LED Detectors

[Falls, Jim@DOC]

Clever!

I used a low current/low voltage LED successfully in a crystal set to receive a local station in the daytime. It also doubled as a tuning indicator.

It was not as sensitive as old faithful 1N34A’s, but didn’t overload either.

I’ve also had good luck with photodiodes at night illuminated by a candle. They approach 1N34A’s in sensitivity given these deaf old ears of mine.

 

Jim Falls K6FWT

 

[Robert Nickels]

On 12/7/2012 5:42 PM, Falls, Jim@DOC wrote:
> low current/low voltage LED successfully in a crystal set to receive a
> local station in the daytime. It also doubled as a tuning indicator

Now that would be cool, I have to try it! I think there are tales of
people who lived next to 50KW BC stations who got plenty of light from
their fluorescent fixtures, without even turning them on...but it was a
problem when they wanted to sleep ;-)

For a small AM transmitter I built the other day I was looking for a way
to provide an indication of RF power without resorting to a meter or
anything that would steal much of my already QRP 2 watts. I found that a
low current LED and a few turns of wire coupled to the PA tank worked
perfectly!

73, Bob W9RAN