| Author |
Message |
    
Jyd
| | Posted on Saturday, July 06, 2002 - 8:54 pm: | 
|
i have noticed something,i run a vr-9000 and a maverick 250 and a antron.i can talk on it and turn it off and unplug the coax.when i go to screw it back on i see sparks,like the antenna is holding a charge.is this normal? |
Tech181
| | Posted on Monday, July 08, 2002 - 12:15 am: |
|
Uhhh no. Are you getting the sparks from the coax itself or from the SO-239 connector on the back of the 250?
Steve
Tech181
Tech181@copperelectronics.com |
Jyd
| | Posted on Monday, July 08, 2002 - 8:37 am: |
|
i can unplug my coax from my meter,then when i go to plug it back in i see little sparks.like i can talk on it then turn it off.unhook it, then come back and and go to screw the coax back on i can touch the center conducter of the coax to the ground on the back of my meter(the conector)and sparks.like a 6volt flashlight battery. |
307
| | Posted on Monday, July 08, 2002 - 11:00 am: |
|
I have seen this many times. How close is your antenna to a High Voltage Power Line? If you are close to one you have an EMI Field that the antenna picks up. The Antron is NOT DC ground , it floats so the antenna is acting as a conductor to the EMI Feild. The only place to dis-charge the feild is when you plug in your antenna to a device that is plugged into a wall (117 VAC). This is where it picks up ground for dis-charge.
307 |
Scrapiron63
| | Posted on Monday, July 08, 2002 - 1:32 pm: |
|
I believe the voltage is coming from your equipment, I've been shocked many times while connecting the coax, expecially to the older amplifiers with the two pin AC cords. Sometimes you can turn the plug over and stop it. Check with a volt meter between the so-239 on the back of the amp and the antenna coax. You might have anywhere between 50 and 120 volts, AC. I've had base stations, like the Galaxy Saturn also have ac voltage on the S0-239 connector, this is caused sometimes by a small lightning charge burning out part of the protection components on the small board in the AC line. It lets AC go to ground. Lots of the old tube type equipment was bad about this also. |
Jyd
| | Posted on Monday, July 08, 2002 - 12:53 pm: |
|
i dont understand,my antenna is at least 4 blocks from the nearest power line.would the coax hold power for some reason? |
307
| | Posted on Monday, July 08, 2002 - 3:42 pm: |
|
Ya that is a bit far...I would then agree with Scrapiron63...
307 |
Jyd
| | Posted on Monday, July 08, 2002 - 4:00 pm: |
|
thanks gentlemen |
Marconi
| | Posted on Monday, July 08, 2002 - 7:13 pm: |
|
JYD, Scrapiron is probably right about the older amps. Try the trick he notes if you have the old style two prong wiring in your home. Sometimes the ground is not attached to the correct pole in those old wall boxes and your old amps ground side is hooking up to the hot lead at the wall plug. Try turning the plug over and it may stop the arching.
Marconi |
Bigbob
| | Posted on Monday, July 08, 2002 - 7:59 pm: |
|
jyd also check your house ground at the service pole or box,make sure the clamp on ground the rod is secure,if it looks nasty call an electrician.I new a man that had a bad house ground on his metal trailer,everytime it rained,someone would come to the door and get knocked on their butt. |
Jyd
| | Posted on Tuesday, July 09, 2002 - 6:52 am: |
|
well i think i figured it out the third prong is broke off of my amp plug.i will buy another end.as far as house wireing the house is 5 years old. thanks guys |
Scrapiron63
| | Posted on Tuesday, July 09, 2002 - 1:32 pm: |
|
Jyd, I would pull the bottom of the amp, and make sure the AC cord has three wires, lots of the older amps were just two wire. If it's not three wire, I would change the complete cord with a three wire and three pronged plug. Make sure the black wire goes to the fuse, the white wire will go to the other supply wire for the transformer, and the third wire, which should be green, should be souldered to the case. This will give you another ground for your radio equipment back to the ground of your electrical system. Lots of times this will help on noise and interference plus get rid of that stray voltage that's lurking around waiting to zap you. Those old two wire, two prong plugs are dangerous on any equipment, especially if they can be plugged in either way. You might have the equipment turned off, and still have 120 volts on the case. Of course you can touch it without a ground, and never know it's there. Like the birds sitting on the high lines, they don't feel a thing, unless it gets grounded. |
Jyd
| | Posted on Tuesday, July 09, 2002 - 7:52 pm: |
|
yeah,it had 3 wires.but someone had broke the ground off of the plug so it would fit a extension cord.i put a new end on it and it fixed the problem.i put black as ground on the plug and white and green as hot.it works fine.no more sparks.why would the green go to the case?green is hot right,and white is to,and black is ground.that is the way i done it when i put a new end on the cord.now you are confuseing me.black goes to the case.white and green are hot.307 i need input on the subject please |
Insider
| | Posted on Wednesday, July 10, 2002 - 12:56 am: |
|
Some times manufactures stray from the standard color coding system when designing their products. In that case, I would use a a multi meter on the existing cord and match the pins the way they were origionally. However, there is only one hot wire. You do not want the case to be hot under any circumstances.
Common color coding is
White=neutral
Black=hot
Green=earth ground
From my rudimentiry knowledge, neutral and ground are the same in unbalanced 120VAC systems. The difference being white goes to the center tap on the 220 transformer at the pole, while the green goes directly to the earth. |
Scrapiron63
| | Posted on Tuesday, July 09, 2002 - 11:09 pm: |
|
Black is hot for DC current. But for AC, Black is hot, white is netural, and green is ground for supply cords or extension cords. In the house wiring, black is hot, white and the bare copper is ground. Look in your panel, Black wires go to the breakers, white and the bare to ground. This is from a 30 year master electrican. Green is never hot for any type of wiring. |
Jellybean
| | Posted on Tuesday, July 09, 2002 - 10:16 pm: |
|
In house ac, black is hot, white is neutral, green is ground. If 220, black and white are hot, green is gound, and you should have a bare copper wire for ground as well. In a true 220 usually black and red are hot, white is neutral, copper ground. This is standard color code for house wiring. You should have a good case ground as well for your amp. You can get an rf spark from that as well if not case grounded either.
Just another .02 worth. |
Scrapiron63
| | Posted on Wednesday, July 10, 2002 - 10:45 am: |
|
Jellybean your right about house wiring, lots of electricans use just two wire with the bare ground for 240 runs. This is ok for some things, like hot water heaters, they just use the 240 volts, really a dead short between the two 120 volt lines. But in appliances like cook stoves, dryers, etc, they should be wired with three wire and ground, as they use 120 volts also for fans, lights, timers, etc, and they should have a neutral as well as the ground wire. However, many houses are not wired like this, as they are not inspected. The national code says any color wire can be used for hot except white and green. In commercial buildings, you will have dozens of colors for the hot wires, but white and green is neutral and ground. |
Jyd
| | Posted on Wednesday, July 10, 2002 - 9:11 am: |
|
well i put the plug on useing black as ground and it works fine.i will just take it apart and check it. |
Insider
| | Posted on Wednesday, July 10, 2002 - 9:54 pm: |
|
Maybe this illustration will help. This is the plug at the end of the line cord, not the outlet.
The reason I suggested using the multi tester to ensure that all three pins were wired correctly is because some products, including line cords that are made outside the country may not closely adhere to the color coding standard. I believe I had an air conditioner like that at one point. For stuff like this, I think they can get away it because they state that their products should be serviced by a qualified technician.
More recently, the power cord on my G4 doesn't have white, black and green. the colors are green, red, and blue. Green is ground, but I can't easily tell what the other two are.
|
Jyd
| | Posted on Wednesday, July 10, 2002 - 4:27 pm: |
|
i redone it again this time green is ground. |
|
