ANAN 8000 DLE Intermittent Audio frequency drift

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vk6cpu
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Location: Perth, Western Australia

ANAN 8000 DLE Intermittent Audio frequency drift

Postby vk6cpu » Fri Nov 22, 2019 12:09 pm

MOVED FROM Orion Mk II (7000DLE, 7000DLE MKII, 8000DLE) section

I have an intermittent problem on both RX/TX in digital modes ( I don't have a mic' so can't comment on analogue :oops: ).

The screenshots below probably serve better than words to describe the issue.

When the problem occurs the frequency drifts by ~+- 15 Hz with a periodicity close to 60 secs and gradually "decays/Returns" to normal over a total period of 8 mins.
Within this period its not possible to decode a received or transmitted WSPR signal.

The issue can be seen on all types of signals/traces (beacons on spectran, FT8 etc) but for convenience I've used WSPR in the screengrabs

The problem is intermittent and the RX can run for hours without an issue.
However, turning VAC1 off and back on again whilst the radio is running will trigger the issue.

The issue affects both received and transmitted signals.

Has anyone else experienced a similar issue or can offer advice on trouble shooting to determine whether its a hardware or software issue?
I'm tending towards a hardware problem unless there is something I have set up incorrectly in Thetis.

Set up is as follows :
Hardware:
Anan 8000DLE
INTEL NUC 8i5 16GB RAM
BG7TBL GPSDO
Software
Thetis v2.6.9
Muzychenko VAC v4.60 :: (Cable 1 (VAC1) RX1 OP, Cable 2 (VAC1) IP, Cable 3 RX2 (VAC2) OP)
I installed VMB in place of VAC and got the same issues. So unless its a set up issue with both ..guess not likely cause.

I've eliminated the following as being the cause ... the drift on RX signal is seen on whatever S/W displays the digital Audio signal.
JTDX 2.1.0 rc142 / WSJTX 2.1 / Spectran V2

The "drift" occurs with or without the GPSDO being connected.

VAC1(DDC2) & VAC2(DDC1) both use ADC0 - the issue is present on outputs from both DACs

Zooming in on the panadapter and reducing FPS I have not been able to see this drift - thats not to says its not present.

2019-11-22 RX shift decay.PNG
2019-11-22 RX shift decay.PNG (552.59 KiB) Viewed 447 times


(Above screen grab - showing WSPR RX)

composit TX.png
composit TX.png (592.27 KiB) Viewed 447 times

(Screen grab showing transmitted WSPR signal captured on another RX in shack Upper trace normal, Lower trace showing frequency shift/cycle)

2019_11_22 VAC set up.PNG
2019_11_22 VAC set up.PNG (37.5 KiB) Viewed 447 times

VAC Setup

I have also tested on a desktop PC I7 with 32 Gb Ram with same results - so I guess that excludes PC hardware as the underlying issue.

Any helpful comments appreciated.

I spend most of my days restoring 1930's tube/valve radios - so trouble shooting digital is a new and not as tangible (or even intuitive) experience (to me anyways).

Thanks
Last edited by vk6cpu on Fri Nov 22, 2019 12:26 pm, edited 1 time in total.
All the best
Nigel
VK6CPU

Anan 8000 DLE, Thetis v2.6.9 (a5_1) , Protocol 2 V2 pre-2
INTEL NUC8i5BEH 16.0 GB Ram
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vk6cpu
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Location: Perth, Western Australia

Re: ANAN 8000 DLE Intermittent Audio frequency drift

Postby vk6cpu » Fri Nov 22, 2019 12:13 pm

Another couple of screen grabs.

First showing issue after cycling VAC1 off/on.
Black dark line across screen indicates where VAC was cycled

desk top cycle VAC.PNG
desk top cycle VAC.PNG (693.05 KiB) Viewed 445 times


Second Screenshot below shows "random" occurrence with no obvious trigger

randopm wobbles.PNG
randopm wobbles.PNG (663 KiB) Viewed 440 times
All the best
Nigel
VK6CPU

Anan 8000 DLE, Thetis v2.6.9 (a5_1) , Protocol 2 V2 pre-2
INTEL NUC8i5BEH 16.0 GB Ram
Helmut
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Joined: Sat Jul 15, 2017 3:08 pm

Re: ANAN 8000 DLE Intermittent Audio frequency drift

Postby Helmut » Fri Nov 22, 2019 2:28 pm

Hello Nigel,

this is similar to what I posted some time ago,

Image

I have set now both VAC to Force. It is here Vac2 but same settings for Vac1 when doing FT8 etc.

Image

So I see that it is not only with the VoicemeterBanana Drivers that I use, also with your Muzychenko VAC´s.
And I use also an GPDSO 10MHz with my 7000dleMKII.


73 Helmut
dl9eri / oe9eri
Last edited by Helmut on Fri Nov 22, 2019 6:26 pm, edited 2 times in total.
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w-u-2-o
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Re: ANAN 8000 DLE Intermittent Audio frequency drift

Postby w-u-2-o » Fri Nov 22, 2019 4:50 pm

Yes, this is almost certainly the resampler in VAC being unstable.

Show us a screen shot of your VAC1 settings please, and describe what the over and underflow counters are doing when you see drift.

Thanks,

Scott
Helmut
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Joined: Sat Jul 15, 2017 3:08 pm

Re: ANAN 8000 DLE Intermittent Audio frequency drift

Postby Helmut » Fri Nov 22, 2019 5:34 pm

Hi Scott,

no under and overflows when VAC Force is disabled - the waterfall looks like normal, but the audio is pigtail hihi.... 73 Helmut
When Force is enabled I can run for hours in FT8 without any flaws and flows....

Image

Sorry, Scott, was to fast ..... so let´s wait until sunrise in Australia !
Last edited by Helmut on Fri Nov 22, 2019 6:27 pm, edited 2 times in total.
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Re: ANAN 8000 DLE Intermittent Audio frequency drift

Postby w-u-2-o » Fri Nov 22, 2019 5:52 pm

Helmut,

I was really asking Nigel.

Also, under and overflow counters don't operate when "force" is checked: the resampler is disabled.

What I wanted to know was whether or not Nigel was achieving stable resampler operation, i.e. under and overflows not significantly accumulating (a few per hour is acceptable) with the resampler enabled (force off).

You must be cautious in your VAC settings in order to achieve stable resampler operation. That's why I wanted a screen shot of Nigel's VAC1 screen.

Finally, don't forget that you can click on the counters to zero them in order to better keep an eye on things. It is normal to obtain a burst of under and overflow counts at startup, but they should stop accumulating if you have VAC settings correct for stable resampler operation on your system.

If you can run the resampler in stable fashion then theoretically digi mode performance is improved. Whether that improvement is perceptible to you is another story.

73,

Scott
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vk6cpu
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Re: ANAN 8000 DLE Intermittent Audio frequency drift

Postby vk6cpu » Sat Nov 23, 2019 1:44 am

Scott/Helmut

Thanks for your responses .. I think you have nailed it for me.

I had to wait quite a while this morning for condition to manifest itself.

On start up there were about 6 underflow/overflows reported - I cleared these and the system ran fine for about 2
hours. I spotted the frequency drift and simultaneously noticed under/overflows jumped from 0 to 5 with no further change.

Screen capture below.

vac2.PNG
vac2.PNG (221.59 KiB) Viewed 385 times


I then checked the 'force' boxes and "frequency drift" appears to have gone.

I'll keep monitoring and keep my fingers crossed.
All the best
Nigel
VK6CPU

Anan 8000 DLE, Thetis v2.6.9 (a5_1) , Protocol 2 V2 pre-2
INTEL NUC8i5BEH 16.0 GB Ram
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w-u-2-o
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Re: ANAN 8000 DLE Intermittent Audio frequency drift

Postby w-u-2-o » Sat Nov 23, 2019 1:56 am

"Clearing" the counters has no bearing on the issue.

Only a few under/over flows in an hour should not cause any appreciable frequency drift.

I run the resampler with JS8Call on a regular basis, see occasional counts in the counter, but do not see any frequency drift.
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vk6cpu
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Location: Perth, Western Australia

Re: ANAN 8000 DLE Intermittent Audio frequency drift

Postby vk6cpu » Sat Nov 23, 2019 3:04 am

Following on from Helmut's comments - I also found the " resampler" thread which was very helpful in explaining/understanding whats happening.

I didn't expect clearing the counters would have any affect .. just easier for me to spot a change from 0 to something.

Really appreciate all your explanations in the various threads Scott.
All the best
Nigel
VK6CPU

Anan 8000 DLE, Thetis v2.6.9 (a5_1) , Protocol 2 V2 pre-2
INTEL NUC8i5BEH 16.0 GB Ram

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