Transmit Audio Quality Question

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  • Updated 3 years ago
I recognize I may be having some transmit distortion.  However, putting that aside, I tried to adjust my audio quality.  I noticed that with the stock mic and some tweak you get get some pretty good audio using the tricks shown in Ken's Videos.  I would say as good if not better than my FTDX.

However, during the contest numerous stations I had to repeat my call sign.  More than I have ever with previous radios.  Even with my AL80b AMP I had to repeat my call sign numerous times.  Again, the 6300 is very new for me with my station setup right now.  The only difference is the radio.

What I have noticed however, is that my average output is MUCH lower than my FTDX.  With my FTDX I typically would get an average of 65 watts or better.  With the 6300 I am lucky I am getting 30 - 40.   I recognized this and why I went to my amp... but still had issues.

I checked my station for any issues and could not find anything out of sort.  The 6300 PEP is 98 watts OR more from 6 meters to 20 meters.  On 20 meters I actually get 104 watts recorded by my W2 watt meter!  So I know power is NOT an issue.  

Will changing the stock Mic out for a Heil or other really improve the audio that much to make a difference?  Why if I can get nice clean audio from the stock mic with the proper settings?

I want to add as a disclaimer that I may have had that audio distortion issue - BUT.. Honestly in my SSB on 20 meter I dont see the signal showing a bad one.  I only see it in CW at 100 watts - But honestly I am not a radio engineer so knowing what a clean signal looks like is somewhat foreign to me.

Any suggestions appreciated.

My Station:
6300
Windows 10
All LMR400 feedline
Hex Beam at 35 feet
AL80B Amp
Elecraft W2 Watt Meter
Elecraft KAT500 Tuner
SWR all 1.5:1 or better without tuner on 20 - 6 meters
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Mike KD2CJJ

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Posted 3 years ago

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Roy - W5TKZ

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Mike,
I chased a similar problem with my 6300. Mild audio distortion on SSB. I suspected RF in the shack but it took me several months to find the problem. A friend suggested I wind a choke with 25 ft. of RG-8X. I wound one starting at about 8" diameter and placed it between my radio and amp. I put the coil on top of my amp and ran about 5' to the radio.
The last of my distortion was gone. I now have good clean audio.

Good Luck,

Roy - W5TKZ
   
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Mike KD2CJJ

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Roy - I have numerous high quality chokes..
1.  At the antenna feed line - Mix31 Ferrites 8 of them
2.  Balun Designs  Guanella Isolation Choke 5kw when the feedline enters my office
3.  Another Mix31 Ferrites 8 of them on the feedline right before my radio
4.  Ferrites Mix31 on EVERY wire going in into my PC
5.  Everything is grounded to the same point - I am using a water pipe as I do not have access to a ground rod - but this is also a balanced antenna.  Using it more to deal with common mode rather than a RF ground.

All the above I have NO issues with my FTDX3k.  I literally unplug one radio for another.

PS- I stay away from "ugly balun" approach as it adds inductance which will throw off my SWR.
(Edited)
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Gerd Henjes

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Hello...

If the peak to average range in the average voice is 14 DB, how much average power would you expect from a 100 watt PEP radio? Let's make it easy and narrow down that 14 DB to 10 DB and then do the numbers.

For contest, or weak signal work with your FLEX let me suggest starting with you low end cutoff no lower than 150 cycles, with a higher number up to around 300 cycles really cutting the bass. I'd also roll down the lows with additional emphasis on the highs 2,000 range in your equalizer.

The processor in the Flex is an amazing piece of work... try the different settings and watch your average power increase.

On that power question, if you are seeing 50 watts average voice, or a 3 DB peak to average ratio, I can understand why no one else can.

Gerd, W2ISB
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Ken - NM9P, Elmer

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Per your second question:  The short answer is, Yes, the  standard hand mike can be made to sound pretty good with some work with the EQ.  And Yes... A better mike would sound better than the standard hand mike. 

I can't comment about your particular voice/mike situation, but if you compare the audio I get with my Heil PR22 in my "tour of transmit profiles" video and the audio I get using the hand mike in tutorial # 3 then you can tell that a good mike makes a difference.  (You may not be able to tell if you listen using the speaker on your smart phone or laptop.)

You can't put back in what a poor mike leaves out, and it is hard to remove strange peaks, gaps, and resonances generated by a poor mike without some very sophisticated processing software. 

But it doesn't take hundreds of dollars to get a good sounding mike.  A friend of mine has a $19.95 Radio Shack mike on his Flex-3000 and it sounds really good. 
http://www.radioshack.com/unidirectional-dynamic-microphone/3303038.html
It comes with an attached cord with a 1/4 phone plug. 

They have a better one for $39.95 that would probably sound great. 
http://www.radioshack.com/super-cardioid-dynamic-microphone/3300128.html
It has an XLR connector on the mike, like a standard balanced input mike should have. 

Ken - NM9P
(Edited)
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Mike KD2CJJ

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I am using the out of the box Flex settings... I have also implemented some of Ken's suggestions having multiple profiles.  All of which make a nice crisp audio... - however very low average power.

I will keep playing around.

Is it suggested that I still get another mic?
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Gerd Henjes

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Mike... what do you think you average power should be to be correct?

I run my Flex 6300 at about 10 watts average voice power... I drive my Alpha 89 with 45 watts peak. The amplifier produces 1,500 watts PEP output... my average power 100 to 150 watts.

Do you think it would get out better, or sound better, if I cranked it up more... no.

Gerd, W2ISB
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Mike KD2CJJ

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I guess Im chasing the reason why with my FTDX I rarely get a question about my call sign and with the Flex so far I have had nothing but trouble getting good reports.  I will spend some more time with the settings and getting feedback on my audio reports.

I have tried using Kens suggestions and the audio does sound good.. However it hasnt materialized into better clarity for the station working me.

On my FTDX3K I average about 60 watts ... on the flex I am lucky if I am seeing 30 - 40 watts.

Of course I recognize all this may have nothing to do with why I was not being heard as well as my other radio.
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Tim - W4TME, Customer Experience Manager

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Mike.  A few things.  Ken has already answered your question on if a different mic will be better.  I would recommend upgrading from the communications quality FHM-1 mic.  A nice dynamic wide response range vocal mic can be had for a decent price.

Second, average power tells you nothing realist about the power output.  You need a true peak reading wattmeter.  Power output can change due to numerous factors.  Having too much bass in your audio can show up as more power output, but lower talk power (intelligibility).  A good peak reading wattmeter is an invaluable tool for your shack.

Third, with an SDR you have to make sure that you provide enough time for signals inside the radio to process and be converted to RF.  If you release PTT the exact moment you stop talking, there is a good chance you will truncate the last syllable of your transmission.  This is a little different dynamic from analog transceivers.  So you need to wait about 1/4 second after you stop talking before you release PTT.

Fourth, you have not provided your mic setup information, such as the mic gain settings, PROC settings, TX band width, TX EQ and DEXP settings.  When you are speaking into the mic, where is the level meter peaking?  This information is crucial for getting a reasonable reply for this type of question.
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EA4GLI - 8P9EH - Salvador

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I use a Yamaha CM500 Headset with electret capsule and have great success in last weekends CQWW SSB contest using No EQ and PROC enabled on DX, BIAS on, +20dB on and MIC GAIN at 25.

For regular rag chewing I like to disable PROC and use the EQ. For my voice I like to add +4 to 500, +6 to 1k, +6 to 2k and +2 on 4k (zero or below for the rest).
(Edited)
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Bill -VA3WTB

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I have been using that headset for some time, wonderful!!!