Re: Spectrum window crash / spot persistence


Patrick Herborn
 

On Tue, 23 Jul 2019 07:07:44 -0400
"Tom Wagner (N1MM)" <n1mmtomwagner@...> wrote:

Had an opportunity to do some testing tonight, so reporting results.

There is a bug on transmit. Try right-click reset radios to start it
going again.
I tried this method, on the 18Jul release, and the latest release, but
it does not reset the SDR - it is still necessary to exit and restart
N1MM+ - sometimes with Task Manager to clear out a zombie process.

In some configurations, I prevent the spectrum from displaying during
transmit. This is intentional. Transmitting overloads the SDRPlay and
wipes out signals near the transmit frequency.
I can confirm that with the existing setup, using a PTT footswitch
direct to the radio, the spectrum does keep rolling during TX, BUT
it is slower. I don't know if it is supposed to.... but thought I'de
report what I observed. Both releases seem to react the same.

Now to the bulk of the info :

Test set 1 : Checks with nothing changed
----------------------------------------

o It was possible to freeze/crash Waterfall Bandmap with a CW carrier
on 20m. 40W was enough for consistent freezes.
o With the antenna feed to the SDR removed, it was possible to
key up as many times as I wanted, it would not freeze/crash,
even with 100W.
o With the SDR connected to the switch, but tuned to 40m, it was
possible to key up as many times as I wanted on 20m, it would not
freeze / crash, even on 100W

o It was possible to freeze/crash N1MM+ (N1MM+ controlling SDR) on
20m. 40W was enough for consistent freezes. Reset Radios did
not bring the spectrum window back to life.
o With the antenna feed to the SDR removed, it was possible to
key up as many times as I wanted, and N1MM+ would not freeze/crash,
even with 100W
o With the SDR connected to the switch, but tuned to 40m, it
was possible to key up as many times as I wanted on 20m, it would
not freeze/ crash N1MM+, even with 100W


Test Set 2 : Try Steve N2IC's ExtIO DLL version
-----------------------------------------------

o Tests were abandoned - Steve's DLL was the same version already in use


Test Set 3 : New version of N1MM+
---------------------------------

o It initially looked good, but eventually managed to get N1MM+ spectrum
window to freeze/crash using a 100W CW carrier.
o It was noted that the spectrum window appeared to be suppressing the
carrier (it used to be there - guess this is new)
o Reset Radios did not recover the spectrum window - again a full restart
of N1MM+ was needed - and Task Manager may have been necessary (sorry,
notes don't say)
o It seems to be considerably more robust than it was when operating a CW
carrier.
o When operating SSB, the sideband is visible, but an area round the
(suppressed) carrier is attentuated. Whereas CW was more likely to
cause issues before, now SSB has the higher risk of freeze/crash.
This shift is most likely down to the increased resilience to CW,
NOT some new unintended side effect.
o Detaching the SDR antenna feed, transmitting into a dummy load, or
having the SDR on 40m with the rig transmitting on 20m all allow
the SDR to endure as many TX events as I could give it - ie I could
not break it.

The above leads me to conclude that something is not liking the higher
ADC drive levels associated with the SDR being connected. What is
interesting is that the carrier suppression on CW seems to help. I
am guessing this is done in N1MM+ not in the DLL ?

I did not get a chance to try HDSDR with the RSP1A ExtIO DLL, I'll need
to try that in the next coulple of days.

It does seem clear that there is one "sure fire" way of fixing the
issue - reduce the signal level into the SDR. I'll look to make
a second RX/TX switch to block to -20dBm level signal that is
still making its way through - but hopefully it will be possible
to implement a software fix eventually. Indeed Steve has shared
his RSP1A settings - with any luck that may be enough, just
setting the RSP1A up differently...

I'll report back further findings :)

Best regards,

Pat. (M0MGO)

--
Patrick Herborn <pat@...>

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