I saw the post about the YC156's, and would like to make a few comments.
I have no connection with the person advertising them, but did purchase
2 tubes from him a month or two ago.
1) The YC156 is a forced air cooled, 5 kW dissipation triode, rated at
full ratings to 110 MHz. Its designed for pulsed use, but Eiamc tell me
there is no problem in using it for CW/SSB in amateur service.
2) According to Eimac, the YC156 is identical, apart from some
electrical tests performed at Eimac, to the 3CPX5000A7 (pulsed tube). In
fact the chap at Eiamc sent me a data sheet on the 3CPX5000A7 and wrote
in pen 'YC156'. My guess is that the YC156, being for medical use, is
given a different number to prevent end users replacing it, without
going through the manufacturer of the medical equipment. There are
obvious safety reasons why this might be done - perhaps commercial ones
too!
3) The YC156 is physically identical, but electrically a bit different,
from the 3CX5000A7. In particular, the heater voltage of the YC156 is
higher (15V at 15A), and some of the capacitance's are a bit larger.
(This is of particular interest to me, as I have a 3CX5000A7 too).
4) Being for pulsed use, the YC156 data sheet does not give any
information about SSB service. The source at Eimac said that the tube
shares the same heater, cathode and grid with the 3CX15000B7. Obviously
the anode on the 15 kW tube is bigger. However, it was suggested that
the 3CX15000B7 data sheet is used as a guide to using the YC156 or
3CPX5000A7 in SSB service.
5) I've been advised by Eimac the tubes have good gain, but work best at
4.5 to 6 kV HT.
6) There are several errors on the data sheets of the 3CPX5000A7 and
YC156. Most are incorrect calculations in the metric measurements (size,
weight etc.). The imperial data is okay. There is also one 'funny' about
the cooling data, which says you need more air flow to cool the tube at
sea level if the incoming air is at 25 deg C, than if its at 35 deg C.
After scaling the 10000' data down to sea level, I conclude the 25 and
35 deg C sea level data are transposed.
If anyone is contemplating using the tube, I would be interested in
sharing ideas.
--
Dave Kirkby G8WRB
Department of Medical Physics,
University College London,
11-20 Capper Street,
London,
WC1E 6JA.
Tel: 0171 209 6406 (International +44 171 209 6406)
Fax: 0171 209 6269 (International +44 171 209 6269)
--
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