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I have been lurking on these board for a while and recently purchased an XTL5000 with an 05 Control head.
I would like to make the unit standalone so I can just plug it into the cigarette lighter so I can move it between my vehicles or go portable .
I have been reading the install guide and it says that the unit should be connected to the chassis of the car and not the negative terminal of the battery.
Why is that? Can I do anything so I can just connect it to the - and + of a battery? Also is the ignition sense wire needed to be installed or can I just skip it and ignore it.
Any help and guidance would be appreciated. I do not want to ruin the radio.
The reason to not connect the negative lead directly to the battery is that the radios power lead becomes an alternate path from the battery to the chassis (via the antenna coax and the radios mounting bracket). In the event that the vehicles battery to chassis ground strap becomes loose and the battery needs to find a path for the 200 to 300 amps of starter current, your radio becomes that path and a burnt up radio results.
The old Marconi radios used to come with fuses in both the Positive and Negative wires. I always wondered why until I troubleshoot a radio problem and found the negative fuse blown. Traced the issue to a bad battery to engine block ground.
phoenix wrote:Does that mean I'll have to make sure the antenna is not touching the car body if I use the lighter plug?
No, I was just indicating the concern if you were to connect the negative lead of the radio directly to the negative post on the battery. You are not doing this.
phoenix wrote:Should I install fuses on the positive and negative like the Marconi radio to protect it just in case? 3 amps?
No, not required (same reason as above). If you were to, it would need to be 15 to 20 amps assuming you are running the radio somewhere in the 30 to 50 watt TX range.
If your mounting the radio in a fairly new vehicle, the ground wire from the battery to the vehicle frame should be in good condition. If your going to use a vehicle over a few years old, it would be best to check the battery to frame ground wire. Clean the connection, put some anti oxide compound on the joint and make the connection again.
The lighter connection on most of these vehicles today are only good for about 10 amps or so. The XTL in high power exceeds that. Now your looking at running heavier wire and using a larger fuse to feed the lighter connection.
These are generally the facts. Do as you please, but don't come back to the board complaining about problems if you don't do your homework.
Thanks for the advice. I think I will run a lead from the battery into the car to bypass the lighter plug for each car so that I can just connect it up and go.
Would there be any problems to connect it to a 12v car battery charger to program it and test it?
The answer to your question has to be answered with a question. How much current will the charger put out and at what voltage under load and light load?
A battery charger is generally a poor choice to run a radio off of. Normally they don't have the ability to supply the current needed to run the transmitter. The other part of the answer is that most of the battery chargers that I have had to deal with, have poor voltage regulation from no load to full load. This makes for a good chance of doing damage to the radio.
Do as you choose, the facts have been presented.
Jim
phoenix wrote:Thanks for the advice. I think I will run a lead from the battery into the car to bypass the lighter plug for each car so that I can just connect it up and go.
Would there be any problems to connect it to a 12v car battery charger to program it and test it?
Would a linear regulated power supply 12v 20amp max be good enough to run the radio? I gather from RFGuy's comment that at 50w
it would draw about 20amps and since I plan to run the radio at 30w - 40w I should be safe?
.