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Helix Feed for a Dish



Just a sanity check for a new-bie building the AO-40 receive portion
of his station:

I'm looking for RHCP, so for a dish feed I need to wind LHCP (because
of  the reflection)?

I have a DSS dish that I hope to use a G3RUH design helix (about 4
turns?), and a Hammond aluminum box as the cup reflector.

For mounting, I'm thinking of cutting the DSS feed horn just below the
flared end, removing the plastic shell (leaving a metal tube), and
mounting the helix base with a tube over the remaining tube of the DSS
horn. I have the W1GHZ dimensions to located the focus. I've read that
one or two turns up from the base of the helix seems to be the sweet
spot.

Thanks to all on the list... some I have contacted directly. I have a
folder 1.5" thick with info on pre-amps, down converters, helix,
dishes, and operating norms pulled from this list just from when the
AO-40 transponder was first turned on. Quite the education.

Bill
W1PA



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