[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: seeking advice on easy sats

on 9/9/01 6:38 PM, Phil at phil@spiderweb.com.au wrote:

> I'm wondering if I might be expecting too much from AO 14 and FO 20 because
> I don't seem to receiving either of them as well as some operators appear
> to. My expectations are bases on RS 12 which is receivable from horizon to
> horizon.

UO-14 (not AO-14) should be very easily readable.  I've heard it on a rubber
duck in the past.  Getting into it is probably another story!  FO-20 is a
bit tougher particularly now when it goes into eclipse.  The batteries are

> AO 14 is often only receivable for short bursts and periods of say 30 seconds
> to a minute two or three time during each pass. Signal strength is usually
> between S1 and S4 during those times. I'm only guessing that the reason might
> be that the satellite may be tumbling slowly which means that the satellite's
> antenna is pointing away from the earth for long periods of time. Is this
> correct?

In the times I've worked UO-14, I've never really seen this except that the
polarization does rotate a bit during the pass, but you should be able to
hear it always.
> FO 20 is very weak and I'm not sure if the signal fades to the same extent as
> AO 14 although it does seem more consistant. The difficulty with this one is
> compounded because it receives little use although the whistles and hellos
> does indicate that the satellite is still functioning.

The best way to track the bird when just listening is to listen to the

> My station is very modest and consists of an FT-817 and a hand-held home
> built 6 element Yagi. I don't have a preamplifier and I can't be sure that
> the antenna is performing to it's peak because I don't have access to a UHF
> SWR meter. However the beam width is around 25 degrees which I expect is
> normal and it certainly out performs a rubber duckie.

My guess is that you may be having a tracking problem.  It can be very
difficult to track LEOs by hand and it takes a bit of trying with it to get
good at it.  Also, are you inside or outside during the passes.  Trying
going outside if you aren't.  Rotate the antenna to try to compensate for
the circular polarization of the satellite.  You may be able to hear the
bird during those fades if you rotate the polarization of the antenna.  You
may also be having difficulty if you are on a side lobe of your antenna
rather than the main lobe.  This could happen if your tracking or keps are
off.  It's easy to do by hand.  Lastly, with rapid doppler shift, it can get
easy to lose the birds while moving the antenna (your arm gets tired!) and
tuning the radio, etc.

I hope this helps.

Good luck!



Jon Ogden
NA9D (ex: KE9NA)



"A life lived in fear is a life half lived."

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org