PTT intermitently not dropping for amp

K1ESE

I can't explain it either but have had it happen.  The most recent time I saw the VOX was mysteriously on and shut it off and all was well after that.  That doesn't mean it was cause and effect.  But, I feel your pain and it's something to try.

AA0KM

I moved things around my radio room and had issues and it was my wired keyboard into the computer. I went to wireless keyboard problem solved.

I put toroid 240-43 on wired keyboard right near going into the computer. Problem sovled.

Had intermittent transmit issues.

KD0RC

Wow...  Good catch.  I always think about RF getting back into the rig, but tend to forget the other equipment like computers.  Glad you got that one solved.
73,
Len, KD0RC

AA0KM

I'm still learning. Rf can get into anything hooked to the computer. This issue with the computer took me a few months to figure it out. Also some keyboards must not be rf prone as i did a little experiment on one i had Torroids would not **** the rf going into to computer. And i have heard some wireless keyboards have issues too. So not at all simple to figure these things out either.

Clay N9IO

Hi John,
I too am having the same issue, 3.1.12 ruñning the 2KFA med or hi power doesn't matter I have to tap the foot switch for the receiver to come back. My foot switch is a simple make/break repurposed Dictaphone foot switch.
It's RF alright, I was thinking of placing a relay right at the ptt input and key the relay with the footswitch from a 12vdc supply to see if the short run from the relay does not excite from the RF. Running PTT from N1MM+ or WSJT via the Virtual PTT in Flex CAT working perfectly. So yep RF on the physical PTT cable.

W9ILY

Yes, Clay, everything other than SSB using the footswitch works perfectly. I have a listing of things that others suggested that I will try during the next SSB contest to see if any are effective. They are:
1. Watch the VOX to be sure it isn't mysteriously engaged.
2. Try using the MOX rather than the F/S.
3. Put torroids on both the wired keyboard and wired mouse. Yes, I use the wired ones to eliminate hesitation that the wireless ones encountered.
4. Put a .1 cap on the F/S.
Will advise what is the result.
John W9ILY

W9ILY

I can rule the VOX issue as being the culprit. I have found that I have some floating RF issues on 40M that may cause the problem. I must replace several connectors on coax lines to fix it. I will replace all my coax feedlines in a few weeks and that should correct everything (hopefully).

Bob Needleman

In addition to the toroids and ferrite clips on all the I/O cables, it may help to add a common mode check on the antenna output, immediately after the external ATU (I understand you're using an amp). Some antennas, especially multiband types, like OCF Windoms, are notorious for causing RF getting back into the shack and a common mode choke will often cut down on that and solve the PTT non-drop issue when operating QRO. 
Bob K3AC

W9ILY

Thanks for the idea Bob. I'll add it to the list. For my amps they all have internal tuners. Where would you suggest placing the choke?
John W9ILY

Clay N9IO

John,
You know I already have toroids on the keyboard line as I too have tried wireless keyboards and can't deal/won't deal with it.  To eliminate the keyboard as the issue just disconnect the keyboard after everything is booted up and see if the PTT delay persists.  I'll give it a try as well and report back.

Larry A. NN5O

I find this conversation very interesting--and helpful. Actually, I was looking for different information when I found this thread. So, here goes: (Note: The vast majority of my operating is contesting)

a) I am seeking some kind of step-by-step instruction on connecting a foot switch and Yamaha CM500 headset to my 6600M--- mainly for contesting, but also for demonstrating to potential young hams. (I've had my 6600M for 2+ years and have not yet taken the microphone out of the cardboard box! I am a 95% CW operator, with occasional RTTY and FT8/FT4). Yes, you're right, I want a very detailed "idiot proof" description of "what goes where" so I don't **** up. I COULD sit down and figure this out, but if such a document existed, it would be great to pass along to others wanting to do the same thing I am interested in accomplishing. I am a visual learner.

b) One of the commenters in this thread stated: "try more ferrites and/or a .01 uf cap across the PTT cable." Can you be more specific? Are you saying to solder the capacitor across the leads of the cable or phone/RCA connector at the point of entry into the radio?

Thanks for your keen insight!

--Dr Larry S. Anderson, NN5O • Tupelo, MS (birthplace of Elvis)

KD0RC

Hi Larry, if you just want the footswitch to key the rig, you need an RCA male to 1/4 or 1/8 inch jack adapter depending on the plug on the footswitch. Plug the RCA part into the PTT jack on the back of the rig. If you want the ability to key the rig from different places (e.g. footswitch, mic PTT button), then you would need a Y connector to give you parallel PTT inputs.

I am unfamiliar with the CM500, so someone else will have to guide you there.

73,

Len, KD0RC

Larry A. NN5O

Thanks so much, Len KD0RC! I believe I have those cables prepped out in the garage shack and can make those connections.

For the CM500 (or any other headset, I suppose), I just need to make sure I get the mic audio routed into the radio. Then, I'll go to work and set up some profiles for that arrangement.

73,

Larry Anderson NN5O

W9ILY

Larry,

For the CM500 that I also have, you need to turn the bias ON for it to work, I have made a Yamaha profile that automatically turns the bias on.

John W9ILY

Bill -VA3WTB

If your CM500 comes with a battery box for two batteries, you don't use Bias.

W9ILY

The original discussion concerned my PTT holding the amp on along with the MOX indicator. Those who suggested RFI to be the issue were correct but in a strange way, To make a log story short I found that a powered USB hub was causing several problems like COM ports not being randomly available, etc. Anyway I just replaced this device with one that was recommended and all the problems, at least to date, have disappeared. Thanks to all for the suggestions and support.

73,

John W9ILY