The first transmitter that I owned was a heathkit DX100.  I would set the
grid current by the time it took the meter needle to hit the zero peg.  I
set the plate current and dipped the rig using transformer hum.  I used to
have a sighted person check my readings every couple of months and I was
always right on, they  couldn't believe it.

My receiver was an old airforce bc348q and I made heavy use of a 100khz
calibrator.  Later on i modified a small swr meter by drilling it to accept
a one quarter inch jack hooked across the meter movement.  I plugged a
Conway auditory gimmick in to this meter and that let me start tuning my own
antennas, before that, I had to rely on someone who had a grid dip meter.
Bob Tinney, K8LR, [log in to unmask]
www.access-devices.com
----- Original Message -----
From: "Mike Freeman" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, November 21, 2002 9:45 AM
Subject: Re: Tuning an antenna


Hi!

First, tube amplifiers hat "pi networks" to match them to the antenna.
Such a network could be designed to match a far wider range of SWR than
most transmitters and amplifiers can tolerate now (they're now
broad-banded and *expect* a narrow range of SWR).

Second, there were meter-reading devices for the blind which could allow
us to tune just as accurately (if not more so) than could a sighted
person.  These were based upon two designs.  One was a Wheatstone bridge
with a current-interrupting mechanism and resistor with audio amplifier
across it so that when the bridge legs were unbalanced, one heard a
tone; when the legs were balanced, no tone was heard.  The potentiometer
in one of the legs was brought out to a braille scale and pointer so
that one could either determine the reading by adjusting for null noise
or adjust controls to match a wanted reading by tuning for a null.  The
second way was by using a voltage-sensitive oscillator (larger voltage,
higher pitch) and calibrating against a known voltage source with two
separate inputs which could be switched -- one across the meter in
question and the other going, again, to a potentiometer brought out to a
calibrated touch-readable scale.  One either tuned for lowest pitch
(tuning an amplifier for resonance) or highest pitch (maximizing output)
and one could determine the meter reading by matching the pitch with
that on the braille scale.  It should be noted that most latter-day SSB
tube amplifiers (either linears or finals on a transmitter) were running
Class B so that one could just tune for max output and be fine.

But to the SWR.  These same meter-reading designs could be made to serve
to read SWR meters.  If one had a "match box", one could put raised
scales on the dials and either match the antenna(s) oneself using these
audible meters or have a sighted person do it and then one could write
down what the scales read for band and frequency range.

And, then as now, there were automatic antenna tuners -- great motorized
contraptions.  I wish I had one.

You could also use things like power-supply hum to adjust a final
amplifier and could adjust AM audio output by listening to the
modulation transformer.  You could balance out the carrier on an SSB
transmitter by using a transistor radio tuned to a subharmonic of the
signal.  I knew a guy who tuned his SWAN 350 using a transistor radio.

In other words, things didn't *have* to talk and ingenuity was the name
of the game.  And there were crystal calibrators to determine 100 kHz
points (or down to 10kHz for some calibrators) and one could gestimate
between these points.  For instance, on a Drake TR-4, each revolution of
the tuning knob (which had a raised dot on the skirt) was 25kHz.  We
actually got pretty good at finding frequency.

Bottom line:  where there was a will, there was a way and, frankly, I
think rigs were easier to operate forty years ago than they are now.

Mike Freeman < K 7 U I J >
"All men tend to become that which they oppose." - Laurence van der Post
----- Original Message -----
From: "Michael Ryan" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, November 21, 2002 1:22 AM
Subject: Tuning an antenna


> Hi fokes:
>
> Just have a question regarding blind ham tuning an antenna in the
early days.
> How was it accomplished? I'm pretty sure there were no talking SWR
Meters
> or automatic antenna tuners.
> Did sited fokes build antennas for the blind ham for the exact band
and
> then was a "let her writ" attitude adapted due to the tubes in the
> transceiver?
>
> Thanks and 73:
> Michael VO1RYN
>
>