[Drake] Drake TR4C USB/LSB indicators

[fkamp@comcast.net]

Richard Keller wrote:

> Ok guys, has anyone tried to improve the visibility of the little red
> indicators for USB/LSB? I tried changing the bulbs to 44 instead of 47
> but cannot see a difference.
> 73, Dick KF4NS
> St. Petersburg, FL 33714 USA
> Keep the glow!

When I first saw that my reaction was, 'he has USB/LSB indicators!?'.

Then I realized you were talking about the transceiver.

I don't have a transceiver but I have had indicator visibility problems
with other equipment.  Red filters and incandenscent bulbs just don't seem
to do the job anymore.

I solved my indicator visibility problems by replacing the indicator with
a red LED.  Red LEDs come in a variety of sizes.  Pick one that will be a
close fit in place of the red filter.  Then run the LED off the same
supply that powered the incandescent bulb.  Use a series power diode and
current limiting resistor.  Any of the 1N400x series of diodes will work.
Try a 1k resistor to start.  Change the value of the resistor up or down
depening on if you need more or less brightness.

Regards,
Frank Kamp
K5DKZ