Help me get video out from a 38.9 MHz IF signal

haii i want to get video out from 38.9 mhz if signal....i found tda 9800 but it use a coil and cap to set the if frequency....can someone help mee to do this without using aa coil

Dear friend:

in your request you did not give any information about your IF signal to be detected, to get video.
Typically, 38.9 MHz is a video RF carrier in an AM modulated TV signal. To obtain a detected video signal, you will need a simple diode detector like used in any TV receiver.
If your signal is FM-modulated, you can find a FM detector IC but many such ICs require a quadrature LC circuit which must be adjusted for a good performance.

There are many interesting ICs used in TV receivers for both purposes. For your project it may be useful to try find a broken TV receiver, and use its circuits. Mostly a "broken TV" has only its HV block faulty while all other blocks still operate.

okk now i found an if unit from a broken vcr...i found the pins for if input vcc video out etc....i am giving the if input from an analogue tuner.....i want to make it more sensitive so that it will pick signal from my tv transmitter.....can anyone help me

Added after 1 minutes:

also help me to make a tv transmitter...now i am using an a/v to rf converter as my transmitter

http://www.circuitstoday.com/wp-cont...er-circuit.jpg
http://www.tech-systems-labs.com/pdf...TVTransmit.pdf

haiii i would like to get c code for controlling pll tsa5522 in a tuner...is there any other way to tune this tuner..it has a 30v tuning voltage will it be enough t adjust it with a pot....i want to use it to receive signals from my tv transmitter...shoulg i use and antenna for it..or some booster

what freq will your transmitter be on ?
what power output will it have ?
what distance are you wanting to transmit and receive over ?
metres, 10's of metres, 100's of metres, more ? which?

the tuner will need some sort of basic antenna say a dipole at least, that should be cut/tuned for the frequency you are wanting to use

answer these Q's and see if we can help further

Dave
VK2TDN

i will be using a tv transmitter in vhf band.
say about 85db output power or little less.
i want to transmit within a large hall of 10 meter length,our project is demo is done in seminar hall

when u say dipole,do u mean yagi uda dipole.sorry i am not good with antenna

ok :)
you need to be a little more specific in frequency within the VHF Band so we can determine the appropriate measurements for the dipole antenna. and also for the transmitter tuning.
( no, a yagi is more complex than just a dipole, its a dipole with extra elements to give it more gain) you dont need that for your situation in a large hall. a plain 1/2 wave dipole will be ample
( HINT... you would be better off using the UHF part of the TV band as the antenna size is physically much smaller)

85dB isnt a power level. 85dBm would be but thats a huge amount of power
316kW the amount of a major commercial TV station :)

for your application you would want somthing in the range of 20 - 30dBm that is ... 100mW to 1 Watt

you need to ...
1) decide freq and power of transmitter and build or maybe buy a ready built unit
2) build simple dipole antenna for it
3) build a second antenna for the receiver.
4) you could use an old VCR as the receiver, (wont cost you anything ) that you can get the audio and video signals out of the back connectors of the unit.
that saves any complicated construction.
5) feed those signals to a monitor and an audio amplifier system to suit your requirements

once you determine the freq you want to use let me know and I can show you have to build the dipoles :)

cheers
Dave

i will be transmitting around 200mhz in vhf band.i need a power of 1w

ok for determining wavelength .... 300 / freq (in MHz) = λ (wavelength (in metres)

ok so 300 / 200MHz = 1.5 metres now you only need a 1/2 λ for the dipole
so 1.5 / 2 = 0.75m (750mm) now each 1/2 of the dipole is 1/4 λ long
an it has to be an electrical 1/4 λ

firstly 750mm / 2 = 375mm (free space 1/4 λ) x .95 (to get elect. /length)

375mm x .95 = 356mm <<--- will be the length of each arm of the dipole

see pic below

cheers
Dave
VK2TDN

thanks buddy u were really helpful.

Added after 37 seconds:

do u know anything about making a tv transmitter