Can channel buttons be put to proper use?
 

Hi

I was just wondering if TV channel buttons could actually be put to use in the way of changing channels?

I have a Hitachi CTP213, which has 8 channel selectors, 7 of which were used for watching broadcasts, and an 8th for any other inputs (VCR, games consoles etc)

I use (did use, when the TV was working properly) channel 8 for a VCR input and i’d like (if possible now) to change the channels with the ultrasonic remote, or the channel selector, and not through a TiVo box or the likes.

Thanks

Re: Can channel buttons be put to proper use?
 

Well... If you have deep pockets then yes.

As we have no analogue services any more you'll have to create your own. You'd need a modulator and set top box for each channel you'd like to watch.

Re: Can channel buttons be put to proper use?
 

They could be tuned to the same channel and an interpreter* switch the TiVo box.

*ultrasonic RX, decode re-encode and IR transmitter.

Re: Can channel buttons be put to proper use?
 

You would then need to multiplex the output from each modulator into a single input for the television's aerial socket.

Re: Can channel buttons be put to proper use?
 

I have some cheap modulator on my CCTV system that have loop through capability.

Re: Can channel buttons be put to proper use?
 

I did wonder if that would be the case, but i wasn’t sure if it would be the only way.

By this do you mean that changing the channel would also trigger the TiVos channel to change? I could see this as a possibility..

Thank you all for your replies. Much appreciated

Re: Can channel buttons be put to proper use?
 

Yes, it sounds like an interesting project for a microcontroller.

Re: Can channel buttons be put to proper use?
 

I've done it with two channels, and a band I/band III diplexer, so I suppose you could do it with five or six.
Quite a lot of duplicate equipment, though.

Re: Can channel buttons be put to proper use?
 

I think i’ll look into this when I get my TV working again, I’ll definately be interested in doing something like this.

Brigham - I wouldnt mind duplicate equipment as the cabinet the TV sits on has a lot of spare space and holes in the back for wires, so all could be kept in there, maybe have some a little bit further away if need be.

If i were to take this route, would i need only Band I and Band III diplexers or more?

Thanks for your help!

Re: Can channel buttons be put to proper use?
 

Yes there is a way and you can find some info in the link below about using the Multiview T35 which was a box produced to help out Hotels, Schools ans businesses maintain existing TVs after digital switch over. They come up from time to time buit some peoples experience has been mixed.
https://www.radios-tv.co.uk/communit...s-lives-again/
Chris

Re: Can channel buttons be put to proper use?
 

I don't think a Band I/Band III (VHF) diplexer is going to be much use here, as I assume the channels involved will be in the UHF bands.

As pichacker says, if your modulators include a loop-through capability you would simply need to chain them together. Otherwise, you will need some circuitry to multiplex together however many modulator outputs you have. Others here may be able to advise you of what that circuitry needs to consist.

Re: Can channel buttons be put to proper use?
 

The Multiview is for 625 lines Bands IV & V but has enough modulators and loop throughs to do 5 channel simultaneously you could use a Band I & II diplexer with an Aurora or Hedghog to add your 405 line signals for distribution .
Chris

Re: Can channel buttons be put to proper use?
 

Chriswood - My TV is 625 lind standard, would 405 work properly or not? (Or have i hust got confused?) also thank you for the link. I shall read that now

Dave Moll - So if there is no looping capability, i would have to make a circuit which the modulators plug into, then that circuit chooses which modulator to use for the corresponding channel?

Thank you for your help

Re: Can channel buttons be put to proper use?
 

No, you can't feed a 405-line signal into a 625-line set - or rather you can, but the set wouldn't make any sense of it. The reference to 405-line would have been in the context of a dual-standard set.

The first part is correct, but that circuit would not do anything as clever as choosing which signal to use - that is done by the tuner unit in your television. All the multiplexing circuitry does is mix the outputs together so that they are all presented to the aerial socket in the same way as they would have been when the analogue signals were received by an aerial.

I'll leave detailed description of the required circuitry to those with more knowledge in this area than I have, but it should be fairly straightforward and may not need any "active" components. In effect (and being rather simplistic), you are connecting each signal in parallel, but in a manner that will avoid unwanted interactions between each one.

Re: Can channel buttons be put to proper use?
 

Oh okay, so dual standard means it will take 405 line and 625? (I'm new to TVs)

I'd be willing to give anything a try, but I would probably need some help as to what will work, what wont, what to do and what not to do.

I think at the moment, to keep it simple, i'll keep an eye out for a Multiview T35 unless someone could tell me how to make my own?

Thanks for your help.

Re: Can channel buttons be put to proper use?
 

be careful about chaining-together a load of UHF modulators-with-passthrough: they often have relatively low-gain amplifiers to boost the 'passthrough' signal, and a chain of these can introduce significant additional noise and/or lead to overloading of the TV.

I saw this for-real some years ago in a "Video distribution system" that had been modified to include the output from half a dozen CCTV cameras so the residents could see who was at their doors. While it gave the required CCTV-functionality it totally messed-up their TV reception!

Re: Can channel buttons be put to proper use?
 

Oh, maybe a T35 is the best way to? I've seen a couple online for sale, which I could buy.

How hard would it be to make it so the TV reception isn't messed with?

I wouldn't mind too much if only 4 channels were used as BBC1 and 2 are repeated, along with ITV 1. (I can always tune the TV to pick up these channels twice, if need be.)

Thanks.

Re: Can channel buttons be put to proper use?
 

To my recollection, there were discussions here about finding a way to rig 625 Line sets to select channels from the original buttons not so long after Terrestrial Broadcasting switched from Analogue to Digit-Al [2009 in Rammy]. Same conclusion then-probaly can be done but may involve a considerable amount of work and this was from people experienced in the TV area8-\. I don't think anybody got as far as enabling 7 buttons [if at all] and some even wondered why you would do it :shrug: Whether it really enhances "originality", for example, is probaly open to question but it was an interesting question to pose in the first place. Showing people a pre-remote control era Rediffusion cable set [without any channel select buttons at all] gets an interesting response!

Dave W

Re: Can channel buttons be put to proper use?
 

Insertnamehere. If you let us know the type of TV you propose to use we could be more specific, my reference to 405 lines was a general reference if you were using a dual standard TV. I suspect if your TV dates from the 70's onward it is a pre digital 625 line set for which the Mulitview would suit and it gets over the problem of balancing multiple modulators.

Re: Can channel buttons be put to proper use?
 

I don't mind not being able to use the 7 buttons fully (As I said they're just duplicates - why is this?)

I'll have a look to see if I can find the thread(s) related to this.

Chris - I have a 1977 Hitachi 625 line single standard, UHF coverage.


I've attached a picture of the front cover of the service manual, which should also help.

Thanks