[amsat-bb] Re: AO-51 Mode L/U
gouldsmi at bellsouth.net
Wed Apr 9 16:16:16 PDT 2008
I routinely get the downlink quite well using an 8 element 70 cm yagi, with
a pre-amp at the antenna, fixed elevation, tracking in AZ . The digital
transmission is currently about 500 mW, but you need a good S/N ratio to
decode the data, even if your modem locks on to the clock.
The AMSAT Digital Guide has a very good description from actual experiments
by Mike, N1JEZ on what is need in a 1.2 GHz uplink signal for digital
operation on AO-51. GO-32 also has a 1.2 GHz uplink, but it has also needs
more signal than you are delivering.
The downlink reception is pretty easily and inexpensively corrected. I am
not sure how the increase in TX delay time to a second will help your uplink
as you didn't mention an amplifier needed to switch in.
A good deal of the enjoyment for many of us is the challenge of getting
operations on the satellites and the multiple modes they present. I am sure
the digital guide would be of assistance to you.
--- Original Message -----
From: "James Denneny" <57JNDenneny at comcast.net>
To: <amsat-bb at amsat.org>
Sent: Wednesday, April 09, 2008 3:16 PM
Subject: [amsat-bb] AO-51 Mode L/U
>I have had no luck uplinking on Mode L. I even followed a suggestion to
> increase TX delay to 999 ms and tail time to 100 ms to give the bird extra
> time to grab me. However, 10w from my 910H on 23cm with a single twisted
> helix 1.2G antenna does not cut the mustard. I also have had very limited
> success on the 70cm downlink grabbing the DIR. All in all - a bust.
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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