# Video Monitor over Coaxial Cable



## dcolson003 (Feb 27, 2010)

We are in the process of going into our biggest production of the year. We have over a hundred performers in the show, located in 10 dressing rooms. I would like to run a video monitor to select rooms, so performers know when they need to report to our “staging” room. I am using regular camcorder and converting the output to RG-6 Coaxial Cable. We are then running the coaxial cable to the various TVs. We have only attached one TV to the system and the image is already distorted. I went out and got an amplifier from Menards and attached it to the beginning of the feed, this image doesn’t seemed to be improved with that. Does anyone have any suggestions on how to improve this system. My other plan was to run a camera over the network and pull it up on computers located in the dressing rooms. Any suggestions on this way? 

Let me know if more information is necessary and any ideas are greatly appreciated!
Thanks, 
David


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## TheDonkey (Feb 27, 2010)

For cueing, a computer/network solution probably won't work too well. With the amount of time it would take to buffer and with network lag, what people will be seeing would be about 5-10 seconds behind live.


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## ruinexplorer (Feb 27, 2010)

What kind of distortion are you getting? When you are "converting the output to RG-6 Coaxial Cable", what do you mean by that? A cable is not a signal type, but a method of passing the signal. Different types of signal can pass down a co-axial cable. Are you using a modulator to convert a composite base-band video signal?


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## dcolson003 (Feb 27, 2010)

Yes. I'm using a modulator to convert a composite base-band video signal to coaxial cable.


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## avkid (Feb 27, 2010)

Do you know all your cables are good?


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## ruinexplorer (Feb 28, 2010)

I assume that you have made sure that the modulated RF signal is the same as the channel set on your monitor. I would recommend to have both signals on channel 4 instead of channel 3, as I have always had better luck with a cleaner signal. 

What are you using for a modulator?


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## dcolson003 (Feb 28, 2010)

We purchased a big spool of the Cable, so I would assume that its good. We are cutting the cable to length and then adding the connectors on. The RF modulator we using it a simple one from Radio Shack. I did stop by and switched the system to channel 4, and it did improve the image a little better, but it still is fuzzy.


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## SHARYNF (Feb 28, 2010)

are you sure it is RG6 sometimes you will find someone selling you rg-58 which was 50 ohm old coax over ethernet cable

I would NOT do the distribution the way you are doing it

I would not use a rf converter if I could avoid it I would send composite and then put a composite distribution unit close to the first dressing room. and feed the individual rooms from there BUT that means that you would have to have control of the cabling


How are you connecting it to the camcorder are you sure you have the right connection, is there anything else feeding the coax run? if you have a cable tv run that is using this coax then using channel 4 might not work.

Sharyn


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## dcolson003 (Feb 28, 2010)

Can you buy a spool of composite cable? If so where?


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## SHARYNF (Feb 28, 2010)

If it really is RG6 75 ohm Cable then is is very good for Composite.


Sharyn


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## dcolson003 (Mar 1, 2010)

So instead of adding the twist connector, I should put on Composite connectors?


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## ruinexplorer (Mar 1, 2010)

Composite is the signal type. Instead of using the RF modulator to convert your signal, keep the signal as the base-band composite video and send that down the RG6 75ohm cable. Most likely you will need RCA or BNC connectors as opposed to the F type connectors used for connecting an antennae. You will see on the monitor an "AV" jack (which is the composite). Usually this will have a yellow RCA, but depending on the model of your monitor, it could be BNC.


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## dcolson003 (Mar 1, 2010)

So something like this? 

HDMI Cable, Home Theater Accessories, HDMI Products, Cables, Adapters, Video/Audio Switch, Networking, USB, Firewire, Printer Toner, and more!


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## SHARYNF (Mar 1, 2010)

dcolson003 said:


> So instead of adding the twist connector, I should put on Composite connectors?



The best way to go is to leave the F connectors in place (the twist connectors you refer to) and then add an adaptor that give you female rca to f connector female

F Female to RCA Female Adapter | ShowMeCables

on the tv end you well need female f connector to male rca

F Female to RCA Male Adapter | ShowMeCables

Trying to attach a standard rca connector directly to RG6 is difficult, so the f connector route works best

Check the ends of your cables and see if there is any sort of goop leaking out. A lot of the rg 6 cable being sold is from satellite or cable installs, and some of them had a projective goop added that can interfere with the termination if it is not done properly. If you can get a "cable guy" to put the f connectors on your Rg6 with their tool. The more home done connectors that push on and then screw in place tend not to work very well in the long term as they work their way loose, the Cable company versions tend to compressor in two pieces and last


The above links assume you have F connectors, the ones that have the cable center and then screw on to the connection like the antenna connection on your tv. Most RF setups use these types of connectors 

If you have BNC connectors that you would need those types of adaptors which are just inserted and lock 

in that case you would use this connector most likely at the camera end

http://www.monoprice.com/products/p...=10401&cs_id=1040116&p_id=4126&seq=1&format=2

so you do not have to have a rca to rca barrel adaptor.

So it is important to know what type of connection you have, and has it been properly installed on the cable, this also can be the source of problems
Sharyn


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## dcolson003 (Mar 1, 2010)

What is the best way to distribute all of this. I was originally planning to us Y's F connectors. Is this a good idea or do you have another suggestion? 

Thanks, 
David


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## SHARYNF (Mar 1, 2010)

If you are using y's that is your potential problem. Video is terminated at 75 ohm in consumer gear, only pro gear has the option for a loop thru, so you need a composite distribution amp

you would have to daisy chain these, so you could run to the area of first 3 and then run one line to the next location of three etc

4-Way Distribution Amplifier (Composite Video) - Smarthome

or there is a 7 way

7-Way Composite Distribution Amplifier - eBay (item 350313301553 end time Mar-06-10 12:08:35 PST)

these are on the consumer side of things

you can go more pro with

TecNec Distributing OMX-DA10XL

if you can buy off ebay, this unit looks pretty good (you just dont use the audio0

KRAMER VM-10YC Composite/S-Video Audio Distribution Amp - eBay (item 310203901107 end time Mar-07-10 18:34:50 PST)

or this one (they have 2)

http://cgi.ebay.com/Laird-LTM-CVDA2...emQQptZLH_DefaultDomain_0?hash=item335aacf850

here is a lower end unit

1x6 Composite RCA Audio Video Distribution Amp Splitter - eBay (item 270526226399 end time Mar-06-10 09:11:23 PST)

You get the idea

Sharyn


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## museav (Mar 2, 2010)

As noted, a composite distribution system requires a distribution amplifier (DA) and a separate cable run from that device to each display. An RF distribution system would require a modulator and some combination of taps and/or splitters (not 'T' or 'Y' connectors), you essentially have a backbone that you tap off of for each monitor. In both cases the signal amplification required, the appropriate cable type (typically RG-59 or RG-6) and the details of the distribution would be dependent on the actual distribution necessary and factors like monitor locations and physical relationships, run lengths, etc. For example, if you have multiple monitors located together with RF distribution then a multi-way splitter or tap may make sense, which would affect the cable run lengths and losses involved.

Personally, I think RF distribution makes sense for your application as running home run cabling for every monitor may be impractical. However, there still has to be some thought put into the system layout. Typically the first step in laying out an RF distribution system is figuring out where to put taps or splitters to serve the individual displays and where you will use single output or multiple output devices. The difference between a splitter and a tap is that a splitter literally splits the signal, each output is the same and is typically lower than the input level (-3 to -4dB for a two way split, -6 to -7dB for a four way split and so on), while a tap has one 'through' output with minimal loss (typically around -1dB) and one or more outputs with some greater loss (you select from among several tap values as required). The idea behind taps is that locations further away incur greater losses due to the length of cable and other intervening taps and splitters so in order to try to maintain the same level at all locations you use taps that insert a desired loss with the tap values or losses typically decreasing as you get further down the line. That is the general concept of RF distribution design but for a temporary setup it may not be necessary to go into the level of detail that you might for a permanent system.

It looks like Radio Shack only carries one RF modulator, RF Modulator - RadioShack.com, so I assume that is what you have. That product is apparently intended to connect a video game to a TV, the manual provides nothing on the output level, however I doubt it would drive a distribution system. I don't know what the amp you purchased is but I would guess that an RF amplifier would be required after the Radio Shack modulator.

For both RF and composite video distribution, the termination quality can be crucial. You mentioned getting a spool of cable and adding connectors. Nothing wrong with that as long as the connectors are properly terminated meaning the proper strippers and either crimpers or compression tool for the cable and connectors used. Poor terminations will result in poor image quality.

You might also have to watch where you run cable as if it is above ceilings or in cases, etc. then you may be dealing with plenum spaces. If the cable is run in plenum spaces then it needs to either be in conduit or plenum rated cable. Similar for risers between floors, that cable may need to be riser rated or in conduit.


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