[TenTec] Hercules 444 amp

[Douglas via TenTec]

 Date: Sat, 9 Aug 2014 10:12:45 -0400
 From: Brian Carling <bcarling at cfl.rr.com>
 To: "k9yc at arrl.net" <k9yc at arrl.net>,   
 Discussion of Ten-Tec Equipment
     <tentec at contesting.com>
 Subject: Re: [TenTec] Hercules 444 amp
 Message-ID: <86F80EE5-1044-42AA-9641-D8859123467B at 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
 
 ------------------------------------------------------------

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