| Author |
Message |
    
Orion
| | Posted on Friday, June 20, 2003 - 7:34 pm: | 
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Every once in a while I talk on a 636L and it feels like the mic grill is yanking a hair out of my "8 o'clock" shadow. It's like an annoying little burning sensation. I checked all wires, the grounding.. whatever. Nothing. It's a noise cancelling mic so I can't help but get close up to it. I hate the feeling of getting a shock.. I've been a shockaphobic ever since trying to sneak into a summer camp to meet some girl when I was 18. No flashlight, sneaking through the woods by the horse stable and all these waist high wires everywhere like booby traps. Met her an hour late, covered in horse sh*t and so sweaty and traumatized it looked like I had malaria. Anyway I could test this mic without having to touch my tongue to it?.. can't bring myself to do it. Don't have a VM. The radio is a Grant XL, mic is a 636L, barefoot. |
Tech808
| | Posted on Friday, June 20, 2003 - 8:50 pm: |
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Orion,
I would suggest checking the wiring on it to make sure none of the pins are shorting.
Wiring should be:
Pin #1 - White
Pin #2 - Shield
Pin #3 - Black
Pin #4 - Blue
Pin #5 - Red
Yellow N/C |
2600
| | Posted on Friday, June 20, 2003 - 11:42 pm: |
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Assuming you don't have a mike wiring boo-boo, the 'buzz' is coming from a fraction of your transmitter power traveling on the OUTSIDE of the coax. It is supposed to stay on the inside surface of that shield braid, on its trip to the antenna. A SWR meter won't know how to tell about this.
If you have a hunk of metal that is grounded to the vehicle chassis, like a dashboard support strut, floor, or firewall near the radio, a short ground connection from a cover screw on the radio to the vehicle chassis will often stop this problem. If this added ground wire gets much more than a couple of feet in length, this trick loses effectiveness.
This tends to happen most often with magnetic mounts. It's cheap to try, and if it doesn't help you didn't waste a lot to find out.
73 |
Orion
| | Posted on Saturday, June 21, 2003 - 1:50 am: |
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Thanks guys, actually it was a loose solder joint to one of the pins..the obvious but I failed to catch it the first time I looked. In the future if I get dumbfounded beyond the obvious, I'll keep you're info in mind 2600. Thanks to both...808/2600 |
Bigbob
| | Posted on Sunday, June 22, 2003 - 9:59 pm: |
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I made an rf ground with a 9' piece of wire,any gauge will work,trimmed it 1/4" at a time until the bite went away,just hook one end to radio chassis then string it under the floor mats in a big U,don't coil it or it won't work. |
2600
| | Posted on Sunday, June 22, 2003 - 11:13 pm: |
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Cool.. Simple problems are always better than tricky ones.
73 |
Tech808
| | Posted on Sunday, June 22, 2003 - 11:32 pm: |
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Orion,
After many, many miles of otr driving and useing the Astatic 636L and having that sucker nail my lip and chin I learned to check the plug and wire first.
People do not realize how many times they stretch that little itty bitty mic cord and pull on the mic plug.
But at 2 or 3 in the morning when your tired and it Bites you good, It sure does wake you up.
Even got the 1st Sargant one nite, she darned near killed me throwing that thing across the Cab and then it flew back and wacked her. I had it hanging on small bungee cord from ceiling. 
Lon
Tech808 |
de
| | Posted on Monday, June 23, 2003 - 8:20 am: |
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RE 808
A fine morning to you.
My ham radio bites me every now and then. I for some reason when I move the radio pull off the gounding line from the grounding rod in back of the rig.
And natually when I am holding the mike/metal exterior of course the ungounded radio thinks that I am the ground path and reminds me to connect the ground to the radio.
May your day be productive and your radios only need replacement fuses.
DE |
Znut
| | Posted on Monday, June 23, 2003 - 3:17 pm: |
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I did indeed have that problem with a mag mount antenna. I wasn't barefoot either! While I was trying to trace the RF feedback (at the time I was blaming it on my FC 390 hooked up to my Euro 3900) my thumb became the path to ground and I got I slight burn which took a long time to heal. I finally figured out that my antenna wasn't decoupling.
Solution: I wound several feet of coax into a choke of 6 turns about 4 inches in diameter right by the antenna and wire-tied it tight. This helped but my freq-counter was still jumping a little. Next I wound an identical choke in the jumper going between the 3900 and the Shooting Star. Problem solved and my SWR meter gives more stable readings. My 575 M6 mike was burned up before I fixed the problem, now I'm stuck with the crappy stock mike. I guess some of you have noticed that I'm fond of the little coil of coax, right? |
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