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- With high technology, this Multi Band Radio has a higher sensitivity and stability
- This Multi Band Radio can turn off automatically after 1-2 hour if you set
- This world band radio can memorize programs you like
- With fashion look, this best portable radio can show your taste
- This multi band radio is made of high quality material, durable and it can last for a long time
- You can search the program by hand or input the frequency range With this radio, you can also scan the program saved before
- Power: 4 x D Batteries
- Size: 173 x 272 x 88mm/6.8 x 10.7 x 3.5in(L x W x T)
- The powerful Multi Band Radio provides a comfortable handle designed to ensures you can easy to take it to anywhere with you
- This multi band radio's MW and SW also can be connected to the 500 ohm antenna and earth
- The medium wave radio provide up to five wave band FM, MW, SW option which allows you receive more of your favorite radio station
- The Multi band radio comes with 30MHz LPF make it free from the interference of the locate FM signal and the VHF communication signal
Size in Detail:
How Does FM Radio Work?
Sound Waves and Frequency:
- All sound energy is in the form of a wave. The frequency of a wave is the measurement of the number of cycles that it undergoes in a given time frame. Hertz is a measurement of frequency that depicts the number of wave cycles per second. FM signals are measured in megahertz so an FM signal of 97.5 relates to 97,500,000 waves/second
- FM actually stands for Frequency Modulation. FM signals use various frequency levels that reproduce the sound of the originating source (i.e. music). You've probably noticed that FM contains all your music channels while AM radio is limited to news and talk programming. This is because frequency modulation allows for the transmission of the greater range of frequencies (high and low sounds) contained within music.
- FM radio originates at the broadcast source (radio stations). These stations use large antennas to send out their broadcast signal. Electrical charges are pushed up and down the broadcast antenna at a rate that relates to the carrier frequency. The movement of electrical charges creates an electromagnetic field which sends out
- electromagnetic waves. The waves are sent in all directions. Carrier waves are sent out at a frequency that can be detected by your antenna (the radio station number). They carry sound information that includes the different frequencies of the original broadcast
- The electromagnetic carrier wave travels through the atmosphere until it is picked up by a receiver antenna (i.e. your car radio antenna). At this time the wave causes electrical charges to be pushed up and down your antenna and on into your receiver. The receiver decodes the modulated frequency information and then passes it to the speakers
Processing and Hearing:
- The speaker vibrates according to the processed frequencies and pushes air molecules that recreate the original sound waves and pass them to your ears. You hear the music or talk that was sent in the original broadcast. Since electricity works at the speed of light, this process, from broadcast to listener, is instantaneous
Loss of Signal:
- You've probably noticed, particularly if you listen to FM radio in the car, that eventually you will lose your signal. The simple reason for this is that the short wavelength of FM radio waves cause them to travel in straight lines. The earth, however, is curved. Therefore, as the earth curves, FM waves continue in a straight line into the atmosphere and are no longer receptible. The short waves are also affected by obstacles like mountains
Differences Between AM and FM Receivers:
- In an AM transmission the carrier wave is constant in frequency and varies in amplitude (strength) according to the sounds present at the microphone; in FM the carrier is constant in amplitude and varies in frequency. FM is also used in television sound systems. In both radio and television receivers, once the basic signals have been separated from the carrier wave they are fed to a loudspeaker or a display device (usually a cathode-ray tube), where they are converted into sound and visual images, respectively.
How to Build an FM Radio?
- A radio provides signal transmission via the use of electromagnetic waves. The frequencies a radio uses are lower than those of visible light. A German scientist by the name of Heinrich Hertz was the first to detect and product radio frequencies, in 1888. Radios are still in wide use, even in this internet age. Building a simple FM radio only requires a small amount of time and materials. Although this radio is fully functioning, it isn't very pretty
- Solder the ferrite loop to the variable capacitor. Only solder the ferrite wire that is painted black. Make sure you are soldering the ferrite loop to the center lead of the variable capacitor
- Solder the unpainted wire of the ferrite loop to the variable capacitor's right lead
- Solder the germanium diode to the same right lead of the variable capacitor as the unpainted wire of the ferrite loop. Only connect one end of the germanium diode
- Solder one end of the piezoelectric wire to the other (free) end of the germanium diode
- Solder the other end of the piezoelectric wire to the variable capacitor's center lead
- Take note of the red-painted wire of the ferrite coil. Use an alligator clip to attach it to the antenna wire
- Use the remaining alligator clip lead to attach the green-painted wire of the ferrite coil to a good ground. You can use a cold water pipe for the ground
- 1 x Radio
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If the order has already been shipped; you may return the item to us postmarked within 30 calendar days of delivery. Before that, please contact our Live Support to inform that.
In that case we will refund you the payment excluding actual shipping fees already incurred.
If the item is defective, please contact DinoDirect Live Support and send an email to us at email@example.com attached an image or video file clearly showing the defect of the product. And we will give you a response within 24 hours whether we will resend the item or refund the payment to you for compensation.
For customization, please consider carefully before ordering.Because we do not accept return and replacement.
|Unit Price||USD$ 75.14||USD$ 72.78||USD$ 70.43||USD$ 67.29|
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• If the order has not been shipped; please contact DinoDirect Live Support for order cancellation.You will get your refund within 24 hours.
• If the order has already been shipped; you may return the item to us postmarked within 30 calendar days of delivery. Please contact our Live Support to inform that.
• Please contact Live Chat or click here to learn more return policy.