[amsat-bb] Advice for a portable ground station

tom.wz9u at gmail.com tom.wz9u at gmail.com
Fri Jan 16 07:06:29 UTC 2015


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.


Can anyone clarify my understanding here?


Tom WZ9U




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