[amsat-bb] What preamp to use for SO-50 and Arrow II antenna?

John Brier johnbrier at gmail.com
Fri May 1 04:09:17 UTC 2015

Thanks, I found that at their website:


I'm going to use two radios so that won't be an issue.

Man, so they do require power, or at least this one does.

I'm already starting to get tired of trying to track the satellites
with the Arrow II. Adding a preamp with a battery pack and a second
radio (I've mostly just been listening to the ISS lately) is going to
get even more cumbersome, plus you have to operate two radios while
compensating for doppler, right? How do you operate portably with your
FT-817s? Do you attach one to each hip?! I'm starting to think about
circularly polarized antennas I can just set and forget, but with a
low power satellite like SO-50 that might not work so well. Hmm.

On Fri, May 1, 2015 at 12:00 AM, Paul Stoetzer <n8hm at arrl.net> wrote:
> I use a High Sierra Microwave LNAA432 preamp powered by a 11.1v LiPo
> battery pack (AAs or AAAs work fine too). I can work SO-50 down to the
> horizon with the Arrow Antenna if I have a clear shot. I lost at about
> a degree on the pass earlier. It's usually S1-2 below a couple of
> degrees, S7 above 10 degrees, and my FT-817 shows S+ above 30 degrees
> or so.
> You have to be careful not to transmit into a receive only preamp like
> this. I use two FT-817s, one for receive and one for transmit, so this
> is not a problem for me, but if you use a single radio, you would need
> to be sure that the preamp is between the 70cm antenna connection and
> the diplexer so you don't fry it.
> 73,
> Paul, N8HM
> On Thu, Apr 30, 2015 at 11:49 PM, John Brier <johnbrier at gmail.com> wrote:
>> Since a lot of people are talking about SO-50 right now, let me ask a question:
>> I did try to work SO-50 once when all I had ever worked before was
>> SO-35, UO-14 and AO-27 and I was horrified by how hard it was to hear
>> and track.
>> I found a thread on qrz.com where they said it's very helpful to use a
>> preamp for SO-50 since it's so low power, even with the short runs of
>> coax required for an Arrow II satellite antenna. I know almost nothing
>> about preamps. What's the deal? Do they need power to work
>> (active/passive?). What do you recommend?
>> John Brier, KG4AKV, Raleigh, NC, FM05
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