[amsat-bb] Re: Suggestions for Mode L antenna

i8cvs domenico.i8cvs at tin.it
Mon May 12 01:34:03 PDT 2008


Hi Greg, KO6TH

Your helix for 23 cm seems to be 16 turns RHCP and the gain should be
in the order of 16 dBic minimum with half-power beamwidth less then 30°
depending on the pitch angle.

The beamwidth is narrow and without  a full az/el rotor system you cannot
use it for satellite.

I have a similar 15 turns helix RHCP for 70 cm on a full az/el rotor
system as well

In a separate email I have sent to you a picture of the above antenna mainly
used for AO40

Congrats for your experimental activity.

73" de

i8CVS Domenico

----- Original Message -----
From: "Greg D." <ko6th_greg at hotmail.com>
To: <amsat-bb at amsat.org>
Sent: Monday, May 12, 2008 9:25 AM
Subject: [amsat-bb] Re: Suggestions for Mode L antenna


>
> Hi Ron,
>
> I've done ok on AO-51 with a homemade helix.  See
http://home.wavecable.com/~ko6th at the bottom of the page.  I also have
watts in the shack, but a full az/el rotor system.  I don't know how sharp
the pattern is for the helix, so I don't know how effective a fixed
elevation system will be.  But from the reports I've received, the 10 watts
and my 60' of hardline with about 7 feet of RG-214 at each end seems to be
quite adequate.
>
> Good luck,
>
> Greg  KO6TH
>
> ----------------------------------------
> > Date: Sun, 11 May 2008 20:49:23 -0500
> > From: rnutter at networkref.com
> > To: amsat-bb at amsat.org
> > Subject: [amsat-bb]  Suggestions for Mode L antenna
> >
> > I am considering purchasing the 1.2 ghz module for my IC-910H.  For my
> > satellite work, I have my antennas angled at about 20 degrees since I
> > dont have an az/el rotor.  This setup worked reasonably well with Mode S
> > this weekend.  What are my chances to be able to work Mode L with this
> > kind of setup ?  Also, I would appreciate any suggestions for an antenna
> > that I could use.  With only 10 watts, I am not expecting a great signal
> > but I would hope to have at least a readable signal.  Also, would
> > appreciate any suggestions as to coax/feedline that I should look at
> > buying ?
> >
> > Thanks,
> >
> > Ron
> > KA4KYI
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