R F Modulator question

[tallyho8]

My barn is 1/4 mile from my house on my property and years ago I installed a surveillance camera in my barn so I could keep an eye on my pregnant mare and I ran coax cable to a small tv in my house. The camera hooked up to an RF Modulator that you could set to watch it on either channel 3 or 4.

Now I would like to set up another camera in my barn using the same coax cable which is buried. I tried getting another RF modulator using a splitter and setting one camera for channel 3 and one for channel 4 so I could just change the channel on my tv to see either camera. Of course having the channels this close together gave bleed-over making the picture fuzzy. Just like in the old days when you could only get channels 2, 4, 6, 8, 10 and 12 because any channel in between those would interfere with the channel next to it.

My question, is there any type of Rf modulator sold that gets channels other than 3 and 4? If not, does anyone know a cheap fix to get these cameras working correctly.

 

[bunyip]

Wifi cameras?
I had some but my 1000metres was a bit too long, not sure what the range is on them now.

 

[s219]

Hopefully an electrical engineer will chime in (I'm an ME) but I am pretty sure you could slightly modify the components inside the RF modulator to customize the frequency, to bump it away from 3/4. They are very simple devices, I remember using and modifying them back in the 1980s for video games and VCRs. Always thought it was a cool idea.

There are some on Amazon that claim to support multiple frequencies and even UHF -- maybe that is an easier option?

https://www.amazon.com/Modulator-KKmoon-Compact-Converter-Amplifier/dp/B079JXQKQJ

 

[MossRoad]

You could try a $40 experiment.

https://www.amazon.com/Modulator-KK...earch-10&pf_rd_t=BROWSE&pf_rd_i=11042001&th=1

 

[k0ua]

Try this on.. It will do UHF channels.

Pico Digital Consumer Audio-Video RF Modulators (USM-8D) from Solid Signal

 

[k0ua]

Moral of story... Don't start down the road of old technology. While we have come up with some UHF RF modulators that will likely solve your problem, a better solution for anyone starting out and needing a solution of a distant outbuilding camera is to use an IP camera to start with. With wifi for a link between the outbuilding and the viewing building. With and IP camera system you are not limited by the number of "channels" you would be able to find an RF modulator for as RF modulators are an old dying technology. Also with IP cameras and wifi as the link you avoid the lightning strike threat of having copper cable (the coax) in the ground. IP cameras are cheap, readily available and are controllable for tilt pan and zoom all over the IP network. This is the way I would start to build out a camera network in this modern age. And you can have as many of them as you want and give them seperate IP addresses.

 

[Roadworthy]

I suspect you'll find both cameras produce composite video. Some of the old computer monitors worked with composite video as an input. The RF modulator took in the composite video and put it onto a carrier at channel three or four (your choice). It sounds as though you are combining these two composite signals and feeding them both into one modulator. You've already figured out you can't do that very well. Each camera needs its own modulator. The television can't separate them because you're putting them onto the same channel. Wireless cameras may be an option but I don't know your budget or how far they transmit. There are also internet cameras but they depend upon a nearby internet connection, be it a bridge or a router. There's nothing really wrong with the old technology - properly applied.

 

[k0ua]

As Dudley has found out, the reason for the channel 3 OR 4 switch on the old RF modulators was so you could AVOID your local channel 3 OR 4. As the FCC never put a channel 3 AND a channel 4 in the same service area. The reason for this is possibility for them to interfere with each other being adjacent AND the RF field strength not being controlled like they are on a cable closed system. Dudley has run into this problem of trying to put ONE rf modulator on channel 3 an Another ONE on Channel 4. As these are the only two choices he has with the equipment his has available. Of course there are other RF modulators available on different channels as we and others have pointed links at. But still the technology is old and there are just better ways of doing things if one was starting out to build a camera network. And that better way of doing things is IP cameras.

 

[k0ua]

Keep in mind, I am not saying for Dudley to scrap his present installation, no far from it. He already has money put into the cameras, the underground cable and the existing RF modulators. In fact if it was me, I would possibly even for reasons of economy be looking at building some RF "pads" to pad down the signal strength out of the existing RF modulators to allow the channel 3 and channel 4 to possibly co-exist and have a balanced level on the same coax. But this requires skills and or finding pre built level pads which may cost more than just buying a second RF modulator for UHF channels. All I am saying is if someone else is considering a multi camera installation than IP cameras are the way to go starting out.

 

[hawkeye08]

It has been too many years to think clearly on this, but I think the RF modulators might need to be at the camera end to send the signal down the coax on separate channels.. but I really don't know. You would need a convertor for the connector on house end to hook to tv, but not a modulator..