Maxtrac antenna question

Dispatcher85 · Post by **Dispatcher85** » Tue Feb 22, 2005 11:24 pm

As I stated to you all before I am new to the radio word. I have a Maxtrac Low band mobile-42 to 50 mhz and want to get a smaller type antenna than what I have currently. As of right now there is a big whip antenna on the top of the vehicle. I would like to get something shorter and sleeker. Any suggestions?

transistor747 · Post by **transistor747** » Wed Feb 23, 2005 8:54 am

The length of an antenna is a function of the frequency the radios operates on. It's just a law of physics and no amount of desire on your part will alter that. The lower the frequency, the longer the antenna.
Now, antennas can be electrically long, but physically short. As an example, a CB antenna if it was full size would be about 108" long. Most antennas incorporate a "loading coil" at the bottom of the antenna that makes the antenna electrically long enough to satisfy the demands of the transmitter, but physically shorter.
Therefore, if your antenna on the vehicle is on the order of 70-80 inches, you can get a physically shorter antenna.
If however, your antenna is about 40" long, with a coil at the bottom, you already have the best compromise antenna you can get.

kf4sqb · Post by **kf4sqb** » Wed Feb 23, 2005 9:40 am

Keep in mind, however, that the shorter your antenna as compared to a "full size" one, the less efficient it will be. In other words, the shorter you make it physically, the worse it will perform.

Max-trac · Post by **Max-trac** » Wed Feb 23, 2005 10:00 am

Motorola Spectrum NMO (or similar) in the middle of the roof away from any other antennas or metal = Good as you are going to get.
It should be about 40" long.

kf4sqb · Post by **kf4sqb** » Wed Feb 23, 2005 10:19 am

Max-trac wrote:Motorola Spectrum NMO (or similar) in the middle of the roof away from any other antennas or metal = Good as you are going to get.
It should be about 40" long.

Well, unless you use a "full-size" antenna, that is

!

Dispatcher85 · Post by **Dispatcher85** » Wed Feb 23, 2005 5:45 pm

40"??? Ok, thanks guys for the help I just thought that there was something a little smaller. Thanks again, Corey

thebigphish · Post by **thebigphish** » Wed Feb 23, 2005 7:12 pm

there is, but not for your application. The words "low band" tend to denote long whips....it's the physics of the game man....

AEC · Post by **AEC** » Wed Feb 23, 2005 9:14 pm

You can also use a Larsen 5/8 wave 2M antennaas a loaded 1/4wave on 6M.

It's a well tried method and does work with respectable results as well.

OR.......

Cut down a 102" CB whip to your needed length.

I prefer the "NMO" mount as it is the most versatile and is a industry standard so to speak.

I've emptied my account when I dropped my $.02 worth....

73!