Half Zhen Zitian line and amount to Zhen Zitian the gain of the line is small, wave segment or section is broad, ahead and rear have identical reception ability, so they apply to signal only strong, disturb little place, should receive a dot to leave a TV station further, signal weaker or signal is stronger but interference is bigger when reflection wave effect is more serious, be about to use multivariate tall gain is directional aerial, this is multivariate brace up child aerial, call 8 wood aerial again, in active brace up child reflector is added at the back of, director is added in front, form multivariate brace up child aerial, bring Xiang Zhenzi, reflex brace up child with active brace up child the unit number that the amount that add up is aerial. 
Multivariate the rear wave valve of Zhen Zitian line disappears, ahead sensitivity rises greatly, the principle is as follows:
please Click here to get our dipole antenna
1. reflector chooses the action of the signal that come to ahead P dot and rear Q
The active in right graph brace up child the job is in syntonic condition, its impedance is pure resistor, reflector grows 5%-15% than having Zhenzi with length, and present sensibility. Set reflector and active Zhen Zixiang to be apart from λ / 4, the electromagnetic wave that from the P of aerial ahead the point comes arrives at active first brace up child, the E1 of generation reaction electromotive force that makes, faradic I1. Electromagnetic wave repass λ / the by way of of 4 just arrives at reflector, the E2 of generation reaction electromotive force that makes and faradic I2. As a result of reflector and active brace up child in λ of empty photogenic difference / the distance of 4, e2 is so more backward than E1 90 ° , and I2 presents sensibility as a result of reflector again and lag behind than E2 90 ° , reason I2 is more backward than E1 180 ° , the radiation field that I2 of reflector electric current produces arrives at active brace up child formation magnetic field H2 lags behind than I2 again 90 ° , namely H2 is more backward than E1 270 ° . According to electromagnetism induction law, the E1-2 of inductive electromotive force that H2 produces in active Zhenzi is more backward than H2 90 ° , result E1-2 is more backward than E1 360 ° , that is to say reflector is in active brace up child the E1 of inductive electromotive force of the E1-2 of inductive electromotive force that produces and Yuan Zhenzi is inphase, aerial output voltage is to be equal to E1 and E1-2 the sum, before visible reflector makes aerial is received advocate the sensitivity of signal rose, the derivation with similar ground is knowable: 絈 of midge of courtyard of porcelain Gan Ju nods the signal that come to have the effect of quits output.
The action of 2. director
Director compares active brace up child short 5%-10% , its impedance shows capacitance sex, hypothesis director and active brace up child the distance between also is λ / 4, it is OK to use same method derivation gives undermentioned verdict: Is amine of Yun of Zha Ju chewed blow a small tinkling bell other Hu of card of male lotus root to engrave illuminate does lotus root of Ling Su triangular bream cast Yong?
The place on put together is narrated, the move since reflector removes the effect of the valve after aerial direction pursues, reflector and director have the effect that heightens aerial ahead sensitivity.
please Click here to get our dipole antenna
Our other product:
