[amsat-bb] Re: OH2AUE P3E transponder demo video
Gordon JC Pearce
gordonjcp at gjcp.net
Wed Oct 17 14:38:36 PDT 2012
On 16/10/12 03:18, Ben Jackson wrote:
>> It may be easy to reliably work a future generation of satellites with
>> an HT and a rubber duckie. But that won't be challenging. And we (the
>> operators) won't be learning anything new.
> But instead folks are promoting an anachronism. They're discussing
> learning something new at the same time saying we should be using a
> technology that has been in use since the 1960s.
> So then instead of focusing on linear transponders how about deploying
> HSMM nodes into space, TDMA, or DMR technology? (No idea how feasible
> any of of this is)
DMR as it stands isn't viable because it relies on really tight timing
in the slots - the "book figure" is 75 miles but people have pushed it
to over 100. The trouble here is that the speed of light just isn't
that fast ;-)
In any case, the challenge has changed. I don't see any real challenge
in the "hard sats", because the "hard sat" brigade all seem to use
massive aerial arrays, with computer-controlled steering and tuning. I
don't see what's "hard" about it - it's just throwing technology and no
real skill at the problem. Once you've figured out the mysteries of the
crappy proprietary software that people use to steer the aerials and
tune the rig, it's point-and-shoot.
The FM sats can be worked with something as simple as a dual-band handie
and a homebrew crossband pair of Yagis - and a great deal of operator skill.
No, the challenge today is this - are you ready? The challenge is:
Get something flying, for less than the GDP of a small nation.
There, I've said it. It's down to money. You know what else I'm going
There is almost certainly never going to be another amateur HEO satellite.
There, I've said *that*, too. Want to know why? Because we're a
tightfisted bunch and no-one is going to fly us for very nearly free.
The HEO crowd have some amazing technology, but it's going to cost a
fortune - a very large fortune - to fly these Death Star-sized
satellites *at all*, never mind into HEO.
The future is small satellites, where we will have to cram as much radio
into a tiny cubesat payload as we can. Even then it's going to be
expensive, so we're going to need to look at countries that are
developing their space programme to get launches - and that's going to
be India, Pakistan, Iran if they get their shit together, maybe Israel
if we can get them interested in anything other than "observation"
satellites and probably one or two others. Maybe some wealthyish
African countries will get in on it, like the DRC or Kenya.
We're going to have to try coming up with clever satellites, rather than
flying a bent-pipe box the size of a fridge. No-one is going to want to
lift that, without us paying full price.
Gordon JC Pearce MM0YEQ
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