That's cool.

 

I like how it looks. "Steampunk", why not!

The spring and the copper pipe, the best details.

I like the project.

 

Thanks, the copper pipe is actually the sheath for +250 Volt DC,
and the filament supply for the magic eye.
The high tension is exposed at the base of the valve socket...
This is the only exposed high voltage above the chassis,
so I still have to look into some housing at least for the socket.
I was thinking PVC pipe cut at an angle to make a visor for the front,
and painted silver/grey with black speckles over that.

I like how it looks. "Steampunk", why not!

The spring and the copper pipe, the best details.

I like the project.

 

I got a bit of an update

This CRT is tested good, but is a bit unsuitable for the voltages it wants.
I might be able to swap it at the club for something more available.
A scope on the radio will want it's own transformer, but secondary 600-750 volt transformers
are a little out of alignment with Hammond's product range.
Getting a CRT happy with five hundred something volts would be more suitable.

The scope is going on the left side where I haven't yet extended the copper frame.
It will be done like the magic eye so high tension can be routed through copper pipe earthed to chassis.
For the magic eye I did the copper first, then routed the wire through with string
so that the wire sheath didn't have to cop the heat of soldering the copper.

I will keep it up to scratch, it needs some shield behind the magic eye to surround a live point, and make it earth if anything comes loose. I'm trying to blow a fuse if anything happens, and possibly also watch the temperature of the transformer.

 

Hello,

Would it not be possible to use a voltage doubler to feed the crt tube?
The current used by the tube will be rather low.

Bertus

 

Yes, but it's time for the second transformer anyway,
and it would be very nice if the second one could be identical to the first,
which I think it can be with the right CRT that is more common anyway.

The Hammond power transformer (modern) on it now was warmer than
I liked before even adding the extra filament of the magic eye valve.
These are much smaller than vintage transformers of the same specs,
and run hotter at the same current draw than the vintage ones.

I was hoping to use lower voltage and get away with a big resistor in the power supply:
http://www.electronixandmore.com/projects/simplescope/circuit7.gif
There is also a solid state version of this circuit which I'm inclined to go for just to make it easy to shield everything.
I should be able too also cut it down a little. It doesn't need variable ranges for example,
and only needs the internal horizontal sweep.

Hello,

Would it not be possible to use a voltage doubler to feed the crt tube?
The current used by the tube will be rather low.

Bertus

 

Here's an experiment I did over the last two nights that I'll put to permanent use

It's essentially a 359 kHz receiver for a runway beacon near me (temperature, wind, visibility, etc.)
made almost entirely from a 100 kHz station marker.
I just finished a filtered rectifier tonight to run it from the 6.3 Volt valve filament supply.

The module mixes the 100 kHz clock freq with the incoming 359 kHz signal,
and the result is 459 kHz which is close enough to make it through the 455 kHz IF filters
and IF amplifier in the radio! So it ends up a crystal locked superhet of sorts

https://www.youtube.com/watch?v=LGaQ2stU6Zc

Cheers, Art.

 

Very interesting, Art, but what am I looking at? What are the big cylinders?

As for your circuit construction I think I can improve on it. As I see it there are no protrusions beneath your board. It's sort of a case of pseudo surface mount in that you put the wires on top of the board so that the board can lay flat on a nonconductive surface. I have developed a way of surface mounting components on a copper clad board whose plastic backside can be glued to a metal surface. I'm thinking of starting a new thread to show this.

 

Yes Paul, surface mounting thru-hole components is deliberate.
I started doing that years ago to save scratching desks, and when it does come time
to box projects, the boards can be stuck flat somewhere inside the box.

The thing you are looking at is the 100 kHz oscillator that mixes the incoming
359 kHz beacon with it (it also has a two transistor amplifier).
The big metal can is the biggest crystal I've ever seen, the tube at the bottom
of the pic is a heavy duty trimmer for the 100 kHz crystal,
and the blue packages are inductors.. part of the filters for the transistor amplifier.

This needs to be connected to another AM radio, and use it's detector to work.
It either works to short the LO to stop it oscillating, or tune to a clear part of the dial.

Very interesting, Art, but what am I looking at? What are the big cylinders?

As for your circuit construction I think I can improve on it. As I see it there are no protrusions beneath your board. It's sort of a case of pseudo surface mount in that you put the wires on top of the board so that the board can lay flat on a nonconductive surface. I have developed a way of surface mounting components on a copper clad board whose plastic backside can be glued to a metal surface. I'm thinking of starting a new thread to show this.

 

Your method of construction makes sense to me. I, too, need to glue my boards to a surface and so I came up with the scheme I showed. But now, I'm thinking that boards with both sides copper clad is better in that the other side serves as a better ground plane. It could be fastened to a metal box and thus expand the ground plane to the box, too.

I like your airport receiver. Good job.

 

I've just decided to try solid copper clad board today, and use my dremel for my next circuit
It helped in my decision that the small protoboard design I would normally use isn't in stock where I get them!
You'd want to be sure the board with copper both sides is cheaper than two single sided ones back to back.. I haven't checked that!

This time though, it's just any old noise is welcome

Optional radio modules (commercial) have a meaningless name, followed by a meaningful one.
SS-AMB-2000. Solid State Beacon Receiver Module