[amsat-bb] Re: drake 2880

Edward Cole kl7uw at acsalaska.net
Wed Feb 24 00:27:15 PST 2010

At 02:26 PM 2/23/2010, Jim wrote:
>Has any one used the Drake 2880 downconverter on the air.
>I have 2 of them 1 I did the mod on and one that has not has any thing done
>to it.
>Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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I have two Drakes that were used on AO-40.  One is converted to 
435-MHz IF and the second unmodified runs with 123-MHz IF.  I feed 
both with a MKU-232A2 preamp directly connected to a 6-1/4 turn 
helical feed in front of a 85cm (33-in) offset feed dish.  I have not 
re-installed my Drakes but the dish/preamp are ready for use.

The Drakes do not have very good noise figure (~7 dB) so a low-noise 
preamp is mandatory.  The db6nt preamp has 0.6 dBNF with 40-dB gain, 
easily able to feed both Drakes thru a coaxial tee.

I also have a DEMI 2400-MHz preamp which I am thinking of feeding 
with a patch antenna.  I am thinking that the patch should provide 
ample gain for S-band Leo satellites.  The two antenna/preamps will 
be connected to the Drakes via a cross-over relay (not yet installed).

I will need auto-tracking/tuning for S-band operation on Leo's.

73, Ed - KL7UW, WD2XSH/45
  BP40IQ   500 KHz - 10-GHz   www.kl7uw.com
500-KHz/CW, 144-MHz EME, 1296-MHz EME
DUBUS Magazine USA Rep dubususa at hotmail.com

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