Simple antenna aero mod

[ac7ss]

My geo had a broken antenna when I got it, I just stuck an aftermarket stick antenna (Designed to be in a fender) in the front window, laying across the dash. Ugly, but it worked.

[BamZipPow]

Keep in safety in mind. You don't need to find out the hard way if you git into an emergency situation that you end up gitting injured by yer antenna...

[cosmic_kid]

I tried the antenna elimination from saturnfans that CarloSW2 posted. It may or may not have affected my MPG, but it has definitely degraded my reception. I live in ND, and am usually 50+ miles from the station's tower, so I think I may have to put the antenna back, or I'll be without my radio most of the time.

[Otto]

OK, since some of you guys are knowledgeable on antenna stuff and I'm not, could we review a few things and answer a few questions?

1. Antenna length is a function of radio wave length, i.e., a radio signal of 1 meter length should have an antenna of also 1 meter, 0.9 meter signal needs 0.9 meter antenna, etc.. Is this correct?

2. If correct, that suggests an adjustable or telescoping antenna would be most versatile and receptive, so you could tweak it to the particular station?

3. Inside the car reception is nearly as good as outside, and better from an aero standpoint?

4. An antenna stuck in the weather strip between door and roof works about as well as one stuck out vertically in the breeze?

5. You can hook up your antenna circuit to your rear window defroster wire inside the glass, and that also works pretty good?

6. The type and thickness of antenna wire or pole is irrelevant, it's the proper length that counts?

7. Some windshields have antennas inside the glass, much more expensive than an otherwise identical windshield without antenna. So, why not just glue or tape a wire up along the inside upper surface of the windshield, horizontally, and save a bunch of money on a new windshield? Does Radio Shack or anybody sell a decent kit for this purpose? Or, why not just insert the right length of antenna wire in the rubber windshield seal at the top?

8. Why not do the same at the back window, and inside the weather strips above the doors, with a switch so you could choose which antenna gets best reception from the station you like as you drive along?

I know squat about this stuff, so please chime in with suggestions for improvement.

[comptiger5000]

Otto - For transmitting antennas, length matters bigtime, although they can be 1/2 wave, 1/4 wave, etc. For a receiving antenna, it makes up much less difference.

[ac7ss]

Long winded reply follows, you have been warned.

Comptiger is right, it is not that critical for receiving, however...

The most efficient length of an antenna is (in meters)

L=1/4*300/F

L=Length in Meters
F=Frequency in Mhz
You can substitute 3/4 for 1/4 but that will give you a longer antenna.

So your standard FM antenna is 1/4*300/100=0.75 meters. with a range of 0.84 meters to 0.69 meters. (Not worth adjusting for, you will have other errors not accounted for here.)

AM is considerably longer: 1/4*300/1 = 75 Meters. (AM antennas are usually coils of wire, not a straight stick.)

If you are in a metropolitan area, window mounted antenna work fine, sometimes even better than external. (due to your signal being overpowered by other stations.)

a close proximity to a parallel piece of metal will degrade the performance of any antenna. They work best with an ground plane at the bottom (or top) for this type of antenna. (You can use a reflector if you work it out right but it is very directional.)

If you remove the other connections to the defogger wire, Yes, it can make a decent antenna. If you don't unhook the voltage and ground, you can either fry your radio or it could be useless because it is grounded. (you could use other parts to make this work and have a defogger that works, but that is beyond the scope of this reply.)

You can use 30ga magnet wire to recieve, the size is for structural integrity.

I remember my dad getting a kit for a windshield antenna. Some scotch tape and magnet wire will do.

Build the antenna right, and you don't have to switch around.

One last thing, a vertical wire is better than an horizontal wire for a mobile application.

In conclusion, take a coax cable from the radio to a point in the middle of your windshield, solder some 30 gauge magnet wire to it, and tape it up the middle of your windshield stopping about 2 inches from the top. Use good tape (3m "Magic" will work well.) and you have an invisible antenna.

Originally Posted by Otto

OK, since some of you guys are knowledgeable on antenna stuff and I'm not, could we review a few things and answer a few questions?

1. Antenna length is a function of radio wave length...

2. If correct, that suggests an adjustable or telescoping antenna would be most versatile and receptive...

3. Inside the car reception is nearly as good as outside...

4. An antenna stuck in the weather strip between door and roof ...

5. You can hook up your antenna circuit to your rear window defroster ...

6. The type and thickness of antenna wire or pole is irrelevant,...

7. Some windshields have antennas inside the glass, ...

8. Why not do the same at the back window, ...

I know squat about this stuff, so please chime in with suggestions for improvement.

[sid]

This electronics engineer confirms that ac7ss has got it right in his above post.

[ac7ss]

Originally Posted by sid

This electronics engineer confirms that ac7ss has got it right in his above post.

My handle is my callsign.

[crexcrex]

Kiss my ass....may ecomodder kick me from this site i personally dont care you hick

[euromodder]

Originally Posted by Piwoslaw

After reading about internal antennas I decided that pulling mine would further smooth my roofline once I get rid of the railings. But life isn't that easy

I feel your pain.

While Volvo put the radio antenna on the right rear window (defroster-style), they also put a fake and unpainted GSM/GPS antenna cover on the roof

Rather than just glueing it on, they decided to make holes in the roof as well.
If I want to remove the useless antenna cover, I'll end up with holes in the roof