When I had my Drake Tr-4 I had a ham friend mark the bezel every 
5 KHZ with smaller dots.  Those Drake rigs had great linear 
tuning across the bands.  Pretty good for back in the 70's.  I 
also had an audible tuner that I still have, but it no longer 
functions.  That was hooked into a cheap Radio Shack SWR meter 
and I could tune for the highest tone out of the audio box.  Jim 
WA6EKS

----- Original Message -----
From: Howard Kaufman <[log in to unmask]
To: [log in to unmask]
Date sent: Fri, 24 May 2013 06:44:18 -0500
Subject: acessible radios

All in the ear of the beholder.
I started out with a johnson valiant.  I tuned the transmitter by 
pressing
my ear to the metal case, and listening for the dip in hum.  I 
tuned the
grid by listening to the click of the meter needle.  Later I 
counted the
dial turns on the drake radios.  Since each turn was 25 khz, you 
could get
with in 2 khz or so quite easilly.  I have wondered if a neon 
light coupled
to a feed line could be read by an audible light probe.  How good 
would
maximum brightness be?  Interesting experiment.  Then in the late 
80's I
bought a triton 4 and found the speech box that tentec made for 
it.  I
thought I had died and gone to heaven.
I have an Omni D and still have that box.  That's a backup radio.
We've come a long way.
H T Kaufman MSW LCSW
Adaptive Technology Instructor