|
|
Post by wvengineer on Jan 9, 2016 0:29:29 GMT
I need some help. I have a camera that I want to use as a baby monitor. The camera is wireless to a receiver, that connects via mono RCA plugs (yellow and white) to a TV to watch the camera. I would like to be able to watch that monitor on any TV in the house. I got an RF modulator to take the RCA jacks to coax. My current system is as follows: Cable in the house -> RF amp -> 8-way cable splitter -> Cable modem & 4 TV's So far where ever I put in the RF modulator, it interferes with the modem. It can't connect to the ISP servers. It can get down-link, but it can't establish an up-link connection. I have tried the following setups: Cable in the house -> RF amp -> RF Modulator -> 8-way cable splitter -> Cable modem & 4 TV's Cable in the house -> RF Modulator -> RF amp -> 8-way cable splitter -> Cable modem & 4 TV's Cable in the house -> RF Modulator -> 8-way cable splitter -> Cable modem & 4 TV's\ Any recomendations on how I can set this up to work for me? So far the only option that lets the internet work is not having the RF modulator in there at all. |
|
|
|
Post by GTCGreg on Jan 9, 2016 3:37:17 GMT
Here's the setup I used to connect up 4 security cameras so I could view them on any TV. This was before my cable provider went all digital. Channels 90 through 98 were not being used on the cable system, so that's where I set the 4 camera channels. I didn't want my camera signals leaking back out into the cable system where the neighbors could see them, so I added a band stop filter as shown. I purchased a stop filter tuned to block cable channels 90 through 95. The distribution amplifier is really just an amplifier and 5 way splitter combined into one unit. The only thing unique about it is it has to pass signals both ways because the cable boxes have to be able to talk back to the cable provider's head office. They do this on one of the unused lower 100's channels. This system worked great for about 5 years after which my cable provider went all digital. After that, the cable boxes would no longer tune to any unused frequencies. At that time, I switch over the security system to an 8 channel DVR and internet interface. I can no longer call up the cameras on the home TV's but I can view them from anywhere on my cell phone or laptop computer. The DVR also records all 8 channels and stores the video for about 3 weeks. Attachment Deleted |
|
|
|
Post by silverdragon on Jan 9, 2016 10:24:02 GMT
Some steam-punk suggestions that may work or may not...
An old VCR with those inputs for external may help, plug that into the usual RF areal supply to the house, presuming you have one of course, and that you dont use it for TV reception, presuming you now have digital TV's, then tune your TV's to channel [0] to see the vcr output?...
If you get to the stage of having to buy extra equipment, I have an idea that may work...
Get some Raspberry pi's, and get them WIFI enabled.
Set up one single WIFI that is NOT internet connected. (And also secure...) separate to your usual internet WIFI network.
Connect camera's to the Raspberry inputs and use the apps you can get to share via WIFI, have the one on the back of [Any} tv tuned in to that WIFI.
OR....
Just share via your usual home network, but set up in your WIFI router firewall that that one single MAC address is prohibited from any internet communication outside your own home network, if your router allows that.
On that, I have had to set up a WIFI connection just for my TV, in that it cant see my usual WIFI router, and I now use that network and that alone to stream from mobile devices to my TV, and that router is hard-wired into the back of the usual router.
As long as two WIFI systems are not on the same channel, this will work just fine.
As the password for that network is only known by ME, it also stops my kids from messing with the TV from other rooms "For a laugh"....
|
|
|
|
Post by wvengineer on Jan 9, 2016 12:55:02 GMT
Greg, I think I may be able to use part of that.
I am thinking about installing a 1:2 splitter for the modem before the RF modulator, that way the modem can still talk to the ISP servers and then put the camera feed (channel 3 or 4) after that. I am wondering if something in the circuitry of the RF modulator acts as a choke to permit only single direction rf flow. That would explain why the modem can't establish full duplex communication.
Now to see if i can find a 1:2 slitter laying around the house somewhere...
|
|
|
|
Post by silverdragon on Jan 10, 2016 8:31:32 GMT
Yes thats right, it sorts out the modem (Modulate demodulate) problems of RF signals input to whatever the receiving end can "see", but is not designed to work both ways. This sort of explains it better if you need it?... en.wikipedia.org/wiki/RF_modulatorI have a large axe that you can borrow?.. its a hand axe sharpened to (beep) but can slit logs like no other?...  |
|
|
|
Post by wvengineer on Jan 10, 2016 12:40:13 GMT
I have a large axe that you can borrow?.. its a hand axe sharpened to (beep) but can slit logs like no other?... Great! However, I think the shipping would be more than it could cost to get one here. There are some good saw and axe shops in my area. |
|
|
|
Post by wvengineer on Jan 10, 2016 13:37:30 GMT
Update:
Found another splitter laying around so my system now looks like this:
Cable in the house -> RF amp -> 2-way splitter -> RF Modulator -> 8-way cable splitter ->4 TV's
-> Cable modem
Internet works and camera feed works, however, now I don't get any outside cable feeds. A couple analog channels have so much interference that you can barely makeout anything and none of the digital channels works. THe camera feed comes in clear though.
Any ideas?
|
|
|
|
Post by GTCGreg on Jan 10, 2016 16:30:43 GMT
When you say cable modem, are you talking about the modem that gives you Internet service? If that's the case, I'm surprised it works at all in your current set up. My cable TV provider told me the Internet modem has to be one of the first things the Cable system "sees." If everything is working except the cable channels, what you can try is just disconnecting the camera modulator and see it the cable channels start to work. If they do, then you know that the modulator is shunting out the cable channels. If that's the case, you have to isolate the modulator. It could be that the output of the modulator is so strong that it is overpowering everything else. A simple attenuator on the output of the modulator could help. You may also be able to isolate the modulator with an active splitter. |
|
|
|
Post by wvengineer on Jan 10, 2016 21:08:00 GMT
Modem works fine like that.
I took out the RF modulator and I got the TV signals back. So I think you are right that it is overpowering the other signals. So how to to temper the RF modulator? Greg, you link to three different attenuators, what would I want to use?
|
|
|
|
Post by GTCGreg on Jan 10, 2016 22:35:26 GMT
Modem works fine like that. I took out the RF modulator and I got the TV signals back. So I think you are right that it is overpowering the other signals. So how to to temper the RF modulator? Greg, you link to three different attenuators, what would I want to use? I'd start with the one with the highest attenuation first. -12dB. If you don't get a strong enough signal from the modulator with that one in line, try the -6dB one. If you need more attenuation than -12, you can put two in series. A -12 and a -6 will give you -18dB of attenuation. They're cheap enough, order one of each and then you can play around with them. |
|
|
|
Post by silverdragon on Jan 11, 2016 9:08:28 GMT
Modem works fine like that. I took out the RF modulator and I got the TV signals back. So I think you are right that it is overpowering the other signals. So how to to temper the RF modulator? Greg, you link to three different attenuators, what would I want to use? I'd start with the one with the highest attenuation first. -12dB. If you don't get a strong enough signal from the modulator with that one in line, try the -6dB one. If you need more attenuation than -12, you can put two in series. A -12 and a -6 will give you -18dB of attenuation. They're cheap enough, order one of each and then you can play around with them. I have a couple of them hanging about, I wish it was cheep enough to be able to post them, but even though they are smaller than a pen drive, they become too bulky to go as "letter" post, so would be expensive to send... |
|
|
|
Post by wvengineer on Jan 12, 2016 3:20:55 GMT
Yeah, It would likely cost more to ship them from Brittan than I could get them locally, if I can find them locally. Don't have a Radio Shack in town any more. Looks like I will be ordering them online.
|
|
|
|
Post by GTCGreg on Jan 12, 2016 3:48:07 GMT
Yeah, It would likely cost more to ship them from Brittan than I could get them locally, if I can find them locally. Don't have a Radio Shack in town any more. Looks like I will be ordering them online. Parts Express is a pretty good distributor. After all, they sell two of my products. They are out of the Dayton Ohio area and it would probably be next day via UPS ground. |
|
|
|
Post by wvengineer on Jan 12, 2016 11:13:21 GMT
Ill be checking them out. I needs some other parts and their website looks a lot easier to navigate than digikey's.
|
|
|
|
Post by GTCGreg on Jan 12, 2016 12:29:12 GMT
Ill be checking them out. I needs some other parts and their website looks a lot easier to navigate than digikey's. Digikey is more of a high-volume parts distributor. Another one you could check out is MCM electronics. They are more in line with Parts Express for this type of thing. |
|
|
|
Post by wvengineer on Jan 31, 2016 2:47:47 GMT
How do splitter/combiner's work? Are they any different from normal splitters?
I was wondering about maybe trying something like this:
Cable in -> RF amp -> combiner -> 8-way splitter -> TVs/ Cable modem.
RF Modulator ------->
Thoughts?
|
|
|
|
Post by GTCGreg on Jan 31, 2016 3:00:36 GMT
How do splitter/combiner's work? Are they any different from normal splitters? I was wondering about maybe trying something like this:
Cable in -> RF amp -> combiner -> 8-way splitter -> TVs/ Cable modem.
RF Modulator ------->
Thoughts? A passive splitter can also be a combiner. When a 2-way splitter is used "backwards" to combine signals, there is a 3dB loss between each input and the output and a 6dB isolation between inputs. That means that some (-6dB or about 1/4th) of your signal from one input, will "leak" out the other input. -3dB (or about 1/2) of each of the two inputs will make it out the single output. As far as your idea, I don't see why it wouldn't work as long as the signal levels from the output of the RF amp and from the modulator are about the same strength. Another thing to be aware of is that, while channel 3 or 4 or whatever your modulator is outputting on, may not be used by the cable company, there may still be a lot of noise introduced on that channel that could interfere with your modulator signal. I also assume that the 8 way splatter is an active device (has a power input of some type). Otherwise there will be about 12dB loss to each TV. That's not too terrible as long as there is a strong signal going into it. If it has a power input, then it has a built in distribution amp and you have nothing to worry about single loss wise. Give it a try and see what happens. The worse thing that can go wrong is one of the signals doesn't make it to the TVs. You're not going to blow anything up if it doesn't work. |
|
|
|
Post by wvengineer on Jan 31, 2016 22:07:35 GMT
That worked! I have everything working the way I want it to. Cable modem works, I have the camera feed on channel 4 on every TV in the house and I actually have less interference on the cable TV channels then I did with previous configurations.
One question, I was looking at the 1:2 splitter I am using as my combiner and it has one port labeled "in," one labeled "out," and one labeled "tap." What does that mean?
|
|
|
|
Post by GTCGreg on Jan 31, 2016 22:52:39 GMT
That worked! I have everything working the way I want it to. Cable modem works, I have the camera feed on channel 4 on every TV in the house and I actually have less interference on the cable TV channels then I did with previous configurations. One question, I was looking at the 1:2 splitter I am using as my combiner and it has one port labeled "in," one labeled "out," and one labeled "tap." What does that mean? Those types of splitters were used by cable companies as drop points. The main cable signal was fed in the "in" and the customers drop was tied to the "tap" output. The "out" connection then went on to feed the next splitter and so on down the line. They usually had some preset reduction of signal at the tap output. It wasn't a regular 1 to 2 type splitter with equal levels on both output. The tap output was much weaker than the "out" output. If the signal levels of both the cable and modulator are where you want them to be, don't worry about it. |
|
|
|
Post by wvengineer on Feb 1, 2016 2:12:25 GMT
It actually may be better this way. AS we talked about earlier, it was behaving like the modulator was overpowering the cable signal. I have it installed on the tap connection. The tap may be working in reverse to limit the power of the RF modulator coming into the device to something reasonable and preventing it from killing the other signals.
So yea, I've got what I want, so I'll leave it alone. Guess I don't have to order the new splitter and attenuators after all.
One question. Is there anyway that the camera signal that I am putting into my household cable system is leaking out to other houses nearby? If they tune to channel 4, would they get my feed?
|
|
