Have you ever wondered about short car antenna vs. long ones? In the past, you would see long antennas on vehicles.
But today, antennas seem to be getting shorter and shorter, yet the signal is just as strong, even stronger.
Naturally, such observations might leave you wondering, does antenna length matter?
And what exactly is the difference between a short antenna and a long one?
Read on to understand how short and long antennas differ in various aspects, such as frequency, bandwidth, and range.
Table of Contents
- Short Car Antenna
- Long Car Antenna
- Does the Length of a Car Antenna Matter?
- What Is the Difference Between Short and Long Car Antennas?
- Why Do Modern Cars Have Short Antennas?
Short Car Antenna
Typically, these antennas are relatively short. But don’t underestimate their length, for these antennas only appear short.
They have a coil base that shortens the antenna length, making a long antenna appear short.
Also, the coiling ensures the antenna attains the length needed for any EM band it’s intended to pick up.
Interestingly, the short antenna still maintains the quarter wave rule characteristic of long antennas.
That means the length is a quarter of the wavelength of the radio signal.
That way, the antenna achieves a heightened signal transmission and reception efficiency.
Often, you’ll see short antennas attached to the windshield. By mounting the antenna on the windshield, you minimize signal interference.
Also, you can install short antennas on the side mirror or trunk cover.
(Caption: Short car antenna)
Are Short Car Antennas Effective?
Additionally, manufacturers have found other ways to amplify the performance of short antennas.
For example, they employ antenna amplifiers to help boost the short antenna signals.
Another vital feature manufacturers use signal filter circuits. These enhance the short antenna’s reception.
The circuits containing capacitors and inductors help with tuning signals.
See, the capacitors enhance the antenna’s ability to have better impedance matching and frequency tuning.
They do this by helping adjust the resonant frequency. Also, a matching impedance helps filter out any noise in the transmitted signal.
Further, some versions of short antennas incorporate several to increase their reception.
For example, shark fin antennas have multiple antennas installed in one for better reception.
(Caption: Shark fin antenna)
Long Car Antenna
This type of car antenna is long, extending about 32 inches in length.
Usually, they’re straight rods mounted on the car’s roof or trunk.
Often, you’ll find them connected to the different parts of the vehicle for excellent reception.
(Caption: Long antenna on the roof of the car)
Usually, there are two primary types of long antennas: extendable and non-extendable.
With extendable antennas, you can vary the length by pulling the antenna up and down as desired.
Thus, you can adjust them depending on the needed frequency for better signal reception.
Additionally, long antennas can either be flexible or stiff.
Does the Length of a Car Antenna Matter?
Yes, it does. Generally, longer antennas have better signal reception. And one reason for that is that they have better resonance.
Thus, a long antenna can pick a signal over a wider range of low frequencies more effectively than a shorter antenna.
Note antenna length is inversely proportional to the frequency and directly related to the wavelength.
See, if the antenna is to detect a certain wavelength, it should be at least a quarter the length of the wavelength.
Therefore, if the antenna is too short, it will have poor reception as it does not meet the length threshold to wavelength.
See, an antenna must be at least 32 inches long to have clear FM reception. Therefore, a short antenna will require a preamplifier to work.
Short antennas can respond comfortably to signals with high frequencies and short wavelengths.
The problem is very few cases of radio communication utilize very high frequencies.
Thus, a long antenna comes in handy in many FM radio receptions.
What Is the Difference Between Short and Long Car Antennas?
Below, we look at how short antennas differ from long ones in the following aspects:
Frequency and Wavelength
And the frequency at which the vehicle will operate determines the antenna length. This, in turn, is proportional to the wavelength.
In short, the length is directly related to the wavelength of the working frequency.
Thus, the higher the frequency and the shorter the wavelength, the shorter the antenna you can use.
On the other hand, the lower the frequency, the longer the wavelength and the longer the antenna you should use.
Now bandwidth is the range of frequencies over which an antenna can effectively transmit or receive a signal.
And it’s a fundamental factor in an antenna, influencing the type of antenna you should use.
For example, if the signals the antenna is receiving fall within a specific frequency band, then the appropriate antenna would be one with a narrow bandwidth.
But if the signals the antenna will receive are of a frequency range that’s not restricted, then you would use an antenna with broad bandwidth.
Antenna range means how far an antenna can transmit or receive a signal. Generally, the longer the antenna, the higher the range, and vice versa.
However, as mentioned earlier, antenna manufacturers now use technology that enables short antennas to work as effectively as long ones.
And these technologies include features such as coil bases, amplifiers, and signal filter circuits with capacitors. For this reason, car antennas today are short.
See the alternating current applied to the antenna, charging them, after which they emit an electric field.
Now the strength of this electric field is called radiated electromagnetic power.
Interestingly, this REM power is directly proportional to the increase in frequency.
For example, the shorter the antenna, the higher the radiated EM power at high frequencies.
And the longer antennas work well at low frequencies and have a lower radiated EM power.
Also, it’s interesting how the shape of the antenna also influences how it radiates EM power.
For example, at a reduced frequency, longer antennas will have a higher radiated EM power than short antennas.
Gain is the ability of the antenna to focus a specific signal and the radiated energy while ignoring other signals.
That way, the antenna can receive a clear signal with limited interference.
Now there’s a correlation between gain and antenna size.
For example, larger antennas have a higher gain than small antennas. Thus, they’re able to focus the signal better than short antennas.
Then here, too, the shape of the antenna also matters.
For example, a thin, long antenna can direct more of its gain power in a given direction than a short, wide antenna.
Why Do Modern Cars Have Short Antennas?
Since the longer the antenna, the longer the range, you’d expect cars to have long antennas.
But that’s not the case. Only old cars have long antennas.
One reason is that long antennas are vulnerable to breakage.
They can easily suffer damage from harsh weather conditions like windstorms or snow.
Also, long antennas don’t last as long as short ones.
Often, they wear out, and the antenna won’t work in just a few years, even faster if you live close to the ocean, where they get corrupted.
Are Taller Antennas Better?
Generally, longer antennas have better signal reception than short ones.
See, many of the radio-transmitted signals have longer wavelengths but lower frequencies.
And the longer antenna works best at lower frequencies.
That’s because they meet at least a quarter or half the length of the wavelength of the signal wave.
What Matters More, Antenna Height or Length?
The height of an antenna is more important than its length.
And one reason for this is that it’s possible to have a longer antenna mounted at the lowest part of the car.
Similarly, you can mount a short antenna at the car’s highest point.
Either way, the antenna must meet the required height to detect the VHF signal from the transmission station.
What Is the Best Length for a Car Antenna?
See, a good antenna should meet at least a quarter of the length of the wavelength of the signal.
And that would be about 32 inches. But remember, the technological innovations manufacturers employ today have made it possible to compress this length and make short but effective antennas.
So that’s it on short car antenna vs. long. We’ve seen that longer antennas have better signal reception than their shorter counterparts.
That said, the latest technology has made it possible to make antennas much shorter without compromising signal reception.
In addition, there are devices like filter circuits with capacitors, inductors, and amplifiers to help boost the signal of short antennas.