[amsat-bb] SSB via satellite (was Re: Protocol)

[Patrick STODDARD (WD9EWK/VA7EWK)]

Hi Gordon!

> Because AO-51 is the most reliable satellite in terms of actually
> finding and working it.  SO-50 seems to be almost impossible to lift,
> and the linear transponder ones require extremely expensive radios.  You
> can work AO-51 with an el-cheapo dual-band handie and a homebrew
> antenna, and you can work /P really easily because you don't need a
> rotator or satellite tracking software.

SO-50 isn't impossible, but your receiver and antenna system need to
be able to deal with weaker signals than you hear from other FM birds.
SO-50 is transmitting at 250mW, and it gets regular workouts on passes
over here.  AO-51 is now running with more power on the downlink than
usual, which will make the difference between it and SO-50's downlink
more noticeable.  PL tones are also mandatory on SO-50, to turn it on
(transmit briefly with 74.4 Hz) and to talk through the satellite (67.0 Hz).

> I'm not going to rush out and buy a VHF/UHF SSB rig just to work the odd
> pass, especially since I've never heard anyone on the linear birds.  I
> don't know if VO-52 works - I've never even heard its beacon - and AO-27
> is only ever enabled over the US, making it useless for most of the
> world.  It would be great to attempt a QSO through AO-7 but again I'm
> not going to go and buy a rig that costs as much as a car to do it.

I would not characterize a Yaesu FT-817ND and Kenwood TH-F6A (outside
North America, TH-F7) as "extremely expensive" radios.  Sure, these two
radios are more expensive than a single 2m/70cm FM HT, even more
expensive than the new TH-D72A HT, but not like the prices were on all-
mode 2m and 70cm gear were in years past.  I regularly work the linear
birds with either two FT-817NDs or one 817 and a TH-F6A receiving the
downlink.  With an FT-817ND, you also get a radio capable of QRP HF and
6m operation.  The 817s have been in production for a decade, so you
could also look at picking up a used 817 (or two) to try SSB on the birds.
The 817s have a CAT control port on them, so they can be controlled with
software like SatPC32.  Two 817s can be controlled by SatPC32, if you are
looking for an all-mode full-duplex satellite ground station with those radios.

Besides an 817, you could also look at radios like the IC-706Mk2 or Mk2G,
IC-7000, FT-857, FT-897, etc.  You'd need a larger battery to run them
than you would an 817, but all of these are capable of being used for SSB
satellite work.

VO-52's beacon is just a carrier on 145.936 MHz.  It is on all the time,
and the VO-52 downlink is easy to copy.  It is a great satellite for someone
interested in starting out on SSB via satellite.  AO-27 is available on
daylight passes over the Northern Hemisphere, not just over North America.
If the web site is accurate, you can get an updated schedule for AO-27
for the upcoming 24 hours at:

http://www.ao27.org/

You can also download a program that shows when AO-27 will be on for
any particular date from:

http://sites.google.com/site/ao27satellitescheduler/

The SSB birds are not as busy as the FM birds, but you can find activity
on them.  Many will work SSB with computer-controlled radios or
antennas/rotator, but I - and others - do this without the benefit of computer
control.  It may be "old school", but with practice it is possible.  If you are
looking to work these birds from a portable station, that is entirely possible.
I do that all the time - at hamfests, parks, from the back of my truck, with
my gear laid out on the roof or trunk of a rental car, wherever I happen to
be.  All of my satellite station, excluding antennas and items deemed unsafe
in a carry-on bag for air travel, fit in an old laptop bag.  The antenna and
other stuff go in a duffel bag that gets checked for air travel.  You don't get
the numbers of QSOs on an SSB bird that you might on AO-51, but I have
fun with it.

73!






Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/