[GreenKeys] Jack Polarity

[Tom Hunter]

Tip positive has always felt right to me. I have meters at each of my
patchbays and, after installation, I check each jack for tip positive. When
I recently installed an SB-1210 it matched right in.

Note: The wiring for remotely powered loops must be reversed from the
locally powered loops on the 1210 or the meter will read backwards and the
jacks will be tip negative. Almost certainly on the 1203 as well.

It took me about five days to get it all figured out and working. Now that
I have six loops instead of four I need to run wires for the two new loops
from the radio building to the house. That is about 200 feet of wire with
half of that underground in plastic pipes that are already pretty full. I
will probably pull another piece of cat-5. It is cheap and I will have two
extra pairs. I used cat-5 for the first four loops. I install plugs and use
jacks to make the connections.

Because each loop is vertical on the 1210, I have to rewire the jack panel
in the cellar to match.

As power bills are going up, I have stopped running all my TU's and loop
supplies 24/7.  I have relays in the radio building, in the den and the
cellar. to turn it all on only when I need it. I use lock on / lock off
24VAC lighting relays with on and off push buttons at each location. A side
effect I was not expecting is that when I turn off everything that supplies
loop current, I can work on my loop wiring in complete safety!

Another note: The Heath HD 3030 came with a 2-wire jack with the sleeve
grounded to the chassis. I have replaced them with 3-wire jacks with the
sleeve and ring grounded. Now I can use a 2-wire plug or 3-wire plug,
whichever is convenient. I also use a normalling jack, since the manual
warns you use a shorting plug if your loop is not connected. Now it is
automatically shorted. By the way, tip is positive on the heathkits.

I am in the process of bringing two HD 3030's with bad power transformers
back to life. I found two 15-015 Volt transformers, that just barely fit
inside, to power the electronics.I will be using an external transformer to
power the loop supplies. I have to replace a couple filter adjustment pots
on the first one and it will be done.

I have some bad pots in the other and can only get 55 mils of loop current
but I think I know why and can fix it.

On the Flesher TU-170 The ring is not at ground. I will be replacing mine
with one of the repaired Heatkits.
The Flesher will go on the shelf in case I need in a pinch again or maybe
to loan to a another ham I may try to get interested in RTTY.

Tom   N3CRK
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/greenkeys/attachments/20230119/58ed66be/attachment.html>