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PureSignal Problems

Posted: Sat Oct 26, 2019 8:15 pm
by K9RX

Ok ... so i've re-read your document on PureSignal in this subforum. You've given info on what things are doing - but unfortunately I still don't know how I can impact what is happening with my station.

I've mentioned this more than a few times before - there are some that chime in - and there are those like yourself that say "i never have any issues with Puresignal" ... so I've lived with the fact that my PS will what seems to be on its own go bananas (technical term) where you can see the TX pan is FILLED with a signal (which must be just wonderful on those within say 50Khz of me either side) ... the lights flash all over and it takes a few seconds for it to re-establish correction and I'm back in business again. This is related to how heavily the signal is processed as if i select my "BROAD" TX profile, which has no processing and is for wider conversational audi - I don't know that I've seen this happen. But I've used that profile all of maybe - 0 times. I AM a DXer ... that is what I do - that is what I have the radio (and antennas) for ... and that is what I need to work.

So - I've lived with it - it hasn't been a problem other than as described for that brief period of time. EXCEPT when the amplifier is using a tuner. My Expert 2K has a wonderful tuner that works extremely well. I have a rotatable dipole for 80M at 144' and it has 3 coil sets and thus 8 band segments to cover the band. The SWR is rock solid stable albeit at the edge of each segment it is around 1.7:1. OCCASIONALLY on the EXpert what will happen is this loss of lock happens, the signal gets WIDE and strong - and the amp will trip out on high SWR since it is now seeing reflections from frequencies OUTSIDE of where I am sitting (and my TX passband). Generally not an issue but it happens once in a while.

I've now purchased a new KPA1500 ... and it is another story. IT trips out frequently. If PS is on I can't get through more than 2 sentences w/o a trip. So now I'm forced to not use PS which is contrary to the reason I have this radio.

So - is there ANYTHING I can do re the settings: PIN, MAP, TINT that will lesson this effect - hopefully eliminate it as even if less frequent its still ugly as hell and not 'neighborly". And I fear it might damage the KPA - expensive fix if it happens.

Can I turn AUTO-CAL off and if so what should i see re the lights if PS is turned on (I see different colors)?

I really wish that someone would put some effort back in to 3.4.9 instead of what seems like totally abandoning it for Thetis. Thetis is a long way from being usable w/o concerns for reliability - and there are still things in 3.4.9 that need fixing. For example - I still have issues when I go on CW and PS seems to still be doing something because all of a sudden the ATT is set to 0 and I have seriously bad distortion in the signal. Setting it back up to say 31 sometimes works - other times it doesn't do a thing because it is back to 0 again. PS should be OFF in ANY mode other than those it is intended for - off for CW, DIGU/L. AND when off the ATT should be set at the highest value needed to ensure the max power it has seen is represented. I.e. if one typically runs 200W then maybe it is set to 20 when on CW ... if one occasionally goes to 1.5Kw then it might need to be at 31 (in both cases independent of the actual power in use, done as a precaution and only effecting the TX signal placement on the panadpater). PS OFF/ON should be mode dependent!

Thanks for your time and consideration.
Gary , K9RX

Re: PureSignal Problems

Posted: Sun Oct 27, 2019 1:52 pm
by w-u-2-o

I split this topic out from "PureSignal Release Notes" since it is a specific problem, worthy of it's own topic, and not directly related to the discussion of the release notes themselves.

Are you able to make a screen capture of the the "bananas" waveform that displays when this problem occurs? If you can do that it might be possible to better debug the problem.



Re: PureSignal Problems

Posted: Sun Oct 27, 2019 7:39 pm
by K9RX
I can try to capture it - but it is fleeting at best. The spectrum goes wild - WIDE - with the shoulders only a few db down from the peak. But again that event only lasts for a 1/4 second at best. Its there and gone but then PS takes over trying to re-correct and I immediately stop talking. If I'm trying to work someone I have the choice of going off to a clear frequency and saying 'ah ah ah' for it to come back in and then I go back - of course always done on a clear frequency.

I'll see what I can find.

And again back to my post: I'm not saying it isn't me. I'd be happy to find out its something I'm doing wrong if someone can just direct/correct me in that regard.

OR - to the point of the original post - can i maybe use those advanced items: PIN/MAP/TINT/turn off Auto-CAL and use it that way? Even if as a test to find out what is going on. I have the feedback line in clamp on ferrites (its only a few ft long) and it is doing the same with the KPA coupler as it did with the external Xytronic.


Re: PureSignal Problems

Posted: Sun Oct 27, 2019 8:06 pm
by w-u-2-o
I am totally guessing at what you are seeing. I suspect it looks like a massive picket fence across the entire IF bandwidth (192, 384, 768KHz, etc.)

If so, I have seen this behavior on my own system here under Protocol 1 and PowerSDR. This is on the 100D. However, in every case it was associated with a high VSWR event that I believe, meaning I'm not sure, caused the firmware/FPGA to malfunction due to some sort of internal EMI. Power cycling the ANAN hardware was the only way I could solve the problem.

Ultimately I solved this issue through improving my antenna, feedline and tuner layout and design, as well as a ferrite choke at the far end of the antenna coax such that I no longer got excessive shield currents at the ANAN during tuning (or a tuning--i.e. WU2O operator--error).

Because the issue is so fleeting you could try to capture video using OBS, then make a screen capture of the playback (i.e. no need to post the entire video).

Note that it is easy to believe that this only happens when PureSignal is enabled. The complexity of the processing in the FPGA gets much more complex when PureSignal is on. Thus it would take less of a firmware/hardware upset to cause problems.

IF any of my suppositions are correct, then it is not a problem with PureSignal per se, nor your software or audio configurations. If it's a problem when using two-tone then it's definitely not audio related in any way.