Hi Mike, you brought back some great memories. My first rig was a WRL
Globechief 90a. I used to tune this using the power supply hum. When the
meter just tickeled the far side, I knew |I was on 200 mills that needed for
max output.
This was back in 1959. I used that rig for some 15 years, or so.

----- Original Message -----
From: "Mike Freeman" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, November 21, 2002 2:45 PM
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
> >
> >