[amsat-bb] Re Mode L/S

Clare Fowler lcfowler at magma.ca
Wed Sep 12 07:52:11 PDT 2007

I had two QSO's on AO-51 mode L/S this morning on
the 1310 UTC pass. I normally use a 1.2 meter dish
for the mode S downlink antenna with a DEM

On this pass I tested a 52 turn helix with an AIDC-3731
Receiver performance was very good with consistent
S7 to S9 signal strength and full quieting of the FT-736R 
for all of the pass except at low elevations at AOS and LOS.

This performance tends to confirm my direct comparison measurements and dissagrees with statements made in
ARRL publications and expressed elswhere that the gain
of helix antennas flattens out above about 20 turns. 


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