maybe a dumb question...

rafale01010 · #1 (**permalink**) 07-25-2009, 09:27 PM

I got a few old antennaes for a cb, 3 were fiberglass whips and 1 was a metal whip with a coiled section about 3in from the base. it opens up, not 3in from the bottom, and has coiled copper i think and goes back to the whip after about another 2-3"and the last whip section is a pretty good length, not as long as my 102" whipthough. Does the coiled section improve reception or something else, i cant remember now. Any input greatly appreciated.

w8jjr · #2 (**permalink**) 07-25-2009, 10:00 PM

simply the coil of wire electricly replaces the missing part of the 102'.

so you could have 30'' rod and the coil would be 72'' of wire. More to it, but thats it in a nut shell

rafale01010 · #3 (**permalink**) 07-25-2009, 10:28 PM

Where would the best pace to put it be at? Right now i have it mounted in th mount i had for my 102"whip, which came out a while back, right on the passenger side of the back bumper.

w8jjr · #4 (**permalink**) 07-26-2009, 01:16 AM

the best would be the 102 1/4 wave at that location. . Best spot would be center of the car- roof.
if size is not limiting.

rafale01010 · #5 (**permalink**) 07-26-2009, 01:42 PM

Ah, thats what i figured. Where would i be able to just get the magnetic roof mount for the antennae instead of mounting it directly on the hood itself?

BNSFrailfan · #6 (**permalink**) 07-29-2009, 09:12 AM

What type of vehicle are you installing your Antenna too?

N_Jay · #7 (**permalink**) 07-29-2009, 09:16 AM

Quote:

Originally Posted by w8jjr

simply the coil of wire electricly replaces the missing part of the 102'.

so you could have 30'' rod and the coil would be 72'' of wire. More to it, but thats it in a nut shell

Yes, and No.
The coil "replaces" the length of the whip "electrically" but not physically.

The coil will have an inductance that is needed due to the whip being shorter then proper to resonate at the desired frequency, but the length of the wire in the coil is not directly related to the missing length of the antenna.

BNSFrailfan · #8 (**permalink**) 07-29-2009, 09:20 AM

But doesn't the signal going through the "Coil" get speedup before it get's to the Antenna's rod tip?

N_Jay · #9 (**permalink**) 07-29-2009, 09:55 AM

Quote:

Originally Posted by BNSFrailfan

But doesn't the signal going through the "Coil" get speedup before it get's to the Antenna's rod tip?

That is not a good analogy.

va3hub · #10 (**permalink**) 07-29-2009, 11:01 AM

Quote:

Originally Posted by N_Jay

That is not a good analogy.

Analogy's us if you please, and set us straight on what would be a good analogy,keeping the topic posted in mind of course.

N_Jay · #11 (**permalink**) 07-29-2009, 11:17 AM

At antenna at resonance looks like a tuned L/C (Coil (Inductor)/Capacitor) network.

When it is not at its physical resonance frequency it either lacking capacitance or lacking inductance.
You add an appropriate capacitor or inductor at the appropriate point to return the circuit to resonance it the frequency you desire.

I find that analogies are hard to use because what seems like it helps explain it to one person ends up confusing others.

Even if we tried your "speed" analogy, the coil would be said to "Slow Down" the signal, so it takes a whole quarter cycle of time to get from the base of the antenna to the tip.

rafale01010 · #12 (**permalink**) 07-29-2009, 05:02 PM

That helps me out a little, and the vehicle i'm mounting it to, if i can find the right mount, will be a 1994 Toyota Pickup. I really wont care if it'll look tacky, my trucks already has antennaes galore with 2 pieces of metal pipe for flag pole. The only thing i dont want to do is drill a hole in the roof of the cab