Museum TV installation

[ppppenguin]

Photo of some the bits that will go into the new Freeview rack at the Vintage Wireless Museum. The one I built a while ago is a bit of an abortion so time for a better job. The skilled wood and metalworkers here at GVR will likely be appalled but unless somebody is volunteering it's yours truly doing the work.

The idea is to stack 3x Freeview boxes to give BBC1, ITV and BBC2 all available simultaneously. Freeview boxes aren't entirely reliable so it will be easy enough to pull one out and replace it. The sizing (2" high gap between shelves) and full rack width is ample to take just about any box we're likely to find. A Poundland 3 way mains block will be hooked up to the IEC inlet. Each box will have a pair of Scarts feeding dual audio/video Phonos/BNCs on the back panel. The aerial inlet is an F barrel from which a co-ax will be looped to each box.

At the moment the shelves will be offcuts of laminate floor supported on bits of 2"x1" batten. The whole thing needs to come in at under 7" high, or 4 rack units. Since the boxes run quite warm the 2" gaps should give adequate ventilation.

If anyone can think of a better method of doing the shelves that's easy for a wood/metal bodger like me then please say.

[pwdrive]

Presumably it's the one rack unit as shown with the three "shelve" units stacked on it?

Lawrence.

[ppppenguin]

It's actually a 2U rack shelf kindly donated to the Museum. It will be the bottom shelf and I'll build 2 shelves above it. I had some scrap laminate flooring which seems like a good shelf material. Not too thick, easy to work and feels rigid over that length. The excess space to the side of each Freeview box will be ideal for storing the remote controls.

The 2 photos show different stages of the TV installation rebuild. Originally all the kit was housed in the house, in the analogue standards converter cabinet. Since Gerry's death last year there's been a lot of re-organisation. The analogue converter (CO6/501) has now gone to another museum where I hope it will be displayed one day. Part of the refit has been moving the TV head end to the sheds. The first pass needed to be done in a hurry and is basically a pile of kit. The current version is fitted in a wooden rack cabinet. This started life as a custom built unit for the BBC. I cut it down in all 3 dimensions to make it fit the available space.

You can see the current and horrible Freeview box assembly in both photos.

[Terry]

Ah, yes! The second one shows off your 'bit of firewood' ventilation separator for the stacked Freeview boxes very well!

If it helps, I think I may have some rack shelf supports somewhere. These are ali sheets bent into a right angle that are intended to be bolted inside a 19" rack and protrude about 10cm into the rack on either side. They were intended to support heavy items prior to them being mounted in the usual way. Your laminate shelves could be either fixed to them or allowed to slide in and out, if you prefer.

If they sound suitable, I'll have a rummage when I get home next week.

Terry

[ppppenguin]

Terry, not sure about your rack support shelves. Can't quite picture them at the moment.

I've built the simple shelf unit with bits of 2x1 and laminate floor. Here's a front view with some random Freeview boxes. A coat of paint might be nice but hardly essential. Everything else will disappear behind this. All cable terminations will be on the panel you saw in my first post.

[ppppenguin]

A view from the back. The back panel is clearly visible. 3 sets of audio/video connections, the F barrel for the aerial and the mains block temporarily fixed.

Main job now is making up some a total of 6 cables to run from the tuners to the signal sockets. I've got plenty of Scart-Scart cables so I'll butcher some to get the bits. The co-axes in the Scart cables may be a bit thin to be used reliably so I'll probably use just a pair of medium thickness co-xes from each Scart to its BNC/phono pair. Left and right channels will be combined with a pair of resistors. Value is not critical, probably 1K.

PS: It's nice not having to worry about picture re-sizing. Though I would try not to post any huge image files.

[pamphonica]

Jeffrey,
If you need any more of the metal rack shelves I think I have some tucked away. Just shout.
Jeremy

[ppppenguin]

Thanks Jeremy. I have a stock of 2U rack shelves thanks to a guy who I met at Gerry's memorial party. He lives near Brian Cuff which is why I collected them at the last get together.

I know I've built out the unit to 4U high but it's mechanically OK.

[Terry]

Having looked at your pictures, I'm not sure that the supports I mentioned would be of any assistance.

One observation, though. Might I suggest that you screw both shelves to another sacrificial piece and drill lots of ventilation holes through them. Some of those Freeview boxes run very hot - as you well know - and the boxes at the museum will really need as long a lifetime as possible, so the cooler they run, the better - unless you've sourced an unlimited supply of replacements!

Remember, it was you who impressed upon me the necessity to design a distribution system with a 25 year lifespan - it would be a pity if it ran out of signals to distribute after a few years!

[ppppenguin]

The vent holes are a good idea. I might even mount a small fan, run at much reduced speed, behind the boxes. Even a very gentle breeze keeps the temperature down a lot. I will also stagger the boxes, so that the middle one is at the other side from the top and bottom ones.