FTV-200 Low power TV transmitter
* Possibility of operation in any channel 21-69 (channel to order), VHF range is possible to order
* Delivery set comprises: AVT-200/A amplifier, AVT-200/F modulator, PS-113/12-4, PS-115/28-1,5 power supply devices , Å-6 framework, ÐÒ-12 power riser
|Video input||frequency band||20 Hz - 6 MHz|
|Audio input||frequency band||20Hz - 20 kHz|
|power/impedance||200 mW / 75 Ω|
|Amplitude-frequency response unevenness in video-band||± 1 dB|
|Amplitude-frequency response preequalization of Sound Channel||50 μs|
|Frequency setting accuracy||± 10 kHz
or (± 150 Hz to order)
|Frequency instability not less||10-5|
|Output level instability||± 0.5 dB|
|Modulation kind|| Video: AM
|Left side-band component suppression when 129dB/µV output level (Picture carrier/sound carrier ratio = 10dB)||> 50 dB|
|Supply voltage/Consumption current||12V/1.2A|
|Operating temperature range||0...+50î Ñ|
|Dimensions (with frame)||200x120x340mm|
* A customised frequency setting accuracy may be ± 150 Hz with an additional possibility of a frequency change relatively to the intended frequency in a 1 kHz step.
PT-12 Power Riser
* It is intended to enhance output level
ÐÒ-12/1 Power Riser
* Wide operating frequency range: 21-69 channels
A PT-12/1 power riser differentiates from a PT-12 in a wide operating frequency range: from 21 to 69 channel. It results in having a low-power single-band TV transmitter tunable from 21 to 69 channel with a 1 W power with leakage radiation suppression >=55dB when using the power riser together with the FTV-200. The power riser is installed directly near the antenna, its gain is 30dB.
Transmitter FTV-200 User Manual
A 4 W TV transmitter implementation scheme is given in fig. 1. A power riser should be located in immediate proximity of an antenna. (Do not turn on a PT-12 power riser on without an antenna. The power riser and the (AVT-200/F + AVT-200/A) shaper should be diversed from each other for a distance of ≥ 7-10m). Connect a PS-115/28-1,5 power supply device to the PT-12 power riser to avoid a considerable voltage dip in wires, link the PS-115/28-1,5 with the ÐÒ-12 power riser by a wire with a 1,5mm 2wire section.
Power loss in power-to-voltage ratio is defined according to the formula:
(where R=4km, 24 channel -λ≈ 0,6m)
As far as the level delivered by the ÐÒ-12 power riser is 144dB/µV then the signal level will amount to 144-100+5=49 dB/µV at the distance of approximately 4 km from a transmitter during transmission and reception to a (TA-203) nondirectional antenna with the gain of 5dB.
If TV receiver sensitivity is 38dB/µV, then it can be counted with an additional 49dB/µV-38dB/µV = 11dB sensitivity.
Rising of transmitting antenna level is very important.
The reception level can be considerably less than the calculated level if a necessary transmitting antenna rising is not provided.
Note that every 6dB of receiving or transmitting antenna gain double transmission range. Thus using an TAR-200 array instead of the TA-203 transmitting antenna enhances transmission range up to 32km. Earth curvature should be considered at such distances. Transmitting and receiving antenna height should be calculated using the formula R=4,12 √(h12+h22), where R is a line-of-sight-distance, km; h1, h2 are transmitting and receiving antenna height, m.
Besides, it should be considered that there should be no physical obstacles in the first Frenel zone while choosing receiving and transmitting antenna height. It can be explained by the fact that a larger part of antenna radiation is in the first Frenel zone. Energy from the zones with even numbers is in antiphase with the energy from the first zone. Thus it is recommended that the energy from all the zones should be reduced except the energy from the first zone. It is necessary to have quite a big gap for the first zone. That is why a value is chosen as the minimum gap which amounts to 0,6 from the radius of the first Frenel zone:
F=9,526 √ (AB/f(A+B)),
where F is the minimum gap in m,
f is a frequency in GHz,
A, B is a distance in km (see. fig.3)).