[Lowfer] LF Receivers

[Lyle Koehler]

If the sensitivity of the selective level meter is 250 uV full scale, that's
not as bad as it may sound. The most sensitive range on my Sierra 303B is
100 uV full scale, and it is capable of detecting signals considerably
weaker than that.

Just for kicks I connected the Sierra 303B to the output of the preamp on my
8-foot balanced loop (details on my web page at www.computerpro.com/~lyle).
LowFER BRO from Duluth, about 75 miles away, kicks the meter up to 200 uV.
LowFER BK is a bit farther away and gives a reading of about  60 uV. Both
signals can be copied easily by ear with the meter set for 3.1 kHz
bandwidth, and with the audio gain cranked wide open in the 3 millivolt
full-scale position.

My Sierra 303B isn't stable enough for the really narrow-band LowFER modes,
and the 1.8 kHz BFO pitch, which is fairly common among selective level
meters, is far from optimum for copying weak CW signals by ear. But it *is*
usable as a receiver.

Lyle, K0LR