Sunday, February 6, 2011

Update on the Bazooka Antennas

The 75m bazooka got its first ice load test recently.  We had a winter storm that accumulated approximately 1/2" of ice on the antenna.  I had no failures of the antenna.  I did have to lower it, that's when I took the photos, and shake the ice off to get the SWR down.  I had not expected the icing to effect the antenna as bad as it did.  The ice raised the SWR to 2:1 and up across the bandwidth of the antenna that was resonant before.  After I removed the ice and raised the antenna back to it's proper place, it was back to business as usual on 75m.

The prototype I had up as NVIS on 40m has a problem.  I think the strain from the ice has caused one of the shorting points, or the feed point to pull apart.  The SWR is so high the antenna is unusable.  The 40m antenna had not been epoxy sealed so it is likely the feed point.