Commonly used shortwave antenna

Main component is commonly used shortwave antenna 3 kinds, the first kind is perpendicular antenna (GP) , the 2nd kind is occasionally class antenna (DP) , the 3rd kind is 8 wood antenna (YAGI) . Besides, still have circle model, diamond, dish etc, before we basically discuss here 3 kinds of antenna, discuss mainly among them occasionally class antenna reachs his to be out of shape. From use in light of, GP antenna basically is used at close quarters, middle distance communication, especially wave of ground of support of close quarters communication is deferent, the effect is first-rate. And the effect of close quarters communication of DP antenna is horrible. As a result of high limitation, common lover is impossible the antenna with very tall erect, generally speaking the GP antenna of 5-10 rice height suits him erect. But to shortwave wavelengh, such height is far insufficient, for example 180 metric wave, although 1/2 wavelengh also has 90 meters tall, to common lover this is essential impossible implementation. If the shortwave antenna with 5-10 accordingly tall rice hopes to be used at shortwave complete paragraph must add feeling, the efficiency that such launching is very low.
Normally GP antenna is used at 21-29M frequency paragraph relatively general, again low frequency paragraph use GP antenna no longer. In addition, of GP antenna prevent Lei Ye to be done harder, always cultivate impossibly to return tall iron pipe to become lightning rod than aerial by aerial?

This is the structure of a typical DP antenna, among them gules part is insulator, separate with the drawing rope of two end. Advocate Zhenzi length shortens for 1/2 wavelengh *0.95 rate. Why should use 1/2 wavelengh? Because the two end after take a percentage of a deal of 1/2 wavelengh center are 1/4 wavelengh each,this is, the impedance of such antenna is 50 ohm, ability matchs with catapult photograph quite.

 

DP antenna basically uses day wave news report, remote the effect of communication is first-rate, and erect is simple, do not need the very tall antenna since vertical stroke, the cost that make is low, because this is most radio lover,be used. DP antenna has a lot of is out of shape, I make an introduction one by one to everybody below.

 

Fall " V " aerial, one kind this is DP antenna is out of shape means, of a OK and economic antenna that such doing cover an area of an area, on the other hand, can improve former the effect of communication of wave of close quarters ground of DP antenna. But after such doing, aerial was had directional, refer to the direction of the biggest radiate in the graph.

Because short wave transmitter can work each wave band in 0-30M, because this is onefold,the antenna of length needed with respect to what cannot satisfy us, and make an antenna respectively for each wave band not actual.
Such, we need a multichannel to fall " V " aerial. The profit that such doing is economic cover an area of an area, do not need a few antenna to make a round trip again switch. But the harm that such doing is each wave band Zhenzi is affected each other, clip of need one by one brace up child length, match condition in order to achieve first-rate.

Occasionally class antenna needs to make two half model same brace up child, for the HAM to having experience, a hour can be made finish antenna of a pair of many wave band. So to the novice, what tweak can be used immediately in one's hand machine? OK of course! We talk about sheet pole antenna below. What what show in the graph is the prototype of antenna of a sheet pole. As long as brace up child length is enough long, can cover each frequency paragraph. Only course antenna has only brace up child, if use as much