[amsat-bb] Re: FO-29 and VO-52

[John Papay]

Some General Guidelines to Working the Birds with Omni Antennas:
(My opinion for what it's worth; others may disagree.)

A lot of people are using omni antennas.  Some use
preamps and some do not.  The important thing to remember
when using omni antennas is that you will be getting into
the bird much better than you can hear it, if you can
hear it at all. A preamp will really help.

If you have a full duplex radio and can't hear yourself on
the ssb downlink, there's a problem.  If you can hear others,
try calling them and see if you can make a contact.  Don't
call CQ if you can't hear yourself.  You may be calling on
top of a qso and if you are not doppler controlled, you will
likely drift into a qso and cause interference.  If you hear
others on the bird, try to find yourself and determine your
offset.  Setting your uplink and downlink manually is challenging
but not impossible.  Use a program like SatPC32 to help you
determine what tx frequency corresponds to the receive frequency.
Ultimately, use the program to control your radio.  Once you calibrate
your uplink to your downlink, you will make more qso's.  Make
sure your computer clock is set to a few seconds of the correct time
and your keps are current.  If these are not set, you will not have
the proper doppler control, especially when the bird is overhead and
the frequency is changing rapidly.  If you can only manage to change
one of the frequencies, change the one that is higher (e.g. tx (UHF)
on VO-52 and rx (UHF) on FO-29).  The UHF frequency changes much
faster than the VHF frequency.

On the FM birds, don't announce yourself unless you are full
duplex, can hear yourself and there is little or no activity
on the bird.  Wait until you can hear other stations and then
call someone you can copy.  They will likely come back to you.
Once you make a qso, others will call you so pay attention.  If
you are in an inactive grid, expect a pileup.  Use a recorder
so you don't have to write anything down.  Don't disappear after
your initial qso.  Stay with it as long as you can hear.  You
will make more qso's.

There is always activity on any daylight pass of AO27 and AO51.
If you don't hear anyone, you are likely not hearing the satellite.

As the bird comes over the horizon,
adjust your fm rx frequency 10 KHz higher than the published
center frequency.  As the bird moves toward you, lower the frequency
in 5 KHz steps.  The bird should be on the center frequency when
overhead and then -5KHz as it moves away and then -10KHz as it
gets closer to the horizon.  No computer control is necessary on
the FM birds.  When the audio sounds a little distorted, it's time
to change the frequency.  Use your ears; a computer is not necessary.
It is not necessary to change your uplink (145 MHz) tx frequency.

Working the birds with omni antennas is challenging. As long as
you know your limitations and operate accordingly, you will be fine.
But don't expect to be able to hear very well.  If omni antennas
worked that well, everyone would be using them, and there would be
a lot more than 21 stations that have 350 or more grids confirmed
on satellite VUCC.

John K8YSE




>------------------------------
>
>Message: 2
>Date: Tue, 4 Aug 2009 13:41:27 +0000 (UTC)
>From: aa2tx at comcast.net
>Subject: [amsat-bb] Re: FO-29 and VO-52
>To: Jean-Fran?ois M?nard <jf.va2ss at gmail.com>
>Cc: AMSAT-BB at amsat.org
>Message-ID:
> 
><87800968.8532491249393287738.JavaMail.root at sz0024a.westchester.pa.mail.comcast.net>
>
>Content-Type: text/plain; charset=utf-8
>
>
>
>Hello Jean-Francois,
>
>
>
>I have worked VO-52 with omni antennas and an FT-817
>
>on SSB with no problem at all. FO-29 should work?too as long
>
>as there are no high-power stations pumping the satellite AGC.
>
>
>
>73,
>
>Tony AA2TX
>
>---
>
>
>
>----- Original Message -----
>From: "Jean-Fran?ois M?nard" <jf.va2ss at gmail.com>
>To: AMSAT-BB at amsat.org
>Sent: Tuesday, August 4, 2009 8:53:17 AM GMT -05:00 US/Canada Eastern
>Subject: [amsat-bb] ?FO-29 and VO-52
>
>Hi,
>
>I would like to know if I'm dreaming, but will it be possible for me
>to use these two satellites with my pair of FT-817 running on
>SatPC32??
>
>Am I asking too much for my 5W only radios ?? I'm using 2 Eggbeater
>antenna from M?... EB-144 and EB432 with AR? preamps on both antennas
>feed with heliax.
>
>73
>
>--
>Jean-Fran?ois M?nard
>VA2SS
>
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