[amsat-bb] Preamp source

[John Kludt]

Nick,

I also have several of their (ARR) preamps, some with the choke for
power-over-coax and some without the choke for power via an independent
line.  I have been following this thread and it is a little confusing at
times as EME requirements get lumped in with the satellite requirements.  I
do both Sats and EME and I see them as very different animals.  With EME
you are running many hundreds of watts probably a KW or more.  Many EME
stations used separate feeds for Tx and Rx.  The path loss is on the order
of 252 dB which means noise figure is really important.  The
required relays in an EME preamp system can cost more than the preamp
itself.  The switching requirements are pretty steep and everyone uses a
sequencer.  The noise figure of the preamp is everything

For satellite work 20 watts is QRO.  Most of us have gotten used to RF
switched preamps and that means no sequencer.  In satellite work there is
most often a single feedline for Tx and Rx.  Noise figure while still
important is not as  strigent as with EME.  The one thing a
satellite preamp has in common with an EME preamp is the need to be mounted
as close to the antenna as possible to be maximally effective.

The challenge I see with many of the cheaper preamps is all you are getting
is the preamp.  Chances are you need to figure out how to box it up in a
weather proof enclosure.  With a single feedline you will probably need at
least two relays to switch it in and out of line.  Either you are going to
need to build your own RF sensing circuit or most probably invest in a
sequencer.

My point is when shopping around just make sure you are comparing apples to
apples  A bare bones preamp with no switching circuit may look cheaper
until you look at everything else you are going to need to put it into
service.

73,

John

On Thu, Nov 7, 2019 at 6:24 PM Nicholas Mahr KE8AKW via AMSAT-BB <
amsat-bb at amsat.org> wrote:

> Thats interesting if thats the case that they arent making preamps anymore.
> I ordered two of their Mast mounted 160W preamps 5 months ago. It took a
> month to get them. They told me when I ordered that it would be a good
> while before I got them because they did not have the parts in stock for
> them to make them due to their supplier "being back logged". I have them
> and are very happy with them they work very well but they are not cheap
> like all other pre amps out there. Maybe someone out their can confirm for
> sure they dont make them anymore?
>
> - Nick KE8AKW
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
>