[amsat-bb] Re: OH2AUE P3E transponder demo video

Gordon JC Pearce gordonjcp at gjcp.net
Wed Oct 17 23:47:20 PDT 2012

On 18/10/12 03:28, Gus 8P6SM wrote:
> On 10/17/2012 05:38 PM, Gordon JC Pearce wrote:
>> 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.
> I may not be 100% on the 'bent pipe' definition, but if it means hams
> 'talk' on the UP and other hams 'listens' on the DOWN, then that's what

What I am referring to is linear transponders.  They're heavy and 
consume a lot of power.  We need to either devise a new way of doing 
that, that doesn't involve heavy inefficient linear amplifiers, or stick 
to something like FM or GMSK where a little lightweight PA that doesn't 
dissipate most of the input power as heat will do the job.

> we need.  Whether it be the size of a fridge of a matchbox, if ham radio
> operators can't use it to communicate, then it's pretty pointless.  It

If it's big it won't fly, unless you pay for the whole flight.  Have you 
noticed how airlines have stopped carrying children for free, too?

> don't matter how much telemetry it sends, how many LEDs it blinks, how
> clever the beacons, or what purty pictures it downlinks.  If hams can't
> use it to QSO, then why bother?

It depends what you're trying to achieve.  I'll respond to Domenico's 
comments here, too.

Most satellites are not built by radio amateurs.  They're not there so 
you can talk to your friends.  They are built so the engineering 
students that will build the satellites and spacecraft of the future. 
Like it or not, amateur radio is a secondary service on 70cm.  We don't 
own that chunk of band.  If you want to work a band free from "beep 
sats", stick to 2m and good luck with your build.

Gordon JC Pearce MM0YEQ

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