Narrow-Bandwidth Television Association

Apologies to those waiting on further updates to this. I have a backlog of 'real work' to contend with and at the moment I'm in the UK on family related matters which have come at the wrong time...as they always do.

So stay with me, this project is a priority of mine, but now I'm away from my office/workshop there's not much I can do.

Steve A.

No Problem Steve,

I'm just getting around to testing the demodulator. Like you say it's a long term project and it give us something to do when the winter nights are drawing in.

Regards Chris Lewis.

PS where are you now in the UK?

Hi Chris, it's under my avatar, Epsom, north Surrey. I'll be here I suspect for a couple of weeks more.

However as I'm away from my office-cum-workshop and have plenty of time on my hands I have decided to knuckle down and learn Eagle - the PCB generation software as Andrew has done. It's a steep learning curve but I have managed to produce my first very simple board layout this afternoon, complete with a ground plane.

Now I need to find out how to generate the 'blocks' (AutoCad speak) for something like a microcontroler that's not in the default library. Suppliers often will have .scr files for a component, but not always - generally not the ones you really need, or in the wrong packaging- such is life.

So there is the danger that a PCB may be available for this up-converter after all - watch this space.

Steve A.

Good Luck Steve. I look forward to your progress.

I to am going to build Steve's converter gathering parts for it at the moment ,i will build the power supply and Demodulator when my project case turns up...
As i mentioned to Steve if i could it be nice to have the monitor and converter to be in the same case a bit like they use to do in th mid 70's not easy to get the right size case or 625 line monitor to fit ..just an idea .
Yes Steve take your time i to will build it when your ready .

For those contemplating building this there's very few, actually no, specialist parts required.

The exception is the two pic microcontrollers, buying blank ones is no problem but I will need to program them with the firmware. I can get them here at a better price than the UK, burn them and send them on. Alternatively if you can burn your own micros I'll e-mail the .hex file. Check your software (or whatever) can burn PIC18F25K20s with High-voltage programming. The LVP pin is used as an I/O.

Harry has had a bit of a problem with getting 8-pin DIP versions of the 23LC1024 RAM chips. He's ordered SOIC versions and some 8-pin SOIC-to-DIP adapter boards. Futurelec Australia have them, I'm sure there'll be a supplier in the UK. SOIC has a pin spacing of 1.27mm, half the usual 2.54mm (0.1"). With a fine-tipped soldering iron these can be assembled quite easily, anything smaller is a no-no for me.

It's too early to publish a parts list although some 90%+ are defined. No precision parts, Rs & Cs can all be 5% or better, make sure you have plenty of 100n disk-ceramic capacitors. I suggest using sockets for all chips, there's bound to be updates to the micros now and then.

As mentioned before, if I can get to grips with Eagle a PCB may be available too.

Steve A.

Funny enough the SOIC-to-DIP adapters turned up today i see one side does this and the other the next size down have to get my pc microscope for that one a a pin soldering iron .
Yes i went this for that size chip as the price was a bit high think i got the 5 ics for the price of one DIP version ,looked into the adapter idea and will give this a go ,should do the same job /

Conrad.de (germany) has the 23LC1024 memory chips in 8 pin DIL available. They cost € 3,21. I also found the PIC18F25K20-I/SP controller in DIL version in their catalogue. It is difficult to search there, but at the end I found them. They cost € 3,30 each. I don't know if my PIC-kit 2 can program it, I hope so. Then, if you send a HEX-file I can program it. I made in the near past a socket for 28 pin DIL versions.

I think I join in making it. The ROBOT gives rather crude pictures with its 4 bits resolution. May be this is less visible on signals coming from short-wave with their unavoidable noise, but I see it as an inhaerent drawback.

Steve,

If you email me with your temporary address in the UK I will send you monies for the PICs, postage and PCB if it is produced.

Regards Chris Lewis

Do these look OK Steve?

Regards Chris Lewis

Chris,

You could try Farnell.

Part number 2212152
Device 23LC1024-I/P
Unit cost £2.06

217 in UK stock

Cheers,

Graham

Chris, at this stage I have no idea what the boards will cost - probably the same as Andrew's Arduino televisor boards as I'll probably use the same company.

So don't fret over the cash, we'll deal with that when we get there...

Yep, those chips should be fine, As Ancient Brit pointed out, it's always worth checking out the 'big two' suppliers in the UK, they can sometimes be cheaper than e-bay and the like and you know you're getting branded full-spec devices. I bought my 23LC1024s from Farnell.

Steve A.

OK, that makes three plus myself who intend to have a bash at this, Chris, Harry and Klaas, plus myself. I'm just keeping track of quantities required for future ordering etc..

Steve A.

Steve Anderson wrote:OK, that makes three plus myself who intend to have a bash at this, Chris, Harry and Klaas, plus myself. I'm just keeping track of quantities required for future ordering etc..

Steve A.

I'll join the crowd, though I have little idea what it does :p

Andrew Davie wrote:

Steve Anderson wrote:OK, that makes three plus myself who intend to have a bash at this, Chris, Harry and Klaas, plus myself. I'm just keeping track of quantities required for future ordering etc..

Steve A.

I'll join the crowd, though I have little idea what it does :p

Great Andrew ,it will pretty much display classic SSTV and NBTV on a 625 line tv so if you have a little one handy or can find one at your reuse shop ..
I should have a few ic spares of part of it so don't buy the ic's Andrew i will let you know once you are working out the parts list .