I am not a fan of using RG-58 for satellite portable. I've worked with too many people trying to use 5-10' runs of RG-58 only to see them become very frustrated at their inability to work SO-50. Keep your feedline as short as possible if you are using RG-58. Remember, not all RG-58 is created equal.
My preferred feedline is LMR-240uf (UltraFlex) for portable use. It's a little more expensive but I can easily get away with a 10' length between the Arrow and my transceiver. Use quality connectors installed on quality feedline. Try to avoid gender-changing adapters if possible.
A lot of published material on the Internet and in print specifically talks about FM satellites like AO-27 and AO-51. They had great downlink signals compared to SO-50. With SO-50 being our only FM bird, we need to set realistic expectations that extended whips and RG-58 coax are not going to perform as well as they did on the former FM satellites.
Fox-1 series satellites, on the other hand, should be a game-changer and open the door again for more modest portable stations.
73 Clayton W5PFG
On Fri, Jan 16, 2015 at 1:06 AM, tom.wz9u@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.
Can anyone clarify my understanding here?
Tom WZ9U
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