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.
Jim
K7UDG
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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@hotmail.com ======================================