Hi Magnus,
Check the ground system, makes the cables as short as possible, each equipment
must have its own ground wire to any common type of bar, you need to connect
all ground (chassis of the computer, rotor control, radio, amp ) Ferrites
Resomer help those of youa lot Amidon Corp.
The audio and control cables that are interconnected with the entire system be
as short as possible, any extra roll up to form a coil and if possible also put
him ferrites
73...
Sal
HK1T
2011/5/28 Mark Robinson <markrob@mindspring.com>
Did you shorten your coaxes or coil them up? What grounding do you have
right now? Maybe you can you one of those MFJ artificial grounds and a
counterpoise.
What antennas are you running and what bands are causing problems?
73 Mark N1UK
----- Original Message -----
From: "Magnus Aronsson" <sm6wet@telia.com>
To: "towertalk" <towertalk@contesting.com>
Sent: Saturday, 28 May, 2011 5:27 PM
Subject: [TowerTalk] Need help with HF problems
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
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