[amsat-bb] Re: "Newbie" Need's Help working AO-07

Greg D. ko6th_greg at hotmail.com
Tue Dec 30 23:52:39 PST 2008

Great write-up for SSB satellites, in general.

If I may, a couple of further thoughts...

 - Instead of whistling, I say the word "Tune" a few times.  (Actually, it comes out Tuuuuuuuuune, but you get the idea.)  I can still zero-beat my own voice close enough, and it lets anyone else on that part of the passband know what I'm doing.  It also seems to be a great source of entertainment for my wife, when she's in the room, so use it at your own risk.

 - AO-07 is a Mode-B bird, with the uplink on the higher band.  FO-29, another excellent choice for SSB/CW satellite operating, is Mode-J, where the bands are reversed.  For FO-29, you should chase Doppler with the downlink (receive) side, leaving the transmitter alone.  With manual operation, use the higher band to track Doppler, as you mentioned.

 - I also have a Yaesu 736R, but I use the Normal and Reverse Satellite modes all the time.  This is where the Tx and Rx sides of the radio are locked together, so you can move around the band without having to find yourself again.  There are two uses for this - scanning around the band for an active CQ or QSO to join, and also so that you can pick an out-of-the-way spot in the passband to find your self, before moving to the more popular band center to call CQ.  Note that for both AO-07 and FO-29, their having Inverting Transceivers means you need to use the Reverse satellite position for grazing around the passband.  If you don't lock the two sides, remember that if you tune up on one, you need to go down on the other.

 - Finally, Doppler adjustment is not even across the duration of a pass.  It's slowest at the beginning and end, and fastest in the middle.  So, if you're just starting out, pick a good pass - one that you can hear easily - but not an overhead one, to practice Doppler tracking.  It's easy to get lost in the middle section, especially if the other station is yacking for a while as the bird goes overhead.

Greg  KO6TH

> Date: Tue, 30 Dec 2008 21:27:22 -0600
> From: wb5rmg at somenet.net
> To: amsat-bb at amsat.org
> Subject: [amsat-bb] Re: "Newbie" Need's Help working AO-07
> N0FJP said:
> > I am new to working the Sats so if I am in need of "directions"
> > please feel free to set me in the right direction.
> >
> > With that said, I am having problems working AO-07 and the other SSB sats.
> >
> >I can copy stations vary well but I can't seem to keep on track with them.
> Marv,
> I can provide some direction ...
>  - whether it is considered the 'right direction' remains to be seen.
> I was brought up in the 'old school' before CAT and HRD assisted tuning,
> so I'll describe the manual tuning mode I've used since way back.
> A couple of starting points to keep in mind:
> 1. doppler affects both uplink and downlink, moreso the higher freq.
> 2. you need hear yourself, anyone calling you back will be on your downlink.
> 3. It is not considerate to 'sweep' your Tx around the band
>    looking for yourself - better to sweep your receiver.
> I'll have a table of 'un-doppler-d' transponder freqs, like this for VU-52:
>     up (LSB)   dn (USB)
>      ...        ...
>    435.260    145.290
>    435.250    145.900
>    435.240    145.910
>      ...        ...
> As the pass starts, lets say I'll set Tx for 435.240 (LSB)...
> then I'll set the Tx to CW and send a string of dits with the keyer.
> I'll tune around with the Rx until I hear my dits, and zero beat them.
> In otherwords, tune Rx until the pitch goes down to nothing. Then I'll
> switch Tx back to LSB and whistle, and slightly adjust Rx to perfectly match
> the pitch of my whistle in the headset. Now as I call CQ, I can gradually
> tweak the Tx freq to keep the pitch normal so that I don't need to adj
> the Rx. I try to keep the Rx coming out in the same place, so I'm only
> trying to keep up with one knob (Tx)... When someone comes back, they may
> drift across the band a bit, and I follow them (Rx) - assuming they are
> also following themself. Then when it is my turn to Tx, I first whistle
> and tweak my Tx for that zero-beat of the pitch, and start talking...
> I guess I've had plenty of practice, as it comes easy for me.
> If the other station is adjusting their Tx to keep a steady Rx freq,
> then each of us only needs adjust the Tx freq along the way...
> At least that's the way I learnt it, you know - back in the day.
> Sometimes good practice for 'newbies' is to whistle to themselves,
> and get some practice finding their downlink and matching the tone.
> This method works with manual tuning, others may have additional suggestions.
> Probably the guys using CAT have methods that better suit their needs.
> The FM satellites obviously don't have the passband to waller'round in.
> My radio is a Yaesu FT-736 and has the ability to lock the two VFOs once
> you hit that zero-beat, but as short as the LEO passes are, I hardly ever
> do that. Back in the day of AO-13, it was common to lock them and run up
> and down the passband looking for other stations. Find one, unlock for a
> quick zero-beat whistle, and lock it back... I do miss that bird...
> I don't get on a lot, and may only get one or two contacts per pass, but
> I prefer linear transponders over FM, so listen for me... I'll be the one
> whistling alot. Looks like VO-52 is coming up AOS about 0340z for me.
>    73 for now, let us know how it goes.   /;^)
> -- 
>   <- Licensed in 1976, WB5RMG = Alan Sieg * AMSAT#20554 ->
>   <- http://www.somenet.net * http://wb5rmg.somenet.net ->
>   <- http://www.linkedin.com/in/alansieg * My 'Day Job' ->
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