Are we dying?

[Viewmaster]

There is also a different need to help beginners too....Many may be building their first NBTV on a limited budget and do not have, or cannot afford, an oscilloscope for checking the various circuit stages for correct pulse shape and amplitude. Also they may not be as 'up' on their electronic knowledge as many here are.

For these folk it would be helpful to have a list of test points.
Such as the opto fork o/p, the opto pulses into the 4064 after shaping in the 4011, the sync pulse into the 4064 from the sync seperator, o/p to the motor control ccct etc etc.

Each point to have what voltage might be measured, say, on an AC voltmeter and what the sound should sound like when injected into a small amplifier and loudspeaker. ...maybe a few audio files of the correct sounds?

Agreed, all this is 'very' rough and ready but it might help beginners to find any initial obvious faults.

For those with a 'scope' a set of scope pictures would help them too, without searching the forum for such things.

It just needs someone whose NBTV is running perfectly(!), to put a meter across a few points and print the results in a suitable place for beginners to see.

Also the club PCBs not being those shown in the handbook is a real turnoff for beginners as the Dr mentioned......it certainly greatly confused me last year when I started.
Albert.

[Steve Anderson]

You cannot expect from a starter to read the hole forum first.

Agreed, and seeing it from that perspective the prospect can seem quite daunting. Especially as time goes on and threads get longer or go off at a tangent. A consice guide to to getting ones first televisor going with the minimum hassle is now I feel vital. Preferably with an index of where to get the bits required which in a few places are a little specialized.

The club produces the CDs which is an excellent starting point when you have no source of test signals, plus on this forum there is a section for sound files (NBTV flavour) as a source, the rest needs filling in.

What might be an insiration to newcomers is to be offered a kit, just as in the old days, which as a minimum includes the parts which are not off-the-shelf, plus perhaps an option for an all-inclusive version. This would require quite an expenditure of effort on someones part.

It would require research into a reliable source of parts of known specification and should be available for at least a decade and at a sane price. In the UK this would mean Farnell, Cricklewood Electronics and to a lesser extent Maplin and RS.

For the mechanical parts there's quite a few around and here's a link worth following for tools too..

http://www.ifwtech.co.uk/g3sek/in-prac/components.htm

I used quite a few of the above when I was in the UK a couple of years ago and found the reports quite accurate.

With the headaches many have found what is needed is a 'standard' motor, disc and mechanical drive arrangement that is matched to a similarly 'standard' drive circuit. Which has to use minimum parts and be easy to fault-find with just say a multimeter. That's quite a tall order.

Steve A.

Albert, our posts have crossed, but you're quite correct...

[Phil Hunter]

I think the Forum is an excellent communication method and should stay in it's present form, the NBTVA is a "Broad Church" with many varied directions of interest - some technical - some not, the forum has allways reflected and encouraged this.
Some drop off of input is inevitable - but the ammount of material now available is very impressive and a testiment to the commitment of all contributers.
I am certain many the guests to the site have come away with information that would have been denied otherwise (An excellent "shop window" for the NBTVA)
It can be daunting (or feel daunting) as a newcomer to post an article onto the forum - given the fantastic technical input by many of the contributers however the support given to users asking questions has allways been excellent.
Keep up the good work !

[AncientBrit]

Dying forum, I certainly hope not?

I may not have posted much recently but I have been following the collaborative efforts of the two Steves on the Luxeon 80 line project with great interest.

I tend to keep quiet if I don't have anything to contribute. In this case I listened and learned. (I downloaded Steve A's PMT cicuits, they certainly will be of use!)

And I admire Steve O's perseverance with the construction.

I doubt if this type of venture would have been possible through snail mail. And it would have taken about 3 years if published in quarterly issues.

So well done guys.

At the moment I'm writing software. Just finished a utility to analyse and view WAV files with emphasis on NBTV formats.

Regards,

GL

[NutmegCT]

A consice guide to to getting ones first televisor going with the minimum hassle is now I feel vital. Preferably with an index of where to get the bits required which in a few places are a little specialized.

The club produces the CDs which is an excellent starting point when you have no source of test signals, plus on this forum there is a section for sound files (NBTV flavour) as a source, the rest needs filling in.

What might be an insiration to newcomers is to be offered a kit, just as in the old days, which as a minimum includes the parts which are not off-the-shelf, plus perhaps an option for an all-inclusive version. This would require quite an expenditure of effort on someones part.

Sign me up as the first kit purchaser! Seriously - if there could be the "official beginner's kit of parts and instructions", I'd be first in line. I'd also be happy to serve as a "test beginner" for trying to find the parts and sources in the USA, and step-by-step photos of the assembly, if that would be helpful.

Consider - my first difficulty was searching for appropriate disk, hub, and motor. A member kindly sent me a scanned Club Sales page from the newsletter. It shows "12inch Nipkow disc 1.5 turn spiral". Is that a 32 hole disc? What does "1.5 turn" mean? I ask, as at the bottom of the page, I also read "Larger Nipkow discs (see text)" but there is no explanatory "text" to see.

I also see "Cassette motors (various)", and "gear wheels (plastic)". Are these "matched"? I'm just assuming that the wheels mount on the motor and on the disc, so I need two gear wheels, a "meshing" pair? Do I ask for a particular motor rpm and voltage?

I'm just mentioning the above as example of questions I had while trying to put together my own "kit" from the Club Sales page. Perhaps if there were a website (and/or newsletter) photo of a specific set of "parts for your first receiver", and a way to simply "purchase this collection", the beginner could get started more easily. (Aside: after reading posts here by members much more experienced than me, saying the PCBs don't match the Handbook diagrams, I'm glad I hadn't yet sent an order.)

With the headaches many have found what is needed is a 'standard' motor, disc and mechanical drive arrangement that is matched to a similarly 'standard' drive circuit. Which has to use minimum parts and be easy to fault-find with just say a multimeter. That's quite a tall order.

Steve A.

This would be incredibly helpful to get one started. Even without pre-made PCBs, just "official" circuit schematics and instructions along with the motor, disc and drive bits. To simplify, perhaps just change the online Handbook circuits and accompanying diagrams to match the available PCBs, and include current PCBs, motor, disc, gears, hub and mounts as a basis for the "kit"?

With Gary's excellent Video2NBTV to provide almost unlimited source input, and over a dozen colleagues at the Air Museum where I work interested in how this adventure is going for me, I'm still quite eager to continue the adventure.

Best,
Tom

[Viewmaster]

Consider - my first difficulty was searching for appropriate disk, hub, and motor. A member kindly sent me a scanned Club Sales page from the newsletter. It shows "12inch Nipkow disc 1.5 turn spiral". Is that a 32 hole disc? What does "1.5 turn" mean? I ask, as at the bottom of the page, I also read "Larger Nipkow discs (see text)" but there is no explanatory "text" to see.

You are going through the same heartaches I had last year. The 1.5 turn disc is for a NBTV camera plus NBTV televisor. BUT you can use it for just a 32 hole televisor.

The handbook gives constructional details for the 'combi' of both. 1.5 = 48 holes in one and one half turns of the disc as the viewer is on the RH side (using the first 32 holes) and the Camera on the LH side. (using the last 32 with a 16 hole overlap). This disc is perfectly OK for just a 32 line NBTV, the last 16 holes being unused.

I built this using both the club 1.5 turn disc and my own one in aluminium, using all the circuits in the handbook.
But when I ordered the PCB's they were for the circuits of another beastie shown on the NBTVA website.
So I built all the handbook ccts on veroboard.
Confused? Join my club!

I also see "Cassette motors (various)", and "gear wheels (plastic)". Are these "matched"? I'm just assuming that the wheels mount on the motor and on the disc, so I need two gear wheels, a "meshing" pair? Do I ask for a particular motor rpm and voltage?

Just use a small Cassette motor driving the Disc by a decent rubber belt.
I don't use any gears.
'(various)' probably means different designs are sold BUT they all do the same job so don't worry about 'various'
The disc bearing can be the drum taken out of an old VHS machine...they are about 2" dia. The belt drives these drums which has excellent bearings, (that is why it is used for NBTV) You will need to carefully mount the disc on the drum face so that it runs true and on centre...else your NBTV picture will wobble or the disc will hit the opto fork etc.

I'm just mentioning the above as example of questions I had while trying to put together my own "kit" from the Club Sales page. Perhaps if there were a website (and/or newsletter) photo of a specific set of "parts for your first receiver", and a way to simply "purchase this collection", the beginner could get started more easily. (Aside: after reading posts here by members much more experienced than me, saying the PCBs don't match the Handbook diagrams, I'm glad I hadn't yet sent an order.)

Just to recap...if you are a dab hand at vero construction you can build the handbook ccts. If not, buy the club PCB and go for the other beastie.
BUT bear in mind that if you go for the handbook cct and have no interest in the camera side then you no need to build the sync adding cct.

I hope that this helps you a little. Don't be put off by your initial problems, as watching a NBTV in a darkened room is an experience never to be missed.

Now it wouldn't surprise me to find that someone tells me that the PCBs in the handbook are still available!

Albert.

[gary]

I don't think the gears are meant to be used as a gear train (i.e. meshed), this is rarely done in NBTV due to the noise created, although Peter Yanczer, for one, has done it to provide a right angle dog leg for a compact camera.

I believe the purpose of these gears is just to provide a cheap hub for mounting the disk directly to the motor. Having a belt drive is recommended, however, where a higher torque is needed, and, I would expect, that electronic speed control is easier with a speed reduction via the belt. I have noticed, however, that some experienced members think that a belt drive reduces speed accuracy. Having a belt drive increases build difficulty to some extent, and, direct drive does work, so is often the first method used.

PS, so yes, I think the gears do match the motor shafts, at least the ones I have bought in the past (~10 years) did. I also bought a brass hub, made from some kind of pipe fitting, which is a better option, in my opinion, but I am not sure they are still available.

[Steve Anderson]

Well, from the above I can only conclude things are alive and well which is great news.

The conclusion I come to is that we wish to attract new members, it's perhaps we're not that good at it. Potential members quite understandably might be put off with things like PWM, PMT's and the mention of 1000V when there is no mention of a safe and easy way to get started.

A seperate section on 'How to get started' or 'NBTV is as easy as 123' is needed. This would deal solely with beginners issues, requests for information and a 'library' which cannot be posted to, much like the reference section in a public library. But I don't wish to make the forum difficult to navigate.

I think the aim should be to get a consise handbook together which not only directly refers to the 'kit', but NBTV in general, much like the current handbook.

If no-one beats me to it I'll start a new thread to deal with these two issues.

Steve A.

[Ralph]

The Internet lends itself to hosting forums from the very large to the small and specialized. It doesn't get any more specialized than what we do here. I also belong to some specialized stereo photography groups. Each has tended do be very busy when they first come on line and then they drop to a lower but sustained level of activity. Often the activity pattern is episodic. It is simply indicative of the demographics, not a symptom of terminal illness.

I think the forum has a solid future, but we cannot expect it to be as frantic as a group devoted to motorbikes or the comings and goings of the rich and infamous.

Ralph Taggart

[Steve Anderson]

Thank you Ralph for those words of encouragement. This is the first forum that I have ever really been involved in this deeply...perhaps it shows. But I enjoy it and long may it continue.

I raised what could be seen as a depressing subject only to be told "No way". So for that I am thankful. The responses since that posting, and not just within this thread, have already multiplied manyfold.

We are getting to a stage where we (or at least I) think that 'It pays to advertise' and that's my next question, how can we raise our profile?

With the mechanical aspect to all this I would feel there might be a great repository of potential members within the railroad/railway modeling fratenaty. A lot model from Bairds era and before, it invloves electrics as well as mechanics, it involves moving parts, they'll also have the skills and tools to go with it.

If we were able to come up with a version as simple as the MUTR one perhaps we might get a few 'fish on the line'. Of course there is the 'second stage' which is where Tom is, and at this instant that's my focus.

Steve A.

[Viewmaster]

We are getting to a stage where we (or at least I) think that 'It pays to advertise' and that's my next question, how can we raise our profile?

With the mechanical aspect to all this I would feel there might be a great repository of potential members within the railroad/railway modeling fratenaty. A lot model from Bairds era and before, it invloves electrics as well as mechanics, it involves moving parts, they'll also have the skills and tools to go with it.
Steve A.

The membership per month to this forum is dropping...none this year so far.

I was prepared to write to model engineering clubs with web sites on the net, pointing out that the NBTVA exists and how exciting it is for an engineer to build his first NBTV.

But I didn't because until the handbook circuits match the club pcb's it is unfair to lead more beginners into such muddy waters.

I wrote to Chris Lewis about this when he put up the audio intro on NBTVA.

So, when a beginner such as Tom, can easily be introduced into a logical
system of circuiits and pbs I will bide my time.
Albert.