[amsat-bb] circular polarized Arrow antenna

[Estes Wayne-W10191 <W10191@xxxxxxxxxxxx>]

Today I ordered a split-boom Arrow antenna to use for demos at hamfests, and also hopefully for portable AO40 operation.

I entered the numbers for the Arrow antenna into the Gene Marcus AO40 link calculator and wasn't thrilled with the uplink I would get with 50W, 1 dB cable loss, and (optimistically) 11 dB gain with linear polarization.  But the uplink would be more respectable if I convert the antenna to circular polarization.

So now I'm thinking about making a circular-polarized 70cm Arrow antenna.  For operation on AO40 only, I could remove the 2m elements and install another set of 70cm elements on that plane.  The handle must be extended slightly to offset the second set of elements by ¼ wavelength.  Construction of the power splitter and matching cables shouldn't be very difficult.

The objective is to have a circular-polarized AO40 uplink antenna that can be easily disassembled to fit in a suitcase.  Is there an easier way to get a "traveler's" CP antenna than converting 2 Arrow antennas into a single CP 70cm antenna?  Is it worth the trouble to make a CP antenna, compared to just making do with a linear-polarized uplink?  Of course I should TRY the linear Arrow antenna on the AO40 uplink to see how good or bad it is.

Wayne Estes W9AE
Mundelein, IL, USA
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