Jim,
If I remember correctly 1004 hz tone was used to qualify an outside cable
pair, launch power versus received power. The twist of the cable
(capacitance) and the 88mH loading coil at the frame block equates to
something around a 1004Hz resonance for the twisted pair. And wasn't a
1004Hz tone also used for tandem (Toll) switches for signaling to grab a
trunk out of the switch, or am I mistaking that for like 1200 or 1300 hertz
or so? It has been so long, can't quite remember.
Now 404/1004/2704/2904 will send shivers up and down any Telco Techs neck.
That is a frequency run for an MFT, which was an in line equalizer used for
radio circuits. Having to align an MFT can be quite frustrating as it is
purely analog, so what ever you do to one filter affects the other. So it
takes several passes to get it right. Too much adjusting and you had to
start all over again, hence the frustration.
I probably should try white noise for tuning up my amp just to see what it
does. And Rob, 200Hz does pass right through my rigs just fine; they will
pass 20Hz if you let them. But good point, probably should use something
like 200Hz & 1200Hz or maybe 1800Hz at the high end.
73,
Mike
W5CUL
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Jim Thomson
Sent: Thursday, September 23, 2010 10:14 AM
To: amps@contesting.com
Subject: [Amps] Pulse tuning
Date: Thu, 23 Sep 2010 07:39:24 -0500
From: "W5CUL" <w5cul@sbcglobal.net>
Subject: Re: [Amps] Pulse tuning
I use a piece of software called Test Tone Generator to pulse tune my amp.
It is set for 200Hz for one pulse tone, and 600Hz for the other. I have the
duty cycle for each tone set for 30%, which seems to work very well given I
operate SSB. It seems to me that it would be a more efficient tune if you
can mimic the mode of operation you plan on using when tuning your amp.
73,
Mike
W5CUL
## Hi mike. What else that works good is the white noise generator,
that's built into my Behringer 2496 mastering processor. The plate current
ends up exactly 1/2.... IE: dead on 50% duty cycle...but occupies the
entire TX BW..and u can't notch it out.
## Hey, somebody told me yrs ago why telco's use a 404 / 1004/ 2704/2904
hz tone for
testing, and I have long forgotten. It had nothing to do with harmonix
either. It had nothing
to do with A/D and D/A conversions either. We were using 1004 back in the
old toll office days,
and on analog 46-A cxr systems etc, analog microwave... long before digital
multiplexer's,
and 5ESS / GTD-5 CO's came into existence. Does anybody remember the real
reason ?
## for the fellow that used to tweak microwave sites, Mike and I dabble in
ESSB, so the xcvr's
will easily pass low freqs. I can get 200 w at < 20 hz quite easily. I
retired from the telco after 34
yrs, [mike is still there ! ] and I don't want to hear 1004 hz for the
next 30 yrs thank you.
Later... Jim VE7RF
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