On 03/15/20 13:48, Jeff Johns via AMSAT-BB wrote:
The general public seems to want more FM satellites, but organizations don’t seem to be building them and getting them into orbit fast enough to keep up with demand.
The single-channel, repeater-in-the-sky model was always destined for this sort of abuse (or simple ignorance). I've seen this happen on a local repeater, with a footprint of less than 50 miles. Why wouldn't it be expected on something with a footprint 100-1000 times as large?
Hams clamor for FM satellites because it reduces the cost of user equipment. Beofeng hasn't yet come out with a $30 2m/440 all-mode HT.
Linear satellites would work better for capacity, and better utilize the amount of bandwidth "lifted" to orbit by a launch vehicle. However, AMSAT can't alienate the $30 FM users, so it is a delicate balance.
Adding a linear transponder right alongside the FM card might work, but that incurs additional solar/power requirements which drives up system complexity, cost, testing, etc.
There are many variables, and it is impossible to optimize for them all. That's the engineering trade-off that I imagine AMSAT must face.
Here are a few of my thoughts:
Some enterprising soul should design, using common, off-the-shelf ICs, a simple PCB that is a SSB/CW 2m/440 duplex radio. Make the plans available freely on the WWW, etc. Get a groundswell behind it, and then watch the Asian clone makers swoop in and commercialize it (while also optimizing every last penny spent). Presto, lots of 2m/440 linear operators. Worked for nanoVNA, mikrocontroller's transistortester, etc. Should work for our crowd.
Also, donate early, donate often to AMSAT. Building, testing, and launching satellites isn't cheap, and your donations help put more birds into space.
"Cheap, fast, good. Pick any two."
--- Zach N0ZGO