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Re: [RFI] Shielding a ground wire

To: rfi@contesting.com
Subject: Re: [RFI] Shielding a ground wire
From: Christopher Brown <cbrown@woods.net>
Date: Sat, 27 Apr 2013 12:32:40 -0800
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
I just stopped and shook my head when "Scenario 1" jumped up and smacked
me.  Fig 1 and 2 being the same circuit, with the only diff being the
possible changes in the bonding connections (possible more approp
cable/better connections when re-done).


My station is properly _bonded_, with careful attention to keeping
everything at the same DC and RF common.  Due to port manufacturer
practices (treating shield and DC common as the same thing), this means
paying close attention to DC current flow via other than DC common power
cable.

Far too many "RF" problems with clean audio/etc have more to do with AF
modulated DC current flow dividing between the DC common power
connection and coax/other connections to other devices and out through
their DC common connection (is your radio going to be happy if you amp
is effectivly modulating the radios DC supply 1v PtP?).  (This is all
the same thing as Jims "Pin 1 proplem")


I do have a "ground", multiple rods and buried flashing, all NEC
compliant and proper bonded to main ground.  It is even connected to
station bonding bus with strap, and is used (in combination with proper
chokes) as part of RF suppression on coax shield.  But it is not a magic
RF sink, and as far as the station goes.....station is second
floor...strap or not, it is not a "RF ground" or some such for anything
above 80M.

On 4/27/13 8:36 AM, Jim Brown wrote:
> Virtually everything in this piece is WRONG.
> 
> 73, Jim K9YC
> 
> On 4/27/2013 12:26 AM, Timo Toro wrote:
>> Aaron,
>>
>> Figure 7 shows how to do it with coaxial cable. 
>> http://kc.flexradio.com/KnowledgebaseArticle50426.aspx
>>
>> 73, Timo_oh5kw 
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