Possible RF problem in Shack

PhilipG

allenfr

Rick - W5FCX

Phil,

I have experienced similar lockup’s with my 6700. It turned out to be common mode RF causing problems. Powering the 6700 down and back up resolved it. It happened with or without the amp.

I inserted a 1:1 RF choke on the coax between the amp output and antenna, which resolved it. The 6xxx are somewhat sensitive to RFI from common mode, perhaps due to the Ethernet interface or power supply (not sure where RFI gets in there). In my case, I was using an OCF multiband dipole, which is well known to be buddies with common mode.

Hope that’s helpful.

Rick W5FCX

AH0U

Have you tried it with a dummy load to see if it freezes??

Bill -VA3WTB

Al_NN4ZZ

Bill W2PKY

May want to try a sleeve balun at the antenna, such as Wireman 827. My 6300 was sensitive to long earphone cables.

N8AUM

Erika - KØDD

bahillen

Don’t forget to check your coax for a poor shield connection.

Clay N9IO

PhilipG

Thanks for the reply. Did you make your RF choke or just use a torroid and loop the coax around?

PhilipG

Al, Thanks so much for the reply and the link to your extensive documentation. I have already installed the bonding cables to a 1/2 inch copper pipe that runs along the wall of the shack and then gets grounded to two rods outside, I have used only 1/4 inch braid, which may be enough  for bonding, but not for lightning protect. .So far, I still have an RF problem, mostly when I run over 50 watts. So the next step, following your guide, is to get some ferrites on the cables. Behing my desk is a rabbit's nest of wires - speaker wires, 12v low amp wires to power the antenna switch, speakers, weather station, headphone, key, headset wires. Not to mention the Ethernet wires running all over the place. Following your lead, I will start with the jumpers between the Flex, Amp, and tuner, then move on to the Ethernet wires. Thanks

PhilipG

Yes I had the problems but only with the Flex, not the K3 (now sold) or the K2 which is only 10 watts

PhilipG

Thanks, I am starting over with grounding and ferrite beads on the wires 

Erika - KØDD

no offense at all...  But with what you are describing.  The FIRST thing I'd do is remove EVERY PIECE of wire and cable from that installation INCLUDING the weather station.  Setup the radio, and absolutely the minimum of a computer.  See if you have RF then.  Then start adding USING best practices your gear back in...  There WILL be a point the offender will light up your shack... Then throw that piece away! Erika DD

Erika - KØDD

Really Phil...  Disconnect everything and rebuild a piece at a time.  I have 4 monitors here.  When I rebuilt the computer only one monitor had power and a video cable on it.  I stripped the desk clean,  wiring wise.  But in my case the issue was an afci breaker.  That got replaced first and then the station was wired up.  If you just start hanging ferrites on everything... (Somethings do not like large inductance slapped on them) It will wreck waveforms and cause other issues.

It doesn't take very many wires to get a Signature Series to work at minimum connections...  You're going to find a cable that is running somewhere not related to the radio is going to be your huge offender.  If you don't start with it out of there, you'll never find it.  Erika Dd

PhilipG

Thanks, Erica. You are right. I just rebuilt the station, and I am totally exhausted from that, but going back to basics is the way to find the issue. As I said elsewhere, I did not have this problem with the K3 and Amp (and the weather station also in the shack), so I am guessing that it is one of the cables involving the flex - let's see there is the Ethernet, the key, headphone, headset, speakers all connected to Flex box. Thanks for the advice.

Erika - KØDD

I'm rooten for you to have success! 

WK2Y

Erika - KØDD

Oh yeah, when I put things back together the computer is now as far away from the radio and antenna leads as I can get it and all the video and ethernet are going two different ways to the radio and computer.  RF on one side and computer on the other side of the desk...  That did help considerably...  I do remember a weirdness back in the early 70's ALL OF A SUDDEN on SSB I had RF on the mic audio.  It just started up seemingly on its own.  It was a Drake setup...  The audio was completely broken up though.  I climbed up on my desk and found a coax junction two pl259's a barrel connector and it over time had moved slightly and the connectors were brushing up against the old Steelcase desk...  While that wasn't a flex issue, strange things do happen and a new jumper of RG8 and a pair of connectors without a barrel fixed that one.  1 hour repair...  Erika DD

Erika - KØDD

Wave of the future...  That and virtual cables.  What  huge difference between the early flexes and these units.  DD

PhilipG

Thinking about ethernet to fiber converters, since the Flex has already been repaired for some kind of ESD problem. Whats the best way to do this? Converter at the router, run fiber towards router and then another converter, running CAT5 to switch, then run CAT5 from switch to FLEX and other devices? Or should I buy a switch that has a fiber port? I already have a switch but it doesn't have fiber port.So one way I would have to buy a new switch, plus a converter. The other way I need two converters.

Bill -VA3WTB

Try doing a search on this here in the community,, I remember reading a lot about this and the people using it telling how they do it.

WK2Y

Al_NN4ZZ

PhilipG

Thanks, Al. I can't find a reasonably priced switch with ethernet and fiber ports.

Lasse Moell

Philip, you may look at Routerboard router/switches they have often one or more SFT ports. And you can use a fiber converter if needed. I just bought some converters from FS.com. Great prices and speedy shipping, all with-in EU.

N2WQ

Before you go crazy rebuilding the station, running fiber, adding new routers, start with the root cause of your RFI. Common mode chokes are not particularly effective unless they are the antenna feed point.

Neal Pollack, N6YFM

WK2Y

I totally agree with these recommendations, even if you go optical.  One unrelated reason for using the optical connection is the spikesurge isolation.