6700 Frequency shifting plus a problem with DIGU

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  • Updated 8 months ago
I normally use digital modes and I have run into a problem that is making them impossible.
After the 6700 has been running a while even if not transmitting the received audio frequency shifts by a few 100hz.
This is very noticeable on WSJT where the signals on the WSJT display show a sawtooth pattern of about 200 to 400hz. of course WSJT wont receive signals like that.
I have just been using Olivia and the same problem occurred.

Also I used DIGU for tranmitting olivia, but when I went to receive, the 6700  did not receive any signals, the only way to get back into receive mode was to change from DIGU to USB, (the receiver came to life) then back to DIGU to continue receiving.

So 2 problems, could it be a heat problem with the 6700, causing the frequency shift?, the room is cool about 55 to 60F and when transmitting I am not using more that 55watts output. and if not what is causing the problem??
And what is causing the 6700 to not receive after a transmission.??

I am using the latest SmartSDR

Comments please.

Thanks
Ross
ZL1WN
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Ross Biggar

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Posted 3 years ago

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Al K0VM, Elmer

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Ross,
   I have not heard of anyone reporting a problem like this with Flex 6xxx...  When the shift occurs does the SSDR dial also indicate a freqeuncy shift or just a shift in the WSJT waterfall.  If you shut down SSDR CAT does the shift still occur  ( shift coming thru CAT control ) ?  Do you have a Flex Knob ( try running without the knob) ?   

AL, K0VM
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Steve (N9SKM)

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Very odd indeed, mine seems very stable frequency wise. DigiU works fine for me for rx ant tx so possibly a HelpDesk ticket is needed.
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Steve K9ZW, Elmer

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Curious if the swing is persistent after software/hardware restarts, or mode changes when return to DIGU?

Sounds like a Zendesk Helpticket would be the route to dig deep into this one.

73

Steve K9ZW

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Alex - DH2ID, Elmer

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Is your power supply output stable? Have you tried another one?
73, Alex - Dh2ID
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Ross Biggar

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Thanks for the comments, yes the frequency shift is obvious on the SSSDR waterfall. I have just swapped the power supply from the 6500 to the 6700. I will see if the problem still occurs when testing today. One point I forgot to mention, after having the freq shift, I tried leaving the rig switched off for a few hours the problem did not reoccur after restarting, however it did start again after a further couple of hours.
Ross
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Al K0VM, Elmer

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Curious as to the amount of shift you are seeing..    The only thing I could think of would be a defective internal frequency reference,  a defective GPS DO if you have that, or if your using an external frequency reference it could be a marginal level..

Probably time  for the helpdesk to get involved.  


AL, K0VM
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Ross Biggar

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Thanks for the comment, I am not using a GPS either internal or external.
The frequency shift is about 100 to 150 hz and a period of 2 to 5 seconds, (both dimensions approx as it is they are the nearest I can estimate).
I have sent a note to the helpdesk.
By the way it does appear to be a heat or similar problem, as the shift started again after 2 hours this morning, I turned the rig off for an hour and the shift did not reappear. I will wait another hour to see what happens.
Ross
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Bob Sarnecki

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Hi, Ross.  Was curious to know if/how this was resolved; I am having the exact same problem.  Does not appear to be heat related; 6700 seems to be running cool, but it does appear after a few hours of use.  When it occurs, WSJT-X will not decode on FT-8.  Any insights would be appreciated! 

Thanks & 73,

Bob
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