Field Day, June 28, 2003 - Testing the newly lined dish...

 

 

 

 Due to family schedules, only the Saturday pass of AO-40 was an option. I started setting up around 9AM (PST), and used the original dipole feed to find the beacon. I had a hard time, until I used a protractor to look at the elevation angle, instead of eyeballing it. I realized I was about 15 degrees low! Once that was fixed, I found the middle beacon quickly.

Then I put in place the cupped helix feed, with the down converter direct-attached. I used a 3/4" pvc pipe to attached to the cup, and a hose clamp to lock it to the grid dish. The above picture show some of the details. You can also see some extra mesh that is folded around the back; this is to use if/when I plan on making the dish round instead of the current rectangle.

Right of the bat, it was obvious that the circular feed was substantially better. I had a better signal, and substantially less fading. I played around with finding the sweet spot (aka focal point), and found that placing the cup bottom (i.e. the back side) about 1.5 inches behind the focal point of the dish gave me the best reception.

By this time, field day had started, and I mounted my uplink yagi. I tried a bit, but only once, very faintly, heard my own downlink. I suspect that
a-I got lucky last time,
b-all the field day activity raised the agc on the receiver, and
c-my uplink needs improvement (both tx power and circular antenna)

I did hear numerous qso's once the contest had started. It seemed appropriate that K5OE was the first person I heard...