kenwood th 2 handie

I have recently bought a Ken th 2, along with the matching hmc3 vox headset. Apart from the silly earplug that keeps dropping out, everything is fine, UNTIL I connect a WatsOn minimag antenna. If I use the ptt, still no probs, but if I use the headset vox, as soon as I transmit, the rig goes into an oscillatory loop, where when the vox switches to rx, it triggers a new tx mode, no matter what level the sensivity is set at. It is obviously rf pickup, as it doesn't happen with the set's internal vox, or when the rubber stubbie is fitted.

[N5RLR]

Hmm...try grounding the chassis of the radio to the body of your vehicle [I'll assume that this is a mobile situation].

One expedient would be to form a loop of wire around the base of the antenna connector, and on the other end a crocodile clip [or any other method you'd prefer] to a known body ground [try a bolt that attaches the seat to the floor, just be sure to remove any paint or grease from it].

Good luck. http://www.qrz.com/iB_html/non-cgi/emoticons/wink.gif

Thanks, Mike. I tried that, to no avail. i have now discovered that it also does it on the newly installed home-base antenna! Nobody else seems to have come across this problem, either Never mind, as I said, i can always use the internal vox. That works just fine, but it's a pain in the rear orifice to adjust, becasue i have to keep going into the menus. It might be simpler not to bother, and just use the ptt!
I'd like to put a proper antenna on the company van, but the 'Boss' won't let me drill holes in the cab roof!

I found the cause, and the solution, by accident. After about a dozen uses, the headset stopped txing audio, although I was still putting an empty carrier out. a short while later, the recieved audio disappeared as well!
So, rather than having the aggro of sending the thing back to the sales company at the other end of the country, and as I was fed up with the earplug that wouldn't stay in my ear anyway, I decided to modify the set to a proper headphone. That is where the fun started. I took the vox-box to bits, and found that Kenwood have not used decent cable. The screen and the signal feeds to both the mic and the earpiece are only separated by a layer of enamel, both of which had fractured, and added to that, the screen wasn't connected to the vox board screen, it was flapping about in free space. When I tried to re-solder the hair-thin mic wire to the vox board, the enamel melted, so I just chased a short along the cable. Eventually, I gave up, and completely rewired the whole thing, using the twin cable from a cheap set of stereo headphones.
Now I have a nice headset that really works, the oscillation has gone, and the audio is better than ever! Plus the earplug that kept dropping out of my ear has been consigned to the bin, and one of the headphone earpads has been grafted onto the folding spring band of the original HMC-3 headset. The end product is more comfortable to wear for long periods, and more practical as well.

[2E0DTO]

..(Note the change of callsign, I've moved up the ladder!) Further to my last, After a further day's use, the transmitted audio from the headset went intermittent again.
When I opened the fiddly little plastic box up, I found that the pot track of the mic gain/vox sensitivity control had cracked, and was hanging out of the side of the pot!
When I tried to measure it, to find out what to use as a replacement, it fell out completely. So I guessed at 50k for a ballpark figure, and tried that, (I happened to have a 50k pre-set handy!) - one side is paralleled with the wiper, so only two connections needed.
Result, VERY low audio, even with the resistance turned down to zero! After a lot of head-scratching, and inspection of the double-sided board with a high-power lamp and a magnifying lens, I found that there is an extremely fine track on the board, no thicker than a human hair, which runs from the pot wiper plate-through to a 151 ohm resistor, the track had failed at the plate-through. A bridging wire to the resistor created an earsplitting howl-round because I was monitoring my tx audio on another trx. Turning the gain down sorted that, and I soldered the bridging wire into place, solving another problem with the HMC3 junk pile.
For info, I found the best resistance setting on the preset was 5.8k
If you have one of these damn things I hope it works better than mine did. I must emphasize that the Kenwood TH2 handie is working perfectly, it is just the headset that is rubbish.