CB install - best place for live feed

i've bought a CB and plan to install it this weekend. in order to make the job quicker where's the best / easiest place under the dash to tap into a live feed. stereo perhaps ?
any advice will hopefully avoid me fumbling around under the dash testing various wires
thanks

I Fitted mine in the passenger foot well, so it was out of sight and it is feed from the live of the cigarette socket. I have had no problem with electrics in doing this. Oh i also have a in line fuse from the socket to the CB. I have a soft top so i feed the aerial lead to the back under the carpet and when i want the CB on i pop the aerial though the small gap at the top of the side windows.

i took a live from the stero in the end, the cable harness for the stereo is easily accessed.
i did think about the cig lighter but wasnt sure if that was a permanent live or just an ignition on live. there is a permanent live going to the stereo to keep the memory so i linked into that so that i dont loose the chanel if i turn ignotion off
i've been told i should get it SWR'd for best results ?
what's this and do i need get it done ?

SWR has something to do wuth the calibaration of the antennae of the cb and in no way affects your unit a small (inexpensive) meter which needs no power of its own is linked in to the antennae cable between the cb and the antennae and can be left in place (advisable) or removed after the antennae has been calibrated a good earth for the antennae is needed and although I had a base unit and never fitted a cb to a car, the antennae manufacturer should be able to supply you with instructions on a more powerful antennae and best I can remember, as a rule small rubber duck type antennae are less likely to transmit any reasonable distance

SWR (Standing Wave Ratio) is the "matching" of the aerial to the CB radio. In order to achieve the maximum efficiency you need the two to be matched together so that every milliwatt of power your transmitter puts out goes into the atmosphere.

This is why is is called standing wave ratio, if the two are not matched then the power is reflected back into the front of the transmitter and could burn it out (note the use of the word "could" - CBs are lower powered transmitters and are pretty robust)

Think of it like plumbing. If you connected a 22mm pipe to a 15mm pipe then back pressure will build up as it cannot all fit inside the 15mm pipe. Or the other way around, connect a 15mm pipe to a 22mm pipe and you will not be able to fill the 22mm pipe properly.

The way to sort out SWR is to use a SWR meter (or reflectometer). This measures the radio waves boucing back from the aerial into the transmitter. You keep watching the meter and adjusting the length of the aerial (by cutting the aerial or by sliding it in and out of the base). You adjust for minimum reflections - anything below "2" is probably ok. 1.4 or 1.6 is better.

Martin

the oracle has spoke !!

thanks martin understood i know someone with an SWR meter so i'll get it done