4g cell phone jammer From low to high frequency radio band is divided into a number of discrete bands, commonly used HF band, VHF band and UHF band, then a high frequency microwave frequencies used only for amateur satellite communications, and microwave communications experiments. The following brief introduction about the common amateur
Propagation of the radio band.
l. 160m band (1.80 ~ 2.00MHz)
4g cell phone jammer This is to allow the use of amateur radio lowest band. Propagation of this wave is very similar with the band during the day mainly by ground waves close communication, the evening can be long-distance communication through the ionosphere D layer reflection, the best communication timing is communication double
Parties are at the time of sunrise and sunset at the junction. In winter evening or dawn, with 160m bands when long-distance communication. Because of this relatively low frequency band, you need to set up a large antenna, the ionosphere its attenuation is relatively large, require larger
Power in order to achieve long-distance communication, therefore, fewer people operate, and multi-use CW liaison.
2.80m band (3.50 ~ 3.90MHz)
The propagation of bands with similar bands 160m, mainly in F layer and E layer hybrid spread-based. Summer day due to the high electron density and the D layer and the E layer is less than this band wave will be absorbed and not reflected by the ionosphere, the daytime only 100 ~
Communication distance of 200km. Meanwhile, in the summer often lightning occurs, the upper band with a lot of noise, the weak signal can not be heard. In winter evening or dawn, the effect of long-distance communication better than the 160m band, Radio Communications to the opportunity to distance
Is also large. This band antenna is relatively large, but the antenna band than 160m has narrowed a lot, Besides, now there are many products shortened antenna, so the difficulty of reducing this band antenna erection. Easy to set up multi-level general half-wave dipole antenna
, Shortened product wireless multi-antenna vertical grounding type, there is a large site and erection sufficient funds can be set up in the tens of meters from the huge tower Yagi directional antenna! Effect of a good antenna is necessary to stand too high, but also the length enough.
3.40m band (7.00 ~ 7.10MHz)
This is one of the entry points shortwave band beginners, but also the most crowded lively band. This band is relatively narrow operating range, but most can be almost 24/7/365 QSO, the day can be hundreds of kilometers of Communications, in the evening or dawn is opened remotely
A good opportunity to communicate, many countries in the crowded station then in a narrow band with each other, with serious noise band itself together into a bustling marketplace in Fig. In the middle of the night, is often a good time to intercontinental communication, therefore, often hunting in this band Rare
HAM radio has a "night owl" reputation. Domestic more HAM between 7.050 ~ 7.070MHz with the LSB Communications, and many provinces have set up some frequency fixed local network. The frequency of the antenna, whether a simple dipole antenna, antenna vertical ground
Or complex rotary Yagi directional antenna can have fun, and even some of the shortened clip whip antenna in the car, on the way to work carried out through the continent over the province of Communications.
4.20m band (14.00 ~ 14.350MHz)
4g cell phone jammer The band is known for DX (long distance communication) band, because this band is mainly carried out by the ionospheric F layer, global communications. Propagation characteristics of this band is relatively stable, and seasonal changes in solar activity influence on the spread is relatively small, the opening of the ionosphere
A long time. Spread somewhat less in the winter, the main opening spread to Southeast Asia, the global spread of spring and autumn began opening in the summer, even in the daytime there DX communication possible. Most international competitions and radio expedition activities, can operate in this band, with
Most stations are also using this band for DX communication for the purpose, therefore, this band is the best hunting of rare radio band. More famous in the country is 14.180MHz frequency of Chinese old ham network, several decades every morning in Southeast Asia
Chinese old ham are gathering at this frequency, called tea together. Another is the Chinese Radio Sports Association 14.330MHz frequency point (CRSA) network, every Tuesday ten o'clock start, by BY1PK master, reporting activities throughout the recent work of Ann and CRSA
Row and so on. This addition to the usual bands CW and USB communication mode, you can also make RTTY and SSTY communications. The band antenna can be done has been relatively small, often used Yagi directional antenna, antenna gain is relatively high, there are many multi-band 4g cell phone jammer
Common antenna operation.
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