Amateur Radio

[JohnW2]

... I have one peizo crystal earpiece left, they don't seem to sell them any more ...

Kind Regards, John

 

[JohnW2]

Agree with that, but the ability to easily program the unit during manufacture reduced the cost to manufacture a wide range variants from the same hardware. It was inevitable that others would work out how to use the socket.

If there were an externally accessible socket. Programming the equipment 'during manufacture' could surely be done via some 'internal' connector/connection, not immediately accessibly by users/consumers?

Kind Regards, John

 

[Jackrae]

Yellow stuff?

I have one peizo crystal earpiece left, they don't seem to sell them any more - I find them invaluable for all sorts of things - they require so little power to drive them. One use I have for one, is to connect to a car's ABS system, should I need it - the earpieces are so sensitive they can pick up the switching click from the Hall Effect wheel sensor, as a wheel is rotated.

I used to use one for tracing mains wiring buried under plaster. Simply placed finger on one connection on the jack and dragged the tip of the jack across the plaster.

 

[JohnW2]

... did build a crystal set using a loo role and a bit of coal with the yellow stuff in ...

Yellow stuff?

Galena - a natural semiconductor

Indeed. In fact, one could even do it with a bit of 'rusty iron', since the junction between rust and iron has some diode-like characteristics (a but like the metal oxide rectifiers). One of the things we had to learn about 'back then' in order to answer potential questions in Part I of the RAE was that things like rusty joints in cast iron guttering close to our transmitting aerials could result in the generation of harmonics of our transmissions which could cause what we then called "TVI" (interference to nearby TVs)!

Kind Regards, John

 

[Jackrae]

The trusty rusty rhone pipe and guttering is still in the current syllabus

 

[bernardgreen]

The trusty rusty rhone pipe and guttering is still in the current syllabus

The science of radio transmissions is as much a black art as it is pure science

 

[JohnW2]

The trusty rusty rhone pipe and guttering is still in the current syllabus

Ah, some things don't change

Kind Regards, John