RedDog382

Are there any guidelines or parameters to determine optimum cable length for a VHF radio antenna installation, or does the length of the cable not really matter?

In the old days of CB radios, one had to "tune" the antenna to be "in phase" with the signal. Does this apply to VHF radios?

Wally

iTrader: (1)

I still have (somewhere) an old SWF meter i used back in the CB days to tune my antenna's on my truck. I also remember that when you had a non-adjustable antenna that you were to keep the cable in 8' lengths or multiple of for best tunning. So if you have 15' of cable, you would want it closeer to 12' if you have the extra amount or ideally cut it down to 8' for better results. There was no problem as far as i remember about coiling up the excess in a bundle either. Ive never tried useing the SWF meter on a VHF......now that i have an adjustable antenna for my boat i may just try it and see if it woudl work. Keep in mind what i said above was for CB tuning i have no idea if its the same or not for marine VHF's.....I'm sure someone on here will chime in soon that knows better then I.

offthefront

iTrader: (1)

VHF doesnt matter .....just 4' min cable .....

I just installed a new Shakespeare Antenna and got the info off the Shakespear site ......Mike

from FAQ .....

Can I cut the coax on my VHF antenna? Yes, if you need to. However, you should leave at least three feet of coax. Note that this is not true for all antennas. CB antennas' coax should not be cut.

fund razor

This is true. Roughly 3 foot min and 25 foot max for VHF.
Coil won't change resistance enough to matter.

fund razor

Although having said that, the coax from my scanner to my VHF antenna on my roof is probably 40 feet but there's no TX, just RX.