| 摘要 |
FIELD: radio engineering, production of antennae used for reception of TV broadcasting signals in I, II and III meter and also in decimeter wavelength ranges in closely built urban and rural areas. SUBSTANCE: miniature active television antenna has symmetric band type frame, total length "l" of which is less than 0,4λ( with λ- maximum wavelength of first television channel) and in cut-off of which active resistance is connected; low-noise amplifier. To increase sensitivity in working range of 1 - 12 television channels total length "l" of the frame and band width "h" are taken from ratios 0,281λ≅ l ≅ 0,357λand 0,0087λ≅ h ≅ 0,0162λ, and low noise amplifier is connected to symmetric output of frame through wideband symmetric transformer with transformation factor of 4 : 1. Gain factor of the antenna in active mode as compared with isotropic antenna is changing in range of 1 - 33 television channels wavelengths from 14 to 25 dB and signal to noise powers ratio P/P≥ 15 dB in all television channels of meter and decimeter wavelength ranges. EFFECT: increased sensitivity in working range of 1 - 12 television channels. |
