View Single Post
  #6   Report Post  
Old October 3rd 06, 10:00 PM posted to rec.radio.amateur.antenna
KØHB KØHB is offline
external usenet poster
 
First recorded activity by RadioBanter: Sep 2006
Posts: 125
Default GAP resonance shift


"KØHB" wrote in message
ink.net...
I have a GAP Voyageur-DX vertical (160, 80, 40, 20M) which has recently shifted
its' resonance points.

160 now resonant at 1990kHz, previously at 1825
80 now resonant at 3980, previously at 3725
40 not resonant in band, previously at 7100
20 now resonant at 13775, previously at 14150

The antenna is physically solid, all wires are OK and properly attached, the
three counterpoise wires are intact and connected. I have changed out the
capacitor buried at the top with no change in symptoms.

Any suggestions?


Turned out that under power the center conductor of the matching network
embedded in the top main section of the antenna migrated through the dilectric
and shorted to the sleeve, thus making the lower and mid matching rods "hot",
and effectively changing the antenna from a vertical loaded dipole to a random
length vertical ground plane.

73, de Hans, K0HB