Fully Coiled Antenna?

I'm new to building antennas but I know how to make a Monopole ground plane.

For now I'm only interested in the antenna being able to receive. Receive Only.

Would I be able to make a, say, 27MHz 102 inch antenna with 102 inch ground plane but tightly coil the elements?

(So the entire antenna looks like the center loaded part of an antenna and so I don't have a nearly two story (18ft) antenna)

Yes, but it won't be as efficient as full sized antenna and if you make a coil with 102 inches of wire it will not be resonant at 27 MHz.

nd5y said:

Yes, but it won't be as efficient as full sized antenna and if you make a coil with 102 inches of wire it will not be resonant at 27 MHz.

Click to expand...

I'm still new to radio frequency stuff, so I'm going to try not sound overly stupid when asking this.
By Resonate, do you mean that it won't transmit at 27mhz?

Would a diy coiled antenna be better or worse than a brand name 27MHz-1.3GHz scanner antenna for receiving? Better than a cb rubber ducky?

Resonance identifies the frequency that the antenna operates best. Length is just one factor, and a coil can make the antenna seem longer, which lowers the frequency. There are many resources available, that can help explain antenna design theory.

The scanner antenna you describe in the second part will probably work better than a rubber duck, for receive. Is this antenna outside, or directly connected to the radio antenna jack? (Once again, many factors tie in to being a "better" antenna.)

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krokus said:

Resonance identifies the frequency that the antenna operates best. Length is just one factor, and a coil can make the antenna seem longer, which lowers the frequency. There are many resources available, that can help explain antenna design theory.

The scanner antenna you describe in the second part will probably work better than a rubber duck, for receive. Is this antenna outside, or directly connected to the radio antenna jack? (Once again, many factors tie in to being a "better" antenna.)

Sent via Tapatalk

Click to expand...

So the DIY coiled antenna is going to be worse than my duck and my mag mount antennas?

And I assume any coiling antenna like I was thinking(something like the coils on a vehicle's shocks), is going to not be worth building?

I think what you're referring to is called a helically wound antenna. Many shortened CB antennas are helically wound.

Do a Google search on them.

John
Peoria, AZ

How to explain antenna theory to someone without any... OK, here goes...

A coil is a compromise. It's a way of making the radio happy. The antenna will be electrically the correct length, but its efficiency will be poor. When it comes to the classic antenna, it's not about the width, it's all about the length. Madam.

Ahem.

KB7MIB said:

I think what you're referring to is called a helically wound antenna. Many shortened CB antennas are helically wound.

Click to expand...

AKA Firestick antenna.

A 'coil' has both inductance, like the 102" whip, AND capacitance between the turns in the coil. Increased capacitance in the coil means the wire length must be shorter for the helical to resonate/operate on the same frequency.

But as you physically shorten the radiator element, as in a coil, it does not intercept as much of the RF field. So receiving is not as good. Intercepting RF fields is what a receiving antenna needs to do. More 'iron' in the air....

I remember way back a ground plane antenna with Firesticks for the radiator and for the three 'ground plane' elements.