[amsat-bb] Re: Finding yourself on the linear transponders

Clayton Coleman kayakfishtx at gmail.com
Wed Jan 8 06:43:57 PST 2014


Bringing up a view of the entire satellite pass band can be very
enlightening when using a FlexRadio, FUNCube Dongle, or similar
device.  What do you think about those people who run so much power
their signal sounds like garbage and images are seen and heard on
other parts of the passband?  It's cool (NOT) to see the waterfall of
someone FM'ing AO-7.

Whistling and swishing across the passband is certainly annoying.
Equally annoying are those who pass after pass refuse to reduce their
power levels.   I understand many people use stations designed for
working satellites at greater distances (i.e. 20,000 km vs 1000 km.)
Adjust transmit power accordingly, please.  Good or bad, we live in a
LEO-sat world.

In your post you mention that using computer control or using a series
of short dits are methods to minimize the 'swishing' effect.  Both
very good options.  However, as someone who does a lot of portable
operating, it is very annoying when I cannot ever hear myself because
someone is killing/hogging the transponder. Often it can be caused by
as little as two stations.  I can usually gauge where I will be on the
transponder based on desired frequency.  This comes with a lot of
practice manually correcting for Doppler.

I'm fond of Jeff KB2M's suggestion of moving off the pass band center
to "find one's self."  The center of the pass band is not some magical
vortex guaranteed to produce rare DX contacts.  For example, when I'm
portable I like to start around 435.875 on FO-29.

There's plenty of room for improvement across the board.  We can move
today's 'swisher' to tomorrow's elmer with the right instruction and


* Still learning every day and making mistakes.

On Tue, Jan 7, 2014 at 6:59 PM, Ronald G. Parsons <w5rkn at w5rkn.com> wrote:
> Perhaps it’s just me, but it seems like an increasing number of operators are trying to find their downlink by speaking into their mic while tuning up and down the band, often plus or minus 20-30 kHz. Not only is this disruptive to existing QSOs, it is not the most effective way to do it. My receiver has a panadapter with a 40 KHz bandwidth, and I can see these SSB signals swishing up and down, over and over.
> If you don’t have computer control of your frequency, set up a switch by which you can send a SHORT series of dits. Then don’t swish. Adjust your transmitter is steps of about 3 kHz. Send a burst of dits at low power and listen. If you don’t hear yourself, tune up or down. This way you will have an effective way to find yourself and you won’t interrupt other QSOs repeatedly.
> Once you find yourself, make sure you are not interfering with an existing QSO. Then refine your tuning until your frequency is nearly right. If you are operating CW, your done. If you are operating SSB, try holding a tone generator near your mic and adjust your transmitter or receiver until the tone on the downlink matches the tone generator.
> There is probably a free tone generator available for your smart phone.
> Better yet, try computer control of your transmitter and receiver. You can easily find an Elmer on the air if you need help.
> But, PLEASE. don’t swish!
> Ron W5RKN
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

More information about the AMSAT-BB mailing list