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[TowerTalk] FW: R7000 VSWR Problems

To: <>
Subject: [TowerTalk] FW: R7000 VSWR Problems
From: (Charley Schwartz)
Date: Sun, 07 Jun 1998 13:54:55 -0400
Hello Tom:

I had a similar problem with an R-7000 .. I set up the antenna and it tuned 
just like the book said .. After
running about 200-300 watts on 20M RTTY the 20/30/40 meters were not tunable .. 
Cushcraft reps told me the
problem was installation .. This is installed on a mash fastened to a chimney 
and was 15+ feet above the roof
and chimney.

Cushcraft sent me a replacement trap .. I installed the new trap and it acted 
new. This worked fine until I
run about 300 watts on RTTY .. The problem returned .. I did not want to bother 
with the antenna any more
because I heard many others with the same problem .. I believe N1SIX at 
Cushcraft may be able to help ..

I have several R-7 antennas installed in three station locations. These have 
been run at 1 kW without problem.

GL Charley

Tim Billings wrote:

> -----Original Message-----
> From:   Tim Billings []
> Sent:   June 7, 1998 1:38 PM
> To:     ''
> Subject:        FW: R7000 VSWR Problems
> -----Original Message-----
> From:   Tim Billings []
> Sent:   June 3, 1998 8:24 PM
> To:     ''
> Subject:        R7000 VSWR Problems
> HI.....I am an owner of a R7000 Vertical and I have been having problems in 
> trying to
> lower the SWR on this antenna. The 10M, 15M and 17M band VSWR is fine...But I 
> have been unable to
> lower the VSWR on 20M and 40M.
> I have tried the following...
> * Tested antenna at both feedpoint and at transmitter with no noticeable 
> change in VSWR
> * Changed out coax feedline in an attempt to find problem in coax.
> * Tested VSWR with 3 meters (Autek, radio, tuner)
> * Relocated antenna
> * Varied height above ground.
> * Adjusted the lengths of the antenna sections in question.
> * Checked the VSWR readings with another  MN7000.... No change
> * Cleaned all contacts and joints
> All the above resulted in no changes in the high (6 to 9) VSWR.
> HOWEVER.... I did disassemble the top two traps and cleaned the contact 
> points. When I reassembled
> the traps and reinstalled the antenna with the dimensions as per the 
> manual... the VSWR was low...1.2 to 2
> on the two bands in power (80 to 100 watts) was applied the 
> VSWR climbed again to
> 6 to 9 on the 20M and 40M bands.
> I am looking for solutions to correct the problem....Can you help ???
> Thanks
> 73 de Tim VE9XA
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