Date: Sat, 9 Aug 2014 10:12:45 -0400
From: Brian Carling <bcarling@cfl.rr.com>
To: "k9yc@arrl.net" <k9yc@arrl.net>,
Discussion of Ten-Tec Equipment
<tentec@contesting.com>
Subject: Re: [TenTec] Hercules 444 amp
Message-ID: <86F80EE5-1044-42AA-9641-D8859123467B@cfl.rr.com>
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Seems like a lot of RF power transistors are similar, so it
should not be too difficult to find a substitute.
Best regards - Bry Carling
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Ah - but it is hard to find a substitute. The Ten-Tec factory can't find one.
There were only a few designs of 250 to 300 watt 50V bi-polar power transistors
made. The remaining ones are hard to get and have an HFE that is too high.
Several such transistors have been totally discontinued. Motorola for example
is out of that business. M/AComm bought some of their designs but in general
bi-polar RF transistors are considered passe. RF MOSFETS are now the name of
the game.
Per another poster: I've not had trouble with the power supply drifting upward
with temperature rise. Perhaps they solved that with compensation.
73,
Doug/WA1TUT
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