It is more than likely one of the units from the Siledis (spelling?)
project of when they held the America's Cup off Fremantle here in
Western Australia. They were pulse transmitters on 70cm. Locals were
not allowed to use the band at the time that they were racing. There
were 2 types. One had the 8938. I think that was the 60kW unit. The
other was a 20kW unit and it ran the 3CX400U7 or in some cases the 3CX600U7.
As you say, they were conduction cooled with a big beryllium disc to
conduct the heat to the heatsink.
A mate of mine fired up one of the smaller units on 70cm. I think he
still has it. Instead of its intended pulse service, he used it in
SSB mode and it worked a treat but it had to have such a huge amount
of air over the heatsink that he ended up shelving it. It just got too hot.
If we are talking about the same units, they would be difficult, if
not impossible to convert to forced air cooling.
Local hams got all the units but nobody really used them. I believe
they all would have ended up at the scrap metal dealers. We had a few
8938s which we swapped for other tubes and I think I still have one
of the 3CX400U7 or 3CX600U7 tubes floating around somewhere and I
believe I tripped over one of the small cavities at my club a few weeks ago. .
Good luck with it.
At 05:55 PM 6/05/2010, Glenn McNeil wrote:
>I have come across a 3CX1500C7 UHF Cavity, conduction cooled, which
>I am assuming is an Eimac product. The thing does not have any
>indentifying marks on it, but is in very good condition. The Guy I
>got it from tells me that he had it functioning on 70cms...does
>anyone have any knowledge of these things ?
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