[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: An V/U antenna for LEOs? Collinear's are not really Omni Directional



You're exactly right, Chris!

There's no such thing as a free lunch, right?  A collinear gets its gain, by
giving gain at the horizon, so, as you said, it actually isn't a good
satellite antenna.  I had the experience once of hearing U0MIR get very loud
on 146.55 as he approached the horizon.  I called him, and he responded, but
missed the last letter of my call--and of course he was gone below the
horizon before I could get him to correct my call in the log. -s-

Getting back to "beltclip stations," to use a term I just saw here, I agreed
with Bob's observation in this thread that whips don't function well once
satellites are at less than 20 degrees or so elevation.  I recall though,
that a Spanish (EA) station posted to this list that he's made some
successful low angle contacts to North America, including Mike when he was
FP/.  So, I guess from an extremely good location, it can work.

73,
Frank

----- Original Message -----
From: Christopher Cox <cobox@urec.net>
To: Frank Grossman <fgrossma@idt.net>; Bob Bruninga
<bruninga@nadn.navy.mil>; Miguel A. Vallejo <ea4eoz@jazzfree.com>
Cc: <amsat-bb@AMSAT.Org>; <shr@dei.inf.uc3m.es>
Sent: Sunday, October 15, 2000 9:03 PM
Subject: [amsat-bb] An V/U antenna for LEOs? Collinear's are not really Omni
Directional


> Hi Frank,
>
> I would think that a Collinear would make a fairly poor antenna for
> satellite work.
>
> You see a Collinear is NOT Omni  Directional. True in a terrestrial sense
> it is, but its "gain" comes from redirecting radiation that would be
headed
> skyward towards the ground. Indeed, unless it is a steerable antenna, the
> term "gain"  in an Omni generally means "not for satellite use".
>
> What kind of coax are you using and how long?
>
>
> Regards
>
> Christopher Cox
> KC8FRJ
>
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>

----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home