[AATV] Easy HAM TV - 1960's Style

[Bil Munsil]

I just found November 1962 QST magazine with an article titled "Amateur 
TV -- The Easy Way" written by E Laird Campbell, W1CUT.

To begin with you need a black & white TV camera with video output.

Then you buy a "TV Eye" - what today we would call an RF modulator.

The TV Eye consisted of a one tube (!) free running oscillator which 
input video and output a frequency anywhere between channels 2 and 6. 
It was available to amateurs at a discontinued price and included the 
camera unit, a Vidicon camera tube, a control unit with all sync and 
power supply circuits, cable connectors and 25 feet of cable.

It operated on 117 volts, a.c. and drew about 100 watts.

It used one half of a 6U8 as an oscillator which was modified by the 
amateur by adding a 55.25 Mc crystal - a miniature crystal with wire 
leads.  NOTE MHz had not been heard of yet.

>From there the RF was input to a 2 tube 55.25 Mc amplifier consisting of 
a 6DJ8 (2-stage amp) and a 6U8 - one half of which was the third amp and 
the other half of which was a cathode follower.

Now we need to build the linear "end-converter" which consists of 6 
tubes.

We start with an 8006.7 Kc crystal and build an oscillator with one half 
of a 6J6  the output of which was tuned to 24.02 Mc.  The other half of 
the first 6J6 was a doubler tuned to 48.04 Mc and it, in turn, fed 3 
more 6J6's which doubled and doubled and doubled until finally the 
frequency output was 384.32Mc.

The 55.25 Mc from the 6U8 cathode follower in the video amplifier was 
link-coupled into a 6939 push-pull mixer - the paralled cathodes of 
which were also fed by the 384.32 Mc out of the 6J6 doubler chain.

The final output (439.6 Mc) was fed into a push-pull 6939 linear amp 
stage and out to the antenna.

Power requirements were 150 volts DC at 175 ma, 6.3 volts DC at 4 amps 
(!) and a dry-cell battery for the bias voltage.

Coils were made from No. 22 enameled wire and No. 20 tinned wire.

When it was all finished the output was a whopping 2 watts!  The article 
concludes by saying that a linear amplifer of about 50 watts might be 
the next project.

What could be easier?

Bil






K1ATV
Hams should be seen as well as heard.
Mesa AZ