Comments on: Wouxun PTT Voltage Limit

By: Ed

Ed — Mon, 04 Mar 2013 00:36:10 +0000

the UV3D will not transmit unless I press it really fast/hard

That definitely points toward a bad connection between the PTT line (3.5 mm body) and the HT ground (2.5 mm body).

I’ve had problems with the terminals inside an audio plug not making good contact with the corresponding tip / ring / body parts; it seems they use a mechanical pressure fit rather than a soldered / welded joint and, sometimes, it just doesn’t work. Assuming that everything else in your setup works, I’d suspect the 3.5 mm plug’s body terminal first.

Rule of thumb: it’s always the connectors! [sigh]

Good hunting…

By: Dennis

Dennis — Mon, 04 Mar 2013 00:12:54 +0000

Hello Ed, I am working on a project to expand my Wouxun UV3D capabilities while mobile. I got a dual band magnetic antenna, took the handmic from my TS-2000, bought some connectors, solder on, and made a nice little box to connect the HT to the car stereo, external antenna and hand mic. All fine, tested several times, except for the PTT control! The PTT works fine and make a solid short circuit, but the UV3D will not transmit unless I press it really fast/hard, which is really odd. I can’t find out. I thought it should be something related to a capacitive effect, and I see your post and figure it should be something related to 0V… I’ll do some more tests and let you know if I find out what’s going on. Any help would be great, thank you very much, 73, Dennis PY2DZA

By: hexley ball

hexley ball — Sun, 07 Oct 2012 16:07:07 +0000

“never insist that semiconductor fluid tanks be buried in the ground” — later in the 80s I toured a brand new fab site that had been built after that lesson had finally been learned. Our guide pointed out all the piping running over our heads in the hallways and said that building code now required the nasty stuff to run in those pipes, on the theory that any leaks would drip on the heads of management and thus get fixed mucho pronto :-)

He also said that the effluent sent to the sewer system was so thoroughly scrubbed that you could use it for drinking water. Right.

By: Ed

Ed — Sun, 07 Oct 2012 14:04:54 +0000

Note to agencies: never insist that semiconductor fluid tanks be buried in the ground

IBM spent a fortune doing that when they set up the East Fishkill site, back in the day, because it seemed like a Good Idea at the time. Spent an even larger fortune digging up the tanks, mounting them aboveground, and then drilling filtering wells all over the neighborhood, a few decades later…

But the dry cleaners were probably the worst offenders: lower budget and less attention to detail.

By: Red County Pete

Red County Pete — Sat, 06 Oct 2012 16:27:42 +0000

I used to work for HP when they were doing semiconductors. (The group got spun off to Agilent in the Great Breakup, then Agilent sold off the business and I got retired.) Doing a fab in San Jose gave the fire chief a bad case of the flutters, and the LED crystal growing side got them even worse. Back in Palo Alto in the 70s and 80s, I gathered that the crystal growers counted on one small explosion per month. Wasn’t so bad on the silicon side, but we contributed a fair amount of problems for the authorities. Note to agencies: never insist that semiconductor fluid tanks be buried in the ground. When they leak, they’ll cause a mess.
Between us, a biotech outfit and a dry cleaners, PA had some interesting ground water for a couple of years.

By: Ed

Ed — Sat, 06 Oct 2012 10:48:17 +0000

tell enviroMentals just what’s in an LED crystal someday

Or a photovoltaic cell…

Just try to set up a fab line in their back yard, even after they cover their garage roof with, uh, free energy. The stuff doesn’t grow on trees!

By: Red County Pete

Red County Pete — Sat, 06 Oct 2012 02:23:36 +0000

Yeah, I simply couldn’t find a mercury thermostat. We’re not that far from Kalifornia, so some of the loonytunes attitudes about “dangerous” chemicals carry through. Hmm, must tell enviroMentals just what’s in an LED crystal someday. Might be fun.
BTW, I thought you can get bounce in a mercury switch. Not as bad as for a dry switch, but we had problems in some ancient testers we used. I used a reed driven odometer when I rode a lot of miles 20 some years ago. Not too bad for the magnet, and you could scavenge one from a Sonicare toothbrush head for an even smaller unit. Strong ones, those magnets. I do recall having to kick the reed every few hundred miles, but that’s another issue. I like the Hall sensor.