Show Relay Distribution

[IRW]

Hey folks,

What's the best way nowadays to distribute show relay TV? In the olden days before Digital/HD/SDI/1080/999i/SuperDuperProtocolX etc, it was just a case of sticking the roof aerial into a cascade of UHF modulators that had the show relay camera(s) plugged into them, and picking a frequency not occupied by the five main channels, but having not bought a TV for about 15 years, I don't even know if they come with analogue tuners...

I'm looking to keep this simple if possible. I've got a bit of money to spend before the end of the financial year- there's already a UHF distribution network to the dressing rooms from a distribution amp in the roof, which has the show relay going into it via a basic composite - UHF modulator.

I guess what I'm looking for is (a) suggestions of small (19" maybe?) TV's known to have analogue tuners in to put in the dressing rooms that will work on the end of the existing cabling, OR a new 'something' to go in the roof to take either my composite or UHF show relay feed and turn it into a digital signal that a digital tuner  in a bog standard modern TV would pick up? Extra bonus points if there a way to inject free to air digtial TV onto the line too.

[Dave m]

You won’t find many/any old school RF input TVs these days. 
Many TVs don’t have composite either.

But you can buy DVTB modulators which would probably work with your existing cables and maybe the distribution amp.

Then you’d need small Digital TVs capable of free view which the DVTB modulator feeds, having converted your feed to a cop of a free view signal. Most have HDMI inputs which you need to supply the show on. Some have several inputs so you could have several “channels” on the show relay. 
 

There’s bound to be a bit of a delay but show relay doesn’t matter. 

[sandall]

2 hours ago, Dave m said:

There’s bound to be a bit of a delay but show relay doesn’t matter. 

It does to the sound op, if he/she is behind glass, especially if sharing a room with lighting.

[IRW]

Thanks folks...DVb-T Modulator was the key term that I didn't know! @sandall, that won't be a problem in this situation- if we needed visual relay to the box it would come straight from the composite distribution amp, rather than via the TV system.

[sunray]

1 hour ago, IRW said:

Thanks folks...DVb-T Modulator was the key term that I didn't know! @sandall, that won't be a problem in this situation- if we needed visual relay to the box it would come straight from the composite distribution amp, rather than via the TV system.

CPC used to do several but IIRC the called them something like encoders

 

EDIT: Wow I can't believe the price hike, these: https://cpc.farnell.com/antiference/dmsd02/digital-modulator-twin-sd-dvb/dp/AP02864?st=dvb modulator

were <£100, now £510+

another at £289+:  https://www.alltrade.co.uk/shop/conexer-single-sd-dvb-t-modulator

 

also available at Alltrade:  https://www.alltrade.co.uk/shop/conexer-single-sd-dvb-t-modulator  but one has to convince them you are a TV installer

Edited March 6 by sunray

[IRW]

16 minutes ago, sunray said:

CPC used to do several but IIRC the called them something like encoders

 

EDIT: Wow I can't believe the price hike, these: https://cpc.farnell.com/antiference/dmsd02/digital-modulator-twin-sd-dvb/dp/AP02864?st=dvb modulator

were <£100, now £510+

Yup, I found that one...Annoyingly I've only got one composite camera to encode...

[J Pearce]

You may find that the existing antenna cabling will support composite video. It'll probably do better with B&W but may do fine on colour - certainly worth a go if you have TVs with composite input, some new cable ends and a DA will be cheaper than a modulator.

[sunray]

If your current TV's have analogue tuners then the modulator from a VHS machine and the supplier may be pleased you take it off their hands😁

[sandall]

11 hours ago, IRW said:

@sandall, that won't be a problem in this situation- if we needed visual relay to the box it would come straight from the composite distribution amp, rather than via the TV system.

Sorry, crossed-wires🙁 - I was thinking of a using a digital TV system for audio show-relay, which would mean all word cues would have to marked-up about 2 words early!!!

[James]

Interesting thread - It reminds me I still have my old portable show relay system for village halls floating about . Modulator, DA, stacks of cabling and a number of 19" Flat screen TVs with analogue decoders. Probably need to get round to listing it if there is still a demand for this type of thing...

Nowadays If I was to start from scratch I'd probably consider something NDI based (fairly low latency, reasonable quality and can be distributed using standard network infrastructure) 

[J Pearce]

NDI is good but pricey. SDI is good but needs the right cable. CAT5 1-many boxes can be had fairly cheaply if you can site the distribution box at the appropriate switch cabinet.

We have a PTZ camera that outputs both SDI and network stream on RTSP. The locations that need low latency get SDI or composite downconverted from SDI, and the more distant spaces get screens with a NUC (recycled from other duties) or a RasPi set to load the RTSP stream on boot. 
For a cheap(ish) portable setup, you could probably happily do a wifi AP and then a set of cheap android tablets running VLC for dressing rooms and other non-latency-sensitive spaces.

[sandall]

42 minutes ago, James said:

reminds me I still have my old portable show relay system for village halls floating about

A friend of mine used to hump around a load of large CRT TVs for the local am-dram musicals, which all used an off-stage MD & band. 

[sunray]

8 hours ago, sandall said:

A friend of mine used to hump around a load of large CRT TVs for the local am-dram musicals, which all used an off-stage MD & band. 

Me, Me🤫

Initially I had 2* 21" tv's to do show relay to dressing rooms, then used 19" VGA monitors, with CV to VGA  and VGA to CAT5 adapters.

Taking one of the TV's to the tip I was really lucky someone was dumping 2* 19" flatscreen analogue TV's a few days after digital changeover and used those ever since. I tried using TV internal speakers but find it's much easier with Fostex powered speakers.