HD over RF or Cat6?

[STEALMYBUCKS]

OK,

I have been tasked with video/audio distribution at our church. We don't have super long runs (all less than 300 feet). There are a few ways to go and I just want a few more opinions and shared experiences. We are going to go HD. I just want some real life experiences/applications.

We can go Cat6 distribution with baluns.

Or we can go HD Modulators to RF.

Either way we are going to be making a sizable investment in AV distribution. I know this is really vague, but I just want a few more (non salesman) advice on this. The appealing thing about RF is that to add another source it just requires another modulator added into the RF converter, assign a channel and you are done.

I know RF only goes up to 1080i/720p, I am not too concerned about that (they both will look great), just want a few more options on the subject before I start hammering our local AV supplier for the best price possible.

[waynehoskins]

If it's for things like lobby screens, ATSC is sure attractive. The simplicity of adding another display is fabulous, especially since new televisions take that natively. Adding another source is as easy as adding another ATSC modulator into the headend world.

Twisted-pair baluns are great for single-run situations like main projectors, but to me they're less than ideal for distribution.

[petereit]

We tried baluns (FAIL!) and long-run HDMI cables (see my profile picture) but we didn't try ATSC. Eventually ended up doing it "the right way" and switched to using SDI for the long runs (anything more than 30 feet) with SDI-to-HDMI converters/HDMI distribution hubs at the ends.

If I had to do it all over again, I'd go straight to SDI cable. No question.

[luke.irves]

RF can be a headache if you dont know what you are doing, if you are trying to combine multiple rf feeds together you will need proper combiners that allow for aligning the rf modulations, if the rf modulations are out of time they might end up cancelling each other out. SDI is an easy and reliable solution,it will not be affected by hum or most other interferance, it can also carry all your audio needs, you will need to make sure that your cable is decent quality for longer runs otherwise it will start to fall apart. baluns are great if you know what you are doing and get the correct cable and converters (you really need to know what goes with what otherwise another big headache), some will require shielded cat 5/6 and some need particular ratings to be met. If you intend to run analog signals down cat5/6 cables then you need to be careful of running near power and other 'noisy' circuits.

ww.theirves.com/VideoProduction

[mcentrye]

Mark,
Can you explain how you did this? We're looking at using our youth room as an overflow room. A cable run will be probably around 300'.

We were thinking of figuring some kind of streaming method over the network.

Thanks!

[petereit]

Start by converting your analog audio/video to SDI, using something like a BlackMagic Analog-to-SDI mini-converter.

Run 300' of Belden 1505A Digital Video BNC Cable. Terminate each end of the cable with 75-ohm BNC connectors.

At your far end, convert the SDI signal to HDMI using something like a BlackMagic SDI-to-HDMI miniconverter. Run a short HDMI cable into a HDMI distribution amplifier and run quality HDMI cables to each of your flat panels.

[mcentrye]

Since we're all SD, I've never really considered SDI. After reading up on it, it looks like pretty cool tech.

Here's a question... we are looking at possibly using 2 or more rooms for overflow that are in a separate building. Both rooms have multiple screens (one has 2 LCDs and the other has 3 projectors). All are connected via VGA to their respective computers.

Let's say I want to convert our signal from our sanctuary (currently using composite for everything) to SDI (including audio). Run SDI to the second building. Is there a splitter than can used to split the SDI to the separate rooms and keep the audio? Also, once I get it to the rooms, I need to split to get the signal to the multiple LCDs/Projectors, but I also need to get the audio to the soundboard (100' between the projectors and the sound board in one room).

Ideas? Maybe this should have been a separate thread...

[jonack]

Gefen makes a box that is Component HD over cat6 with audio. We use Gefen stuff and it is as bullet proof as it comes. I think we spec'ed out the head end and 10 displays for around $2000. That is a single channel run to those so if you want more it gets way more complicated, but if you are considering SDI it's the same way. You can use this type of system for overflow use and it would just be switching the inputs to a different source at the beginning of the workflow. here is the link for the Gefen boxes I am referring to: http://www.gefen.com/kvm/dproduct.jsp?prod_id=9142

Jon

[mcentrye]

Are you using this Gefen box in a direct connect fashion or over your LAN? It looks like it supports both. Also curious if it supports cascaded switches.

[petereit]

That device just tripped my "too good to be true" flag. Before plunking down your money, I'd press hard to find some references of churches or businesses using them successfully for the same type of video distribution you're planning.

[jonack]

Unfortunately we are not using these boxes right now. We have an antiquated RF system, however I have done a demo with these boxes in a homerun setup and they work really well. Gefen is really friendly and you can call them up and talk with their tech guys about any questions you have.

As for the "too good to be true", I would just talk with Gefen about their products. We have bought a lot of Gefen boxes for different things and have actually sold other brand boxes just to "upgrade" to their distribution and conversion boxes because we believe in them. I'm not knocking what petereit is saying, just that I believe and use Gefen where I work...

[petereit]

I'm not knocking Geffen. Goodness, no. We have a few Geffen products in our chains and they are absolutely rock-solid.

My biggest concern is that 720p seems to be at the bleeding edge of these devices, which to me says that they may not scale well into your future. If you're buying these for mainly DV with a possible HD upgrade path and just need to save money for right now, then I'd say go for it. But if you're looking to make an investment with a move to HD in the future, you'd want to really put these boxes through their paces and make sure they're up to the task.