[amsat-bb] Re: Newbie in Satellite for Amateur Com

Gus 8P6SM 8p6sm at anjo.com
Wed Oct 10 17:30:06 PDT 2012


On 10/10/2012 02:19 AM, situsaja at bshellz.net wrote:
> Hi,
>
> I'm a newbie for amateur satellite stuff, and I want to gain a
> deep knowledge and experience in it.

It's very old and hard to find, but The Satellite Experimenters Handbook 
by Martin Davidoff K2UBC will give you fundamental knowledge on 
satellites, orbits, tracking, antennas, feedlines, etc.  The book is 
old, but the laws of celestial mechanics haven't changed.

> I have a 2-meter band VHF transceiver handheld radio, and has 5
> watt for the output power. Can I use the radio to communicate
> with any satellites that support VHF?

You will need to operate on two bands, to work satellite.  I can't think 
of any satellites offhand that operate on a single band.  You will use 
one band to transmit TO the bird (uplink) and a separate band to receive 
sigs FROM the bird (downlink).

Can you get some 70cm gear?  If you can transmit/receive both VHF 2M and 
UHF 70cm, you can operate Mode-B (70cm UPlink and 2M DOWNlink) or Mode_J 
(2M UPlink and 70cm DOWNlink).  Some birds operate FM, some use a linear 
transponder for use with CW/SSB.  It's *possible* to run FM through a 
linear transponder but it's frowned upon because it hits the satellite 
batteries harder, not to mention bogarts the passband.

Failing this, if you have an HF rig and know CW, you could try AO-7 via 
Mode-A (VHF 2M up, HF 10M down).  Put a key across the PTT line of an FM 
rig, disconnect the mic (no modulation of the carrier) and you have a 
poor-man's CW rig on 2M.  Listen to your sigs and hopefully a few 
replies on your HF rig.

> And please direct me to the resource that I need to start building my
> first small station. Thank you in advance.

Well, once you have gear for two bands, you will need antennas.  A 
rubber duckie is workable, but far from ideal.  Popular these days are 
small, hand-held yagis, of various designs.  But you could experiment 
with other designs, such as the quadrifilar helix, the turnstile, the 
lindenblad, and so forth.

How do you wish to operate?  Portable, from all over the place?  From 
your own back yard?  Out of your shack?

-- 
73, de Gus 8P6SM
The Easternmost Isle


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