[Lowfer] ARGO

[Lyle Koehler]

>> use the CW reverse (CW-R) mode.

>Lyle (et al):

>Perhaps it is my radio but I have a problem when doing this.

Ah, that reminded me of a serious IC-706 quirk in CW-R mode. When you use
CW-R with the standard (SSB bandwidth) filter, the radio no longer operates
in what we used to call "single signal" mode in the good old days. That is,
you can hear the signal on either side of zero beat. So noise and
interference from the other side of zero beat will be present in the audio
output. It's not a problem if you have a narrow CW filter installed, and I
had forgotten about it because I always use the 250 Hz filter when copying
LowFER signals. The moral is, if you want "single signal" non-inverted
reception and don't have a narrow filter, simply use USB mode. You then need
to tune below the carrier you are trying to receive by an amount equal to
the desired audio pitch. For example, set the radio to 184.300 kHz in USB
mode if you want a 1 kHz output from a signal at 185.3.

As for the large frequency shift in CW-R mode, and the apparent discrepancy
between the displayed and actual BFO pitch in Mike's radio, I can't explain
that one. The audio output of my 706 is within 1 Hz of the displayed BFO
pitch in either CW or CW-R mode. On LF, that is. At HF there will be a
larger shift if the master oscillator is off frequency. Since I always use
CW-R for LowFER reception with Argo, I don't have to change the Argo
calibration. But Mike's system of negative numbers is definitely the way to
go if you don't have a narrow CW filter installed!

Lyle, K0LR