[TowerTalk] Need help with HF problems

[K8RI on TT]

On 5/28/2011 5:27 PM, Magnus Aronsson wrote:
> 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.
>
First, did you just move the station a few feet? I'm assuming you 
changed some cables as well?
What did you change with the cables? Grounding for the station?  Are the 
grounds of equal length or are they "daisy chained". Grounds should run 
from each piece of equipment to a common point.

It worked fine before, Moving it a few feet (bout 6) shouldn't have made 
much of a change. Are you still using the same cables and is the 
equipment organized as it was before?  How about AC power tot he 
station? has it been changed in any way? Rerouted, different circuit, 
new circuit?

Evidently something was changed, added, deleted, or forgotten that has 
made the difference.

I once had a contest style station. It went through a number of 
incarnations.  It was this set-up but with some different equipment 
although I did have the KWS1/75A4 in it.  (watch out for line wrap)
  http://www.rogerhalstead.com/ham_files/boat1.htm  There is a *MASS* of 
cables behind that desk as it was set up to run any rig on any antenna 
and you could run 4 of the 6 low bands at the same time.  I decided to 
"neaten it up a bit" and harnessed everything into nice neat bundles. 
<sigh> Every thing and I do mean everything talked to everything else. I 
had to move the desk out from the wall and I think it took close to a 
month to get it all working right *again*!

So the question becomes one of finding out what changed that is causing 
the problem, not adding a bunch of chokes which may or may not eliminate 
this new problem.

73

Roger (K8RI)

> 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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