[CW] Fwd: [Lowfer] Earthing - probes

[Ed Tanton]

>I must preface this by saying I didn't ask permission to forward 
>this, but I am certain Laurence won't mind. I did send him a copy though.
>
>This is part of a very interesting discussion on [LOWFER] about 
>grounds, noise sources, etc. from a receiving of LF signals 
>perspective. I thought this particular message was awfully well 
>said, and wanted you all to see it. It is surely relevant to our HF 
>receiving interest(s) as well.
>
>>As others have point out each location appears with a different 
>>challenges. Most of the successful reductions in non wanted noise 
>>appear in the form of isloating any dc amp probe feed interference 
>>(that's rubbish obtained from the power supply by making the dc 
>>feed high impedenace to rf, and secondary decoupling the rf coax 
>>outer from noise picked up from the shack and carried to the probe 
>>on the outer of the braid or whatever.
>>
>>Don't use switched mode supplies so rx or probe feeds unless they 
>>are very very very screened and cleaned -!!!!
>>
>>
>>My best and most effective solutions have been a combination of 
>>both these using info linked from the on7yd web site by an article 
>>from a " wb " someone (sorry I'm not on my home computer but 
>>presently typing this on my blackberry in a houston walmart!)  Who 
>>deals by choking and decoupling  both the neg and pos dc supply and 
>>transformer isolating the feed too at the rx end. Secondly earthing 
>>the coax or in my case connecting the coax to a house entrance door 
>>and window really is the main improvent effectively sets up the 
>>house as a farday cage trapping and dumping the internal noises to 
>>"ground" before getting to the antennae. Thirdly I have a large 
>>toroid in a box with some 30t of rg174 terminated on insulated bnc 
>>set in a small metal box - this is the last line of defense to 
>>choke off any residue but it doesn't do a lot. The inductance is around 5mH.
>>
>>Sorry for the typos as my shopping cart is being bumped...
>>
>>Laurence KL 1 X mobile 5
>>Tstorms
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>
>72/73 Ed Tanton N4XY <n4xy at earthlink.net>
>
>Ed Tanton N4XY
>189 Pioneer Trail
>Marietta, GA 30068-3466
>
>website: http://www.n4xy.com
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