[amsat-bb] Strange thing occuring.......

[Jon Ogden <jono@xxxxxxxxxxxx>]

OK,

I am stumped.  This evening I decided to try my hand at RS-15.  I tuned my
FT-847 on frequency, pointed my antennas, keyed up on CW and found myself.
However, I noticed that I had to use lower sideband on the uplink for a USB
downlink.  The transponder was also inverting in terms of frequency tracking
which I didn't realize either.

So I called CQ several times and didn't hear anyone but myself.  I also had
to run a fair bit of uplink power (> 60 Watts) for most of the time I was
trying.  Later, I found that I was getting in fine with about 20 Watts.  I
also noticed the passband seemed to be a lot larger than all the data I have
on the bird.  I could spin the dial and hear myself up where RS-13 usually
is.

So....now I began to wonder: Is it desense or the bird?  Well, if it was
desense it was certainly odd.  I could hear myself on my FT-1000D as well if
I switched the beam to the FT-1000D.  Plus the level of audio clarity and
the tracking of the signal wouldn't lead to that conclusion.  If I tuned up
the 10M frequency and the 2M tuned down, the frequencies tracked perfectly.

Well, the satellite disappeared over the horizon.  I could still hear
myself.  As I write the satellite is now somewhere over Russia west of
Moscow and about 25 degrees BELOW my horizon.  Yet I can still hear myself.

So:  I must have some sort of odd desense or there is another bid up there
that I know nothing about!  It's just really odd as the frequencies for the
uplink and the downlink lined up nearly exactly.  And there seemed to be a
minor amount of doppler shift as well.  My satellite antennas and my HF beam
are fairly close, but I've not heard of a 2m radio desensing an HF radio.
Also, I have an ICE lowpass filter on the HF side of things and a DCI 2m
bandpass filter on the 2m side.  So the out of band rejection should be huge
between the radios.  Remember, I don't think it's crosstalk INSIDE the
FT-847 as I heard myself on my FT-1000D as well.

So what gives?  Was I hearing the bird or is something funky with my setup?
Has anyone else experienced this sort of thing?

73,

Jon
KE9NA

-------------------------------------
Jon Ogden
KE9NA

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

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

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