You raise a point regarding "industrial grade sine wave ups". I have one
of those and in my chasing a noise issue, I opened the case to find the
output receptacles each have the neutral terminal {white wire} and the 3rd
pin ground terminal {green wire}connected by a solid strap. This then says
the neutral is connected to 3rd pin ground at several points, both on the
input and output. I seem to recall this is not correct according to NEC.
Anyway, I removed the straps and my noise went away. Now, this does leave
the 3rd pin AC ground terminal on the LOAD side of the UPS connected to the
3rd pin ground on the INPUT side of the UPS. The neutral however is not
connected from the LOAD side to the INPUT side, thus there is significant
isolation between input and output of the UPS. As it should be in my
thinking.
Is there some UL requirement, say UL1499, or other international standard
that I'm not aware that mandates the load neutral and 3rd pin AC must be
bonded? It has been too many years since I worked in this part of the
safety discipline.
Comments anyone?
73
Bob, K4TAX
----- Original Message -----
From: "denton sprague" <denton@oregontrail.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, September 02, 2014 12:36 PM
Subject: Re: [TenTec] TT 940 Power Supply
Ok….I installed a no 10 wire between power supply and Omni 7….that seems(?)
to have cured the problem.
No chopped the 3rd pin ground….I got everything in the shack tied to a
industrial grade sine wave ups running on a dedicated 20 amp circuit.
speaker is on the right of the rig….also have a little astron ss30 and a
huge astron 50m linear power supply that I used to use for entire station.
No rf hash for any of the laptop chargers so far…
On Sep 2, 2014, at 10:13 AM, "Bob McGraw - K4TAX" <RMcGraw@Blomand.net>
wrote:
Do you have a solid ground wire between the supply and the radio? If not
the radio is about 1/8 to 1/4 volt above DC ground.
You haven't chopped the 3rd pin ground have you? For safety reasons, it
must be in place.
Some have reported with the supply on the left it makes noise, on the
right it does not. I may have my left's and right's reversed. Anyway, I
think you get the idea.
The ONLY noise I have from a switching supply is from the charger for my
laptop computer. I've purchased three different ones. All produce noise.
As to the station supply, I use Astron SS-30M's or SS-25's. Have three
and all are quiet.
73
Bob, K4TAX
----- Original Message ----- From: "denton sprague"
<denton@oregontrail.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Tuesday, September 02, 2014 10:43 AM
Subject: Re: [TenTec] TT 940 Power Supply
Well darn…
my 940 has a traveling growling noise on 80 meters….wonder if there is an
easy fix?
Otherwise will sell the darn thing….
On Aug 29, 2014, at 11:36 AM, Ralph Arnold <rea.papaof10@gmail.com> wrote:
I'm interested in PS for my Pegasus will it handle it and how much $$ 73
KD8BTQ Ralph
On Fri, Aug 29, 2014 at 1:17 PM, Charles J. Nagel <cnagel@sbcglobal.net>
wrote:
I have four TT switching power supplies I use for various rigs including
Ten-Tec and Elecraft. Never a noise issue. One is a recently acquired
940,
a perfect match for the Omni VII, in my opinion.
Charles, K0CW
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