My Flex 6400 Tx is showing "hiccups" in its output waveform! Help, please!

N7DK Dave

I've been running my Flex 6400 for more than 5 years with great results -- over 16,000 FT8 contacts with few problems and the best DX I've ever enjoyed! However --

Please see the attached image of spectrum output into a 50-ohm dummy load. The output appears to be "hiccupping" periodically.

I have seen something similar in the past when I would run the rig 24x7 for days at a time. Based on an old recommendation from Tim, I learned that killing and restarting "DAX" would put me back in business. However this new "hiccupping" isn't cured with this method, making my think my beloved Flex 6400 may be dying of old age(?)!

Has anyone else seen this problem? Are there any things I might try to fix this?

Many thanks in advance for any suggestions!

73, Dave, N7DK, david@leeper.com

KT5N Jeff

Same here with my 6500. I thought it was possibly coming from a malfunctioning remote antenna coupler but it persists while using the ZS6BKW as well. I am running 3.4.23.

Eric-KE5DTO

First, I would recommend updating to the latest version (currently v3.5.9). There is a possibility this alone will address what you're seeing.

If that doesn't get you going, to get to the bottom of this I might temporarily change the network setup to directly connect the radio to your PC. This will eliminate any other network devices/config between the PC and the radio. If this eliminates the issue, then it may be time to look at any cables and devices (switches, routers, etc) in the original configuration.

Let us know what you figure out.

David Decoons, wo2x

Besides WSJT-X, what other software is running? Anything changed recently? What version of SmartSDR? If you haven’t upgraded to the latest version SSDr, try that.

Usually the “pops” which show as wide horizontal lines in FT8 happen when TCP commands are being sent to the radio while it is transmitting.

Dave wo2x

N7DK Dave

Replying to Jeff, KT5N, and Eric KE5DTO --

Thanks, Jeff -- it's a comfort to know I'm not alone! I was theorizing I have a marginal/intermittent connection in somewhere in my shack connections & remote tuner (swr monitors, scope, tuners, linear, coax switches, ... ) so I just tried a dummy load on the radio itself -- and the problem persists.

Thanks Eric -- I do have an older version of the software on the radio, and I'll try updating it. Because the "hiccups" occur even with a 50-ohm dummy load connected directly to the Tx output, there is something in the radio itself that has gone awry. I've been running the radio nearly 24x7 since April of 2018, so I've been guessing my final may be "aging out", but from comments of others, it seems more likely it's a software issue of some sort.

I'll post again if I learn more ...

73, Dave, N7DK

N7DK Dave

Replying to David, WO2X

I'm running Version 3.3.32 which is way out of date. It had been working so well that I didn't want to tamper with it. But the first thing I'll try is a software upgrade to the latest version.

Thanks & 73 -- Dave, N7DK

KT5N Jeff

So today I installed 3.5.9 and the pops went away!

Strange thing is why they started in the first place.

Jeff

N7DK Dave

Replying to Jeff KT5N

Your success in clearing the "pops" is encouraging -- I'll try updating my software too and hope I get the same results!

73, Dave, N7DK

John K3MA

I used to have the same issue. A reset of the radio such as when you upgrade the software would temporarily fix the issue but it would come back after a period of time.

Finally, I found what was causing the issue quite by accident. It turned out to be a raspberry pi which I had on the same network. I do not remember what I was using the raspberry pi for since I have many on the network. It might have been NodeRed, Ham Clock, AdGuard or something else but I can't be sure as I have repurposed that raspberry pi for other duties.

N7DK Dave

Replying to John K3MA -

Thanks, John -- that's another avenue to check out -- I only have one added program running that shows me the temperature of my Flex6400 final and the power supply voltage being supplied to the radio.

I'll try disabling that, although I've used it for years without this problem occurring.

I'm headed off to vacation in a couple days, so the tests will have to wait until I get back.

All these inputs have helped a lot -- I was thinking I might have to buy a new radio, having worn this one with 5 years of use almost 24x7! I'll try the software fixes first!!

73, Dave, N7DK