[Towertalk] Antenna Problem

[W4ZW]

My SS performance was marred by a strange anomaly that I have never
experienced before.

On 40M, which is usually my best band here on the ocean, I started
having intermittent spells of signal masking.  All signals would
suddenly drop about 3-4  S units with a slight noise mask and then
reappear normally after an interval of 45 seconds to several minutes.  I
decided the FT1000MP was the culprit, so took it out of the line and
replaced it with the FT-1000D.  Problem persisted.  Took the ATR-30
antenna tuner out of the line thinking perhaps the antenna switch was
the problem (Use the tuner to reach the SSB part of 40M).   Still
persisted.  Then I noticed that the SWR on the 402CD was fluctuating
from 1:1 up to 3:1 that appeared totally random.  No wind, so the 402CD
was perfectly still.  I Run the radios barefoot on 40 and 80.  Too much
RF in the media room next to the shack to run HP, not to mention setting
my alarm system off every few minutes.

Background.  I recently rebuilt the 402CD after a tropical storm took it
down last fall.  Mostly new aluminum, applied the Leesom upgrades, and
installed new coax (9913) feed line.  I suspect a corroded feed point
connection even though I just put the antenna up several months ago with
liberal applications of coax seal, etc.  I did put in a few
strategically placed aluminum rivets in the elements, and four SS screws
in the tips.  (High winds here sometimes blow the tips out of the
elements.)

Any suggestions or ideas before I tackle rebuilding the feed point on
the 402CD which is way out there.  I did put it up with an extra TH-7DXX
mast to boom clamp which will let me tilt the boom down so I can reach
it.



Jon Hamlet,  W4ZW
Casey Key Island, FL

"A little bit of Paradise in the Gulf of Mexico"