HF Active Loop antenna red led

Angel M0HDF


I have an HF active loop antenna. The red led does not glow at all.
The amp is still operational. I see signal amplification vs. power off.
The red low was glowing with power on before.
50m of CAT cable are used between shack and antenna.

I wonder if anybody else has experienced this off or whether this could be a sign of a problem with the amp.

Thanks in advance
73 Angel

Chris Moulding

The voltage across the red LED depends upon the current flowing through the 22 ohm resistor in the base unit.

Under normal conditions if will glow faintly but the actual brightness depends on the individual LED, temperature of the LED, temperature of the amplifier, length of ethernet cable etc.

The idea behind the LED was to show that some current was being taken by the amplifier when connected and to alert the operator to any cable faults indicating a short circuit. It glows brightly then and the 22 ohm resistor limits the fault current to a safe level.

If the antenna is otherwise working normally, I wouldn't worry too much about the LED brightness.