As I write this, the Ham Radio Reception is about to be held at the
National Association of Broadcasters Convention in Las Vegas. This year, it
is hosted by Svetlana. Traditionally it was hosted by Eimac.
I got home from NAB last night, saw lots of neat stuff. High (or low)
definitition digital television was the major focus. In RF, transmitter
manufacturers were gathering their wagons around solid state and tube
transmitters for UHF power, since the FCC is allocating UHF (470 MHz and
up) assignments for the present analog stations in the USA. Lots of money
will be made by all.
Solid State was still more expensive, but has standardized on LDMOS
devices, in hot swappable slabs/drawers of up to 1 - 3 kW each. The
inductive output tube (IOT) is gaining momentum as the device of choice if
a tube is used. CPI/Eimac/Varian, English Electric Valve, Thomson,
Svetlana/Istok, and Litton are all in the business now with IOT's. Some of
the ones I saw are about 70 cm long, with water or air cooling fins. The
old klystron of past was nowhere to be seen. They work for digital TV or
analog, at peak powers to 25-50-even 135 kW, depending on the company
showing them. EEV had the most bottles installed I think. Interesting fact
- 55 digital TV stations are on air in the US now.
One company was running a transmitter on UHF in Las Vegas, with a Thomson
Diacrode (double ended tetrode) around 600 MHz, 12 MHz bandwidth. They
successfully aired two simulataneous transmissions, one digital, and one
NTSC analog, on adjacent TV channels, over the air, through the single
power tube.
OK, where does that leave tubes with handles? The IOTs have screw in
eyebolts for lifting.
Svetlana, Penta, and Triton Services had glass bottles. These, plus
CPI/Eimac, Burle, EEV and Thomson, had ceramic metal power tubes with
handles.
Dick Gross of D&C Electronics of Spring Hill, Florida, was showing the
Triton bottles. He had graphite plate 4-500 (yes, 500), and a pentode as
well. He said Triton of Easton, PA (old ITT/Federal tube plant) was in
production for the 3-500Z using Eimac tooling, with a graphite anode rated
for 600 W. His # is (800) 881-2374. Didn't appear to have a website. Triton
is a much bigger corporation than I expected, having a systems division, an
acquistion division, a construction division, and a lot of military
business that they bought.
The folks from Penta of Chatsworth, CA, were talking about a joint venture
with the Chinese for their 3-500Z.
John
K5PRO
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