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Hi, there are differing views on this. An official GME install video says to the battery direct and others say definitively to the vehicle chassis. Does anyone know what is the correct answer and perhaps why????
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iCOM's installation instructions also say direct wiring to the battery, not from AUX power, or via the chassis.
The reason (my understanding): to minimise noise being introduced to the transceiver circuit.
The manufacturer would know best. However, I'm sure many people are happy with the "good enough" solution of wiring of the AUX.
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Thanks. I plan on wiring the positive direct to the battery terminal with inline fuses, bypassing the actual fuse box. but the question is the earth .... do you think noise in introduced through the chassis ground?Comment
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the chassis is fine, the only issues are if its just a shitty screw in the dash that touches ground vs a good earth.
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I don't really know, but given that noise is basically a signal conducted through a wire, I assume it could come from the ground wire too.Originally posted by DeeBee View Post
Given that you are already running a positive to the battery, why not send the negative along with it?Comment
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Yep, true, I will have the power cable upto the battery anyway. I think I will follow the official instructions (both on the power cable and the official video from GME), and attach the negative directly to the battery.Comment
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Makes absolutely no difference. The chassis/body is the earth for the vehicle. All wiring connects back to the battery via the body anyway.
It’s only necessary to run a positive feed from the battery if you want to be able to run your uhf while the car is off. Otherwise a much easier accessory power source is the cigarette lighter socket positive wire.
More important is to avoid running the aerial cable too close to the main loom which theoretically can cause interference. In the real world, the effects are generally not noticeable though.Comment
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Regarding wiring a 2way radio to your car you should run the positive and the negative to the the battery unless it have a shunt connected then the negative to where the battery earth is connected to the body. To do it the correct way you should also have a fuse in the negative cable as well.Comment
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Hi Loddo
Not sure why you’d have to run a separate negative all the way to the battery? It’s only a return path for the electrons.
A fused negative is a bit of a waste of time! Not sure why it would help even if the main earth strap came loose. The radio would still be the only circuit going through the earth.Last edited by Daniel150; 05-05-2022, 08:57 PM.Comment
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Daniel The fuse in the negative cable of a transmitter is not a waste of time as you say If you have seem many radios destroyed by earth faults going back via the radio earth wire . This is why many expensive transceivers are supplied with fuses in both the power and negative leads . I guess a $200.00 dollar radio does not need it but a $ 3 to 4 thousand radio does .I wire all my transceivers with both fuses in the positive and negative power leads as i will not take the risk with $10000.00 dollars of radios in my Prado, and before you say why so many expansive radios I am a ham radio operator.Comment
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Could you please explain how the negative can cause the radio to burn out. I can’t see how.
If you have run a seperate wire from positive through the radio and back to the negative, it’s completely isolated from any other circuits!
Sorry I’m not trying to be difficult, I just want information shared here to be factual and accurate so it can help people out.
Having a bit of experience in the area, I’ve heard a few people claim these theories but never been able to explain them.Last edited by Daniel150; 05-05-2022, 09:37 PM.Comment
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I have been doing some reading as a result of this sort of conflict we are now discussing. May I suggest reading another discussion via the following link from an electrical engineering forum. I believe it's worth reading and is informative from another source. See the link. I hope it explains/satisfies a few things for us all.Comment
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Put simply, the fuse must go on the +12v feed.
If you don't (and have it on the negative/chassis/ground side), the fuse may blow because of a fault in the two-way or its wiring but the +12v side will remain live. This is asking for trouble when someone tries to diagnose and fix the fault - there will be a live +12v feed to the appliance, so it will also be 'live' (but not working). If any (metal) part of the radio touches the vehicle's chassis/ground, then it's likely to be bye-bye two-way and you'll proabably melt the 12v feed wire and anything it is touching (like expensive Toyota wiring looms).
As an aside, I would not wire both two-way feed wires directly to the battery. I would hate to get into my Prado and find it had a flat battery because I had forgotten to turn off the two-way when I'd left it a couple of days earlier. You need some way of automatically disconnecting the power when the ignition is off or the car is locked.
GeeWhizz - Prado owner and Electronic Engineer.Comment
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Damm, The chassis is excellent; the only question is whether the ground is a sloppy screw in the dash or good earth.Comment
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There is a very good chassis earth/ground right next to the fuse box under the hood and the main chassis earth right next to the battery on the guard. Either of those should do the trick without any dramasComment
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