6300 Echo

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I am going to assume this is RF and going to proceed based on that but thought I would throw it out there for those who own Flex Products.

I have a new 6300 that I am getting reports of a faint echo on my audio and sometimes worse than others.  I have a good RF ground on all my equipment and have added type 31 ferrite on the mic cable but going to start adding more cores on everything else as well as some radio works T4 line isolators I have laying around. I have disconnected as much as possible from the 6300 including the speaker output that goes to my small audio amp to power speakers.

As I said I thought I would toss it out to other owners as RF seems like the logical culprit to me.

Rich
kd0zv
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Rich McCabe

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Posted 4 years ago

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Jack Wren

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I have a 6300 and have had similar issues.  They turned out to be RF getting into the mic input in my case.

Jack
K4VR
(Edited)
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Jay / NO5J

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Rich 
I had a very faint echo on my 6500 too, at first, It was RF getting into a cheapy balanced mic cable. I know your using the front jack but thats where my RF was getting in at. Changing the cable solved the problem. I might not be possible with what you have for mic choices but I added  a couple of of ferrites to the bad mic cable and that solved it too. I've got legal limit power going to a feed point about 25 feet above the shack roof so I'm guessing that will qualify as a high RF environment. Oh well maybe come spring I can move some antenna wires. To cold, it's perfect weather for installing antennas but too cold for the installer  
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Ken - NM9P, Elmer

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Yes, you need to watch those cheap "balanced" cables.  I bought an inexpensive boom with cable and discovered that they had wired the "balanced" cable with the shield and "cold" side of the connectors together on both ends.  It wasn't balanced at all.  After rewiring the connectors it worked fine.  If I hadn't tested it and visually inspected it I may have been running around tracing RF problems all over the place.
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Jay / NO5J

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Mines balanced its just only about 30% spiral shielded. But it did come with a boom.
OC White even. I resoldered both ends when I pulled it out of the boom since it ended in a regular XLR and the Flex5000 needed a 1/4 TRS. The boom works though.
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Rich McCabe

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Well its good to confirm its probably RF.   I have decent cables and boom. Heil stuff.  I am planning on running my mic into my EQplus and iPlus. Julius at W2IHY is sending me a cable wired a little different that he wants me to try with the flex.

This morning I did put a couple snap on toroids on the power line and wrapped the audio output line around a toroid and might add a line isolator transformer as well.  
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Gerald - K5SDR, Employee

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Rich, Heil cables may not be wired properly.  Julius fully understands this so his will probably solve the problem.  Mic minus must NOT be connected to the cable shield.  This causes a ground loop that picks up RF.  You may also need common mode chokes at your antenna to keep RF off your coax.  
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Rich McCabe

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Gerald, I already checked the ground to shell thing per Julius. My cable is a little to short for my installation and he offered to make me a longer cable with a couple changes  including grounding the PTT.  I will have that tomorrow and be back to testing.

One symptom I forgot to mention in original post is the TX is  sticking on occasionally and I have to power rig off to get it to stop.   Pretty sure its related to RF as well.
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John n0snx

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Yep RF is an ugly monster.... Jumps up and bites you when you least expect it.

Rich I ran rack gear for a long time and the monster would rear it head from time to time for no reason what so ever.  Got rid of the rack gear and use w2ihy stuff now and the monster has disappeared.... 8 band EQ, EQplus and Iplus works GREAT... much better than the rack.  Good Luck
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Rich McCabe

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Thanks John. Not to mention Julius is way better to deal with :)
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Bill Roberts

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I had similar reports. I also have what I consider a good ground 8 feet from the rig. Flex and people suggested a possible ground loop. I solved my echo with a $10 line isolator device designed for automotive use. Now, I was also sharing the same Bose Companion 2 speakers between my 6300 and a 5000. One line isolator on one speaker line took care of it. Good luck. BTW, I have loads of 31 mix torroids all over my shack. Ground is 12 foot copper clad rod connected to equipment by 6 gauge copper and 1 inch tinned braid to all equipment. For whatever it's worth...
(Edited)
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Rich McCabe

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I am not making much progress with this. New cable from Julius did not help. I have a line isolator similar to what you are talking about Bill but I do not have speakers attached for testing purposes and just running off headphones for now so dont need it.

Recap of what I have done

Qty 3 type 31 ferrites on mic cable (tried two cables)
Power line from Astron 35m wrapped around type 31
Coax ran through a couple type 31 snap on cores

The Flex and 7800 are on a switch that goes to amp and then tuner. I installed radioworks Line isolators in the coax between rig and amp and am and tuner.

Mic is a EV RE320 but same issues on Heil 780. Both in heil Boom.

I have two 8' ground rods outside shack. There is problem 10 to 15' of cable to get from ground rods to my ground bus on bottom of desk. The PC case (at power supply) is grounded along with both HF rigs, amp and tuner.

I have not tried anything on the network cable yet.

I hope to get time today to pull the Flex off the shelf and totally move it to the other side of desk as a test.

Rich
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Jay / NO5J

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Does the echo stop at qrp levels?
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Rich McCabe

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I really don't as I have not talked to anyone I could work QRP and anything I listen on another receiver I get any echo anyway. Might be in my brain as the delay trips me up.
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Jay / NO5J

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Have you got any loose fillings?
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DrTeeth

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They don't have to be loose to rectify RF.
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Rich McCabe

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haha, I dont think so.
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Jay / NO5J

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Sometime's I hear voices, If the radio's off I tend to ignore them unless I need them for DXCC.
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Bill Roberts

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A had another report of "the echo" from a well meaning op within a mile or so of me.  We receive each other at 40 over 9 at exciter power so the S/N is pretty good.  He played a recording in which I could barely hear the echo perhaps once in a 90 second recording.  I have eliminated two Chinese XLR cables associated with a $20 mic boom and repositioned a few torroids.  On another related thread, I reported installing an isolation transformer between my 6300 and the Bose Companion 2 speakers shared with my 5000.  I thought that minimizing the apparent ground loop had cured my echo.  Apparently, it's still there, albeit faintly.  Otherwise, phones, stereos, powered speakers and other electronics in the shack and house show no RFI.  Go figure!
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KY6LA - Howard, Elmer

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Obviously you still have a very minor ground loop somewhere.

I use a huge "Biggest Clamp ON" toroid as my ground loop detector. I clamp it on a suspected ground loop and if the loop disappears then I use smaller Toroids to fix the issue.
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Rich McCabe

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I am running out of things to try on mine. I think I have issues beyond RF. As a matter of fact when listening to a second receiver I can hear noise on the 6300 transmit signal with no microphone attached !

I have a support ticked with Flex but they have not responded in the last couple days. Ignoring me. LOL
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Jay / NO5J

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The ground loop Isolator, probably eliminated a ground loop being the source of noises and echo's. But the unshielded audio cable past the ground loop isolator may still be acting as the antenna for the RF echo your hearing. A ferrite on that cable placed just before it's connection to the radio may eliminate that. I want my radio to be sensitive, but I don't want it sensitive to it's own TX RF. Sensitivity has it's issues. So do some of the tradeoffs I've made in my own antenna placement and grouding/sheilding scheme.  And Thank you Howard for the idea about the Brute Force clamp on. Another tool for the toolbox I need to purchase.
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Rich McCabe

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Just heard back from Flex. Engineering wants the radio sent back in.  I am glad at this point as I have exhausted about every possible idea I can think of to fix this.

I have owned a couple Pegasus and never been unable to resolve a RF problem and thats saying something. haha.
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Bill Roberts

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Mine is going back, too. Dudley sent an expedited RMA. I appreciate Flex support.
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Jay / NO5J

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Be sure and keep us in the loop, easier resolution of RF issues (fewer ferrites) would be a nice thing to have. 
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Bill Roberts

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I spent all day working on mine. Let's see. Whole cores and split beads everywhere. Just put Radio Works line isolators 6300 to ALS 600 and ALS 600 to antenna. Swapped out Mic cables, now using Heil I bought from Flex. The big discovery today was significant noise (like a Diesel engine) in the monitor with no Mic connected, Mic level set to zero and RF set to zero! Swapped out power supply.

There is RF as the echo now seems to manifest itself at about 60 watts. Like I said earlier, my GAP Voyager is 100 feet away and my ground rod is max. 6-8 feet away via 6 gauge wire. I do have a safety ground and lightning arrestor about 28 feet away. Is that a problem?

Given the noise with Mic disconnected, gain at 0 and RF at zero, think I'll file a trouble ticket and make some recordings to send.

Thanks and good luck to all.
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Jay / NO5J

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Does an unterminated input make noise? Does for me most of the time. Digital hash that gets amplified by the preamp. Turning off the preamp will reduce the effect but not completly eliminate it. Try turning off the Preamp, turning down the mic gain to 0 and repeat your experiment. Then try it without the downward expander, and with it set to 100 and enabled. Is the noise still there? Is a mic cord without the mic better at  rejecting stray RF? Also what kind of signal reports do you get when you have the mic removed.

Jay - NO5J
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Jay / NO5J

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Another possible source of echo/noise might be a microphonic mic cord. I noticed a very faint ringing sound in the shack recently. It seemed to peak when I was typing with my clicky Model M keyboard. Theres a feedback loop thats barely audible when my radio is powered on and the headphones are plugged in. Its not the mic. Holding the headphones directly in front of the mic element doesn't  produce any squeals, but tapping the mic cable or the desk the mic cable lays on produces clunks and clicks that are audible. This is with the radio powered on and without running SmartSDR, but it does it just as happily with SmartSDR running too. I thought it might be tinnitus but it appears to be real audio, unplugging the headphones or putting them on my head eliminates it. Maybe something else to check. 
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Bill Roberts

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Yesterday, I received notice that procedure ECO 75-1006 was applied to my Flex 6300 and that it's being shipped back to me.  Has anyone out there had ECO 75-1006 performed on his/her rig and what were the results of the change?  In the meantime, I've applied even more ferrite to the various cables in the shack and hope my '6300 works well upon return.  Any predictions?
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Jay / NO5J

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Google predicts that you might be the first to receive that ECO. But what does Google really know. ;0)

Hopefully they included a sucker or at least some stickers in the packing materials, when they shipped it back. Some of my doctors do that.      
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Rich McCabe

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Hey Bill be interested to see how that works out.   I sent mine back but opted to upgrade to the 6500 instead of fixing it.  The 6500 has no echo/RF issues so I am loving life and Flex !

It sounded like Flex was confident they could fix the issue regardless.  Wondering how widespread this is.  Guess it doesnt matter as they are taking care of it.

Rich
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Bill Roberts

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Rich,  Honestly I toyed with the possibility of upgrading to a 6500, hoping to get somewhat less RF susceptibility.  Then again, $2,000 is a lot of money!  My '6300 was an "open box" unit that was discounted to me.  For me, its time to wait and see.
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Rich McCabe

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Bill I think you are OK.  It really sounded like they knew the issue and could get it fixed and sent right back.  I just mentioned that I wished I had bought the 6500 and that was all it took. They made it happen !  Funny how that works :)

I figured the balanced mic input on back would help which is what I am running but I did run with with the 8 pin with no issues too.

I am betting you are going to be happy with the 6300 when it gets back. I need to stop spending money for awhile.  I just rebuilt my shack and spent a month working on desk and shelves in the garage and am TAPPED OUT physically and financially. Well I have a new power supply coming but otherwise..........
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Bill Roberts

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Thing is, I was very happy :-) .  Using the 5000 for a few weeks again, I have gained a new sense of how much better (quieter, more selective, more stable) the 6300 and SSDR are.  Yes, I recognize how easy it is to get in the habit of spending lots of money.  That's why I didn't upgrade.
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Bill -VA3WTB

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There are hundreds of 6300 around, I have not heard or seen much reporting of this problem, that's a good thing.
But that being said, echo is an SDR thing and RF.
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George Molnar, KF2T, Elmer

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You know, it could be an echo from your room. With a very clean input, you might just be hearing room noise that was lost in circuit noise before, is your shack acoustically treated?