On Thu, Jun 01, 2017 at 10:31:39AM -0700, Greg D wrote:
Hi Zach,
Whoa, your message raised a bunch of mental dust... Is this for the infamous Drake 2880 downconverter?
Perhaps as an alternative, the approach I took with mine was to not force the IF to be in the 2m ham band, but rather to center it in the Drake's original 200-400mhz passband. I would then use my ICOM IC-R7000 all mode scanning receiver for the remainder of the RF chain. A local oscillator frequency of 2100mhz put AO-40's 2401 mhz downlink at 301 mhz (easy math). It ended up working reasonably well.
Putting the IF outside the ham band gave me the flexibility to use either (any) ham band for the uplink, without worrying about interference. If you are looking to a future as-yet unknown bird, that might be a good idea. If they use 2m for the uplink, using that for the IF as well is going to be a problem. It also left (and used) the Drake's original passband filtering unmodified, improving the unit's performance. In place of the ICOM receiver, I would now use an SDR Dongle, something not yet available back in the day.
Hello Greg,
Good guess, but not quite! This is a California Amplifier LNB that I picked up when AO-40 started having problems, so I tossed it in a box and forgot about it. Recent work has me digging back into those boxes and going down rabbit holes long since forgotten about. :-)
Using an SDR or a general-coverage receiver is a good idea for fixed-base work, but I don't have anything mobile that is general coverage. I do appreciate the ideas!
--- Zach N0ZGO