[amsat-bb] Re: AMSAT-BB Digest, Vol 7, Issue 346

Tom Gentry t.gentry at verizon.net
Thu Oct 18 10:50:22 PDT 2012

Rubbish! I built my own antennae from wood and welding rod, cut my own 
phasing lines and built a computer from scraps to run the tracker 
software.  I did have an AZ-EL motor set from the 80s but it had to have 
the controller rebuilt and the case crack repaired.  My old radio FT726 
doesn't have computer control so I am building a softrock SDR station 
with transverters for 2m and 70cm and my goal is to have it track and 
adjust for doppler while I make contacts whilst I am busy during a 7-10 
min LEO pass.

So far I have learned about Yagi antenna design, transmission line 
theory and practice, Smith charts (impedance and admittance), software 
defined radio theory, full duplex SDR radios and multi-user 
transponders, so if that's what you call throwing technology at the 
problem then color me guilty

and PO.d at your comment.



On 10/18/2012 10:00 AM, amsat-bb-request at amsat.org wrote:
> Message: 2
> Date: Wed, 17 Oct 2012 22:38:36 +0100
> From: Gordon JC Pearce<gordonjcp at gjcp.net>
> To:amsat-bb at amsat.org
> Subject: [amsat-bb] Re: OH2AUE P3E transponder demo video
> Message-ID:<507F255C.9030008 at gjcp.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
<snip> 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 to say? 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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