[Elecraft] Scanning and channel hopping question...

[Wayne Burdick]

> "Scanning while muted (normal scanning mode)
> allows the K3 to ignore stable carriers, unmuting
> only when "interesting" signals are found."

If the signal appears to be an unmodulated carrier, i.e. with little amplitude variation over a period of about 1 second, then it is skipped. Noise can fool the algorithm sometimes, of course.

There's actually a variable in the source code called "scanWorthy" that accrues intel about the signal :)


> ...from the K3 manual - which appears to be a close DSP cousin to the KX3,
> and I've also found some scattered bits about the KX3 that refers to
> stopping when a "modulated signal" is found.  So, what exactly triggers a
> stop scan?

It stops on any signal with a certain S+N/N ratio, then evaluates it as described above.


> Is the scan signal detection
> done after signal processing like noise blanking, noise reduction, notch,
> etc?  That would make it REALLY good at scanning HF !

Yes and yes. It's really useful for discovering signals on a "dead" band (they seldom are truly dead, you will discover). 


> After scan stops on a signal, does it pause until the signal stops, or does
> it continue after some fixed time?

The latter. If the signal is "interesting" it will unmute the receiver and pause a lot longer.


> I see that in VFO scan you can make it
> effectively slow or fast by changing the increment step - , but in channel
> hop, the "increment" is one hop - just not clear on the hops per second.

I believe it's two hops per second if you use "live scan" (continuous, and unmuted) and 5 hops per second with regular scanning/hopping (muted).


> And finally....how does the scanning stop/resume sequence work?
> When a signal is detected, the scanning pauses for some interval, then
> resumes when the signal stops? Or after a time interval if the signal is
> still there it continues scanning until it hits the active channel again?

All of the above. It's not using AI or anything -- just simple rules -- and it will produce consistent results most of the time.


> I've used (channel) scanning on HF quite a bit.  Very useful
> now that VFOs are rock solid and tune in milliseconds. 

As the guy who wrote the firmware, I'm happy to find that someone else finds it useful, *and* is curious about how it works. Thanks.

The K2 has the same scanning feature, by the way.

Wayne
N6KR