just firestik trying to cover their arse when what they sell doesn't work. the only gurantee is when the wavelength and the end of the coax are in phase. that takes some math, which firestik 'minimalizes' by suggesting their 18' length.

 

so what if i do two sticks on the side mirrors?

 

and what would you reccommend for the wire length with duals and with singles?

 

for duals, same thing 18 ft. the only thing that is different is that you should include the Y cable that splits the signal out the back of the CB in the 18ft. as ABE said the article i posted is firestik just covering there arse. BUT fwiw, i work with radios a little bit in the military and when learning about what to use or setup, 18ft increments is what they tell us to use. perfect length is actually done with some math that i dont know. IIRC it is based on the wave length and frequency of the antenna. i dont know the actual equation to use. this is just my opinion, and from what ive learned. And TMAN if you do twin sticks on the side mirrors, tune them together, IE when one is adjusted the other needs to be adjusted the same amount, for the lowest SWR.

 

Here's where I mounted mine.. May not be the best but it works...



I did trim the tube once it was installed.


Just another picture, pay no attention to the crappy spare - it's not really there! Was test fitting it on the retofitted tire carrier.