[amsat-bb] Re: Practical L Band Antenna?

Clare Fowler lcfowler at magma.ca
Fri Nov 17 19:38:27 PST 2006

In my experience polarity switching is certainly a benifit
on V and U.  
On L and S I have had only RH circular and certainly on
AO-40 where I had hundreds of QSO,s with L up and S
down I never had any indication of requiring polarity reversal.

On AO-51 there certainly are fades and perhaps some polarity 
reversal is occuring. However with RH   L and S antennas
I can usually work from AOS to LOS.

For AO-51 a single 27 turn helix driven with 10 watts from
your Icom 910 should work OK provided you dont lose
more than a couple of watts in your feed line. 

For high orbiters you will almost certainly need more 
ERP such as I have with a 4 x 27 turn helix array, which
I am afraid would not fit on your 6 foot boom, but you
could get an amplier.

Construction details for L band helix ants is in the
March/April 2004 AMSAT Journal.

Clare VE3NPC

----- Original Message ----- 
From: "Mark Brueggemann K5LXP" <brueggemail-k5lxp at yahoo.com>
To: <AMSAT-BB at amsat.org>
Sent: Thursday, November 16, 2006 4:00 PM
Subject: [amsat-bb] Practical L Band Antenna?

> I am (and have been for a while now) in the throes of getting a
> satellite station set up.  I currently have V and U circularly
> polarized yagis, and recently acquired a K5GNA barbecue dish and
> converter.  What would be a practical antenna for 1.2GHz?  A helix is
> the first thing that comes to mind, but is the ability to switch
> polarization important?  I was told this was worthwhile for V/U, so I
> went through the extra trouble and expense to add that feature to those
> antennas.  How important is polarity switching for L and S band?
> I am limited to what will fit on a 6' horizontal fiberglass mast of a
> 5400 AZ/EL rotor, so I am interested in finding out what would be a
> modest performance antenna for 1.2GHz for A0-51, and potentially future
> birds.  Rig is an Icom 910.  Thanks.
> Mark K5LXP
> Albuquerque, NM

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