[amsat-bb] Re: LEO tutorial

Tony Langdon vk3jed at gmail.com
Sun Mar 18 13:03:19 PST 2007

At 06:54 PM 3/18/2007, Howard Long wrote:
>Hi Robert
> > http://www.wku.edu/ksgc/sats.pdf
> >
> > This is great stuff and would be a good link (or download) to
> > add to the AMSAT webpage for newbies (like me!)
>I agree it is especially clear and well written. My only caveat is that I
>personally feel that the rejection of full duplex capability in the paper
>promotes blind transmission for longer periods than necessary creating QRM
>for others. Thinking back to when I cut my teeth, I would have found it
>particularly frustrating not knowing if I was making it.

I agree totally.  While it is possible to work without full duplex, 
it is much easier and more efficient if you have this capability.  I 
use full duplex in a number of ways:

To ensure I'm not creating QRM (someone of similar strength may key 
up at the same time).  Because of the quiet conditions here, this can 
also be used to prioritise traffic.  If in a late night ragchew style 
(remember, it's not uncommon to be talking to yourself down here!) 
QSO you hear a heterodyne, you can let the other station use the 
satellite and use it much sooner.

To enable continuous antenna adjustment - conditions can change 
rapidly, and an antenna tweak is sometimes needed.  It takes a bit of 
practice to be able to talk and adjust the antenna at the same 
time.  My signal often has a characteristic where it rapidly becomes 
stronger in the first second or two, as that adjustment is 
made.  This alone is worth a small amplifier (and much lighter!).

And as you say, simply to know if you made it.

>Just my opinion, and the author is to be applauded for his efforts.

Yes, the rest of the article is well written, and lots of good photos 
and diagrams to aid his explanations.

73 de VK3JED

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