A dish like in the picture probably has a beam-width of 15-ish degrees.
I used a 30 inch BBQ grill antenna for AO-40, and would notice a
drop-off when mis-aimed by about that much. ISS moves VERY quickly
compared to AO-40, so some sort of active positioning on both axis is
going to be required.
I need to get that dish back up on the rotisserie...
Greg KO6TH
Roger wrote:
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...
Roger
WA1KAT
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 5.
73 Trevor M5AKA
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