[Lowfer] Using Argo

[Stan, W1LE]

On 12/3/2012 12:51 PM, Eric Smith wrote:
> Please remind me ... it has been a while but I now finally have my
> radios going after moving again:
>
> If I have my R-75 tuned right on a specific beacon's frequency, then
> that signal will appear in Argo at the frequency of my side tone,
> correct?

Correct. The Beat Frequency Oscillator (BFO)or the sidetone is the 
offset at audio frequencies.
The side tone may be different for other radios,, eg ICOM IC-703+ has a 
800 Hz side tone in CW demodulation.
Other radios have a 600 Hz sidetone.
The resulting audio may change with USB or LSB demodulation or a CW 
reverse or the regular CW demodulation.
>
> So if sidetone is 700 Hz, then in this scenario the beacon would
> appear at 700 on the waterfall display, right?

Right, plus or minus the local oscillator accuracies
>
> Also, it seems like the last time I got this working I had to use the
> Reverse feature (CW-R) but I can't remember why.
A perculiarity of the radio. Their design engineer's choice. Some radios 
allow a change with a menu.

For accurate calibrations I use a HP 3336B signal generator with an 
external GPS/DO reference at 10 MHz.
For ARGO ( a great program ! ) I calibrate the soundcard first, 
injecting a audio tone at 1000.00 Hz
or any other known accurate freq you have.
Then I connect the radio audio output to the soundcard and inject the RF 
freq I am listening to.
For example: if I am listening to an RF of 137.000 KHz and my RX has a 
sidetone of 800 Hz in CW reverse,
then I would expect to see the test signal at 800 Hz in ARGO. Then 
calibrate out the minor differences due to your radio's
LO accuracy.

As I recall the G0MRF preamp has a tight bandwidth. Is it tuned to where 
you want it ?

Stan, W1LE    Cape Cod   FN41sr