Intermittent Echo/reverb and modulation % drops

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This is a Flex 6500 running 1.11.12 SW and has perfirmed very well in its present configuration for the last year and a half. No physical changes have been made to the system. I did experiment with creating global profiles but don't believe that has caused this issue.

I have an intermittent echo or reverb on transmit audio and the percentage of modulation drops on AM or the output level on SSB drops. I have made many tests or observations which I will list below. Please bear with me as the list is considerable. Thanks in advance for your suggestions. Here we go:
1. It presents sidebands of who knows what on AM or SSB on the panoramic display with no speech input but there is no RF generated on SSB and only odd noises transmitted on AM.

2. Happens with or without my amplifier.

3. Happens with or without a dummy load or antenna.

4. Happens with or without the processor.

5. Downward expander will help but with 44 setting, it will cause a pulsing in audio. About 65 will eliminate the sidebands but modulation will still drop.

6. Does not happen in tune, of course but there seems to be some noise (junk) on either side of the carrier on the pan display.

7, The only background noise is from the Flex 6500 fans. It is an otherwise very quiet room.

8. I have tried various mics: D-104, Yaesu MD 100 and the hand mic.

9. Modulation percentage will suddenly drop during transmission.

10, I had set various global profiles for AM and SSB operation but to eliminate them I returned to all default conditions and it still does this.

11. This had happened a few times but very rarely in the last few weeks but now it can happen most of the time.

I hope someone can give me an idea as I am out of things to try.    Best 73, Jim     KD1I
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James Del Principe

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Posted 2 months ago

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Rick WN2C

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Have you move the radio, cables or antenna cables? Try re-booting the radio or save profiles that you created to your computer and re-load the software after doing a reset.
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Bill -VA3WTB

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It sounds like RFI, I know you will say nothing has changed,,but it really sounds like RF, will it still do it on low power,,say 10w
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James Del Principe

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Rick, I have not moved the radio nor re-cabled it. That will be next.
Bill, It certainly can be RFI but I wonder how this happened with no changes made. As for power, AM is at 24 watts carrier which is pretty low.    In SSB, the problem happens with no RF output but the audio must be flying as noted on the panadapter with nothing indicated on a wattmeter.

Thank you both for the quick replies.     Jim
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Bill -VA3WTB

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Maybe a factory reset? then bring in your saved profiles
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James Del Principe

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Yes, this might work.   Bill, I will try this in the morning..... getting pretty tired now. Thanks for your help.    Jim
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James Del Principe

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OK, I just tried the power level test.   On AM or SSB, with power at 1 or higher the problem persists. With RF power set to zero, it does not do this.    The DEXP still controls whether the problem occurs.   With the DEXP low or off it has these annoying sidebands. With the DEXP up high, it does not. I thought for sure it was related to FR leaking in somehow but now I am not so certain.... just keying the mic in SSB does not produce RF except for a brief moment of contact as it always has done. But with no audio, it does not have RF out (at normal settings) but the sideband shows up on the panadaptor screen......    Jim
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Rick WN2C

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I had the same problem w/ my 6400 when the processor was set to DX. I had stations tell me that I had an echo but when it put it on normal it was not there. Check you processor level and the mic gain setting.
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WA2SQQ

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RFI due to an intermittent high SWR? Watch ur SWR when it occurs. Is it limited to one band?
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James Del Principe

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Well, the SWR is very low on the antennas due to the tuner and, of course low on the dummy load. I have tried it with processor on and off. For AM, I use the processor off in any event. I have tried various mic levels but not zero mic gain. The D-104 has very high output as does the hand mic so they are set low and the MD-100 has low output, typical for a dynamic mic. The DEXP will eliminate the unwanted sidebands if it is set high, around 65 or so (not the modulation drop, however) but that is masking the fundamental issue, I think.
This occurs on the several bands that I have tried. Thanks for the input.     Jim
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Ken - NM9P, Elmer

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I second the suggestion for a factory reset (after saving your profiles). If that doesn’t help, then you might need to reinstall SSDR.

Other than that, I would look at antenna or grounding changes, changes in your connections to the computer, or other things that may be causing RF feedback, ground loops, etc.
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James Del Principe

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Thanks, Ken. I will reduce the configuration to bare bones and then do the reset you suggested.   If that does not do it, then I will reload SW.......  or go back to the DX 100.   OK, just kidding.     Jim
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WA2SQQ

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What happens when you run the radio into a dummy load?
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Bill -VA3WTB

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3. Happens with or without a dummy load or antenna.
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KC2QMA_John

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I have had the same problem for a few years. Every once and a while People will say they hear RF or some kind of echo on my SSB audio and the thing that fixes it every time is just simply restarting the radio and the problem is gone?

(Edited)
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James Del Principe

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John, I have restarted the radio and rebooted the computer many times. Next, I will strip the computer of peripherals such as the USB hub and speakers leaving only the speakers to the Flex.... Then it is factory reset and finally reload SW.    

Thanks again for input.   Jim
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Michael Walker, Employee

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Here is what Tim recommends and due to the possibility of RF feedback, we need to make 100% that isn't the issue.  

I know that we all think we don't have any (me included), but there are times it does creep in.  I just recently had it and it was 100% related to a loose PL259.

  • Disconnect the antenna and test into a dummy load.  
  • If on a 6600 or a 6700 can you monitor it on 2nd slice while in full duplex? -- on another type of radio, so you have a 2nd radio.  No antenna required.
  • Does this radio have all the ECO updates?
  • Does a warm boot of the radio solve the problem (do the dummy load test first)
  • If not, does a cold boot fix the issue?
  • If that does not work, export the profile w/o the Preferences selected and try a factory reset
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James Del Principe

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Thank you, Michael. I have tried using a dummy load but it runs through a switch and short lengths of coax. I will connect it directly.    
This is a 6500.
ECO updates?    I had removed SW from the computer a few weeks ago to do the Microsoft upgrade and then reloaded Flex SW. Do you think I need to do that again?
Neither warm nor cold reboot corrected this issue.
Not sure what you mean by export the profiles w/o preferences.   I can just delete the profiles if it comes to that.... I just started experimenting with profiles recently (used memories prior) and only have about 12 or so. I can just rebuild them no problem.
As I remember, factory reset is a turn on from cold while holding down the middle button. Correct?     73, Jim
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Michael Walker, Employee

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It was a more generic comment.  There are no ECO updates for the 6500, so I apologize if I confused the situation.  

Yes you can export profiles and reload them.  It is outlined in the SmartSDR  manual.   Cold reboot is to hold the button down until it turns purple (I think).  Sorry, I am at lunch and don't have a manual handy.

What we want to do is make it as basic and simple as possible and see if we can recreate it.

Mike
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Bill -VA3WTB

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James, on restart hold the power button and the center button in together,,the radio display will count to 0 then release the light will turn white for factory reset
(Edited)
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James Del Principe

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Thanks, Guys. I removed the usb hub connection to the computer and speakers. Next, I connected the dummy load directly to the Flex.   Same problem.

I hope I did the factory reset correctly. With the radio off, I held the OK button (center button) down while holding the power button. It gave a countdown to zero and said 'factory reset'.

I had exported the profiles to a folder before doing this. However, after rebooting after the reset, I found the memories and profiles were still present. My understanding is that they would be wiped out.   Did I not do the factory reset correctly?   I honestly did not notice the light color.   Maybe I should just do it yet again.     As always, thanks for all the help.   73, Jim
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James Del Principe

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Guess I did not hold the buttons down long enough.   I held them longer this time and the lamp went into a white flashing mode. Then the memories and profiles were wiped so a re-import brought them back.  I tried recording my voice and playing it back and it sounds OK. The sidebands present in the panadapter display are still there with no DEXP (but not on the waterfall) so I did select some level of DEXP.  
Modulation level is higher now on AM and sideband seems to be putting power out for now.

I will need to do some on air testing with my AM roundtable tomorrow morning to see if the echo / reverb returns.

My sincere thanks to all of you who gave of your time and talents.....    I may be back if it crashes but looks good now.       Best 73, Jim       KD1I
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James Del Principe

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Well, I spent some time on AM today ragchewing and then on SSB with a friend shack ratting.   The Flex worked just fine with no hint of echo, reverb or low modulation level. I believe the 'return to factory settings' did the trick.   Reloading the settings and profiles was quite easy and intuitive (that means I didn't read the manual - just like a true ham) so thanks again to all who helped me.    73, Jim