Some recent queries to TowerTalk and the responses all pointed toward
bad coax/water in coax, or loose connections between balun and front
driven element and/or rear-driven element.
On 1/13/22, we tested the coax and even pulled up a brand new run to
test with. Swept both runs of coax from top of the tower with AA-54,
bottom end connected to a dummy load. Both runs of coax sweep
identically to the dummy load. Connect either run to the antenna,
experience the same symptoms of low SWR being low on all bands.
A call to M2 support; they suggested perhaps water in one or more of the
capacitors. We tilted the tower over to access the capacitors. Removed
all 16 end caps, finding no water. We did, however, find much insect
debris and dirt dauber nests. Cleaned all that out with compressed air
and a long rod to push through the 3/8" inner tube.
We also verified all the mechanical connections on the driven elements
and confirmed good continuity with an ohmmeter.
The SWR curves moved up in frequency, but the minimum point is still
well below the bottom of each band.
Other thoughts or ideas?
--Scott, W5WZ
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|