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

Fri May 1 14:14:17 UTC 2015

Hi Dominic

I can recommend that device in the preamp.
It's the same one that's used in the AMSAT-UK  FUNcube dongle preamp. - But very nice to have the TX/RX switching as well

Thanks for the link

David  G0MRF

-----Original Message-----
From: Dominic Hawken <dominic at del.co.uk>
To: AMSAT BB <amsat-bb at amsat.org>
Sent: Fri, 1 May 2015 12:23
Subject: Re: [amsat-bb] What preamp to use for SO-50 and Arrow II antenna?

The inaugural edition of Radcom Plus came out today, and the first article is on
building a 2m masthead preamp - the DG8. I don't think it's particularly
appropriate for handheld use, but looks interesting in that it uses (cheaper)
mains relays - whilst I've only had a brief scan the article looks really well
written and detailed. I've been looking for a cheaper masthead option for 2m to
build and so far the relays have always been the significant cost. Power to this
one is also over the coax, so it suits me well.

Radcom Plus is available
online for RSGB members -
http://rsgb.org/main/blog/front-page-news/2015/04/30/radcom-plus-vol-1-1/

No
- I don't work for the RSGB - just genuinely impressed!

Best,

Dominic
G6NQO

> On 1 May 2015, at 05:09, John Brier <johnbrier at gmail.com> wrote:
>

> Thanks, I found that at their website:
> 
>
http://www.hsmicrowave.com/Amateur%20LNA.html
> 
> 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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_______________________________________________
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:
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