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Re: New baseline for GEO (rev-1)



Hi All,

In Bob's earlier email, he set the goal of being able to work through a
Mode-B U/V linear transponder for SSB cw and PSK31, using a portable arrow
antenna.

A quick search on the 'net only turned up gain measurements for a "5 element
modified Arrow" on 144MHz, and a "10 element modified arrow" on 432MHz
(7.2dBd and 10.9dBd respectively).
(From http://members.cox.net/csvhfs/2002/antenna_results.htm )

Are these figures typical?

If not, can anyone tell me what an Arrow Antenna has in terms of gain on 2m
and 70cm?

Also, I am assuming that these small-ish antennas have significant
sidelobes.  I am therefore planning to run some calculations using a Tsky of
290K for 70cm, as it seems reasonable that the small 70cm antenna will be
listening to the warm earth, even when pointed at cold sky (eg approaching
5K at elevation angles above 30 degrees).

I will also be using a best-case Tsky of 290K for 2m, and a worst-case Tsky
of 2000K.


Comments anyone?


73 Chris
vk6kch


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