[amsat-bb] Re: ISS HamTV Frequencies
kc6uqh at cox.net
Sun May 12 21:43:36 PDT 2013
A SWAG, (Wild Guess) 1 degree per second at a Zenith of 90 degrees. Anything
less than 90 degrees will be slower with several minutes spent near the
horizon. You can use an orbital program to get exact numbers. With a wide
beam width antenna, the lag overhead may never require the antenna to move
with the object, as there will be time for the antenna system to catch up
after passing overhead.
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
Behalf Of Roger
Sent: Sunday, May 12, 2013 2:34 PM
To: amsat-bb at amsat.org
Subject: [amsat-bb] Re: ISS HamTV Frequencies
Anybody off the top of their heads know how many degrees a second swing
are (is?) required for direct aim at the ISS? I know there are beam
width tolerances, altitude variations and degree above horizon
variations but I'm looking at Bob B's fixed antenna aiming of 15-20
degrees above horizon to evaluate swinging a dish without torque eating
up the drive train...
On 5/12/2013 5:01 PM, M5AKA wrote:
> The AMSAT-UK page at http://amsat-uk.org/2013/05/12/hamtv-from-the-iss/
provides the links, they are:
> Facebook https://www.facebook.com/Hamtvproject
> More information at http://www.amsat.it/Amsat-Italia_HamTV_brochure.pdf
> and http://www.amsat.it/Amsat-Italia_HamTV.pdf
> The HamTV.pdf gives the link budget, looks like there's 7dB of
coax/connector losses to overcome between the ISS transmitter and the
antenna. That document indicates a 90cm dish should be sufficient.
> I believe that it's going up on ATV 4 which is currently slated for June
> 73 Trevor M5AKA
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