Possible clue to the lost power issue

Pat N6PAT

On Monday I worked a lot of FT8 with no problems at all. I had more than 100 contacts throughout the day on 20, 40 and 80 meters.

On Tuesday I noticed the power drop to zero a few times while working FT8 again. I tried to reboot SSDR with no luck and ended up rebooting the 6700.

Today it happened again but I found a solution. When the power drops to zero I move off frequency, shut the amp  and hit the Tune button set at 10 watts. I then move the tuning power up to 49 which is my global limit and the power shows 49 watts.

This returned the radio to normal power output. I've had to replicate this several times while working FT8 and the results are the same. This may be indicating a software rather than a hardware issue as the radio performs normally once I go thru the tune routine.

I've only had this problem with FT8 so far.

I suggest that others try this when they lose power. If others experience the same results then it just might shed light on the source of the problem

fyi...I need Delaware on FT8 so if any of you wonderful folks in Delaware are planning on doing FT8 please let me know

73 Pat

 

Andrew Thall

How much power are you running on FT8.  It is a low-power mode.  10 to 20 watts is more than enough.

Pat N6PAT

Running about 30 but my global limit is set to 49. That's where I move it up to after I tune at 10 to make sure I'm getting the power I expect to.  I then drop it back down after I know all is well.

It's interesting that this only happens with FT8 so far. I don't think it's a heat issue as I'm running two air conditioners and the radio performs for hours without issue after I run my little tune routine.

Don-KB6TSQ

Andrew,

Are you close to an edge of the transmit bandpass width when the power drops?  In the PHNE tab, make sure TX: Low cut is set to 0(zero)  This is the TX bandpass for transmit.  As you approach the low cut or high cut for that matter, you will begin to lose power.

Just my two cents
73 Don

Chris DL5NAM

Andrew, your wrong with << It is a low-power mode>>

It's a weak signal mode (as the name says: WSJT = Weak Signal and JT is the part of the call of WSJT programmer) and any power level you using is dependent on propagation like all other modes we working on bands

KY6LA_Howard

FT8 is NOT A LOW POWER MODE

It is a WEAK SIGNAL MODE

When working weak signals below say -17dB -it helps to boost your power

I typically run 100W when working -17dB or below

Don-KB6TSQ

I should have replied to Pat not Andrew....Kind regards Don

Mark WS7M

The weak signal discussion aside I think the "workaround" is interesting.  I will check my system when I have a chance and see if this makes a difference.

Thanks for posting your results!

Chris DL5NAM

Sorry, yes 

Tim - W4TME

Let's not derail this post by getting into a discussion on a mode's power.

Pat, you need to employ the "divide and conquer" technique of troubleshooting.

First, remove the amp from the TX signal path and work enough stations to see if that makes a difference.

Power output is determined by 2 things, the input signal level, and the PA converting a low-level signal into a high power signal.

When this happens next time, switch the antenna port to a different connector that has a dummy load connected to it and do not change frequency.  The click on TUNE.  If you get the proper power output, then it is safe to say that the PA is working properly and you can eliminate it as a possibility.

How you have to figure out if the digital mode program is sending enough audio drive.  You should be able to hear the tones in the monitor when transmitting.

Also, when you change frequency, that also changes the frequency of the digital mode program and that action may be enough to "wake it up" and make it start working again.

Good luck in your troubleshooting endeavors. 

Pat N6PAT

Don,

I checked and the low cut was set to 50 but I don't think I was close tot he edge.  Also, each time it happened I was right in the middle of an FT8  QSO without any changes to the TX frequency. I would exchange the usual initial messages and then just as I started to send the RRR or 73 it would drop without any changes being made

Ken - NM9P

Another possibility to check...I wonder if this could be a SWR foldback problem?  If your amp or antenna is presenting too high a mismatch, or a reactive load, the protection foldback may be kicking in at certain frequencies.

I have had this happen when I forgot that I had last tuned the ATU on a different antenna and switched from the dipole to the vertical in a hurry.  It often didn't seem to fold back until about 30 seconds or more into my transmission.  When I re-tuned the antenna, the problem went away...

Ken - NM9P

Tim - W4TME

Hence my suggestion to remove the amp from the TX signal path.

Pat N6PAT

Tim,

It just happened again before I read your post. I was working WC3N on 40 FT8 and after sending 2 messages the power cut out. I dropped down the band a little and shut off the amp and hit the tune. The power came back as expected.

I'll use your instructions next time but at least now the actions and results are consistent which gives us something to go on

Pat N6PAT

I have very good SWR. Just using my trusty Hustler 6BTV which is a very remarkable antenna. The amp is a THP 450B. Never had a problem with it in 5 years

Tim - W4TME

Divide and conquer.  Make no assumptions.

Ken - NM9P

Note to self:....make sure my reading glasses are on straight before typing.....he he.

I missed that and thought you were just eliminating the possibility of the amp itself failing.... readjusting glasses and rereading post cleared it up!  ha.  

  /    (dunce cap...)
{oo} 
   >
 ***

Ken - NM9P

Pat N6PAT

OK...I took the amp out and made FT* contacts for a while on 20. I switched to 40 and started to make an FT8 contact. I immediately lost power.

I switched to a dummy load without changing frequency and staying in digi and still no power.

I then switched to LSB to the dummy load and power came back. I then went back to digi on the antenna and still using the same instance of WSJT-X and no power. I shut down WSJT-X and started it up again and the power was back.

It may be happening when I switch bands while WSJT-X remains open. I will start shutting it down whenever I switch bands and see if that fixes it. In the past I  always left it open when switching bands without any problems.

Milen KG2C

Don't you switch bands from within WSJT-X?

Pat N6PAT

It did it again on 30 meters just like before. I just move down the band and tune. That fixes it every time. I've never had this issue with SSB or CW.

Patrick Moonen

I have made profiles for each band for WSJT FT8. In WSJT i only put the mode on FT8 i do not use the bandswith from WSJT. No problems here work with the 1.8.0 RC2 version currently. My waterfall settings let me start at 100 Hz.

73 Pat ON3CQ

Pat N6PAT

OK...I spent several hours working FT8 last night. I experienced the loss of power a few times again and it always fixes itself with the tuning method. I suspect the issue is with WSJT and not the Flex. I'm had no issues with Fldigi.

It's a minor annoyance that I can live with as long as I know how to work around it and it's possible that changes incorporated in v2 will eliminate the problem.

 I'm curious if this is happening to other brand radios or if it's an issue limited to the Flex.

73 Pat

Milen KG2C

I think the new version (with FT8) uses a newer version of hamlib as well, so maybe your problem could be from there. Have you tried changing the way you control the radio when using wsjtx, for example by switching to omnirig?

Patrick Moonen

Which version of WSJT-X you use ?

73 Pat

Pat N6PAT

1.8.0-rc1

Patrick Moonen

Pat this new version 1.8.0-RC2 try this one i have no problems.

https://www.dropbox.com/s/vclsij1733q2p4v/wsjtx-1.8.0-rc2-build-7924.zip?dl=0

73 Pat

Chris DL5NAM

... or you try the better decoding one - JTDX (based on WSJT)   :-)

https://cloud.mail.ru/public/Drcw/JMrg49EU9

Patrick Moonen

Hi Chris JTDX have no FT8 mode

Chris DL5NAM

Oh ! Sorry, your right. But as i read, in short also included.

Pat N6PAT

Last night I was working more FT8 and started losing power again so I decided to make a video of it so you can see what I see. You'll have to excuse the start and stop as my video software stinks as does the resolution but I think you'll  be able to see what's going on.

When it lost power I moved down the band a bit so I don't bother anyone and started TX messages. Notice that there is DAX activity and as I pan down the right side you can see the level meter going. The panadapter also shows what should be TX activity but the power meter stays at zero even when I crank it up to 98

Then I stop the messages and tune. You immediately see the power meter jump. Yet when I return to TX messages (you need to wait about 15 seconds for the next TX interval) it goes back to no power

Now you can see what I see. It looks like WSJT-X is still communicating with the Flex and the Flex is trying to transmit. According to the level meter the radio says it's sending out a signal but with no power

https://www.youtube.com/watch?v=V0gyZBpLq4k

I hope this helps shed some light on what's going on.

Here's the link . It may display better that way

https://youtu.be/V0gyZBpLq4k

73 Pat

Bill W2PKY

Your High Cut is 2900 and you are transmitting @ 3157.
BTW: your receive bandpass is 1K. 
FT8 is usually a 2Kc mode. So not sure how you ended up on 3157 Hz.

Don't feel bad we have all tripped over this one.