SSDR V 1.8.3 Update Problem

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  • Updated 3 years ago
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I have a Flex 6300 and have been running SSDR 1.6.21 successfully for many months, and am able to drive my amp to full power.  I decided to upgrade to SSDR 1.8.3., which went successfully, but now when I use the amp, I get a short burst of full power and then it drops back to almost zero.  In TUNE mode it will drive to almost full power, but as soon as I stop tuning and try to operate, it drops back to a very small power.  If I don't use the amp, the 6300 seems to put out power normally, but only 75 watts max.  The input SWR on the amp is low, but I used the autotuner to make sure.

I subsequently dropped back to SSDR 1.6.21 and everything returned to normal, with full power out of the amp getting about 85 watts max from the 6300.  I notice that there was a "fix" which relates to cutting back power on adverse SWR, and I'm wondering if this is causing my problem.  I'd like to be able to upgrade.

Anyone else seeing this?

Paul - AA6Z


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Paul Burton

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Posted 3 years ago

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Mike va3mw

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Paul

Based on your diagnose and that nothing else has changed, you may want to open a support case.  it does sound like a software issue.

Are you testing in unmodulated FM mode just to make sure you are putting out a constant carrier?

Other than that, I can't think of anything that might make a difference.  Possibly a profile issue?

Mike va3mw
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Paul Burton

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Thanks Michael.  No, I'm just using CW mode.  Everything is the same between the two versions.  My amp is a TenTec Centurion which requires about 100 Watts drive for full power.  It works perfectly with SSDR 1.6.21, but not quite full power since the 6300 is a bit wimpy.
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Bill W2PKY

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Hello Paul-
Others have reported similar issues driving amplifiers. Best enter a help ticket.
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Paul Burton

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OK Bill, thanks,  I didn't see other posts on this.  A support ticket was submitted.
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Cal Spreitzer

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Paul,

I noticed in the SSDR V1.8.3 Change Log there has been a change to the firmware: 

#3644    Firmware: Added automatic power foldback for high SWR situations (starting at 25 W reverse power)

Are you sure your SWR is low between the Flex and your Amp?    Do you have an external tuner inline after the amp?   

Cal/N3CAL
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WX7Y

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I wonder if the Flex is getting a HI SWR false reading with High RF in the Shack or RF Common mode currents on the COAX shielding when the AMP is enabled? 
I have a bunch of fer-rite beads (8 on each jumper) on EVERY Coax jumper between the Radio, Amp, Antenna tuner,  coax switch's and every peace of cable so probably between the radio and each Antenna there are 18 to 24 fer-rite Beads to stop any skin effect or RF Common Mode Current from coming back down the Coax starting with the Antenna feed point. 

I so far have not noticed any RF Power cutbacks here running full legal power at least on 40 and 80 meters, I haven't tried the other bands yet so MY MILEAGE may very. 

Just wondering if this could be the root cause of some people's problems, I do know that my OLD FT847 had this problem and when I first started looking into it years ago the abundant amount of IRON on the COAX jumpers have stayed in my shack design. 

How does it act into a dummy load running the AMP if you have a Dummy load large enough to dissipate the power which every HAM who owns a Amp should have? 

A good Read and a great resource is below.

http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf


Just my thoughts

73's 
Bret
WX7Y
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K7FU

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Having the same issue driving my Denton MLA2500. Downgraded the software to a version without the swr fold back option. Works ok for now.
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K7FU

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Having the same issue driving my Denton MLA2500. Downgraded the software to a version without the swr fold back option. Works ok for now.
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Paul Burton

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Thanks for all the comments.  I don't think I have excessive SWR out of the Flex as I'm using the internal antenna tuner and my amp has a tuned imput.  The SWR is low enough.  Why did they need to make this change? 

Yes, perhaps some common-mode RF is getting back into the Flex.  I have regressed back to SSDR 1.6, but may try some Ferrites over the holiday, to see if it helps.  I don't suppose we will hear any response from Flex until after the holiday.  Cheers.

Paul


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WX7Y

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Common Mode RF has nothing to do with having a high SWR.
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Paul Burton

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Yes, but it may be getting into the detector within the Flex and setting it off.  Stray RF can do lots of weird stuff.  It's all just speculation without further testing.
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AA0KM

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Bypass the Flex internal tuner and see if it works out.

"The input SWR on the amp is low, but I used the autotuner to make sure."
"I don't think I have excessive SWR out of the Flex as I'm using the internal antenna tuner and my amp has a tuned imput."

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Cal Spreitzer

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What's on the other end of your amp?   What antenna do you have hooked to your amp? Could  be your antenna is presenting a high SWR?    If you happen to have a dummy load you could hook that to you amp output and see if you still have the issue with a 50ohm dummy load... 

I use an external  Auto Tuner on the output of my amp which matches any of my antennas.  I keep my Flex 6500 internal tuner off.  Since upgrading to V1.8 I have seen NO issues and have not seen any fold back.  . 

Cal/N3CAL
(Edited)
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Mike Hoing

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Same configuration here works great. Someone made the comment earlier to check your coax jumpers. I have had more then one of those over the years

Mike
(Edited)
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Rob Blackie

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i think there should be an option to turn off the SWR foldback addition. it is clearly a problem for some
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Gerd Henjes

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Why not first establish the actual problem. The former version of the Flex software doesn't have SWR foldback limiting, the new version does. Is the new version seeing something the older version wasn't even looking for, I'd first suspect that is the case?

Why would you run the Flex auto tuner into your amplifier, if you amplifier has a tuned input?

Over the years I can't count the number of bad patch cables and badly soldered PL-259's that I've run into... first thing I always change is the patch cables.

For the fellow with the ML-2500, they did offer an external tuned input which you absolutely need to match to a solid state rig and keep you IMD from going through the roof. I'm also going to be the internal 100 ohm swamping resistor has be cut out of the input circuit... that's not really a good idea either. You can't match the input with an autotuner in the radio as the match changes as the RF cycle is amplifying.

Gerd, W2ISB
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Paul Burton

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I only ran the tuner as an experiment to see if it would help.  The fault occurred with or without the autotuner on.  The SWR was low in either case.
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Mike va3mw

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Gerd makes some good points.   

Common mode currents are something we can't measure, but we know when we have a problem when we have a problem.  :)   

If the radio measures any reverse power, then it will fold back to protect the finals.   This also means any RF on the patch cords that work their way back into the radio can be interpreted as bad SWR.   People with random wire tuners see this all the time.

You might want to try inserting an SWR meter between the radio and the amp.  Try some Mix 31 or Mix 43 chokes.  

There are many excellent articles on the net about RF Common Mode Currents that help explain this much better than I can.

Mike va3mw
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Paul Burton

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I hadn't suspected common mode RF, as I don't have much other indication of it.  The Flex must be really sensitive to it.  I have three different antennas, all with baluns.  This happens on all antennas and bands. 

Yes, when I get some time I'll apply some ferrites and replace the coax jumpers.  I just didn't expect to set off an SWR detector which I have low SWR.  I have seen some other slight indications of RF in the shack, so that's likely the problem. 

(Edited)
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Lawrence Gray

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I have a 6500 driving a Yaesu FL-7000 solid state amp.  I have not experienced any amp drive or power fold back issues since upgrading.  I use a manual tuner following the amp--no issues so far.

Larry, KC1DAD
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Mike va3mw

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I use a KPA500 without issue on my 6300.  I suspect if you are getting SWR foldback, then something else is contributing to it and you should solve that problem rather than try to mask it.

Mike va3mw
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WX7Y

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Also one thing I just thought of, with the AMP in standby or in Receive mode your AREN'T going through the amp's input network so when the AMP is in operate mode the SWR will change because your radio is no longer connected direct to the External tuner or antenna but rather to the AMP's input network.

What's the SWR between the AMP and Radio measured with a EXTERNAL SWR Bridge between the Radio and AMP with the AMP enabled  and internal  Tuner is OFF?

If the SWR is high going into the input to the AMP it will change abruptly going from AMP Bypass to Enabled OR PTT activated to Receive mode.

So maybe it's simply just your input network or lack of on the AMP.
Bret
WX7Y
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Paul Burton

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Bret, the SWR indicated by the Flex is below 1.5:1 when using the amp without the internal Flex autotuner.  With the autotuner on, I can bring it down much lower, but the fault occurs with or without the autotuner.  The SWR on the output of the AMP is  below 1.5:1 on 17 meters, and I have the problem there  as well as with other antennas/bands.  I have no antenna tuner outboard of the Amp. 
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WX7Y

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OK Paul, Well I would really get the toroid's to trap the RF Currents  http://palomar-engineers.com/ferrite-products/ferrite-beads for the proper MIX for your frequency of operation,  and here is there KIT's  with Heat Shrink for outdoor or indoor installation. 
Anyway hope you get it figured out.
73's
Bret
WX7Y
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Paul Burton

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OK, I pulled out the 6300 and totally simplified the installation with a short coax jumper into the amp and put several 31-mix ferrites on all leads in/out of the Flex including the 14 volt power.  The SWR is below 1.5:1 on the antenna and into the amp.   I see no other signs of RF in the shack.   All of this has had no effect on the Fold Back of power.  I am able to run about 500 watts from the amp with just a slight fold-back, but if I go to 600 watts, it folds back to almost zero.  I have no access to a high-power dummy load at this time, which would be a further good test. 

I feel something is wrong with either the 6300 or the implementation of the software fix.  If I bypass the amp there is no fold back to full power on the 6300.  If I revert back to SSDR 1.6  of course I get no fold back.   Once the fold back hardware warms up, it seems to occur at much lower power.  If I wait for it to cool down, then I can run 500 watts.   

Thanks to all for trying to help solve this mystery.  While some seem to have no problem, I now see other posts indicating the same problem.  Why could we go more than a year without this fix with no problems, and now suddenly need it?   I am reverting back to SSDR 1.6 and I'll wait for a response from FRS.

Paul AA6Z

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WW1SS - Steve

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Does it fold back going straight from radio to antenna with no amp. I believe it is a bug in the foldback code in this new feature we had to have.
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Paul Burton

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No, only with the Amp.


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KY6LA - Howard, Elmer

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@Paul

You are seeing @500W no foldback but @600W fold back to zero

My best guess is that you still have RF in the shack but the ferrites are reducing the RF in the shack when you are below 500W so the RF in the shack does not reach a threshold where it may cause fold back. 

Solution: More Ferrites in more places (Power leads and anything else that can pick up RF from common mode currents) and a better grounding system to reduce current loops... Suggest you read my "How to build a Quiet Station" paper posted in this community...


@Steven  - since the code works well for virtually all modern Solid State Amps - you are likely totally wrong about your guess that there is an error in the code relating to the foldback circuit.  

My Expert 2k-FA Amp is capable of running 2,300+W key down.  During beta tests there was NO FOLDBACK whatsoever running this amp so clearly the software is working as it should.  But then I have spent a lot of time and effort to make sure there are minimal common mode currents on my leads...

Also it would appear that you do not understand the benefits of introducing the foldback feature.  Flex PA are very robust. However there may be extra-ordinary circumstances (such as an antenna failure) where having an extra layer of protection on expensive final transistors would be quite beneficial to most people.  I do agree that a simple solution might be to make it optional for those who don't mind blowing finals and have older tube amps with lots of RF in the shack... I suspect however, if your finals blew, then you might one of the first to curse Flex for not having a foldback feature and/or making it optional.    Personally I would rather fix the RF in the shack issue and save my finals...

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Terry Tankersley

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1.8.3 works fine with my 6500 and ALS-1300, I will try it with my SB221 later this weekend.
Terry
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Lawrence Gray

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I agree with you Howard.  My solid state amp has built-in foldback at an SWR of 3 or higher.  It has saved me a couple of times when I misconfigured something.   If the Flex is folding back, there is an issue in the station that needs to be resolved.  Disabling the foldback could easily lead to an expensive repair.   A better idea is to track down the reason for the foldback and eliminate the issue.

I'm happy that the Flex folks added this feature.

Larry, KC1DAD
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W7NGA

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I disagree. The PA transistors failed on my 6500 and I have talked to many owners that experienced the same issue and had to return their Flex for repair. It seems obvious to me that this new fold-back feature is a result of observing the failure rate. The finals were not adequately protected. Most likely, testing did not sample enough older technology to affect a change in the protection implementation and it needs to be altered to a degree that makes it usable in all scenarios.

The Flex circuitry is very sensitive to local RF currents. The joke around the ESSB crowd is that you can always tell a Flex radio from the audible echo on many signals. The same in this situation ... you should not have to add dozens of ferrite cores and burnt offerings to configure a working system. Protection is a grand notion .. but it would appear it needs to be further evaluated and altered to work with dynamic loading.

If you have a working system, making a software change ostensibly for the benefit of the user, should not cause the working system to fail. No one is running 3:1 SWR into their amplifier, especially those with an ATU. Allowing disabling of this feature defeats the purpose Flex intended (premature warranty returns).

W7NGA
Paris, France
(Edited)
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Terry Tankersley

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1.8.3 works fine with my 6500 into my ALS-1300 and the SB221. No ferrite core's  on the antenna lines any where. The fold back feature works as it was designed.
Terry
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Paul Burton

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Thanks again for all the replies and comments on this problem.  I am not suggesting that the fold back protection should be eliminated or disabled, only that it is excessively sensitive to common-mode RF which is present in every ham shack to some degree.  Fold back should not occur due to a small amount of common mode RF.  I'm not suggesting that I have no common-mode RF coming into the shack, but I have no overt indication of RF in the shack other than the Flex which goes belly-up.  All of my three HF antennas have baluns and the fold back occurs with every antenna on every band.  I have used several other transistorized transceivers (which all have SWR protection) without this problem.  I have installed multiple 31-mix clip-on ferrites on every line in or out of the Flex, and it still folds back at 600 watts output with low SWR.

I am waiting for FRS to respond on this and will continue to try to find the source of whatever is causing the fold back.

Paul AA6Z

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KY6LA - Howard, Elmer

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I strongly recommend that you read and implement suggestions in my paper

"How to Build a Quiet Station"   Baluns and Ferrites along won't fix ground loops.  The other radios do not have networks and computers as part of their configuration so they are less likely to have ground loops that will pick up RF in the shack.

https://helpdesk.flexradio.com/hc/en-us/articles/202274599-How-to-Build-a-Quiet-Station-for-Better-R... 


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Paul Burton

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OK Howard, many thanks for the suggestion.  I'll check it out.
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Mike va3mw

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I tripped over this article by the YCCC and once I followed it, ALL and I mean ALL of my RF problem disappeared.  Not only that, I could also hear better as I had less local RF noise on  my feedlines.  The quieter you are, the more you can hear.

Like everyone else, I was in denial regarding RF and common mode currents.  My SGC500 Amp  on my remote base kept tripping off due to high currents, 40M was a mess, etc.  I thought having a good balun was good enough.  However, that doesn't prevent the feedline from other antennas (the ones you aren't using) from picking up RF from the active antenna and feeding it back to the radio.

See what I mean?

http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf 

I highly recommend reviewing it.   For me, I ordered a case of Mix 43 and Mix 31 cores.  It was one of the best purchases I have made for my station.  

Since then, zero issues.  My SGC500 stopped having over current errors.  My KPA500 also works perfectly and all this on my remote base.

Every antenna has cores below the balun.  The feedlines to the radios have cores at the antenna switches and just before the radio.   

You need chokes at the antenna, after the amp, between the amp and the radio, etc.  

I am a choke convert.  Mike va3mw
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Jay / NO5J

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All wire, should come with a big box of ferrites.
Plenty is never enough!
73, Jay - NO5J
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Bill Roberts

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My 6300 folds back on CW but not on phone. Perhaps the foldback isn't fast enough to respond to SSB. Amp is an ALS 600. No fullback into antenna. As to stray RF, house, shack and lightning grounds bonded together. Torroids all over the place. To be sure, HF antenna line goes through a Comtex/DX Engineering l I be isolator. Even the $7.95 computer speakers are silent.

I seem to notice a positive change to AGC-T action so I'd rather not go back to the previous release.
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KY6LA - Howard, Elmer

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You can never have too many ferrites.....

Heck.. I have one of the quietest stations possible .. then the cleaning people moved some wires and BANG suddenly more RF in the shack... More ferrites fixed it...


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Tim - W4TME, Customer Experience Manager

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In general, the 1.8.3 release for SmartSDR for Windows, CAT and DAX is very stable.  There have been a few reports of the SWR foldback affecting a few users (much less than 1%).  We are in the process of characterizing their problem reports.  It has been entered into our bug tracker as issue #3765.  

I would strongly recommend upgrading to 1.8.3 because the items it fixed are more global in nature that the few reports we have received regarding the SWR issue.  If you upgrade and have the SWR issue, I strongly recommend that you open a HelpDesk support ticket so we can characterize your issue.  And you can always easily and conveniently revert back to 1.7.30.

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