[amsat-bb] Re: working ao-51 (finding the bird)

n3tl@bellsouth.net n3tl at bellsouth.net
Mon Nov 10 19:03:19 PST 2008

Hey Eric,

What are you using to find the times and such for passes? Even if you're only using a handheld station - which is all I used for months here with good success - I would suggest downloading and installing one of the tracking programs available online. SatPC32 is very good, especially if you ultimately are going to use it to guide an az/el rotor setup and to tune your radio(s) for Doppler. I am old school here, doing everything manually (and will be for the foreseeable future), and I use a program called Orbitron. I like it a lot for a number of reasons - not the least of which is its ability to provide you with a schedule of upcoming passes based on parameters you provide it. 

Each listing on that schedule gives you the time of Acquisition of Signal (AOS) along with an azimuth position. It also lists time and azimuth for maximum elevation, and time and azimuth for Loss of Signal (LOS). If you have those data and a compass, you can "map" a pass in advance, which is what I do. I note "landmarks" for AOS, mid pass and LOS, then simply turn the compass on its side to check the angle at maximum elevation. From there, it's a matter of visualizing the satellite rising, moving across the sky and setting. Watching visible passes of the International Space Station is a great way to get some visual practice to help when trying to "see" an amateur satellite pass as it happens. You won't actually see the satellite, of course, but watching the ISS will give you an idea of how a satellite moves across the sky - especially if you have a chance to watch passes with different maximum-elevation angles. 

My first handheld station included a Yaesu VX-7R HT and an Arrow, so I have literally hundreds of passes' worth of experience with that antenna. When you're searching for the satellite, are you twisting your wrist to adjust the position of the elements (i.e., the antenna's polariztion relative to the satellite)? If not, you should try that. There have been more than a few times when a twist of the wrist made the difference for me in terms of getting a new grid square, or not.

I hope at least some of this proves helpful. 


Tim - N3TL
AMSAT Member No. 36820
Athens, Ga. - EM84ha
-------------- Original message from "Eric Fort" <eric.fort at gmail.com>: -------------- 

> I think I finally heard the ao-51 downlink sending some form of digital data 
> (likely sstv) this evening from DM14GK at 0218 GMT near the very end of the 
> pass. I had much trouble finding the bird and it took most of the pass to 
> find. What can everyone suggest for making it progressively easier? 
> Antenna is an arrow with duplexer feeding a vx-6 ht. 
> Eric 
> PS 
> I'm curious, who's uplink was that? 
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