Tecsun full-time with FM/Desheng r – 909 – year – old semiconductor portable radio FM radio

R-909Features at a glance

Ultra- sleek design , elegant appearance

FM , AM , shortwave nine -band receiver

Excellent selection of imported radio integrated circuits, high sensitivity , low noise , can clearly receives most of the world shortwave radio program

Touch AM / FM band switch electronic

360 -degree rotating rod antenna

Ad hoc local remote sensitivity control switch

( 3-6 )Volt external DC jack

Product Size : 128 W High x28 x78 thick ( mm )

The main technical indicators

1 .Frequency Range

Frequency Modulation (FM) 87 – 108 megahertz (MHz)

Medium wave (MW) 525 – 1610 kHz (KHz)

Shortwave SW1-7 49-13m (SW1 u003c49mu003e 5.80-6.40MHz SW2 u003c41mu003e 6.90-7.50MHz SW3 u003c31mu003e 9.40-10.00MHz SW4 u003c25mu003e 11.65-12.15MHz SW5 u003c19mu003e 15.00-15.65MHz SW6 u003c 16mu003e 17.52-18.12MHz SW7 u003c13mu003e 21.15-21.95MHz)

2 .SensitivityFrequency Modulation (FM) is better than 5 microvolts (μv) AM (MW) better than 1 mV / m (mv / m) shortwave than 50 microvolts (μv)

3 .Output PowerGreater than 150 milliwatts (mw)

4 .Power supply3V ( section two AA batteries )

5.External headphone8-32Ohm,Stereo headphone

The effect of closing the radio station

Radio Tecsun R-909How many received , depending on local signal conditions , the signal is good, the more income units , signal units received less difference Oh .

The machine comes with a 360-degree rotating antenna to receive a strong signal capability. When listening to shortwave or FM radio , to pull out the antenna , changing the length or angle to get the best results, receiving international radio stations and remote radio signal is weak , we should switch the “local / remote selection sensitive switch ” to the DX ( Remote ) position, and to improve the reception sensitivity .

Radio and treatment of common problems when :

1 : TV , fluorescent lamps, can be linked to a silicon dimming lamps, computers, car engines, electric motors and other electrical equipment on the medium wave and short wave radios have a strong radiation interference when using the radio , keep a certain distance above appliances, avoid interference.

2 : Place the building inside and listen to high-rise buildings around the steel structure of the broadcast signal has some shielding effect , close the window using the radio, can improve the reception.

3 : Listen to a location near the “BB” signal emitted by the machine , it will seriously interfere with listening to shortwave and TV sound , and test appropriate to shorten the length of the rod antenna and adjust the angle , while the change to a different listening position to improve reception .

4 : The easiest way to improve shortwave reception capability , is easy to add an external antenna radios , namely the use of 3-4 meters long wire , one end wrapped around the rod antenna , the other end hanging outside the window , the higher the better.

5 : Listen recommendation: be sure to pay attention to your location when buying radio

a: the city’s FM radio more, can be purchased FM stereo radio

b: the mountains, away from the city ‘s rural areas , due to the distance reasons, tend to listen less FM , FM stereo and TV sound program so buy the spread of high sensitivity shortwave radio

Special Warning: Never install more tired outdoor area an external antenna !

How to maintain the radio ?

How to prevent dust from a radio problem

Dust can enter through the hole on the radio speakers inside the machine , a long time , will inevitably affect the speaker ‘s sound effects , especially in public places more dust , the problem is particularly serious , it is necessary to talk about this problem:

1 Try listening in relatively clean place , if at home , do not put the radio in the living room where the door and window by (antenna can get a long point ) , do not listen to the best time in the cupboard or other closed things , the chance to listen to it , if you feel this is too much trouble , you can use a cardboard box to cover ( with a TV-like cover things like too much trouble , but also easy to wear chassis ) , or to put in cardboard box , and dust can never invade ( Note that the box can not be misplaced or put relatively clean place is wonderful ) . But the best time cleaning the house or put it in the cupboard .
2 best time to come together to listen to the holster , but also in your pocket and listen with headphones , so you can prevent dust intrusion ( do not mean your holster, drill a small hole right ) .
3 If suddenly one day rise , look to Morocco , then we must ensure that the surrounding environment is very clean , the best to use a small brush to clean finished look ( not to break the circuit ah ) .

Two radio how anti- wear problems

1 Do not frequent loading equipment for the original box and original plastic packaging where these things are relatively close , easily rubs cabinet , if it is normal for dust box , it should be more relaxed , do not select and machine about the size of the box , a big point .
2 Do not put frequently put on the holster , unless you want to go out ( of course R101 normally listen in leather ) .
3 radio to be placed on a flat , smooth surface slippery but the will not ( can be put on the table what the piece of paper , put it in the paper, and anything else a little softer stuff also available) , a hard surface will Radio wear the bottom ( who can say that they are completely hands holding it perpendicular to the horizontal angle or something else to put on the table , it is best to keep the contact surface is not very hard.
4 handheld , do not grip too tight , it will oppress the cabinet , not too loose, the slide also has worn, hands flat on the best.

Three radio shock problem of how

This problem is relatively simple, one word on the line , ” light” ; , light and to what extent? Than to treat his glasses again so little light on it. When taking the time to put action to light , usually to be placed relatively stable, no vibration place ( first furniture feet get safe to say ) . Do not run Listen ( radio quality is better , it’s best to do so ) , cycling is also best not to listen , not only to radio, more important is safety.

Four other issues
1 Do not place in direct sunlight house, especially in summer, the temperature is high , do not put more humid , the air circulation is not good house, part time in high humidity environments susceptible to rust .
Time 2 antenna maintenance, if there is an external antenna , it will be directly connected to the rod antenna, rod antenna can use less of it on fewer points , and so your radio whip antenna screw loose , non- supportive hand on know the correctness of doing it.
3 pair of headphones maintenance, not any torn headphone cable, make sure to stretch and smooth lines , not to deadlift , if you want to close up ( for example, you want to travel a month , it does not have the headset ) , it should be folded along the original gently fold marks , not too hard , and finally with the original bundled headphones small stuff ( wire ? ) lightly , do not pull too tight, make sure that it does not own to break open , in fact, around the circle on the line , no need to get how tight . Also, if you let the headphone cable is not too often with clean hands or skin contact , especially sweat, so the headphone cable is easy to get dirty , hardened . My ear like this in two years , the line is still soft as ever , indicating that this is still a little action .
4 external antenna for some maintenance , tight against the wall when you first install the best , as far as possible to prevent rain, for security reasons, you should install lightning protection devices , to compare firmly fixed to avoid the impact of the wind .

The radio should pay attention to :
1 , the use of batteries, can not be polarity reversal. After changing the battery put the original batteries are replaced.
2, various switches and rotary telescopic antenna , do not move too fast , so screw the bad switch and broken antenna.
3, find desk , turn the tuning knob , moving back and forth in the vicinity of the station , until the sound loudest , clearest so far.
4 , the radio has a certain direction, when the poor radio reception can be rotated about the body , or a change of position to get the best reception.
5 , with stereo radio function when receiving a stereo program , stereo indicator lights should be adjusted in order to listen to the satisfaction of the stereo effect.
6, external speakers or headphones , you should pay attention to impedance matching , so as not to affect the results and damage to listen to the radio .
Radio in the usual care should be noted:
1 , the radio should be placed in a dry and ventilated place , can not throw , hit . To dust, avoid direct sunlight.
2 , Radio moisture after the water accidentally , to be ventilated place to dry thoroughly before electricity use , can not be placed in direct sunlight or drying.
3 , when the long-term need , you should remove the batteries to prevent battery leakage and corrosion mechanism, it is best to periodically energized once.
4 , should be cleaned regularly to radio , use a dry cloth to gently wipe clean when not washed with water .
5 , do not arbitrarily change the location of the radio adjustable components.

Radio and television are used which band radio wave propagation ? Are spread rely way?

Currently , AM radio broadcast system divided to long wave, medium wave and short wave three big bands , respectively, from the corresponding band radio waves to transmit signals . Only two of the big -band medium wave and short wave radio broadcasts. AM broadcast band used roughly 550kHz1600kHz, mainly by ground wave propagation , but also accompanied by partial skywave ; shortwave broadcasting band is about 2MHz-24MHz, mainly by sky-wave propagation , accompanied by ground waves close range . Multi- frequency modulation FM radio ( VHF ) radio waves to transmit signals , using a frequency of approximately 88MHz-108MHz, mainly by the spatial wave transmission signal. Currently , terrestrial broadcasters divided to VHF (very high frequency or UHF called ) and UHF ( ultra high frequency or called decimeter ) two bands. In China, the frequency range of the VHF band TV using a 48.5MHz-3MHz, divided into 1-12 channels, using the UHF band frequency range is 470MHz-956MHz, divided into :3 -68 channels. They basically rely on space wave propagation. Provisions of international satellite broadcasting band has six main bands are 12kMHz, also rely on space wave propagation .

[ AM / FM ] describes what is modulated wave ? What is the FM wave ?

Amplitude modulation of the carrier signal is changed according to a modulation method called amplitude modulation. After a wave amplitude modulation is called amplitude waves. It maintains a high-frequency carrier frequency characteristic , but the shape of the envelope waveform of the signal is similar . The amplitude of the wave amplitude is determined by the intensity of the wave amplitude modulated signal represented by the letters AM . The carrier frequency is changed in accordance with the modulating signal modulation scheme called FM . Modulated wave frequency changes in the size , change the modulation period determined by the size of the signal is determined by the frequency of the modulation signal . The amplitude modulated wave remains unchanged . FM wave waveform , like a spring being compressed unevenly , FM wave is represented by letters of the alphabet FM.

What is the TV sound radio ?

TV sound (TV SOUND) using the FM mode of transmission and FM radio just as close spread. VHF and UHF TV sound is divided into two sections , of which : VHF :1-12 Channels ( divided into VHF-L 1-5 and VHF-H 6-12) UHF :13-56 channels. The current principal to receive TV sound radio VHF channels 1-5 and 6-12 , seldom receives 13 channels (UHF) over the radio.

What is the campus radio ?
Campus radio is a low-power FM radio , a lot of universities , secondary and even primary school , and now has a large campus FM radio broadcast of the use of English or any other program , the frequency range is usually between 76-87MHz, ie ordinary the radio can receive TV sound to get . Now some FM radio frequencies directly extended to 76-108MHz, can satisfy the need to listen to campus radio .
Radio full band mean?

The whole band is three bands : FM fm, medium wave am (mw), shortwave sw. fm is generally 87-108mhz, with the campus radio can reach 64-108mhz; am usually in 520-1650khz; sw generally 5-21mhz ( maximum 2-29mhz), is easy to use , and often this frequency band is divided into a number of small frequency band , the specific radio may occur sw1, sw2, ……. This appeared in the so-called 9 -band or 12 -band radio (fm + am + n a sw).

What is the frequency modulation (FM), amplitude modulation (AM), shortwave (SW), longwave (LW)?

In general have a radio or cassette player AM and FM bands , I believe we are already familiar with these two bands are used for you to listen to country radio , and if there is time on the SW band radio , then outside the country in addition to short-wave radio You can also listen to radio programs around the world. To allow you to have a better understanding of the use of the radio , the following is what is AM, FM, SW, LW make a simple explanation . AM and FM refers to the fact that the two different modulation on the radio science . AM: AmplitudeModulation called AM, and FM: Frequency Modulation called FM . Just a general wave radio (MW: Medium Wave) using amplitude modulation (AM) way , unconsciously, between MW and AM would equate . In fact, just a lot of MW Radio AM modulation using a modulation scheme as international shortwave broadcasting in high-frequency (3-30MHz) is also used in the AM, air navigation communications even higher frequency than FM radio (116 – 136MHz) is also a way of using the AM , but our daily said the band refers to the medium wave AM broadcast (MW). That FM it? It is also similar to the same fate MW phase . We customarily used to refer to the general FM FM radio (76-108MHz, in our country for the 87.5-108MHz, Japan 76-90MHz), is also a fact that FM modulation, even in the short-wave range between 27-30MHz , as an amateur radio station , space , band satellite communications applications , but also uses frequency modulation (FM) mode . The SW it? In fact, it can be said is a simple call to the shortwave , the correct statement should be a high-frequency (HF: High Frequency) is more appropriate . The shortwave This name is how come? Wavelength , the wave (MW) between 200-600 meters ( yards ), while HF wavelength is 10 to 100 meters ( yards ) between compared with the above-mentioned wavelength , HF ‘s wavelength is indeed a bit short , so put HF called shortwave (SW: Short Wave). Again, this period between the spectrum 150KHz-284KHz frequency lower than the wave MW is also used as a broadcast to the wavelength is concerned, it is about 1000 to 2000 m ( meters) , and the 200 MW – 600 m compared to the apparently “long” and more, so they made during the broadcast spectrum called longwave (LW: Long Wave). In fact , regardless of the long-wave (LW), medium wave (MW) or shortwave (SW) are based on the AM modulation. For general admission ( recorded ) sound machine is concerned , FM, MW, LW band is used to provide you listen to country radio , but China is not set up LW radio, and SW bands you listen primarily for the domestic / international long-distance radio.

Band features: amplitude modulation ( AM ) to listen to the radio programs in the province ; frequency modulation (FM) radio programs to listen to the city ; FM stereo (FM STEREO) Listening to FM stereo broadcasts city ; shortwave (SW) listen to domestic and international long-distance radio show .

Desheng regional customer service center