BASE Antenna for VHF 39.68mhz CHP ??

[conve36]

I am looking to build a base antenna for chp. The RS 102" whip sounds like a perfect starting point, but will I need to make a ground plane if used for base use? And cutting the whip to a quarter wave on 39.68 is easy. I will NOT be transmitting with this antenna, just scanning CHP.

Please let me know you suggestions! Thanks!!

 

[trooperdude]

I am looking to build a base antenna for chp. The RS 102" whip sounds like a perfect starting point, but will I need to make a ground plane if used for base use? And cutting the whip to a quarter wave on 39.68 is easy. I will NOT be transmitting with this antenna, just scanning CHP.

Please let me know you suggestions! Thanks!!

Google "coaxial sleeve antenna"

or this:

http://scannerbuff.net/lowband/index.html

 

[conve36]

So I purchased the 102" whip and it seems to work great for CHP's 39.xxMhz frequencies. Now should I cut this antenna to 1/4 wave for that freq? I only use it for scanning, no transmitting... And groundplane?

 

[Don_Burke]

So I purchased the 102" whip and it seems to work great for CHP's 39.xxMhz frequencies. Now should I cut this antenna to 1/4 wave for that freq? I only use it for scanning, no transmitting... And groundplane?

If it is working great, why mess with it?

 

[prcguy]

I second the coaxial dipole.
It would be about 12ftlong plus a foot for mounting and would consist of a chunk of coax with the braid pulled back over itself and hung inside a piece of PVC pipe.
prcguy

Google "coaxial sleeve antenna"

or this:

6 Meter Repeater Antenna 1/2 Wave Coaxial Vertical Antenna Design

 

[conve36]

Yeah but I already have the 102" whip. What I have done with it so far; Cut off the very end of the whip where the connector is and replaced it in the "Radio Shack Mag-Mount scanner antenna". Im not getting the results I wanted on CHP low band 39.68... Will a ground plane honestly make a noticable difference with receive only? Cut it for 1/4 wave on 39.68?

 

[mancow]

... Will a ground plane honestly make a noticable difference with receive only?....

Yes, it will. I built a 42 Mhz ground plane from some scrap parts and fed it with regular TV coaxial cable. The results are excellent. I have it hoisted up in a tree at 30 feet where it hangs from the center active element from a piece of nylon cord. I can pretty much hear every troop in Missouri when I used to get one or two with just a whip on a pole.

 

[conve36]

What would you recommend the length of the material I use? The angle? I know lengths probably depend on type of metal, but I just need an idea... Thanks!

 

[N1BHH]

Here you have a calculator for just this purpose: design your own ground plane
A ground plane is a very good antenna. Have had a few and they do the job.

 

[code3cowboy]

Yes, it will. I built a 42 Mhz ground plane from some scrap parts and fed it with regular TV coaxial cable. The results are excellent. I have it hoisted up in a tree at 30 feet where it hangs from the center active element from a piece of nylon cord. I can pretty much hear every troop in Missouri when I used to get one or two with just a whip on a pole.

Cable TV is 75 ohms, radio is 50 ohm in America.

 

[DickH]

Cable TV is 75 ohms, radio is 50 ohm in America.

What is it in France? ... or New Zealand?

 

[kirka127]

Cable TV is 75 ohms, radio is 50 ohm in America.

This is not a big deal on a receive only antenna. A lot of people use 75 ohm coax.