Hi Don, 

Your rational seems reasonable to me.  And you can always change the 70cm to RHCP if needed....tho the first time, while on the ground, is easiest ;)

I learned the power of polarity with AO-51.  Built an 8 turn G3RUH helix RHCP for 70 cm and wondered why it was so hard to hear the one transmitter.  I put up an M2 with LHCP and WOW what a difference.  Was fun being able to listen to both at the same time!

73,
Mark
N8MH 

On Wed, Apr 7, 2021 at 6:47 PM Don Solberg <dsolberg8132@gmail.com> wrote:
In the past I saw a lot of discussion on if it was better to use RHCP or LHCP, but today most of the LEO satellites use linear polarization.

I may be mistaken but the only LEO satellite that I know of that uses circular polarization is SO50, which uses LHCP for the 70 cm downlink.

I am in the process of replacing a dual band linear antenna with the M2 LEO pack.  I was thinking about setting the 70 cm antenna for LHCP and the 2M antenna for RHCP.  This would maximize the downlink from SO50 but also give me a lot of attenuation between 2M and 70 CM which would help with desense.

I have a desense problem with my current Cushcraft antenna, even with a diplexer as a desense filter.  For the LEO pack antennas I will not be using M2's aluminum boom, but instead have a 12 ft fiberglass boom.

Am I missing something or is this the "best" way to go? Most of my operation is thru the linear SSB band birds.

73,

Don K9AQ

-----------------------------------------------------------

Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available
to all interested persons worldwide without requiring membership. Opinions expressed
are solely those of the author, and do not reflect the official views of AMSAT-NA.
Acceptable Use and Privacy Policies available at https://www.amsat.org/about-amsat/

View archives of this mailing list at
https://mailman.amsat.org/hyperkitty/list/amsat-bb@amsat.org
To unsubscribe send an email to amsat-bb-leave(a)amsat.org
Manage all of your AMSAT-NA mailing list preferences at https://mailman.amsat.org
--

Mark L. Hammond [N8MH]