[RFI] Shielding a ground wire

[Timo Toro]

At 14:42 -0700 28/4/13, Roger (K8RI) wrote:
>On 4/28/2013 11:21 AM, Timo Toro wrote:
>>I did fix my problems already. My antenna systems are not incomplete. Of
>>course more and higher masts would be nice, hi.
>>
>>But if I run over 1KW to my 4el Yagi on 40m and my PC stops working, I
>>have to fix that problem. I did not use the band aid either. Nowadays my
>>ham shack is more like Faraday shield, hi. And lightning safe.
>
>Sounds like what I had on 75 with a center fed half wave, sloping, 
>fan dipole. SWR  at resonance is less than 1.1 : 1.  When I'd get to 
>around a KW out, all the LEDs on the control heads in the station 
>would light. To me that said, RF on the feed line which meant it was 
>on the ground as well.
>
>My first thought was a current balun.
>http://www.rogerhalstead.com/ham_files/AntennaFeed1.htm
>Not neat, but a very high impedance for common mod voltages.  It 
>improved the situation but did not cure it, So I inserted another, 
>similar choke where the feed line reached the tower and no more RF 
>in the shack, feed lines, or ground.
>
>I stopped the RF at the source.

Sounds fine. On my to do list there has been also to add common mode 
chokes to the lines coming from mast. The more isolation between 
computers inside the house and antennas the better.

I think all tin roofs should be grounded too. I have done it only to 
my station building.

73, Timo_oh5kw

>
>An antenna may appear to have all its parts, a good SWR, and a good 
>ground, but bear by objects, ground conditions under and near the 
>antenna may leave you with an unbalanced system even though every 
>thing looks good.  Matter of fact, it's extremely unlikely that an 
>antenna will be truly balanced
>
>73
>
>Roger (K8RI)
>
>>
>>I still like to use word "grounding" meaning low impedance route to
>>common point near earth potential.
>>
>>73, Timo_oh5kw