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Re: Advice needed for newcomer to satelites

on 12/28/99 4:23 PM, Gary McKelvie at garym@garym.org.uk wrote:

> Hi to the List ,
> I'm in need is advice on antennas and which satellites to "aim" for and new
> to using satellites.
> I intent to work on 2m and 70cms,my thoughts so far (as to antennas have
> been along the lines of crossed yagi's for 2m and 70 cms properly an 8
> element for 2 and a 13 element for 70.
> The radio I intend to use is a Yaesu FT726R with the satellite board fitted
> and an output of 10 watts to the above antenna system.
> Which leads to my question is the proposed antenna/radio setup sufficient
> to work successfully any of the 2m/70cms satellites?
> Which now leads on to my next question as to which satellites should I be
> looking to work?TIA and Vy 73 Gary

Hi Gary.

I am new to satellites as well, so I thought that advice from another newbie
would offer a different perspective.  Frankly I am addicted to the birds!
Here is what I would offer:

1.) If you wish to work SSB birds here is the current offering:

RS-13  2 meter uplink, 10 meter downlink  Low Earth Orbit (LEO)

RS-15  2 meter uplink, 10 meter downlink LEO higher than RS-13 but not much
activity due to a weak downlink signal.

FO-20  2 meter uplink, 432 downlink  LEO

FO-29  2 meter uplink, 432 downlink LEO - SSB schedule rotates with a packet
BBS and a digitalker as well.

* For all of these birds, egg beater antennas or similar (omni directional,
circularly polarized) will probably be sufficient.  10 Watts is probably
enough power on a good pass.  You'd get better performance with yagis but
these things fly by pretty quickly (20 minute pass time or less) and you do
a lot of antenna turning.  I use Yagis for reasons explained below.  I've
worked the FO birds with as little as 2 watts.

AO-10  432 uplink, 2 M downlink - HEO - High Earth Orbit - Highly Elliptical

* AO-10 is a great bird when it's working.  It has a maximum orbital height
somewhere in the 16,000 mile range and provides lots of good coverage.  The
problem is the satellite works only when it's getting good sunlight.
However, this does not mean you need to have  sunlight where you are to work
the bird!  For this bird, you'll need good circularly polarized Yagis.  The
8 and 13 element units you mention may work but you'd get better luck with
bigger Yagis.  I run 40 elements on the uplink and 22 on the downlink.  Even
so I get generally S3 to S5 signals at the radio.

For AO-10 you may need more power than 10 watts.  It's a long ways away and
since the bird is sometimes unreliable more power helps.  Sometimes the
antennas are not in a good orientation other times they are.  Additionally,
getting antennas where you can switch the polarization between LHCP and RHCP
(left and right hand) is critical.  Last night on an AO-10 pass I had to
switch polarizations every few minutes to keep the signals into the bird
good.  As for power many guys run 50 to 100 Watts to get to AO-10.  I have
run as low as about 20 Watts but the bird has to be in a really good
orientation to get good signals.

I would also recommend getting good, mast mounted preamps.  I have these but
don't have them installed yet - not until spring unfortunately.  These will
help for all of the birds but particularly for AO-10.  If someone doesn't
have an antenna with switchable polarization and they are working on the
"wrong" polarization they will be extremely weak into the bird.  The preamp
will help and will also help to compensate for feedline loss.

Don't scrimp on feedline.  Run 9913 at a minimum and LMR-600 or Heliax if
you can afford it.

2.) FM Birds:

Currently there are a couple of FM voice birds up there - AO-27 is active on
daylight passes over the US.  You can work it with an HT and a small beam.
SO-35 has a rotating schedule and is sometimes available over the US.  I've
not worked anyone on SO-35, but AO-27 is a fun bird and with lots of people
on it.

3.) Digital Birds:

Not played with them yet.  Perhaps someone else will be able to help!

4.) Download the file "Working the Easy Sats" from the AMSAT webpage.  It is
a great primer for working the birds, particularly the LEOs.

5.) Read the satellite sections of the ARRL handbook.

6.) Join AMSAT.

So there you have it!  Your setup will work fine for the LEOs.  For AO-10,
you may be limited a little bit in both antenna gain and power output but
you would probably do OK when the bird is in a good orientation.  Phase 3D
is also going to be in the air soon (we all hope and pray) and your proposed
set up may or may not be enough.  Perhaps it will be since P3D is really a
well designed bird with much more power output available and much better
sensitivity than AO-10.

Regardless of what you decide, welcome to satellites!  I hope I was able to
help a bit.

In the month and a half I've been on the birds, I've probably made a couple
hundred QSOs, worked 9 or 10 countries.  It's a blast!  I've hardly touched
my HF rig!



Jon Ogden


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

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