[amsat-bb] Advice for a portable ground station

B J va6bmj at gmail.com
Fri Jan 16 12:13:18 UTC 2015


On 1/16/15, tom.wz9u at gmail.com <tom.wz9u at gmail.com> wrote:
> The lack of a fully searchable archive for this list has made this post
> necessary, my apologies for a noob-style query.
>
>
> I’m gradually assembling a portable ground station for the FM satellites,
> primarily using John Heath’s (G7HIA) article “Down-to-Earth Satellite
> Communications” (PDF), focusing on his “Awesome” configuration:
>
>
> Dual-band HT
>
>
> Diplexer
>
>
> 2m amplifier
>
>
> 70cm preamplifier
>
>
> Arrow II antenna
>
>
>
> In that article he uses RG58 coax, perhaps 15-20 feet max.  Is there a
> better choice that also works in that application?  Considering the lengths
> involved, price per foot is not really an issue.
>
>
> He also calls out an RF choke at the feed point of the 70cm antenna, but
> gives no detail about its material or construction.  It looks to me like a
> few turns of RG58 on some type of ferrite core.  I’ve spent hours Googling
> for information (commercial or DIY) and have come up mostly empty-handed.
> All the “meaty” stuff is for HF only.
>
>
> A final question concerns the various connectors involved.  The
> illustrations in that article aren’t the best, but it seems that he’s using
> BNC terminators on all the cables, and BNC-to-UHF adapters where required.
> I’m concerned (perhaps too much) about cumulative losses, both from the coax
> and all those adapters.
>
>
> My goal is a tripod-mounted antenna, operating on battery power from various
> parks and forest preserves nearby.

<snip>

I use an FT-817 and a hand-held Arrow dual-band yagi for the FM birds.
The only connectors I use are what came with the radio and the
antenna.

That combination allowed me to reach AO-27, SO-50, AO-51, SO-67, HO-68
and the ISS.  I made lots of good contacts with that, the furthest was
a station in Finland, around 6400 km from my QTH.

73s

Bernhard VA6BMJ @ DO33FL


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