Looking for spare tubes

[W7TFO]

The tube is a lot smaller than the cart.  The cart does not become part of the TX. 

One reason for the careful handling is the pure tungsten filaments are very long internal wires, and after any amount of use they achieve the fragility of pencil lead.

Those pure tungsten filaments were run at white hot heat, making for a wonderful display through the door windows.

Another reason was the entire 'business' part of them was suspended by a small group of welded wires just above the glass-to-metal seal, and any side inertia could snap things apart.

As tube rotation and anode cleaning was necessary for stretching the life of these, handling them was a liability.

Later power grid designs were more efficient and much tougher tubes, just not as cool looking whilst in action.

Not to say the older design wasn't successful, as station logs from where I got my 1940 WECo TX showed the finals would routinely achieve some 40,000 hours run time if properly cared for.

73DG

[Sam KS2AM]

BBC Radio 4 on 198 kc as received on a Perseus SDR in Michigan.

http://www.youtube.com/watch?v=rPLQrYBD93U