RFI shuts down the 6K fast

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  • Updated 5 years ago
Wow, thought I try working UA4 down in Antartaca.
30 meters so it was barefoot.
Hit the key, and bingo, rfi shutdown.
Quick reconnect the 5K but too late, he'd QRTed.
5K is good all bands, I think first thing to look at is the cat cable.
Unfortunately, if I disconnect the cat cable, I can't run the 6K.
hmmm
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Bill-W9OL

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Posted 5 years ago

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Robert -- N5IKD, Elmer

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Sounds like the power supply may have a loose connection or overloaded.
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Bill-W9OL

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I'm pretty sure it's rfi. PS is iron 50amp Astron.
I have two, one each for 5K and one for 6K
Both have separate RigRunners.

I just got through putting toroid on cable from Astron > RigRunner
and
RigRunner to 6K.

Definitely improved the situation as while I can see the 6K screen flicker, it didn't shut down the 6K.
The 5K has no screen flicker (same monitor as 6K) and no rfi is noticeable.
So I made progress and will get more torroids for all the other cables such as KEY, GPS (when the tower is retracted as it is now, the GPS ant is right under the beams and dipoles by about 15 feet)

Living in the antenna pattern my whole ham life and I have learned a lot of tricks to solve RFI.
It's never just one thing, usually requires a shotgun approach.

but I ALWAYS appreciate suggestions.
Bill

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Steve - N5AC, VP Engineering / CTO

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The FLEX-6000 monitors all of its power supply systems continually and if any of them have a reading that would cause an issue for the radio, the supervisor will immediately shut down the radio. When this occurs, a message will be shown in the display that indicates a power supply issue. If you have RF getting back into the radio from your setup and it alters any of the internal voltages to a level that would be an issue, self-protection happens fast. I would be interested in what you find in your setup and if you have a message in the display, we can help you decode it and perhaps better understand what is going on (voltage too high, too low, etc).

As a result of the sophisticated power subsystem in the FLEX-6000, it can also operate well below the voltage levels of most radios.
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Bill-W9OL

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no error messages that I saw
I will investigate.

For what it's worth, the 5K can drive an amp full bore, with no rfi type grief.

But I understand what you said in your message so I will investigate closer
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Al / NN4ZZ

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Bill,
I had similar symptoms a few months ago. I made some changes that corrected it for me and it has not happened for 2 months now. I recently documented the my observations and findings which may be helpful.

Since not everyone has access to the Yahoo forum, Tim asked me to provide my update with my observations and findings here.

******* RFI crash update *******************************************************

Since the last update it's been 2 months without any crashes and the setup has been stable. At this point, the problem appears to be fixed so I thought it might help others if I documented what worked for me. I made the changes one at a time over a period of about a month to try and identify which ones helped the most.

A few other background notes and observations:
--------------------------------------------------------------------
- The problem was the rig would shut down as soon as I tapped the key on CW.

- The radio displayed various errors (voltage errors, sometimes the flashing RED led, lockups requiring multiple pushes of the power button to shut down, etc)

- It happened more when using the amp but on some bands it happened when running barefoot

- Observation - The 6700 seems to be more sensitive to RF than my previous knob radios. Just a guess but the internal voltage metering my be affected! by the RF and triggering the shutdown

- I used a field strength meter (Coaxial Dynamics 7601) to help identify the source of RF

- In my setup the antenna coax terminates at an Xmatch tuner, there is a jumper to my DX2400 amp, and a jumper to the radio.

- I use a fiber link for the ethernet connection so that eliminates the CAT cabling as a source for the RF intrusion

- All of the various devices (radio, tuner, amp, rotator controls, antenna switch, etc) have ground braids to a single point ground.

- I noticed that the SWR reported by the radio was higher than expected on some bands based on independent readings with an antenna analyzer. In fact, although it should have been about 1.2:1 it was high enough to prevent the 6700 ATU from finding a match on some bands.

Findings
-------------
- Using the signal strength meter was helpful in eliminating some cables as the source of the RF. (rotator control, remote switch control, etc)

- The major contributors were RF on the coax from the antenna and the coax jumper to the radio. However this affected the use of the signal strengh meter. As the meter gets closer to the radio, it picks up RF on all of the cables to some degree. So the RF could be coupling to them.

- There were 2 fixes that appeared to provide the most help in solving the problem

- I added ferrites to the antenna coax coming into the shack. I could have used a choke balun but since I had them, I used 25 snapon beads for abo! ut 2Kohms. They are installed just outside the shack on the LMR600 coax cable.

- I added ferriites to the coax jumper between the amp and the radio which also solved the SWR metering problem. The SWR reported on the radio now matches the SWR I get independently on my antenna analyzer. Although it is not needed the ATU will now tune. For the jumper I used enough ferrites to also get about 2K ohms.

- I also added ferrites to the other cables going to the radio (audio, power, etc) although I'm not sure they were significant contributors to the problem. I had the ferrites and will leave them in place since they can't hurt and do more good on the cables than on the shelf.

Although every setup is different, maybe some of this will help if you find you have this problem.

Regards, Al / NN4ZZ
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Bill-W9OL

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Steve, as I wrote above, I've made progress.
I did NOT want to duplicate the shutdown just to see/copy the error message.
Fearful of harming the rig.
But....if I see it in the future, I'll try to copy it.
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Bill-W9OL

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Thanks Al, as I wrote above, living under the tower/antenna creates a LOT of experience with rfi (and in house TVI)
Wonder if a fiber would help...although my cable comes into the house, through the shack wall>comcrap cable modem > router > 16 port switch for other computers in other rooms, weather station, multiple cams. Lots of cat6 through ceilings and walls. As I said, it's all inside the antenna pattern.
(there is no truth that any of my children were born with scales and tentacles. But come to think of it, all 7 have Masters degrees and extremely smart)

Don't know if fiber would be immune to rfi in this environment?
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Al / NN4ZZ

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Bill,
My reasons for installing a fiber link in the shack were two fold. The primary reason was to avoid damaging the ethernet interface in the radio and shack PC in the case of a nearby lighting strike. I have lost ethernet interfaces before because of the emp induced thru the cat5 wiring during nearby strikes. This can be a significant repair issue on devices where the ethernet interface is not on a separate and replaceable daughter board.

The secondary reason was to eliminate any RFI feedback to the radio from the myriad of CAT5 wiring I have in the house. I have about 1,000 feet of CAT5 through out the house so it seems like it could be a problem. The fiber link provides this isolation. I don't know if this would really be an issue but it can't hurt.

In my case, the solution was to convert from CAT5 copper to fiber on the run from the server room to the shack before it connects to a desktop switch. The fiber link is only about 6 feet long and terminates in a 4 port desktop switch that accepts fiber. From the switch, I use short CAT5 patch cables to the radio, PC, etc.

I purchased the converter, fiber patch cable and fiber switch from Amazon. If you are interested I can point you to more details on the models, prices, etc.

Regards, Al / NN4ZZ
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Steve - N5AC, VP Engineering / CTO

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I had a similar problem when I was running a PACTOR Winlink station into a Carolina Windom at my old house. The thing that fixed it for me was a "string of beads" ferrite solution. I purchased a piece of RG-58 that was about 1.5' long and had ferrites all along the feedline and then the whole thing had heat-shrink on it (no active ingredients there, but you get the picture). This got rid of all my problems.

I was looking for the exact product that I bought, but I can't seem to find it. It was shrink-wrapped to a card for sale. At any rate, I did stumble across this presentation dealing with these kinds of issues and some solutions along with graphs showing the efficacy of them: http://audiosystemsgroup.com/NCDXACoa... ... I know AD5X has done some writing on this subject as well. There's a lot of good info out there, but I wouldn't trust anything that doesn't have good accompanying measurements.

Steve
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Al / NN4ZZ

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Steve,
Your cable sounds similar to one I got from The Wireman. It is made for use as a jumper between an amp and radio. It is intended to solve the common mode problems that sometimes occur with regular patch cables. I ordered mine a few years ago and he made one for me that is about 8 feet long. I coiled up the extra length into 5 turns and clamped on some extra ferrites to increase the impedance. I was using another coax jumper initially but when I replaced it with the Wireman balun jumper the false SWR problem was resolved.

And as I noted earlier, that jumper plus the ferrites I added to the coax coming into the shack solved my crashing problem.

Regards, Al / NN4ZZ