[amsat-bb] Re: drake 2880
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 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb 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 dubus...@hotmail.com == ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: drake 2880
At 23:26 23/02/2010, you wrote: Has any one used the Drake 2880 downconverter on the air. Not been on the Sats for some time, but when AO40 was alive, I used the drake for the downlink. my experiences are shown at - http://www.g4dmf.co.uk/dish/antenna.html From what I gather, AO51 is a magnitude stronger than AO40 ever was. The Drake provided solid copy of Telemetry. There are links in the article to various pictures I took, including a screen-shot of AO40 data on screen, and links to the mod pages for some of the many modifications done to that downconvertor. RIP AO40... Praying for a Battery Event on that bird too! ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: drake 2880
Hi Jim, 2880 has been on the tower here since the AO-40 days. System is a G3RUH patch feed/dish. DB6NT preamp connected right to the patch feeding the 2880 which is up on the crossarm. I leave it continuously powered. Works OK on AO-51. Solid copy. 73, Mike, N1JEZ AMSAT 29649 A closed mouth gathers no feet - Original Message - From: Jim hartw...@hartwell.net Subject: [amsat-bb] drake 2880 Has any one used the Drake 2880 downconverter on the air. ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
[amsat-bb] Re: drake 2880
Hi Jim, I have one, and it works ok. Not the brightest panel lamp in the shack, but it was a whole lot better than nothing. I was eventually able to work AO-40 at apogee with it, a good preamp, and a 30 BBQ grill. When you say the mod, you need to be a bit more specific. That converter, probably more so than the others, has a long history of successful (and probably longer non-successful!) modifications, each with a different set of things being optimized for. Personally, I went for swapping out the local oscillator's crystal, moving the LO to 2100 mHz from the original 2278 mHz. (I had to also change a cap in the PLL to keep it in lock.) That moved our satellite band so that it comes out inside the original 200-400 mHz passband. It also makes the conversion math easy, and with an IF outside the Ham bands I use my all-mode scanner for the final leg in the receive chain so I can't mess up and transmit into the 2880's back side... Other mods exist to get you an IF inside one of the Ham bands. Be careful to pick one where the uplink is well separated from the IF, and evaluate which is best for your situation, skill (I had help!), and test bench. For use with AO-51, well, that bird is LOUD compared to AO-40. You almost can't go wrong. Good luck, Greg. From: hartw...@hartwell.net To: AMSAT-BB@amsat.org Date: Tue, 23 Feb 2010 15:26:35 -0800 Subject: [amsat-bb] drake 2880 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 ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/201469227/direct/01/ ___ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
