<how to> combine 2 rf signals

combine tv and cctv signals

:?:
Sirs

I am needing to combine the local terrestre antenna with a (VHF or UHF) modulator on single cable. The modulator carries the CCTV signal from a multiplexer circuit.

How to do it ?

And how to project a video amplifier to VHF/UHF band in order to distribute the resulting signal to 10 differente locations ?

Thanks In Advance
Jean Fernandes

how to cobine in rf

jeanfernandes said:

:?:
Sirs

I am needing to combine the local terrestre antenna with a (VHF or UHF) modulator on single cable. The modulator carries the CCTV signal from a multiplexer circuit.

How to do it ?

And how to project a video amplifier to VHF/UHF band in order to distribute the resulting signal to 10 differente locations ?

Thanks In Advance
Jean Fernandes

Click to expand...

To combine for different frequency signals, it should be used either duplexer or simple combiner. Here is , the most important thing is to avoid impedance mismatching and to procure isolation between signals.

For this purpose you may use lumped duplexer what has a low pass and high pass filters that are convenient combined.

Or..

Use simple ferrite combiner (or commercial TV combiners work up to 2150MHz very well ) .

To distribute TV signal on a same cable to different receptors, you should use modulators that are locked on different carriers. For doing that either use TV modulator IC ( TDA8822T of Philips, I2C Bus Multistandard Modulator) which will be very good project for you or use commercial modulator modules which are available from different brands.

If I were you , I make a project muti modulator in single case with a single microcontroller.It's a good idea..

Rgrds

combine rf signals

why bother
just modulate the cctv signal to the tv band using a simple modulator

then it can be carried along with the tv signal as a normal uhf you can if needed for cctv monitors demodulate it and use tv sets instead

to connect the modulators together use a Tpad attenuator on both outputs
followed by a standard 10 or 24 ways distribution amp
i recomend something like 150 150 150 R to give 1 db level for the distribution amps input
however most of the better dis amps come with more than one input

are are protected in a number of ways