[NLRS] 2.4GHz helix for AO-51 & Aurora

[Dan Larson]

Thanks for your reply Andy.

However, the Amsat web site describes AO-51 as having 
both RCHP  and LHCP helices for both UHF receivers. It
doesn't say much about the S-band receiver.

Do you have a link to more specific information on AO-51
for me?

If I build a helix, at least I won't have to deal with polarization
rotation throughout the pass, though at the expense of 3db
loss for the linear-circular mismatch.  The 12-turn helix should
give me about  16dBi gain, so it sound like there would be
plenty of gain left for the sat.

Dan KC0LUY


>I can address one of these questions:

>The satellite downlinks are RHCP by convention, so you need a RHCP 
>antenna.  If you are using a dish reflector, that means your feed needs 
>to be LHCP so that it is RHCP after the reflection.  AO-51's S-band 
>downlink is linear, so it really won't matter too much for that.  I use 
>a tin-can and some aluminum foil for an antenna.  It's linear, but it 
>gets the job done for ao-51.  My guess is that it is in the ballpart of 
>9dBi of gain or so with the CalAmp 130016 converters.  I use a vertical 
>and 50w for the 2m uplink, which leaves my hands free to point the 
>S-band antenna and correct for doppler.  It takes some practice, but 
>it's good fun!

>Here's a picture:

>http://www.frontiernet.net/~aflowers/ebay/pics/ao51-setup.JPG

>-Andy K0SM/2





>-- 
>No virus found in this outgoing message.
>Checked by AVG Free Edition.
>Version: 7.1.385 / Virus Database: 268.4.1/310 - Release Date: 4/12/2006

>_______________________________________________
>NLRS mailing list
>NLRS at mailman.qth.net
>http://mailman.qth.net/mailman/listinfo/nlrs