[Elecraft] Grounding negative side of power supply?

[Robert Mcgraw]

Yes, do provide a driven ground for the K9AY receiving antenna.  This is
required for lightning protection.  AND be sure to bond this ground to
the AC mains ground for the house.  Failure to do this will produce a
voltage difference or step voltage between the two ground during a nearby
lightning strike.  The voltage difference can be enough to damage or
destroy the radio connected between the antenna and the AC power.  AND,
bonding of all grounds to a common point is a requirement of the NEC.

Remember, lighting has traveled through several thousand feet of air.  A
balun will offer little to no protection in this regard.  Now placing a
choke balun or a 1:1 current balun at the feed point will reduce common
mode noise on the coax feed line.

73
Bob, K4TAX



>
> On Jan 20, 2010, at 11:47 PM, Richard S. Lindzen wrote:
>
>> Dear Don,
>>
>> This leaves me a bit concerned.  I am planning to put up a K9AY
>> receiving antenna in my backyard and it is supposed to be connected
>> to a ground rod.  I had never seen it suggested that this must be
>> connected to the utility ground stake.  I'm not even sure where the
>> utility ground stake is.  I've never noticed one though I will ask my
>> electrician.  If there is one, it is likely to be pretty far from the
>> K9AY.
>
> For the K9AY, your best bet is to make sure the antenna ground and the
> coax ground are completely isolated. I do this by magnetically coupling
> the coax with a 9:1 transformer. Otherwise, common-mode noise can move
> out the shield and be picked up by the antenna.
>
> Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
> Web: http://boringhamradiopart.blogspot.com
> Quote: "Not within a thousand years will man ever fly!"
>             -- Wilbur Wright, 1901
>
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