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Re: Preamps

on 12/10/00 11:08 AM, G Payton at n5gpc@earthlink.net wrote:

> Excuse me if this is not the proper place to pose questions regarding a
> new-comer to satellites establishing his station.

Right place.  Right time.

> As I see it, regardless of what I choose to work (Analog, digital or
> others), I will need good preamps.  I am considering the ARR SP144VDG &
> SP432VDG models.  My question is about "pole mounting" at the antennas.
> These do not appear to be constructed for such.  Are there other models
> from ARR (or other brands) for outside pole mounting?

The ARR models are really nice, but they are pricey.  Probably the best.  If
you have some skill, you can home brew your own from kits by Down East
Microwave.  The switchable preamps are nice, but you have to limit your
power.  You can pretty easily home brew your own switching circuitry and use
non-switched preamps.  If you are interested, e-mail me privately and I'll
tell you how I did mine.

Pole mounting is best.  We had a "noise figure" discussion here a couple of
weeks ago and while you can get away with a shack mounted 2m preamp, you
really need it at the mast for UHF.  No, the units as the come are not
weather tight.  You can easily find weatherproof boxes at hamfests, etc.  Or
go to your local Home Depot and get an outdoor electrical enclosure.  Any
box with a rubber seal around it will work.  I think MFJ/Mirage makes some
outdoor rated pole mountable units, but the ARR or DEM preamps are much
better quality.

> Truthfully, I am really starting from the ground floor on this and doing
> a lot of reading.  I still have to make the decision of what mode of
> satellites to start with.  It probably will be the analog sats till I
> get the hang of it and progress from there.  Again, I'll have to decide
> upon antennas too.  Are the Omni's that effectual?

Don't use the omnis unless you want a lot of frustration.  If you plan on
working AO-40 or any other satellite seriously, go for some good CP beams.
They aren't cheap, but you'll be happier in the long run.  Your antennas are
a KEY part to your system.  Analog sats would be the best way to start for
you.  I'd not get on the FM sats until you have the hang of it (contrary to
popular thought today, but it's best to start out on the linear birds). It's
easier because you can sit there and learn how to do doppler shifting,
finding your downlink, etc. without tying up the bird like you would with
one of the FM birds.  It's just easier even though you need more
sophisticated radios.

I hope this has helped.




Jon Ogden
NA9D (ex: KE9NA)



My President is George W. Bush -> The legal winner in Florida

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