Hi Zach,
Oh, ok. No direct experience here for the CA LNB, but I seem to remember people modifying it in similar ways to the Drake. If so, the same technique could work. The idea is to give yourself the maximum flexibility for whatever bands and modes might be used in the future.
Don't forget, an SDR dongle can work very well mobile, as laptops do well in that environment, and could set you up for some of the digital modes that could be employed. I even plugged mine into my Android tablet with SDRTouch. Lots of options for these versatile gems. Many use them for the current crop of satellites, but be sure to get one with good front-end filtering (or add it externally) or you could get a strong desense.
One of your challenges is going to be knowing exactly what the conversion equation is, i.e. where exactly your LO ended up. Given the frequencies and multipliers involved, a very small offset in the LO crystal can result in a large offset in actual receive, making it difficult to find the satellite the first time. I think mine was off by something like 50 mhz on AO-40, even after tweaking the LO with a frequency counter. Very touchy.
For testing, and given that there's not much ham-related stuff on that band, you might scan the horizon and count microwave ovens (2450 mhz -ish), though they are not very frequency-stable. Best is around dinner time :) I also had good results listening for the 17th harmonic from a 2m transceiver fed to a diode as the load (144*17 = 2448). You might even try that with the 18th or 19th harmonic (2592 or 2736 mhz) on an unmodified unit, to be sure it's still working.
Good luck,
Greg KO6TH
Zach Metzinger wrote:
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