Dipole fed with coax?

--

... Hank

Hank: http://horedson.home.att.net
W0RLI: http://w0rli.home.att.net

"Ken Bessler" wrote in message
...
I've got a 60 hz buzz on my HF reciever. Here are the station details:

HF rig Yaesu FT-817
Tuner LDG Z11
P.S. Pyramid PS-25
Swr meter MFJ-860
Antenna 153'2" dipole, wrapped around
my 3 story brick apartment bldg.

Note - I have a VERY good station RF ground (as tested).

At first I thought the hash was coming from the power supply in
my PC but I discovered if I turn off my monitor (a ViewSonic
"perfect flat" A72f CRT) the noise goes away. The monitor is
about 18" from the 817....

I've tried to run on internal batteries, I've disconnected the
audio, key, speaker & cat cables from the 817 - no luck.

Now I do get rfi from the PC at lower freqs (below 7mhz)
and the only way I've found to kill that is to turn off the PC.

This problem is seperate, though - it's on 14.070.15 and
other freqs not as rf hash but a distinct 60 hz buzz that goes
away when I shut the monitor off.

Do I need to get a LCD flat panel monitor?

72's de Ken KG0WX

"Hank Oredson" wrote in message
...
Dipole fed with coax?

--

... Hank

Yep (11' of rg8x), with a 6 turn, 2-5/8" dia rg8 mini coax choke at the
feedpoint. BTW I just moved here (Denver) from Wichita, KS where
I had a GAP Titan DX installed - had the same problem there, too.

Ken

"Hank Oredson" wrote in message
...
Dipole fed with coax?

--

... Hank

Yep (11' of rg8x), with a 6 turn, 2-5/8" dia rg8 mini coax choke at the
feedpoint. BTW I just moved here (Denver) from Wichita, KS where
I had a GAP Titan DX installed - had the same problem there, too.

Ken

On Sun, 24 Aug 2003 10:17:16 -0600, Ken Bessler wrote:

Dipole fed with coax?

Yep (11' of rg8x), with a 6 turn, 2-5/8" dia rg8 mini coax choke at the
feedpoint. BTW I just moved here (Denver) from Wichita, KS where
I had a GAP Titan DX installed - had the same problem there, too.

Get a pair of clamp-on toroidial chokes and put them around the
monitor lead, one at the computer and one at the monitor. For one
Viewsonic monitor I had several years ago, it was required to meet
FCC data equipment noise leakage standards.

The 60 Hz modulation is probably the vertical scan (refresh) rate of
the monitor.

--
73 de K2ASP - Phil Kane

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon

On Sun, 24 Aug 2003 10:17:16 -0600, Ken Bessler wrote:

Dipole fed with coax?

Yep (11' of rg8x), with a 6 turn, 2-5/8" dia rg8 mini coax choke at the
feedpoint. BTW I just moved here (Denver) from Wichita, KS where
I had a GAP Titan DX installed - had the same problem there, too.

Get a pair of clamp-on toroidial chokes and put them around the
monitor lead, one at the computer and one at the monitor. For one
Viewsonic monitor I had several years ago, it was required to meet
FCC data equipment noise leakage standards.

The 60 Hz modulation is probably the vertical scan (refresh) rate of
the monitor.

--
73 de K2ASP - Phil Kane

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon

"Phil Kane" wrote in message
et...
On Sun, 24 Aug 2003 10:17:16 -0600, Ken Bessler wrote:

Dipole fed with coax?

Yep (11' of rg8x), with a 6 turn, 2-5/8" dia rg8 mini coax choke at the
feedpoint. BTW I just moved here (Denver) from Wichita, KS where
I had a GAP Titan DX installed - had the same problem there, too.

Get a pair of clamp-on toroidial chokes and put them around the
monitor lead, one at the computer and one at the monitor. For one
Viewsonic monitor I had several years ago, it was required to meet
FCC data equipment noise leakage standards.

The 60 Hz modulation is probably the vertical scan (refresh) rate of
the monitor.

--
73 de K2ASP - Phil Kane

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon


You may need to do power cable as well, possibly serial and
parallel port cables and sound card cables depending on how
lucky you get. Six computers running here and it took a good
bit of playing with chokes to get things quieted down.

--

... Hank

From a hill south of that Clearing in the Silicon Forest :-)

Hank: http://horedson.home.att.net
W0RLI: http://w0rli.home.att.net

"Phil Kane" wrote in message
et...
On Sun, 24 Aug 2003 10:17:16 -0600, Ken Bessler wrote:

Dipole fed with coax?

Yep (11' of rg8x), with a 6 turn, 2-5/8" dia rg8 mini coax choke at the
feedpoint. BTW I just moved here (Denver) from Wichita, KS where
I had a GAP Titan DX installed - had the same problem there, too.

Get a pair of clamp-on toroidial chokes and put them around the
monitor lead, one at the computer and one at the monitor. For one
Viewsonic monitor I had several years ago, it was required to meet
FCC data equipment noise leakage standards.

The 60 Hz modulation is probably the vertical scan (refresh) rate of
the monitor.

--
73 de K2ASP - Phil Kane

From a Clearing in the Silicon Forest
Beaverton (Washington County) Oregon


You may need to do power cable as well, possibly serial and
parallel port cables and sound card cables depending on how
lucky you get. Six computers running here and it took a good
bit of playing with chokes to get things quieted down.

--

... Hank

From a hill south of that Clearing in the Silicon Forest :-)

Hank: http://horedson.home.att.net
W0RLI: http://w0rli.home.att.net

On Sun, 24 Aug 2003 08:52:03 -0600, "Ken Bessler"
wrote:

I've got a 60 hz buzz on my HF reciever. Here are the station details:

HF rig Yaesu FT-817
Tuner LDG Z11
P.S. Pyramid PS-25
Swr meter MFJ-860
Antenna 153'2" dipole, wrapped around
my 3 story brick apartment bldg.

Note - I have a VERY good station RF ground (as tested).

At first I thought the hash was coming from the power supply in
my PC but I discovered if I turn off my monitor (a ViewSonic
"perfect flat" A72f CRT) the noise goes away. The monitor is
about 18" from the 817....

I've tried to run on internal batteries, I've disconnected the
audio, key, speaker & cat cables from the 817 - no luck.

Now I do get rfi from the PC at lower freqs (below 7mhz)
and the only way I've found to kill that is to turn off the PC.

This problem is seperate, though - it's on 14.070.15 and
other freqs not as rf hash but a distinct 60 hz buzz that goes
away when I shut the monitor off.


I have seen RFI from various combinations of Monitors and Video cards.
If you can turn off the monitor and the interference immediately stops,
it's probably the monitor.

Do I need to get a LCD flat panel monitor?

I'm currently using a 17" LCD flat panel and have never been able to trace
any RFI directly to that monitor (which sits 2' from the Icom-746)

On Sun, 24 Aug 2003 08:52:03 -0600, "Ken Bessler"
wrote:

I've got a 60 hz buzz on my HF reciever. Here are the station details:

HF rig Yaesu FT-817
Tuner LDG Z11
P.S. Pyramid PS-25
Swr meter MFJ-860
Antenna 153'2" dipole, wrapped around
my 3 story brick apartment bldg.

Note - I have a VERY good station RF ground (as tested).

At first I thought the hash was coming from the power supply in
my PC but I discovered if I turn off my monitor (a ViewSonic
"perfect flat" A72f CRT) the noise goes away. The monitor is
about 18" from the 817....

I've tried to run on internal batteries, I've disconnected the
audio, key, speaker & cat cables from the 817 - no luck.

Now I do get rfi from the PC at lower freqs (below 7mhz)
and the only way I've found to kill that is to turn off the PC.

This problem is seperate, though - it's on 14.070.15 and
other freqs not as rf hash but a distinct 60 hz buzz that goes
away when I shut the monitor off.


I have seen RFI from various combinations of Monitors and Video cards.
If you can turn off the monitor and the interference immediately stops,
it's probably the monitor.

Do I need to get a LCD flat panel monitor?

I'm currently using a 17" LCD flat panel and have never been able to trace
any RFI directly to that monitor (which sits 2' from the Icom-746)

On Sun, 24 Aug 2003 10:17:16 -0600, "Ken Bessler"
wrote:


"Hank Oredson" wrote in message
...
Dipole fed with coax?

--

... Hank

Yep (11' of rg8x), with a 6 turn, 2-5/8" dia rg8 mini coax choke at the
feedpoint. BTW I just moved here (Denver) from Wichita, KS where
I had a GAP Titan DX installed - had the same problem there, too.

Ken

Ken,
I have the same problem with a Sony 200ES, interferes the most with 6
meters, a little on 2 meters and moderate on HF. Have put on
additional ferrite to no avail, like yourself everything is properly
grounded. Even went so far as to put the radio stuff and the computer
goodies on different lines - but ultimately they feed from the same
mains. Went portable with a small antenna and found that the
interference was a problem for nearly a 30 foot radius. I gave up on
fixing it and do my logging on a Palm Pilot and have the pc set to let
the monitor "go to sleep" after 5 minutes of no pc use. Sometimes
there is little you can do aside from finding a 'quieter' monitor or
not running both devices at the same time.

Hope your situation works out better than mine.

73,
Howard