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

Re: FM bird logjam



Quoting Matt Bennett <kaisermuche@yahoo.com>:


> I certainly agree that those who DO have the equipment
> and are passing up the SSB passes are missing out. My
> most distant contacts have been made on these birds
> because of their larger footprints and ability to hold
> the uplink at very low elevations.
> 
> > See you on the sats?
> 
> Sure! FMs for now, SB sats next week!
> 
> 73,

I've been on the SSB sats only for two months or so, and this is one of the
counterintuitive results I've observed. Because of their reputation for
being 'intermediate' birds, I assumed that communications through FO-29,
VO-52 and AO-7 would require more power / better antennas than what I was
used to with AO-51. In fact, FO-29 is a far better DX bird for me: with the
same antennas and the same 5w out, FO-29 can be worked lower to the horizon
on SSB (not to mention CW). It is my impression that VO-52 and AO-7 would
like more power on the uplink, and I'm presently without a preamp for 2m,
but I've had great fun on CW using these, and can certainly hear both quite
well. I suspect this is partly because of the mode involved. FM appears to
require a minimum signal to provide any intelligence at all. 

On the other hand, with fixed elevation, linear polarization yagis, AO-51
is somewhat less satisfactory than it is with an Arrow antenna properly
used, at least in its normal power mode.

One further point on the issue of congestion on the ISS and AO-51. It was
only two years ago that I first heard a satellite. I built a yagi with a
broomstick dowel, some wire and the hacked-off end of old coax. When a
lonely station broke the static, I was overjoyed: my experiment was a
success. That station could have been reading the 'phone book for all I
cared. Similarly, when I first made the uplink to AO-51, with a homebrew
arrow antenna, I was delighted. That was my voice! I probably didn't make a
QSO that evening, but didn't care. 

I imagine that for many operating through the ISS for the first time the
same is true; and the cacophony which we see as a terrible waste of a
resource is music to their ears. If they hear a single syllable of their
own, it might not be so much frustrating as an accomplishment. Once the
glow of that fades, of course, they will prefer to talk to others, exchange
grid squares, etc. 

Finally, while Drew's axiom about the (communication) usefulness of (an
FM?) bird being inversely proportional to its xmit power is generally true,
I think we can fine tune the equation, adding ham population under the
footprint: u = 1 /  P*h :-) I add this because the recent high-power mode
of AO-51 has been wonderful for trans-atlantic DX, or even DX from Canada
to S. America when the bird's footprint is mostly over the Atlantic. 

73, Bruce
VE9QRP
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home