Over modulation in SSB/F6300

RoyS

Has anyone else seen this?  Just got my 6300 back from Flex. They tell me that my problem is the way I set up the audio. Sorry, my 3000 does not have this problem.
Problem: Over modulation in SSB.
Following instructions from Flex, I set the modulation level to a point that no audio appears on the outside of the passband on the panadapter. Starting from about 10 watts on the RF Power slider, I increase the power to around 65. At this point, the panadapter and the waterfall show me some splatter on the outside of the bandpass. The RF output is about 5 watts. I raise the RF Output to max but no power output increase is observed. I now raise the Mic slider to 65 and get about 50 watts RF output. However, the splatter has increased to the point that I have output modulation from 28.480 to 28.495 with a desired 28.488 upper side band.
I have received reports from others that I truly am splattering and appear to be off frequency.

My question again: Has anyone else seen anything like this on SSB?

Roy - W5TKZ  

George KF2T

Don't mind the panadapter - in transmit it's not (yet) fully representative of your situation on-air. DO ensure that the audio level meter never turns red, even on peaks. Unless you are getting RF into the mic, you'll be fine. The 6000's sound best with balanced audio. Any way you can try using a balanced mic (can't recall if the 6300 has a balanced input)?

Steve W6SDM

I was just going to say what George did, don't rely on the panadaptor for monitoring transmit audio.  Nope, the 6300 does not have a balanced mic input.

If all of your settings are okay, not over driven on the processor or too much mic gain, then I would look for RF.  I had that for a while and  my audio was distorted and much wider than it should have been.

Do you have another mic or another mic cable to troubleshoot with?  Maybe place some ferrites?

RoyS

George and Steve, Thanks for your insights. Strange thing about the Panadapter. It's telling me the same thing that other operators tell me they see on their panadapters during a QSO with me. I have tried other mics but no difference.  I'm a little shaky about the idea of RF getting into the system, but hey, I'll look into that also.

Thanks again guys,

Roy - W5TKZ

Charles Talbott

I'm getting "rough" audio reports too.  OK on not relying on the scope, BUT, as Ron commented, the guys on the other end agree that I'm splattering when the Tx displays are right as to compression etc..  I'm having problems getting my mike audio set properly so that I get adequate output power without spattering.  To see a clean signal on the screen, the power meter in my MN-2700's 200 watt scale,  barely flicks to a couple watts.  Comparatlvely, I see 20 to 30 watts average when running 100 watts with the IC-7600 which gets great (clean) audio reports.

Also I must be missing something in the SSB set-up, but for the life of me, I can't find any "COMP" button anywhere.  In the SmartSDR Software User Manual under "Recommended Audio Adjustment Steps for Voice Modes", it says to "Turn on the TX compressor/expander" with the COMP button.  Do they really mean the "DEXP" button ?  ( I don't have much background noise and don't like the choppy sound the DEXP gives the signal even when set very low.)

I also never see any way to "Adjust the compression level"  slider as indicated in the next step which is supposedly to the right of the Comp button that I can't find.

73, Charlie k3ICH

RoyS

Welcome to my world Charlie. I was beginning to think I was alone with this "overdrive" problem.  As for your other problem, stop looking for the COMP button. It's not there. This is where the Smart in SmartSDR comes in. On higher volume peaks, if your driving hard enough, the COMP will activate and you will see the Compression Indicator (right under the output power indicator) light up on the right hand side. There is also no Compression Level Slider. 

Someday the 6300 might be a nice little radio.

73
Roy - W5TKZ

John n0snx

I have been running my 6300 since may and have never had any of the problems stated about....BUT... I do run a Shure SM7B or an electro voice re27 into a preamp... mic set on 10... proc on NOR.... and make sure you don't let the mic level go into the red....EQ turned on and set at the default to start .... Always get great compliments on the audio daily.... come listen on 80 meters after 10pm 3.810 and see for yourselves....ka9meh-Vern and  I will try our best to help anyone out with there audio.....  The Flex6300 is the best radio I have ever had.....  Its a great rig.... when set up right bar none...

John

RoyS

Thanks for the comment John. You don't indicate if you are driving an amplifier with your 6300. I do, anytime I'm on SSB. My amp is a solid state, no tune, ALS-600. I drive it with my 3000 with excellent audio. Depending on the band, I need from 40 to 60 watts of drive to get 400-500 watts output. The output from my 6300 at 40 - 60 watts is distorted. Although I'm not in the red on peaks, the audio is still distorted by side bands. (outside of the passband which is set at Low 100, High 2800). I don't think any preamp is going to make any difference on my machine. I truly believe I have a hardware problem but the minimal test at Flex found no problem. I continue with my frustration.

Roy - W5TKZ        

KY6LA_Howard

Perhaps you may be getting RF into your audio chain that may be causing ur splatter You might try putting the biggest possible clamp-on toroid on ur mike cord to see if it fixes the issue My 6700 continues to get superb "FM Broadcast Quality" Audio reports even when I am remoting fromEurope to the USA using an inexpensive $26 Logitech Bluetooth Mike/headset

Gerald-K5SDR

Roy, I personally took your radio home to test and ran it on the air Monday because they could not find a problem in the shop.  They ran it through all factory tests and calibration in the shop.

It worked perfectly on the air using a PR781.  I had the mic boost set to +20 dB and the mic gain set to 65.  Speaking about 4 inches from the mic, the mic level meter was peaking just at 0 dB.  Driving it much harder than that will cause severe ALC action.  I had the TX audio set for 100 to 3100 Hz and Normal processor.   I had no problem getting full power output.

I asked K7MX to record and play back the audio and it sounded exactly like me.  He said the skirts were very sharp and clean on his panadapter.  We were both S9 +10 dB so we had a very good path.  You cannot set your audio based on the TX panadapter because the high level signals inside the rig will fool you.

When your radio arrived your mic gain was set to 100.  That will cause severe overdrive even with low level dynamic microphones like the PR781.

I am wondering if you have a wiring problem.  You should probably work with support to try to get help finding your problem.  I am confident that the radio is working properly based on factory test and my on air operation.

John n0snx

Yes  Roy I do run an amp.... first I was running a AL800 and now an Aphla 99.... After seeing Gerald's reply I would think its a shack issue and not a radio issue...Believe me I know how frustrating it can be when every thing you try fails... Hang in there...

John

Patrick

The wave form represented in the Panadapter is audio only and not the RF output. The metering in the phone window is the only way to set drive levels. Flex has done a good job of setting the max levels indicated in the audio drive meter. Only other way is with external equipment to measure the linearity of the RF envelope. Pat.

John n0snx

Roy I use the preamp because of the low impedance microphones that I use.

You didn't say what microphone you are trying to use.... I have to agree with KY6LA that maybe RFI is causing your distortion....  There are just too many variables to blame it on the rig its self....  FRS it top notch when it comes to problem fixing.... If Gerald used your rig in his environment and had no issues and you get the radio back and using it in your environment  and the same issues are still present I would be looking at the working environment instead of the rig...

KY6LA_Howard

Roy

I suggest you follow the steps in my Positom Paper on "How to build a Quiet Station" which u can find by searching in this community.

I would bet its 99% likely that you have a ground loop somewhere that is causing ingress of RF into ur audio chain

For example Is you computer, amplifier and radio going to the same Single Point Ground

Jim K4JAF

I would take what Gerald has said as a fact and move on from that.. Must be something on your end, maybe rf in the audio that is causing the distorted audio...  What microphone are you using on the Flex?  I am using the 6300 here with the 781 from Heil and also a Heil ICM and get consistently good audio reports..  Perhaps you need to look inside your station...  73s Jim K4JAF

Ken - NM9P

"Following instructions from Flex, I set the modulation level to a point that no audio appears on the outside of the passband on the panadapter. " I don't remember this technique being part of the instructions. I suspect that you may be continuing to raise the mike gain in an attempt to bring the average power reading up. But the average power reading on a meter or "splatter" seen on the pan adaptor isn't a good way to gauge the proper mike levels. When the audio input is raised above the proper limit, any SDR will get "dirty" very quickly.

RoyS

Ok guys, here is what I have decided to do about my problem. I have decided to fight this thing till I get it right. Even if it hair lips every cow in Texas. The difference between the location at FRS (where the 6300 works) and my place (where I think it doesn't) can't be much but that is where I'll start. I had not noticed it before but I have a high ambient noise from fans at my operating position. I have 3 fans in my computer at 2.5 feet away and 1 fan in my amplifier, also 2.5 ft away. I'll cure that first.

Since I no longer use the screen as a modulation guide, I will set up my F3000 as a monitor. I realize that comes with it's own set of problems but I cannot get enough gain for use of the audio monitor on the 6300 without overdriving plus I may be able to observe the actual output signal of the 6300.

Anyway, I cannot thank you all enough for the inputs, insights and encouragement. My special thanks goes to Gerald - K5SDR and Dudley of FRS. Both gentlemen have gone above and beyond to help me. I could not ask for more.

73 - Roy - W5TKZ
   

Ken - NM9P

BTW... You can get more Monitor output into your headphones if you turn the master Headphone level up and readjust your individual slice volume levels down to balance things out.  Monitor output volume is independent of the individual slice volume level, but it is affected by the master headphone and master speaker volume controls.  

NOTE:  What you hear in the monitor is not a complete replication of your transmitted signal.  It is tapped BEFORE any speech processing and final filtering.

Gerald-K5SDR

Roy, there is a check box on the Phone tab of the Setup form that will allow you to see the audio metering when you are not transmitting.  I like to use this to set my mic level.  You should set the mic gain so that you are just barely touching 0 dB.  Anything over that is wasted and will kick in ALC.  Remember that adjustments to the EQ and bandwidth will affect the gain so you need to check the mic gain after making those adjustments.  You should be able to get perfect audio if you have a decent microphone and get the levels set right.

RoyS

Thank you gentlemen--as always. Here is what I have done today. I have set up my 3000 as a monitor. I use the headphones of the 3000 to listen and view myself on the same freq as the 6300. The 6300 is attached to my dummy load, 1 gallon size. During my first tests I sounded like I was gargling. I disconnected my internet cable from my cable modem and went direct to the computer. That problem went away. I'm now without internet on that computer but I'll worry about that later.

There is also a strong whine with no modulation. I say strong, but that is relative. The radios are so close I can hear a pin drop. Still, worth looking into. I changed mics, no change. I see this on both radios so it is being transmitted. I have set the 6300 with the scale on the top right of the panadapter set at -30 and the bottom at -130 along with the signal base line. Power output is 1 watt. Mic set on 60 and no modulation, I get this whine (sounds like the sound you can get with a small radio held close to a computer) that reads a little over 90. The amplitude can be varied with the mic or power sliders.

That's as far as I have gone so far. I need an "on the air test" and I will try that out on a local net tomorrow.

73
Roy - W5TKZ      

Steve W6SDM

If I understand it correctly, you have RF getting into your station through the cable modem.  So, even though you fixed one of the sources, you still haven't addressed the root cause.  It will be a lot easier to get everything fixed if you try to eliminate as much of the RF problem at the source. I speak from experience.

How's your SWR?  Is your problem more significant on some bands than others? Do you have a really good ground system set up?

I used a device from our friends at MFJ called a MFJ-805 RF detector.  You clamp it onto cables one by one to find out which ones may be "antennas" for inducting RF into your station.  You can get a better description of it on the MFJ web site.  Mine found a store-bought mic cable that was the worst offender.

RF is nasty.  Transmit audio distortion is only the most apparent symptom.  It can cause other unpredictable things to happen in your station.

RF to the ham is like light is to a photographer.  It's your friend as long as you can control it.

73,

Steve
W6SDM

RoyS

How right you are Steve. I've had some pretty nasty RF problems using digital but I got them all squared away over time. My current testing is using 1 watt into a dummy load. Shame I didn't know about the MFJ, but hey, now I do.

Thanks Steve

73
Roy - W5TKZ  

RoyS

Well I think we can put this thread to bed. On a local net last night, everyone thought I had good audio. No distortion. Still need some tweaks to equalizer but otherwise good reports.

Here are the final connections that cleared my distortion:

Instead of connecting my radio directly to my cable modem, I now connect my radio, computer and cable modem through a 10/100 Fast Ethernet Switch made by Dynex.  

I don't fully understand the why of this but distortion gone was the goal.

Many thanks to everyone.

73 - Roy - W5TKZ
 

Ken - NM9P

Excellent!  Now the fun can begin!
Glad you got it sorted out.

the WHY?  WHo knows... Perhaps you were having networking connection/timing errors.  Or perhaps the switch is isolating the rig from some RF interference.
In any case.  That is how I am connected.... rig and computer to a Gigabit switch.... then the switch to the U-verse router/modem.  I have no problems, except for some "popping" in the receiver for a few minutes if I turn everything off for a while.  I guess the "green" function of the switch needs to settle in and finish changing power levels, etc.

Ken - NM9P