Do You Own a Watkins-Johnson* Receiver and Wish the Meter Lit Up?
* or any other radio for that matter
The WJ-8711 and HF1000
have a single meter lamp ...
and it's a little, tiny tungsten
bulb. Personally, I see no
reason to use filament
bulbs for this kind of
premium equipment. LEDs
are less expensive, more
reliable, and consume less
power. Maybe it was a
maybe not, but with an LED
in the color of your choice,
and a current limiting
resistor, this small, albeit
shortcoming can be
The wonderful 8716 and 8718 series of Watkins-Johnson receivers do
not come with a lighted meters. If you have ever manned a surveillance
or intercept monitoring station, Ham Radio station, or SWL listening post,
you will know the need to be able to easily read and log the signal
strength of particular stations, under certain conditions or at certain
times. This can be a bit of an annoyance with some of the W-J gear
unless you have decent light and good eyesight at your operating
position. I'm sure the design team at W-J had their reasons for not
addressing this issue. I can only imagine that the contractual
government/military/agency specifications did not require it, but I am only
Okay, this is really just a minor thing, but if you are like me and want the
most comfortable, most convenient, and most user friendly LP for
long-term listening, then this minor detail can fester into a perfectionist's
major annoyance. My obsessive ideals notwithstanding, this series of
radios are by far the most ergonomic, user-friendly instruments that I've
encountered since I began this stuff back in the mid-1950s. With all due
respect to the many other Mil-Spec radios I've used, I must honestly
concede that a significant number of the others run a very close second,
Still, this is something that had to be done! I've been a communications
product designer for more that 40 years, so the project didn't intimidate
me. But I did want to do enough subjective evaluation and prototyping so
that the final result wouldn't trigger that techno-OCD that I seem to be
plagued with. Maybe it's a hazard of my career, but second place is
always "almost the best."
|It's Not a Big Deal - Why Bother?
The lighted meter of a W-J 8718A. I chose yellow LEDs to match the
frequency display. The visual effect is that the signal strength can be
easily read and the color is very easy on the eyes.
A piece of perfboard, about 3" by .75". You can see the solder
connections for the 4 LEDs which are spaced equally over the 2-inch
meter width. I used the 15 VDC supply and a 270 Ohm limiting resistor
for about 20 mA current draw. The PCB mounts to two L-brackets
which in turn mount to the existing meter bracket with its original
screws. I used T1 size LEDs and filed the lenses down close the solid
state junction since the top cover will be very close to the back of the
PCB. I'd recommend reducing the overall LED length by about one
third. Finally, not shown here, I cut a strip of thin plastic (from the flat
side of a household spray cleaner bottle) and glued it to the cover with
contact cement, just for added short circuit safety.
If you have a #1 phillips offset screwdriver, the job of dealing with the
existing meter screws will be far less tedious. Of course, it's a lot easier
if you take the front panel off, but it really isn't necessary.
I've done about a dozen of these and will continue for any new W-J
that I acquire.
I recently restored a rather beat up, basket case WJ 8718A with a defective meter. Using all the skills I
could muster from my old watch repair (hobby) days, I disassembled it and tried to locate the problem.
No luck; and really not worth an entire Saturday afternoon.
So I got a suitably sized 1 mA meter and headed off to the computer to print a scale plate. I like
Pagemaker, but I'm sure other publishing software will do fine. I considered just scanning the old
meter's face and reproducing that, but since I had the opportunity to be creative, I figured I'd try it.
Besides, how many guys have their initials on the face of their S-meter?
I used peel 'n' stick label stock to print the scale, sprayed it with clear lacquer for protection and
applied it to the meter. The meter case (back) is a translucent white which is perfect for light diffusion
for a nice even illumination effect.
Backlighting seems much nicer than edge lighting, like I did with the stock W-J, but sometimes you are
limited to only certain options, so I figured I'd take advantage of this situation.
|Does Your W-J Need a Meter and You Don't Have One?
Left is a photo of the meter without
lighting. (Note that the camera didn't
wash out the red as it did in the lighted
Right and below is the meter lit with
four flat-top (wide angle) amber T3
Note the even diffusion through the
The washed out red of the meter face is a photography shortcoming and
actually looks more like the "unlighted" photo.