FRG-7
digital
display contrast improvement
by 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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