[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: AO-40 ordering antennas, downconverters



At 05:51 PM 7/23/2002 -0400, AA2AE wrote:
>Group
>
>I'm ready to purchase my AO-40 antenna and downconverter and wondered if you
>might comment on this set-up. I finally settled on a modified Transystem
>AIDC-3731 downconverter from Bob, K5GNA and a 3 foot dish from Glenn, N3IYR.
>Glenn's dish comes ready to go with feed and mount and I'm told all that's
>needed to put it all together is a double-male N.
>
>I would assume that the narrow beamwidth of the 3 ft dish might be a bit
>more sensitive when aiming at the bird, but I'm hopping that the 4db of
>additional gain over the 2ft model is worth the compromise, especially when
>squint angle is large. The spill-over characteristics are very important for
>a quiet RX at 2.4ghz and I'm told this feed/dish combination is.
>
>The Transystem downconverter with 37db gain and 1db NF seems to compare well
>with the SSB Electronics UEK 3000 converter and it's a lot cheaper.
>
>Any comments on this set-up and antenna alignment/mounting tips welcomed.
>
>Thanks for all your help.
>
>73, Tony - AA2AE

Well, Tony you have gotten quite a few opinions!  From what I have heard
about the AIDC-3731 from others reports on the bb, it will do a good job
for you to get started and the price is quite reasonable.  Getting below a
NF=1 dB is helpful and you can upgrade by adding a good preamp, later, if
you wish.  You can chose the UEK 3000 instead, but at a heavy price jump.  

I have a MKU-232A2 preamp that is 0.6 dBNF/40 dB gain (yes those were the
test numbers included with the unit), and it feeds a Drake 2880 stock
convertor which is much worse (about 6 dBNF/15 dB gain...estimates) than
the  AIDC-3731.  The preamp makes the difference for my setup (not
optional).  I use an offset feed (helix) 33-inch dish and hear well.

The N3IYR 3-foot dish comes with a helix feed, if I recall, so that should
work well for you.  You are smart to chose it over the 2-foot dish...it
makes all the difference in hearing!  The G5400/5500 rotators can
adequately point your dish (it will be somewhat touchy and you will have to
"jog" it to get the signal peaked), but you will get used to that.

You might consider investing in a 2400 MHz signal source to make finding
your freq. easier.  After you get things put together come back and ask for
some tips on getting things going the first time (the most challenge for
most of us).  After you know where the dish is "really" pointing and where
to tune for the satellite you will be on your way!  Lots of experience on
the bb so just ask us!

Ed, AL7EB

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home