8000 Series Audio drop out with NR Noise Reduction on SMART-10697

G2YTpeter

I recently took delivery of a new 8600 radio, and it is exhibiting a strange and annoying problem that has been acknowledged by the Flex Radio help desk and has been allocated a fault reference SMART-10697. I am running FW v 3.8.21

I know from searching the Flex Community site that at least two other owners of 8000 series radios have been having the same problem (one 8600 and one 8400). The problem is that when the NR is being used on SSB, quite often, upon unkeying from a transmission all RX audio is lost. The only way to resume reception is to un-check the NR system, whereupon the normal RX is resumed… but of course without any noise reduction.

Once the audio has been lost, disengaging the NR will restore audio, but once it has happened on an active Slice, the moment NR is re-applied to that slice the audio will drop out immediately upon unkeying from a further transmission. The only (temporary) cure is to close the active slice and open another one. Sometimes the audio will drop only after a couple of short transmissions… sometimes it will remain OK for more than an hour, but it always ultimately happens.

Can it really be only three 8000 series users that are experiencing this irritating problem? It seems from where I sit that the 8000 series radios have not been very thoroughly field tested. I also don’t understand why the Help Desk tickets are closed and further emails to Flex asking questions about this irritating situation go unanswered. This is the first time that I have ever had any criticism of the after sales service offered by Flex. It has always been superb in the past.

I access my 8600 my using SmartSDR for Mac and the other two known sufferers are both using SmartSDR for PC, so it is certainly not an issue to do with the Mac.

I have used a 6400M in the same way for several years and never had this issue. Tim Ellison has told me that it is most likely caused by a ‘race condition’, which is essentially a problem caused when figures in calculations being done in firmware do not add up, or go wrong, causing an odd situation…. In this case a loss of RX audio.

I have not been given any priority status on the fixing of this acknowledged fault. I suspect that the firmware resources at Flex are being dedicated to the incorporation of Adaptive Predistortion… which I would really like to see, but I consider this audio loss irritation more of a priority. It has been more than TEN years since Flex announced that the 6000 series would incorporate APD and it never materialised… and we now know that it wasn’t feasible with the hardware in the 6000. So we haven’t had APD for mor than 10 years… what difference would 10 weeks make!?

Mike-VA3MW

I want to acknowledge the frustration you must be feeling. It’s clear that this RX audio loss issue is impacting your ability to enjoy your radio fully.

Regarding the fault you’ve referenced (SMART-10697), our engineering team has indeed identified this as a “race condition”. While such issues can be particularly challenging to resolve, I can confirm that it is an active item on our development team’s list.

I understand your concerns about priorities, and while our team is working on enhancements like Adaptive Predistortion (APD), I want to assure you that resolving critical bugs like the RX audio loss is not being overlooked.

As for the closure of your Help Desk ticket, I apologize if it gave the impression that the matter is not being addressed. The ticket closure system sometimes indicates that a resolution is pending an update and has been passed to engineering.

While I can’t provide a definitive timeline for the fix right now, it is being pursued.

Thank you for your candid feedback.

73

G2YTpeter

Mike, I appreciate your fast response. Before I retired I had past extensive experience of developing market leading complex electronic products involving the development of sophisticated Machine Learning/AI back in the early 1990’s. I have experienced the frustration that your team are probably experiencing now… Having been in the ‘driving seat’ of a company which experienced similar hard-to-track down firmware issues I can appreciate it from your side too. The point is that I never have too bad a feeling when products have problems… its almost a ‘given’… Your direct response has given me some confidence That it will get sorted sooner or later (I hope the former!) My frustation had boiled over to some extent because other than this big irritation it is a terrific radio. I’m also sure that there will be other super developments in NR and ANF that will put the 8000 series at the pinnacle of performance in the coming months.

Yes, I feel let down by lack of feedback from Flex on this issue and the closure of Help Tickets when the problem is evidently still present. I I have never felt let down by Flex before.

G2YTpeter

Mike, I hope that you see this additional response because it might help the people in the company trying to replicate and fix this annoying issue.

This morning I went on the 8600 with NR engaged (but no ANF) at about 07:30 20m SSB and spoke to various fellows in JA, ZL and VK in a fairly long rambling style of 'ragchew' QSOs until 11:15… so more than three hours operating without the audio dropping out. Everything fine.

To be honest, every time I unkeyed the PTT I was expecting to have to disengage NR but it didn't happen. Finally I found myself in QSO on the same band SSB and then there was a CW carrier, so I engaged the ANF.

On the very next un-key of PTT the audio dropped out and I had to uncheck the NR.

Please note… it definitely also happens when the ANF is not used, but it seems more than a coincidence that I can have 3+ hours of continuous correct operation, then the moment I also engage ANF the audio drop-out happens.

Please acknowledge receipt of this observation,

Regards,

Peter Fox

G2YT

n8wrl

I am the 8600-owner running Windows that Peter referred to.

I too have had (very few) periods where the drop-out doesn't occur. One was when a good friend who has an 8600 on order came over to see the problem in action. I couldn't make it happen! Literally minutes after he left it did happen. It happens every time I operate. As Peter said, sometimes it happens right away, other times it will be fine for 20-30 minutes. I operate SSB more than CW so ANF isn't a trigger for me.

I really think Flex should reconsider their close-the-ticket policy. I have worked for and with helpdesks in the past. Customers need assurance their problem is being worked on. Closing a ticket is the wrong message.

73 and thank you!

-Brian n8wrl

G2YTpeter

Further discoveries regarding the audio drop-out issue

Today I arranged a sked on 17m SSB with the other two known sufferers of the 8000 audio drop out issue (KA9EES Ed 8400 and N8WRL Brian 8600). During our QSO’s we were able to identify what seems to initiate these audio drop outs. Hopefully these notes will allow Flex Radio to home in on and fix this firmware defect… I call it a “firmware defect” because that is what Tim Ellison of Flex called it, but our feelings are that if only three of the currently supplied (as of January 2025) 8000 series radios are reporting this problem, maybe it is hardware related too.

I had previously commented that I had only lost audio when unkeying from a transmission when NR was enabled. I have now discovered that this is not the case… it is when I had NOTICED it before, but we have now been able to reproduce the audio drop-out at will. During a QSO with Brian N8WRL we were able to cause loss of RX audio by turning on ANF and NR at the same time. The frequency of the audio drop outs increases massively with both ANF and NR simultaneously enabled… it would usually occur within only one or two ‘overs’. Both our 8600 radios were behaving identically. Mine operated by SmartSDR for Mac and Brian with SmartSDR for PC.

It is clear that although the ‘Audio Dropout’ problem can and does happen when only when NR is engaged (no ANF)… the act of turning on ANF makes it MUCH worse and MUCH more likely to happen. Furthermore, very significantly both Brian N8WRL and myself were able to **** RX audio during reception by enabling NR… so it does NOT only occur when unkeying from a TX on SSB as I had previously commented. 

I also managed to stop RX audio by using the inbuilt ATU in the 8600 whilst NR was enabled, and this is presumably a CW transmission.

Audio recover is obtained by un-checking NR.

Trucker

That is definitely a race condition in the radio's firmware. Two functions trying to use the same resources at the same time. Neither one can complete what it is doing when the other attempts to use shared resources. I believe that it can be fixed. Hopefully, Flex Radio developers will track it down sooner than later. I have tried to replicate the problem with my 6600M and v3.8.21 just to be sure it isn't a shared problem between both series of radios. So far, I have not been able to make it happen.

James

WD5GWY

n8wrl

Good stuff Peter - to summarize my findings. I can make this happen on an 8600:

1. Enable NR and ANF
2. Transmit

When the transmission is over, there will be no audio until I DISengage NR. The state of ANF is not important at this point. As long as NR is engaged, there will be no audio. With NR disenaged, I have audio and can transmit just fine. We tried all four combinations:

NR ANF

OFF OFF Audio ok

OFF ON Audio ok

ON OFF No audio

ON ON No audio

The only remedy is to close the slice as create another. Note that if I enable NR and ANF on that slice audio will be muted.

73

Brian n8wrl

Mike VE3CKO

I have an 8600 and tried to duplicate this problem. With Slice A open in one panadapter, Enabling WNB, NB, NR and ANF, then transmitting via PTT, TUNE or MOX did not cut out the audio. However when using the ATU, upon Success, the audio was muted. Toggling NR to OFF brings back the audio. Toggling the NR to ON brings mutes the audio.

Opening another slice on same panadapter, Slice B, the NR is normal and not muting the audio. With Slice A still open NR on = muted audio, NR off = unmuted audio

Closing Slice A and reopening brings things back to normal.

G2YTpeter

Hi Mike, welcome to the club that nobody wants to be a member of! :-) Now there are four of us.

Yes, I find exactly the same with my 8600… Un-toggling the NR is the action which restores audio.

73

Peter

G2YT

Mike VE3CKO

I'm not worried about it at all, I don't use NR so it doesn't affect my operation one bit. I just chimed in for my perspective, to see if I can duplicate it, then provide the results so to perhaps assist them, not to complain at all. Things happen, they will fix it.

n8wrl

Thank you for sharing your experience Mike. Peter and I are concerned that, if so few others can make this happen, maybe something is wrong with our radios.

8x00 users: Even if you don't use NR or ANF please try to replicate this behavior. The more ops who report it the more interesting it gets to Flex.

Thank you all!

73

-Brian n8wrl

OK2WY

I have tried it as described in Brian's post and can confirm that this error occurred for me as well.. 8400 & v3.8.21

73 Jiri OK2WY

ad4vxtom

Hello, I am an infrequent SSB user, however, I am also a casual contester. This past weekend during the ARRL SSB DX contest, I encountered the same issue stated above. I have an 8600 running SmartSDR v3.8.23 on a Windows 11 PC. Frankly I fixed the problem by swapping the box with my still owned 6400.

The latest dated prior post is from 23 Jan 2025, has this issue been resolved? I do not use the internal 8600 ATU as the 8600 drives an amp, so did not test that configuration. I also did not test closing the slice and opening a new slice. What I did is go to Profile Manager and select CW then return to SSB and audio returned.

Any resolution to this issue would be most appreciated.

-73, Tom, W9TO