On FT8 transmit audio cracks/pops Flex-6600

When running FT8 transmits pops/crack noise when. My radio is a Flex-6600 running SmartSDR 2.4.9, WSJT-X, 100watts. Power Supply is 50 amp Astron (non-switching) Some times 2 or 3 in a 15 second transmission. It is not predictable just when. It seems to be affecting the decoding by the person I am QSOing with. He misses decodes when I am -10 db for example.My computer is a Dell 3668 I7-7700 and SSD drive, plenty of CPU and DRAM. Cat 5 eithernet cables from comcast modem/router.

I am attaching a screen shot I just made and you can see the horizontal spikes on the waterfall as well as hearing it in the MONITOR headphone. I am using the tune button on wsjt-x. It is much more pronounced when in a QSO probably because of wider bandwidth. Also used Flex Tune button. first picture,

Looking for ideas or things to check to further define problem. 2 Image: https://d2r1vs3d9006ap.cloudfront.net/s3_images/1760396/RackMultipart20181104-6048-15j3wrb-Transmission_dummy_load_Tune_inline.png?1541293862

Image: https://d2r1vs3d9006ap.cloudfront.net/s3_images/1760396/RackMultipart20181104-6048-15j3wrb-Transmission_dummy_load_Tune_inline.png?1541293862

pictures attached. Look at the black waterfall segment. The first screenshot is into a dummy load with 100 watts and 0 watts. Keyed with Tune button. Not a bright on 0 watts but there as you can see in first pic. Second screen shot I took first into antenna, 100 watts wsjt-x keyed. This is not new just seeing more missed calls as operating much more FT8. When operating it is not as consistent or repetative as as shown in the pictures. Image: https://d2r1vs3d9006ap.cloudfront.net/s3_images/1760398/RackMultipart20181104-71503-167hy5o-Transmission_with__wider_pan_bandwidth_inline.png?1541294686

Image: https://d2r1vs3d9006ap.cloudfront.net/s3_images/1760398/RackMultipart20181104-71503-167hy5o-Transmission_with__wider_pan_bandwidth_inline.png?1541294686

I just add a third screen shot that is a better picture just above 73s.
73
Bill W9JJB Image: https://d2r1vs3d9006ap.cloudfront.net/s3_images/1760395/RackMultipart20181104-16951-59i5cs-Noise_on_FT8_transmission_inline.png?1541293593

Image: https://d2r1vs3d9006ap.cloudfront.net/s3_images/1760395/RackMultipart20181104-16951-59i5cs-Noise_on_FT8_transmission_inline.png?1541293593

bahillen

162 Posts
57 Reply Likes

Posted 11 months ago

11 months ago

bahillen

162 Posts
57 Reply Likes

I have run some more testing and found something interesting. If I have a panadapter on 20m and one on 15m and one receiver on each band. I get a click on the 20m transmitted signal when I change the 15m receiver slice from say CW to SSB. It is very repeatable and happens every time. I did this by tuning my Yaesu radio FT1000MP to listen to the Flex 6600 transmitted signal. I am using a dummy load. Neither wsjt-x or slicemaster is running for this test. The click signal is about 700 hz below the carrier on only the low side. I also get some click once in a while 10-80 seconds but more centered on the carrier. I see these clicks on the panadapter and in the Yaesu receiver audio.

73
Bill W9JJB

Comment

11 months ago

Gary Wells

6 Posts
3 Reply Likes

I am having the same snap sound every few seconds as well from my 6700 under the same scenario as Bill while in the receive mode. It is unnerving when a loud pop randomly comes from the speakers. I'll do more testing following Bill's approach.

73
Gary
WB9AYD

Comment

11 months ago

donh

10 Posts
0 Reply Likes

I had a similar problem with my Flex 6300 on ft8. I was able to reduce the scope of the problem to using the tune button into a dummy load on low power. I powered down the 6300, turned off the power supply, waited 10 sec., turned on the power supply, turned on the 6300. The problem was gone and has not reappeared.

Speculation: There may be a software synchronization problem among the various radio control processes that is resolved by a hard reset.

73,
don
wa0ruf

Comment

11 months ago

Ben Laws

2 Posts
0 Reply Likes

I had a similar issue which was solved by upgrading the DAX to 2.4.9. It was easy to do, there are instructions at flex. Ben : W6PXE.

(Edited)

Comment

11 months ago

Sergey, R5AU

862 Posts
117 Reply Likes

I have no issues such described above with my 6700 and ver 2.4.9 btw usually I have at least 2 PAN , one with Digi(FT8) and second / third with CW( SSB not my favorite mode)

No interrupts, No cracks, I am running under virtual machine with Parallels ( 4 virtual CPU core split) on my Mac in parallel with CWskimmer+ Log+slice master +DDutil and on Mac as well some apps running simultaneously

CPU utilization :

in Win =~ 30%

Total =~ 40%

(Edited)