in mode "S", I'd like to get
the
> most "bang" for the buck and thought it would be best to ask those of you
> who are already operating on this bird.
>
> From what I've seen via the internet, the SSB Electronics UEK3000
> downconverter looks like the best of the bunch - it offers 30db gain with
a
> .7 noise figure. The Downeast-Microwave unit is cheaper, but offers less
> gain with a greater NF. I havn't researched antennas yet, but I certainly
> don't want to skimp in this department.
>
> I intend to use my existing 70cm / 40 element KLM on the uplink and
wondered
> if the ERP with 40w will do the trick? I've heard some say that it's
> possible to work AO-40 at QRPp power levels (CW) even when the bird is at
> apogee! I would assume this is done with above average RX antennas?
>
> It's been some time since I worked a reliable DX bird ( AO-13 before it
> burned-up ) so I'm looking forward to working AO-40. Any suggestions would
> be greatly appreciated.
>
> 73, Tony - AA2AE
>
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