HT 1000 lighting flashlight on TX

Q-card · Post by **Q-card** » Thu Mar 09, 2006 12:16 pm

I have a HT 1000 UHF that when keyed up near a flashlight , the light comes on.
I have tried cleaning the grounds, replaceing the RF shield , no luck.
Any ideas ??
Thanks Q

kb0nly · Post by **kb0nly** » Thu Mar 09, 2006 12:18 pm

It's probably just RF getting directly into the flashlight, which of course you already knew.

Moving the flashlight farther away maybe? That's weird though, since most flashlights have a mechanical on and off switch.

kf4sqb · Post by **kf4sqb** » Thu Mar 09, 2006 9:48 pm

Scott, you may be missing the obvious here.

Q-card, would this by any chance be an LED flashlight? If so, that's why. There's nothing wrong with your radio, or the flashlight. The simplest RF detector known to man is what? A diode. What's an LED? A diode that emits light. The RF field simply foward-biases the junction in the LED, causing it to light. Isn't it fun to learn weird things?

kb0nly · Post by **kb0nly** » Thu Mar 09, 2006 10:03 pm

Never thought about that.. I guess i'm old school. Led flashlight.. DUH! When i hear flashlight i think bulb, batteries, and a switch.

I figured maybe he might have also meant it was something like one of those emergency flashlights that come on automatically when the power fails, etc. And was hoping he might elaborate on the problem.

I had one of those flashlights plugged in here, whenever i transmitted inside with the HT it would turn on for a minute or two then go back to standby, shutting off and turning the float charge back on. I kept joking that i should put a box around it and an "on air" sign in the front.. LOL

Q-card · Post by **Q-card** » Fri Mar 10, 2006 8:28 am

It's not a LED flashlight , it's a handheld manual switch with a bulb. I have tried other radios and they do not light it up, user complains of discomfort.
Thanks

wa2zdy · Post by **wa2zdy** » Fri Mar 10, 2006 6:34 pm

I'm going to stick my neck out here and take a wild guess. There's a high resistance short somewhere in that flashlight and whatever the short is is rectifying enough RF to light the bulb.

This is commonly seen in RFI cases caused by higher power transmitters. Things that can rectify the RF and cause massive TVI and other RFI complaints include corroded joints between rain gutters, etc.

It's a wild wild wild and even risky guess, but in this case I can't think of a whole lot else that can be going on.

Your user might also report shorter battery life than expected but not necessarily. Just a possibility - as likely as this entire idea. But the report of discomfort . . . what's that about? Is the light getting hot? Or is he getting an RF burn from it? That's an oddity.

Tony Soprano · Post by **Tony Soprano** » Sat Mar 11, 2006 5:29 am

To have a radio light an incandescent bulb on TX is not unusual, I perform a similar final test on portables to ensure radiated power. But you have to hold the bulb close to the antenna to make it light. I wonder what the power output is on this radio? It could be cranked up too high. Check that, or try a different antenna.

nmfire10 · Post by **nmfire10** » Sat Mar 11, 2006 5:40 am

Q-card wrote: user complains of discomfort.

What kind of discomfort?

wa2zdy · Post by **wa2zdy** » Sat Mar 11, 2006 9:42 am

With an open circuit Tony? I've never heard of that. Neon and LED yes but incadecsent I've only used them with a pickup loop.

And yes, I too am waiting to hear more about the discomfort.