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eHam Forums => Elmers => Topic started by: KD8TZC on April 18, 2013, 04:43:02 AM



Title: Echo on headset
Post by: KD8TZC on April 18, 2013, 04:43:02 AM
I'm a newer ham, so I'm looking for an Elmer to give me some advice.  When I send audio and I listen on my headset, I can sort of hear myself in the headset.  Is this RF in the shack that might be causing this?  My Ham shack is in the basement with the coax running to the attic where my antenna's are (three floors above).  Would an unbalanced line without a balun be the possible cause for this?

I used to use a 10M dipole with a 1:1 Balun and have recently switched to a G5RV that does not have a balun.  I don't recall hearing myself or the echo with the dipole.  Just curious how I can improve this.

Also, if I hook the rig up to an external speaker, I will hear the echo as well.  How can I improve my setup.

I do have a grounding wire on all my equipment that goes to a grounding rod in my basement (builder had actually installed one when he poured the basement).

Thanks,

John
KD8TZC


Title: RE: Echo on headset
Post by: AA4PB on April 18, 2013, 05:43:55 AM
First, make sure the radio does not have a transmit monitor function that has been accidentally turned on. Second, transmit into a dummy load. If it's okay on a dummy load then it is an RF issue. If its RF then a choke on the feed line may help. Do you have the problem on all bands, or just one or two?


Title: RE: Echo on headset
Post by: KD8TZC on April 18, 2013, 06:08:58 AM
I will double check the radio on the transmit button and also the dummy load (I should have thought of that myself).  As far as what bands, I am only transmitting on 10M as that is all I am allowed on with voice at this time (I'm a Tech class) so I have no way of testing the other bands.

Thanks for the tips and I will check the items out as I want to get this resolved... very annoying.

John


Title: RE: Echo on headset
Post by: KE3WD on April 18, 2013, 06:32:18 AM
You might shed more light and get better resolution to your problem if you were to tell us the make and model of the radio. 

That way, someone familiar with the features, problems, if any, etc. can possibly give you some very specific answers.


73


Title: RE: Echo on headset
Post by: W8JX on April 18, 2013, 06:32:59 AM
You did not mention what rig you have but it sounds like you have the monitor function on rig enabled. It always you to hear transmitted audio and usually there is a delay of a several milliseconds or so and that can cause a echo of sorts in headset.


Title: RE: Echo on headset
Post by: KD8TZC on April 18, 2013, 06:37:18 AM
Sorry about that, yes it would make sense to add that.  I have the Kenwood TS 440S rig.  I don;t even know if it has a monitor function (never saw anything to that effect in the manual).


Title: RE: Echo on headset
Post by: AA4PB on April 18, 2013, 06:38:19 AM
If it is the monitor function then the audio in the headset should be clear. If its RF then most likely the audio you hear will be very raspy and distorted.


Title: RE: Echo on headset
Post by: KE3WD on April 18, 2013, 06:43:19 AM
You mention "headset" - and not head"phones" - Is this one of the units that contain both the MIC and the Earphones in one headset? 

Is this headset designed for use with a transceiver? 

Or is it a headset designed for some other purpose, being pressed into service with the amateur transceiver. 

The reason I ask is that I have encountered situations where someone has wired one of those headsets designed for computer or perhaps cellphone use to a ham rig and had the in-ear monitoring phenomenon such as you describe happen.  I get called in to torubleshoot and find that the wiring inside the cable of this type of headset is often not shielded between the earphone lines and mic line.  The amount of capacitance between the paralleled wires is enough to conduct the driven earphone audio AC into the mic's input line. 

Often is impractical to try attaching your own shielded lines to such a headset, the answer there is to find a better quality headset made for radio comms and use that. 


73


Title: RE: Echo on headset
Post by: KE3WD on April 18, 2013, 06:45:19 AM
BTW  -- "Echo"  -- Unless what you hear is delayed in time from the original, meaning that you talk, there is a delay in time and then you hear what you said, then it is not termed an "echo" in the audio game.

At the moment, I'm thinking that this is more likely a case of audio "Crosstalk".


73


Title: RE: Echo on headset
Post by: KD8TZC on April 18, 2013, 06:50:16 AM
Yes, they are headphones (Sony MDR-V6 Studio Headphones). 

Crosstalk vs Echo... not really sure... all I know is I can hear myself (faintly) on the headphones when I transmit.  Same with the external speaker (which is nothing more than a Radio with an audio input that I run the audio from the rig to - from the Ext Speaker jack on the back of the rig).


Title: RE: Echo on headset
Post by: KE3WD on April 18, 2013, 06:59:39 AM
Try transmitting with the drive turned all the way down in SSB, or better yet, into a Dummy Load with a very short jumper to radio antenna jack and nothing else. 

If you still hear your Crosstalk (which is what this IS) then you can safely rule out RF being the culprit.  It likely is not RF as that would also be distorted in the headphones as well. 

Try this -  leave the headphone side connected, disconnect the Mic input from the headset and use another mic to modulate the radio (such as the original handheld mic or any other separated mic you have that will work with the radio).  Talk into the separated Mic and listen at the same time via the headset.   When you don't hear yourself that way, you have isolated the problem now, which would point the finger squarely at the mic/headset and nothing else. 

These headphones were not designed to be used in the ham radio environment, needless to say.  It may require a bit of internal modification to the headset to solve the problem. 


73


Title: RE: Echo on headset
Post by: KD8TZC on April 18, 2013, 07:33:12 AM
Okay, I will try all that.  So really dumb question then, but what causes the cross talk?  I see people using all kinds of headphones that were designed more for audio with Ham, and really never gave it much thought.


Title: RE: Echo on headset
Post by: K1WJ on April 18, 2013, 09:02:31 AM
Easy: Since your a Tech. go back to the 10m dipole - Fixed. 73 K1WJ ;D


Title: RE: Echo on headset
Post by: KD8TZC on April 18, 2013, 09:19:55 AM
Sounds more like a "sit down and shut up, we don't want to be bothered by a Tech" comment to me.  The obvious question though is what is causing this to happen.  Yes, I can easily go back to the 10M dipole, and more than likely I will do that (although I seem to recall that I had the same issue with it on the external speaker) but what causes it. 

I'll take some of the comments above and try and isolate the source.

KD8TZC


Title: RE: Echo on headset
Post by: K1WJ on April 18, 2013, 09:30:14 AM
OK, did not mean to make you feel bad - are you using ladder line or coax with G5RV?
If coax at radio, about 6-8ft from radio - take coax & put 10-12 turns around a 4.5 inch form to create a choke - I think this may help. 73 K1WJ 8)


Title: RE: Echo on headset
Post by: KD8TZC on April 18, 2013, 09:49:57 AM
Thanks K1WJ... I have both Coax and Ladder line (Coax to attic and then it switches to the ladder line).  I can give that a try too.  What is causing it though?


Title: RE: Echo on headset
Post by: K8AXW on April 18, 2013, 10:14:32 AM
If you have RF being radiated from the twinlead/antenna in close proximity to your gear, something in your gear or some wire connected to your gear, is picking up this RF and feeding it through the audio circuits on your radio which you hear in the phones.  This is "crosstalk."

Getting rid of this annoyance is another subject to become involved with after you try the aforementioned suggestions.  You always go for the obvious or simplest things first OM.  Then your take on the more involved solutions.

Indoor antennas quite often present problems that outdoor antennas seldom do.  Like inject RF into the house wiring.  This is why it was suggested you go to your dipole and see if you still have the problem.


Title: RE: Echo on headset
Post by: W0FM on April 18, 2013, 11:19:32 AM
I didn't read K1WJ's post as demeaning toward you at all.  His point was clearly that, being a technician class, you are unlikely to need multi-band HF capabilities at this point.  (Soon, hopefully, but not right now).  So the 10M balanced dipole presents somewhat fewer complications than what would have to be addressed with the G5RV.

I really don't think it was a slam against a Tech class licensee.

73,

Terry, WØFM

(either way, a choke in the feed line would still be in order)


Title: RE: Echo on headset
Post by: KE3WD on April 18, 2013, 01:02:19 PM
OK, did not mean to make you feel bad - are you using ladder line or coax with G5RV?
If coax at radio, about 6-8ft from radio - take coax & put 10-12 turns around a 4.5 inch form to create a choke - I think this may help. 73 K1WJ 8)

Yes, the choke balun at feedpoint should be part and parcel of all G5 installations to prevent RF from riding back down the coax shield and into the shack. 

73


Title: RE: Echo on headset
Post by: WG8Z on April 18, 2013, 04:03:27 PM
G5Rv is a crappy antenna for 10M, the dipole will blow the socks off it anyday..... well actually just about anything will out perform a G5 on 10.