Mic audio oscillation

n3eko

I could sure use some help in getting my new Flex 6600M running. It’s been several months and still trouble shooting the radio.

I have had issues since day 1 with front panel display boot issues and after contacting Flex they blamed it on my ISP after lots of tests. I still have issues with the head not syncing  with the radio. The head powers off and the radio is still on. The second issue is when I push operate that’s as far as it goes all with NO internet cable connected.. I called to return the radio soon after I received it and they talked me out of it, right now I know I made a mistake!

I can get around the head issue by rebooting several times, but the thing that has stopped me from enjoying making a contact  and is the real problem“ 7 total in 2019” is the bad audio reports. I have RF getting into the audio on both the stock mic and a replacement INRAD 629. If I run 1 watt with the mic gain higher than about 30 the mic audio goes into oscillation. The Flex has been unusable except as a receiver so far.  “Bottom Line- +20dB on or off by the time you turn the gain up enough to drive the radio it starts an mic audio oscillation. Speakers and or monitor functions turned off.

My Icom 9100 works great from 5w to 500w with the same equipment and antenna and is what I have needed to go back to.

If I use a dummy load the audio is fine on AM and SSB   

I have also isolated the Radio from everything else. Radio with the antenna directly connected and the same issues occurred.

When I can’t run QRP I realize the radio looks to have an issue.

My first thought has been what am I doing wrong but, my Icom is working fine and has worked in much higher RF environments.

Suggestions or Ideas? Everything points to a radio issue. As I said, I wish I never purchased it at this point. I don’t have a lot of time doing the hobby and I have run out of ideas and quite frankly it should not have this issue! Its easy to blame an antenna and I have. I have changed it around many times and the problem stays. Grounding/ ungrounding still the same.

Just tried transmitting 100w nearfield "antenna wire 3 feet away from Flex" with the Icom and Flex in a dummy load on tx, Gain on Flex mic at 100. No issue in a very high rf enviroment.
Hooked Flex up to the near field antenna and tx at 4 watts with reduced mic gain has issue. No issues with the Icom at any power level..  What am I missing? Looks to be as soon as the Flex is on an antenna the issue shows up at 1 to 4 watts but not with a 100 watt TX next to it its fine. What am I missing? Transferred to battery power, same issues.

The stock mic is a FHM-3 that has the same issue.
The 629 settings I use are Bias off and +20dB enabled. It helps to turn the +20 off but turning the mic gain back up to get proper output the issue returns.
At least my $10 cheep powered computer speakers don’t have RFI!

SW Version 3.1.8.71  and same issues with other versions. Have not put a trouble ticket in yet.
I have run out of things to try and my patience is now gone for a new radio. HELP hihi. Looking for ideas or suggestions!

Thanks

Ron

Rick WN2C

The first thing you need to do is open a help desk ticket.

n3eko

The last time I did I was told by Flex I should start here first,,,,   so,,,,

Bill -VA3WTB

Forget about what the icom does or not do, you need to find the source of the RF getting to the radio. Start by unplugging everything from the radio that is not a must. Disconnect the mic and try tuning, or MOX. No head phones, no mic ,,,no speakers...nothing other than coax and power.

WX7Y

does it do it when you have the network cable disconnected at the radio?
I 2nd what Bill commented about.
Connect 1 thing at a time and run ALL test before you connect the next cable / device 

Some ethernet switches, cables, and routers are really susceptible to RF and may not be the Radio at all.

What do you mean by
"Just tried transmitting 100w nearfield "antenna wire 3 feet away from Flex" with the Icom and Flex in a dummy load on tx, Gain on Flex mic at 100. No issue in a very high rf enviroment."
 
and how far away is your normal antenna and Power output level that is causing the issue's. 

hard for us to help you if we don't know the exact setup and circumstances of your station could be something simple that is being overlooked .

73 
Bret 

Dan-N7HQ

Hello Ron,

There is no one at FlexRadio that would ask you to "start on the community first" with a technical question like any you posed here.  They may have suggested the community for a general "how-to" question about a third party application. There are folks in the community that are experts in that regard.  But even then, FlexRadio staff who answer the general phone lines are trained to create a helpdesk ticket when taking a technical call. 

Please open a helpdesk ticket and let our experts (Tim or Ken) work with you. 

73,
Dan

n3eko

I can only say what I was told. I also think it is a great idea. I see others have many of the issues I have or have had. Since after searching and not finding anything like what I am having happen I opened a ticket.

I have some radio hardware to test out to find out what's going on, so the process that I was asked to do works and works well and I thank Flex for having the reference.
Great Idea.

n3eko

WX7Y

Due to continuing boot issues I have not connected the network to the radio except to download updates. Sometimes when it goes south its hard to get it back, thankfully that has not happened in 3 months. I have not had time to get on the radio much.

The process I described is trying to shove as much RF energy at the radio from a close in external source to see if there was any type of interference. Some times I can trip powersuplies and locate issues that way if things are not grounded properly. It's Just a tool. I also did not hear or see any issues when I did this. It's sort of a field day setup but Much much closer.

Yes, The first thing I did was to hook the radio up with only the basic connections, power antenna and mic and I went from there. I used the internal speaker and have also disabled it in testing. As I said, I'm trying to get this operating basically from the box.

  The power on HF where things go south is ONE watt using a FCC050-H05 current choke from DXEng feeding an EFZ 75 feet away and up 45 feet. I have used a 9:1 balun or a remote tuner at the feed point of the wire with no change. Thats a random unmatched impedance with the balun to a rather close 50 ohm at the transmitter with the remote tuner. I have also tried a Palstar AT5K.  With 6m using a dipole antenna located 100 feet away and one floor up it's 10 w where increased power creates distortion.

Power suplies are Astron Linear 75A, Astron ss-30m and the storage battery. No change in issues testing with each.

At this point hold off with comments until I can go through testing the mics and the connections at the request of the support group. Hopefully it may turn up something. I got some great additional ideas about the audio input and the mics. Just because they are new does not mean they are good. This may take some time, busy day tomorrow. I hope this helps. Been around radios and antennas for 40 years from HF to 40 Ghz. I still learn something every day and the day is getting closer when we figure this out and learn again. 

Thanks for your questions.

Brian Denley KB1VBF

Isn’t the FHM-3 mic a condenser type?  If so, bias must be set to ‘on’.

n3eko

Yes, I think you are correct or the mic will not work at all.

Luis del MOlino

I am astonished because nobody has been able to explain to this man that all the problems he is discribing here are due to RF common mode currents coming from an asimetrical coaxial cable that has external currents on the outside braid coming from his antenna. That antenna system has not been balanced with a balun.and Iso,  would recomend to install a balun on his antenna as for example an W2AU balun or an MFJ-815 and an another un-un or ferrite choke as the MFJ-915 at the output of his rig or linear amplifiera  and that would be enough to cure all his RF problems that are not due to any failure of his rig. It is so clear as water.

73 Luis EA3OG

Bill -VA3WTB

Luis, read my comments above.

n3eko

I guess today is a good day. It's narrowed down to a mic jack or something internal within the radio.

I now have both the FM3and the Inrad mics working pretty clean. It looks like there is a bad ground somewhere with in the radio. I cleaned everything with the FM3 and left the 629 alone. Frustrated as I was yesterday I gave the radio a smack. Take your pick what it was or is. Time will tell if it is fixed, I think not, but for now yes. Even 6m works.

Luis I had a great description typed up then the cat jumped on the keyboard.

The short is I have a End Fed Zep thats powered by one of 2 radios. same coax.
From the radios it normally goes to the amp then to a Palstar AT5K with a 1:1 current balun on the input side. From there to a DX Engineering FCC050-H05 or a -B Feed Line current choke. You can look it up if you would like. Then to either a 9:1 balun or a remote tuner feeding the wire. You can have a variable resistance high VSWR in the cable or a rather nomional 50 ohm depending on what you use.

As I understand the antenna the EFZ uses the coax for part of the antenna and it's normal to have RF on the shield Ie: common mode. Per the design of the EFZ a current choke is REQUIRED and was recommended by DXE. With out it you will have lots of RF issues in the shack. You can also use radials if needed. Needless to say but LOTS of variations from grounding to feeding were tried changed and double checked with no changes. I even setup 2 different antennas with no change. The only change I would see at times the noise would come and go and very hard to pin point always when I was using the mic. Yup, I needed to use the mic to transmit.  I now have it narrowed down to the radio and very sure of it.

I would hazard to say just about everyone on HF have some amount of RF in the shack. The radios still work. The current choke through time has shown that it works very well. I have two of them. I love the EFZ and going to have two in the future. They are grounded at the feed point so it is a quiet antenna in my view. Using the correct balun.

Hopefully my setup meets your requirements. If not, I would love to know what you would change and why.

Smacking the radio was wrong and I hope the radio police don't come knocking on my door. After all the time and frustration it felt sooo good! Guess it's time to pop open the covers next and see what I can find.

It's good to have that part of the radio working again! For now. I can finally use it again. 

Now it's on to the display boot and shut down issues without being connected to a lan. What's that fruit that grows on trees and is yellow? And this was a NEW radio with all these issues. Right out of the box! $$$$

n3eko

The latest update is-

Flex has replaced the 6600M. Every single remaining issue that I had to trouble shoot through is GONE with the replacement radio. Almost a week with ZERO issues.

With an external GPSDO the radio shuts down all the way not acting like it has the internal GPSDO installed. Just noticed this one.

The best thing is the replacement radio has ZERO RF getting into the MIC input. It was a plug and play install the way it should be.

It just "Feels" like it's a different radio! It's hard to describe...

Thanks to Tim for listening and working the problem. Most of all I thank Tim and Flex for being able to find a way to make the customer happy and stand behind their products! It would be very easy to just keep blaming the environment the radio was operating in, they did not.

I will be wearing my Flex Radio hat proudly and have no second thoughts about promoting Flex equipment. The first hand experience with customer service has shown that the company stands behind their equipment and they truly care about their customers.

Even retired ones like me!

Thanks again!'

73
Ron
N3EKO




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