Kostas improves the contrast on his FRG-7 digital display

Many thanks to SWLing Post contributor, Kostas (SV3ORA), for sharing the following guest post which originally appeared on his radio website:

FRG-7 digital display contrast improvement

by Kostas (SV3ORA)

The FRG-7 digital by Marcel Jacobs PA8MA, is a very well thought modification KIT for the Yaesu FRG-7 receiver. It really adds to it one of the things it misses (and it misses a lot) to become a more “serious” receiver in the modern era, the digital frequency readout and S-meter. If you are like me and enjoy classic radio gear, but you do not want to compromise much the every-day usability, I recommend you this KIT. I have to say here that, the first thing you would want to do if you use the receiver for SSB, is to perform my SSB-related mods as well.

When I installed this KIT on my FRG-7 The first thing I did not like about it, was the very bright display which blasts your eyes with light especially at night on a low-lit shack. Not only that, but your eye will condinuously focus on the bright display and you loose the magic of the rest of the radio controls and displays. I wanted the digital display to be one of the parts of the radio and not the major thing that my eyes will look all the time. Marcel was smart enough to include 2 brightness levels in software. The low brightness setting does not actually change the backlight of the display, it just changes the graphics in more dim colors. As a result in either setting, the backlight color is very bright and this decreases contrast a lot. The background of the numbers in the display has a blue-ish color and not true black. Not only that, but the edges of the display, are visible too. I have solved all of these problems with a simple modification to the KIT.

The picture above, shows the display after my modification. The picture is taken on a dim-lit shack using my phone, with no further image processing. What you see in this picture, is exactly what it looks in reality, after my modification. Notice how the background of the display, remains pure black and the numbers and graphics of the display do not blind you anymore and are of the same brightness as the rest of the original backlit graphics of the radio. This allows your eye to wander around to the rest of the nice radio backlit things, without focusing all the time on a bright display. This is very relaxing to the eye and the brain as you scan for stations. You actually only look at the digital display when you want more accuracy. Compare this nice display contrast with the one presented on Marcel’s manual and you will notice the difference.

The modification is really simple and it does not need a schematic. It is just a 22k potentiometer, connected as a variable resistor like shown in the picture. I just cut the second cable (from the left), of the ribbon and then soldered the variable resistor there. That’s it. Depended on the light conditions in which you operate the receiver and on your personal preference, you can set the brighness from full to very dim. In the software setting, set the brightness to maximum. Then use this variable resistor to decrease it to your desired level.

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5 thoughts on “Kostas improves the contrast on his FRG-7 digital display

    1. Kostas

      Initially I thought of such films. It should work as well.
      With these, you do not have the ability to set your display backlight to variable brightness (depended on environment lights), but it should work to an extent to improve contrast. The screen used in this KIT is of fine quality and the graphics are crisp. When you fix the contrast issue, it really looks like a high quality product. I bet the creator of the KIT will will include the mod to the next versions, as I have already contacted him.
      I have to say, I did not regret installing this KIT. No matter of a few birdies, if you do not shield it, its so amazingly useful and it really makes the FRG-7 stand out. Oh and at last I removed this awfully-looking CB-type S-meter which to my taste is the only bad-and-cheap-looking part in the FRG-7.
      I know purists will not find it a good idea, to modify the FRG-7 in such a way. I am a purist too, but the FRG-7 has so many things that can be improved to become a more serious SSB receiver. After all, this counter is a mod that can be easily undone. Always keep your original parts and avoid soldering/desoldering where you can.

  1. Andy

    That looks really good. Like Kostas, I always look for the quality of a display, whether it is a digital watch, a frequency readout or gizmo. Blacks must be black (not foggy grey) and the digits must look crisp and smart. It makes a big difference. Although I’ve never been a big fan of the Frog, Kostas has made a very useful difference with his mods.


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