Antenna Length

[Stonewall]

I haven't dealt with this in a while, but if I remember correctly, aren't mag-mount antennas supposed to be a certain length based off our frequencies?

I remember for 148 to 155 MHz there being a specific length and I had to cut an antenna for maximum strength/effectiveness.  Is this a factor?

Playing with my mobile radio and when I put my mag-mount on the roof it made me think.  Should it really be 4 ft high?  Is longer better when dealing with CAP radios?

BTW, how freaky is this.  I used to be a volunteer fire fighter with St. Johns County, FL in 1990-1991 and I happen to remember their freq so I plug it in.  At exactly the same time I program it, a tone goes out, a "last page" for a fallen fire fighter.  I don't know, just got me thinking.  Be safe out there...

[floridacyclist]

Most store-bought antennas are close enough. I would not cut anything without an SWR meter and knowledge of how to use it. Capt Smith should be able to help you with that, or a trip by your local ham radio club meeting might help, but if you can hit the repeater on a stock store-bought antenna, it's probably OK.

[DKruse]

If you can, find an antenna tuned for the ham 2-meter band.  That should provide more than sufficient performance.  I don't recommend cutting and tuning antennas for VHF work if you can help it.

[Trung Si Ma]

468 / Frequency in MHz will give you the half wavelength in feet.  Most VHF antennas for mobile use are 5/8 wavelength.

Using a reliable SWR bridge is still best since it will also take the transmission line into account.

Don, NL7CO