Ok, I'll bite. I'll regret it, but I'll bite.
Ground surges won't arc across stuff and run from place to place through
your rig and other expensive equipment if ALL grounds, everywhere at your
QTH are
SECURLY bonded together. As is required by code anyway. THEN, all grounds
will rise to the same, equal potential when a surge occurs, resulting in no
voltage between
the various grounded points, and thus no current.
Failing this - virtually ensures that the ground path will lie through your
equipment, and will toast it.
73 de Gary, AA2IZ
----- Original Message -----
From: "Stuart Rohre" <rohre@arlut.utexas.edu>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Wednesday, November 25, 2009 3:45 PM
Subject: Re: [TenTec] humm
> Make sure the Astron power supply is under the desk or otherwise remote
> from the rig by at least a couple of feet. Be sure to use the same
> gauge wire as provided by the rig manufacurer for power leads and twist
> them (or use large gauge wire twisted).
>
> You are not changing the mike stand, but just changing a cartridge in
> the same stand? Clearly when you roll off at 200 Hz you are excluding
> 60 Hz and its harmonic at 180. Of course for best SSB comms
> intelligibility, you should restrict the voice passband to 300 Hz to 3
> kHz. That is ALL that is needed for punch thru audio. (If it was good
> enough for the phone company for 123 years, it should be good enough for
> hams.)
>
> Some hams ground the negative terminal of an Astron to its case, but
> that gurantees a ground loop with your antenna coax shields, and will
> lead to lightning damage to the power supply. (Been there saw that with
> a club station grounded by an ex power plant guy who "wanted a good
> ground on everything).
> The lightning surge came down the coax shield and arced across a rig to
> the negative power supply lead, and then returned to ground thru the
> Astron case and AC ground pin of power outlet----what a mess! However,
> if that cures your hum, you might do that until you track down the rest
> of the ground loop. Be sure your mike cable shield is securely
> connected, and a bad connection is not the cause of the hum
> introduction. Are you using a Heil mike stand, or some other brand
> converted to the Heil element?
>
> Change one thing at a time when looking for ground loops and hum problems.
> GL,
> Stuart Rohre
> K5KVH
>
>
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>
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