Have you tried a quarter wave counterpoise or an "artificial ground"? I had RF
into the mic jack, and a quarter wave counterpoise for each band fixed it.
Later, I put in an artificial ground (the shack was on the second floor of the
house), which required retuning for each band, but I had no RF problems after
that. All the rigs (TS-440, TS-480. Omni V) had the same problem, and both of
the fixes worked on all the rigs.
73,
Frank
KF6E
----- Original Message -----
From: Carter
Sent: 05/14/14 04:35 PM
To: tentec@contesting.com
Subject: Re: [TenTec] Eagle problem?
On 5/8/2014 6:51 PM, Stuart Rohre wrote: An interesting thought, but can we
always blame the "antenna being too close to the shack"? I bought my Omni VI
new in 1994 and have never been able to operate SSB or PSK31, SSTV or any other
mode that required the use of the mic jack. (Good thing I am 99% a CW and RTTY
guy. <grin> ) Anything over about 10 (ten) watts of power seems to cause the
problem, utter and complete distortion of the radiated signal. The shack is in
the basement, the antenna is a 132' long dipole about 25 feet high and fed with
ladder (window) line to a Johnson KW Matchbox tuner. The length of the window
line between the Matchbox and the hole in the wall where it exits the basement
is no more than five feet. Yes, when I measure the RF current in each leg of
the window line they are different -- to be expected as this is not a perfect
world and the dipole is not in free space. The coax cable to the Centurion /
Omni VI has a multiple ferrite bead balun. After year
s of unsuccessfully chasing around with ferrite beads and chokes, I was
finally told [by ******] that my dipole was "too close to the house".
Unfortunately, because of the shape of the lot, the location of trees and
zoning/deed restrictions, the antenna HAS to be where it is. So...problem
occurs at around 10 watts of output, the antenna can't be moved and I don't
think I am the only ham in the world using a dipole close to the house fed with
window line. This leads me to do the unthinkable and to ask about the elephant
in the room. Rather than everyone saying the antenna "is too close to the
house", is it possible that this particular vintage of Omni VI option 3 is just
particularly sensitive to RF getting into the mic jack (or other ports)??? Is
this unique to my radio? Do Yaecomwoods suffer from the same issue? The reason
I ask is that I am getting into PSK31, JT9 and JT65-HF (and yes, I realize
these are "low power" modes), but I wouldn't mind going up to 20 or 25 watts -
- or SSTV at (gasp!)100 watts. I would appreciate any thoughts or suggestions.
New /different radio or fixing this radio (how?) is OK, but a 100' tower 300'
away is just not an option. 73, Carter K8VT
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