[TowerTalk] Need help with HF problems

[Magnus Aronsson]

Hi

I have some HF problems.

To try to make this short:

I have my shack in the basement of a 2-storey + basement house.
The antennas are mainly on top of the chimney but also 1 vertical in the 
garden.

The 5 coaxes and rotator control cable comes in on the side of the basement 
window.
Before I renovated the shack I used to have my desk and all the gear 
slightly away from the window, perhaps 2 meters.
Believe me or not but I could run a KW with my Ten-Tec Titan 425 and I had 
no problems with HF.

After I renovated the shack I put my desk right under the window and I have 
HF problems even running low power.
The problems I have:

- I hear myself in my headphones/headset down to about 40W of power (can 
differ, see below)
- My rotator control box is acting strange when turned on, the dial turns 
itself anti-clockwise.
  This problem can be taken down in wattage, it moves less at 50w and at 20w 
you can just see the dial triggering.
- My computer can have programs hang on some of the bands running CW or 
RTTY. The programs
  that do hang has usually something to do with the sound-card. PSK31 
programs, Contest logs (Writelog), CW-Get etc.
- My computer speakers is picking up the noise.
- My computer is making a ticking noise each time I key, you can actually 
hear morse code coming from it. I believe it is the PSU.
  The computer PSU ones dies, and I dont know if it was HF or just bad 
manufacturing - I got it replaced on warranty but they
  never found the reason of failure..............

The only band not making any problems is my 2m but then I only have 50w and 
use it for SSB/CW/FSK441.

I have gotten myself a thick copper tube that I fastened on the back of my 
desk. From it runs a 2cm (approx 7/8") thick cable
out to a grounding rod. It is usually wet where it is situated.
So far, the only thing grounded is my rigs.

I tried experimenting with ferrite cores. Each coax and rotator cable each 
have 5 ferrites.
I also have a ferrite core on my headset and the cable is wound 4 turns 
within the core, core place right next to where the cable
goes into the headset. I tried 2 turns, 3 turns and tonight 4 turns. No 
difference.

Some more experimenting shows me that if I sit in front of the rig and hold 
the remaining stump of headset cable in my hand I can
find some places where it gets almost quiet. But then there are places where 
the noise is unbearable. If I hold the cable near the
rotator control box it gets very load - the rotator control box is at 2 
o´clock from my radio. Same thing if I hold the headset cable
near my computer which is 7 o´clock from the radio. I tried other directions 
but these seem to be the problem areas.

I dont dare to run a amplifier without getting rid of this problem. Or I may 
kill my computer.

My setup:

FTDX-5000D+
FT-920 (same problem)
Antennas varies but I do have problems on the ones with baluns as well as 
RF-Chokes.
Rotator is a Yaesu G-450XL
I have a sound-card interface from the radio to the computer but it is 
opto-coupler.
Heil Proset+


What can I try?
Is there a way of actually measuring RF/HF on the outside of cables or 
devices?
Is the rotor the whole problem?
Should I try the ferrite cores near the antennas instead of outside and 
inside the shack?
Should I try grounding the computer chassi and the rotator to the same 
ground as the rig?

Any suggestions welcome - I am tired of this now and really dont to mess up 
this room and move everything back to the old position.

73 de Magnus SM6WET