fm modulators

[Jon Hunter]

Hello all,

How easy is it to build an fm modulator for taking composite video into a
certain "channel"? How about expense?

Basically, I have some security cameras that I need to run into a
computer (2 to start, up to 4-8 later). Since multi capture cards are too
expensive and use proprietary software that wont work under linux, I'm
thinking I can just use a TV card and rotate channels, thus giving me a
lot of room for cameras.

I was thinking I could just go buy 2 fm modulators, set one on channel 3
and one on channel 4, connect them together, and see if that works. But,
thats like $50 and only gives me 2 channels.

Anyhow, how does this sound? I've seen various schematics for fm
modulators, but I don't quite know how to apply it to my situation.

BTW I can follow a schematic pretty well, but don't know how to make
changes that might affed the rest of the circuit, so I'm guessing
something easy will be best.

Thanks in advance,

Jon

 

[michael turner]

On Wed, 17 Mar 2004 18:21:36 -0800, Jon Hunter wrote:

Hello all,

How easy is it to build an fm modulator for taking composite video into a
certain "channel"? How about expense?

Basically, I have some security cameras that I need to run into a
computer (2 to start, up to 4-8 later). Since multi capture cards are too
expensive and use proprietary software that wont work under linux, I'm
thinking I can just use a TV card and rotate channels, thus giving me a
lot of room for cameras.

I was thinking I could just go buy 2 fm modulators, set one on channel 3
and one on channel 4, connect them together, and see if that works. But,
thats like $50 and only gives me 2 channels.

Anyhow, how does this sound? I've seen various schematics for fm
modulators, but I don't quite know how to apply it to my situation.

BTW I can follow a schematic pretty well, but don't know how to make
changes that might affed the rest of the circuit, so I'm guessing
something easy will be best.

How about just using an automatic/manual external video switching box ?
These are commonly used with CCTV monitors, but there's no reason why they
shouldn't be used in conjuction with a TV capture card. Find a company
that deals with security CCTV systems.

A M20975 four-way video auto/manual switcher is Ł39 at Maplin.

Or do your system have to be a wireless one ?

--
Michael Turner
Email (ROT13)
zvxr.gheare1963@ivetva.arg

 

[Jon Hunter]

On Thu, 18 Mar 2004 07:04:04 -0800, michael turner wrote:

How easy is it to build an fm modulator for taking composite video into
a certain "channel"? How about expense?



How about just using an automatic/manual external video switching box ?
These are commonly used with CCTV monitors, but there's no reason why
they shouldn't be used in conjuction with a TV capture card. Find a
company that deals with security CCTV systems.

A M20975 four-way video auto/manual switcher is Ł39 at Maplin.

Or do your system have to be a wireless one ?

I should have clarified a bit more. I will first off be capturing from
the TV card if needed. It would be easier to control it from my computer
through various ways (remotely) and also there may be another computer,
so I could just split off the output of the fm modulators and have 2
computers that can pick which channel the want to see.

Thanks,

Jon

 

[Watson A.Name \"Watt Sun]

Jon Hunter wrote:

Hello all,

How easy is it to build an fm modulator for taking composite video into a
certain "channel"? How about expense?

Basically, I have some security cameras that I need to run into a
computer (2 to start, up to 4-8 later). Since multi capture cards are too
expensive and use proprietary software that wont work under linux, I'm
thinking I can just use a TV card and rotate channels, thus giving me a
lot of room for cameras.

I was thinking I could just go buy 2 fm modulators, set one on channel 3
and one on channel 4, connect them together, and see if that works. But,
thats like $50 and only gives me 2 channels.

Anyhow, how does this sound? I've seen various schematics for fm
modulators, but I don't quite know how to apply it to my situation.

BTW I can follow a schematic pretty well, but don't know how to make
changes that might affed the rest of the circuit, so I'm guessing
something easy will be best.

Thanks in advance,

Jon

You do _not_ want an FM modulator. You want a TV video modulator, which
is AM. They are easy to make, or buy them premade from mfgrs such as
Astec, Panasonic, etc..