can i make a coaxial cable with two ends: BNC, and a "cable/antenna", or do i need an RF modulator?

Question

It's to connect a surveillance system's DVR to an older TV, but the DVR has only BNC outputs, and the TV has only the older "cable/antenna" input. Thanks in advance for your answers...

Answer 1

I suspect the BNCs are used in place of RCA connectors.
In that case, you will need a BNC to RCA adaptor and and RF modulator.

http://en.wikipedia.org/wiki/BNC_connector

Answer 2

You can get BNC to F connector (the TV antenna jack is not an RCA jack) adapters at most electronics part stores, Radio Shack for example. The DVR may have standard TV out if it was to be connected directly to a TV monitor. If not, you may have to run it to the TV via a VCR that has the proper RF generator built in to send the TV a signal on ch 3 or 4. I have no idea where you are going to come up with a TV RF modulator. FM modulators are quite common but one for TV may be hard to find.

Answer 3

If this is a security type DVR, it probably only has a composite video output. This won't work with older TVs that don't have composite video inputs.

You will need to buy a RF modulator, which can be purchased for around $20 US. A quick web search will reveal hundreds of sources.

If you are really cheap, try looking in a thrift store for the modulator. Many of the older video games and PC's like Commodore and TI used to use them. They would typically be a small metal box that had a RCA type phono jack on one end and a piece of twin-lead antenna cable coming out the other. If your TV is an older type is probably has a place to connect the twin-lead, otherwise you will need the small adapter that convert the twin-lead to the antenna jack.