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
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|