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If you don't know what you're doing, the results could be dangerous

Moleculo

Moleculo

Ham Radio Nerd
Apr 14, 2002
9,200
1,685
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I saw this post elsewhere and thought I'd cross-post it here. The bolding on the last sentence is my own. I don't know if I have enough words for this :eek:

? for the experts, this RF seems to be going through all of the wires coming from some where in the system here's what i got the radio is on the dash with a freq counter and 4pill f/b under the driver seat driving a 16pill f/b powered by a 400amp maul in the back floor broad.

OK now for the wires got an 0GA going from the alt to the maul charge post and 0GA grounds and positives coming from the 4 batts in the back ...........

the 4pill is on an 8GA going to the charge post on the maul radio goes to the batt in the front ps(the alt is 170amp)and all has been ran from the radio to the 4pill to the 16pill to a 22"10k all lmr 400 (the maul was modded to key with the big box) ........

all has been ground strapped from all doors hood exhaust etc. same with all the units radio to the 4pill to the 16 you know the deal..............

so here is where it happens the remote to the maul is mounted on the bottom of the dash i can rest my leg on it in the right position well i did and i key up all on and burn the s**t out of my leg so is this common or bad for this to happen
Click to expand...
 

More likely scenario is he's pumping out tons of RF voltage out of the amplifier onto the positive power line feeding the amp, which in turn is ending up on the remote switch for the maul. This is a pretty common problem for crappy amps. A lot of times the battery that is connected to the amp can shunt the RF to ground, but it sounds like in this case there's probably just too much, especially considering the likely wattage output of that mobile setup.

Of course, he'll probably chase the problem around by improving grounds (which might help), but never get to the root of the problem which is to redesign the amp or toss it in the trash.

edit: oh yeah i just read this part:
the maul was modded to key with the big box
Click to expand...
Uh-huh...I bet it was...RF voltage going right through that relay out to the maul. There's probably so much stray RF you could double that vehicle as a microwave to cook chicken.
 
moleculo said:
More likely scenario is he's pumping out tons of RF voltage out of the amplifier onto the positive power line feeding the amp, which in turn is ending up on the remote switch for the maul. This is a pretty common problem for crappy amps. A lot of times the battery that is connected to the amp can shunt the RF to ground, but it sounds like in this case there's probably just too much, especially considering the likely wattage output of that mobile setup.

Of course, he'll probably chase the problem around by improving grounds (which might help), but never get to the root of the problem which is to redesign the amp or toss it in the trash.

edit: oh yeah i just read this part: Uh-huh...I bet it was...RF voltage going right through that relay out to the maul. There's probably so much stray RF you could double that vehicle as a microwave to cook chicken.
Click to expand...

You're probably right about the microwave scenario, just ask 4040 about big power with no outlet for the rf.
 
Jesus wept, is this a case of buying a $60.00 CB and spending thousands on extras ????
and as an afterthought, what are you all talking about
 
flyingfox,
It's partly a matter of that $60 radio and $$$ in 'accessories', sort of. It's also a matter of exceeding practical limits too (didn't say legal, or possible, just practical limits). It's a lot like knowing the 'biggies' of what you want to do, but not knowing all the little things that make that 'biggy' possible, and that you have to do also. A "Can you get there from here, and what route do you want to take?", sort of thingy. Bunch of different routes, some are just easier/simpler/'better' than others.
(As if you didn't know that to start with, right?)
The rest is sort of 'personal opinion' and comments stuff. You usually hear that kind'a stuff from people who have traveled that road before, or one sort of close to it. One of them, "Oh my! Wait till he gets close to that mic and it burns the mustache off his lip!" thingys ;). [NO, I ain't never! But it felt like I had once.]
- 'Doc


Famous Quote:
"No body lives long enough to make all them mistakes. So pay attention to other's." - who said it? uh... beats me.
 
moleculo said:
More likely scenario is he's pumping out tons of RF voltage out of the amplifier onto the positive power line feeding the amp, which in turn is ending up on the remote switch for the maul.
Click to expand...

Could be grounding too, the only way to be sure is use a dummy load instead of antenna.
If you still get burnt with a dummy load, then its coming out the positive power line feeding the amp.

There is made feed-thru capacitors with enough amperage rating:
http://www.texasspectrum.com/pdf/brochures/hiCurrentFeedCapacitors.pdf
Instead of the (+) wires feeding thru a hole in the amp chassis, these capacitors are mounted in the chassis holes and the positive wire soldered to each side.
They have up to 200 amp ratings, and up to 200 volts with various capacitance values.
 
he shouldnt be running that much power with his brain level. I wonder if they are running a mag mount with that set up. Yes there is one guy with a 16 and mag mount in the area.

the keying circut is nothing more then a grounding circut to key the maul instead of the keying circut to reduce the amount of coax needed.
 
"so is this common or is it bad to have this happen"

That just about tells the story..........stupid is what stupid does.
 
Im with Mack I would like to see pics of this, feedline ETC Is the power wire running along side of this coax??
 
Hopefully the guy will launch the 16 pill before he doses too many passengers with R.F.
 

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