[Lowfer] New to the list. A few questions re: Lowfers and longwave

[Lyle Koehler]

Here's a reference point:

I have an IC-756PRO, which has roughly the same sensitivity (or lack of it)
on LF as the IC-718, according to the ARRL Lab extended test reports. At 100
kHz, the minimum detectable signal on the IC-718 is -109 dBm. The test
report for the 756PRO does not have a measurement at that exact frequency,
but at 150 kHz, the sensitivity is -115 dBm. Considering that the
sensitivity of both radios rolls off rapidly at lower frequencies, I'd guess
that they are comparable at 185 kHz. The built-in preamp in the 756PRO does
not function on LF, and I'm pretty sure the same is true for the IC-718.

With my 8-foot loop and high-gain balanced preamp, Mike is solid copy by
ear, and kicks the S meter up to about S6 (on this radio, that's about 15 dB
above the noise level, with the IF bandwidth set at 50 Hz). That's about
normal for a LowFER at 70 to 100 miles. If I disconnect the shield and leave
only the center conductor of my 80/40 dipole connected to the input of the
radio, I hear no trace of Mike's signal even with the audio gain cranked all
the way up. That's also normal for a LowFER at 70 to 100 miles. Some radios,
like the TS-870 and the IC-751A, do not intentionally attenuate signals
below 500 kHz, and on one of those, I would probably be able to hear a faint
signal from Mike without a preamp. I do hear WWVB at 60 kHz, and fairly
strong Loran pulses at 100 kHz. A few other birdies, probably from switching
power supplies in the house, but nothing else below 200 kHz on my 756PRO.

I'm a bit surprised that the IC-718 isn't picking up a lot of buzz from
light dimmers in the neighborhood, and it should also receive Loran pulses
at 100 kHz (although Jackie is 100 miles farther from the Baudette, MN Loran
station than I am. But like most receivers, it probably just needs a simple
external preamp.

Lyle, K0LR