Old Hi-Gain Whip w/magnetic base

[Alain]

Hello All,

I have just found my old Hi-Gain mobile-mount whip antenna, circa 1980's, I'm guessing.

If I loosen the set screw in the base and pull out the whip, it is 28" long; I'd like to cut it so that it will receive/resonate center of the 151-174 MHz band. where I do most of my summer monitoring, using my old [but still working] BC 210.

How long should I cut the whip to accomplish this? Or is the whip too short already!?

I wouldn't bother the group with such an easy question, but I don't know where to look for the formula!

Many thanks for taking the time to respond!

Alain

 

[LarrySC]

15" would be close to 1/4 wave. Google for that info and check some of the ham radio sites.

 

[DickH]

What freq. was it used for? If it has a loading coil, I don't think there's any way to know what length to make the whip. If it was for 30-50 it probably won't work well on Hi Band no matter what length you make it.

 

[Alain]

Hi Dick,

Do you remember the old "Tune-A-Verter" receivers, that were made in Texas, in the 1970's and 1980's? Well, I had the low band 30-50 Mhz, as well as the high band converter, 150-170 MHz. They worked very well in the car.

I bought the Hi- Gain to use in conjunction with them.

I have just looked at the antenna and it is made in 4 parts; the whip, the chrome spring that the whip gets screwed into, a metal tube [with a plastic sleeve covering it. could this be the loading coil?] and lastly, the mag base. A small quantity of RG 58 is soldered to the underside of the "loading coil", making a very compact antenna.

Hope this helps.

Alain

 

[DickH]

Hi Dick,

Do you remember the old "Tune-A-Verter" receivers, that were made in Texas, in the 1970's and 1980's? Well, I had the low band 30-50 Mhz, as well as the high band converter, 150-170 MHz. They worked very well in the car.

I bought the Hi- Gain to use in conjunction with them.

I have just looked at the antenna and it is made in 4 parts; the whip, the chrome spring that the whip gets screwed into, a metal tube [with a plastic sleeve covering it. could this be the loading coil?] and lastly, the mag base. A small quantity of RG 58 is soldered to the underside of the "loading coil", making a very compact antenna.

If you can remove the loading coil and spring, cut the whip down to 17" or 18" for the 150-170 range. If you can't remove the spring, make the total length, including the spring, 17-18". If you can't remove the loading coil, try it as it is. You may be surprised.