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Topband: High power transistor for HF amp.

To: <topband@contesting.com>
Subject: Topband: High power transistor for HF amp.
From: "Bruce" <k1fz@myfairpoint.net>
Date: Thu, 5 Jul 2012 17:47:00 -0700
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Thanks, I appreciate the information.  The FM Broadcast station, that I do 
engineering, just purchased a new to the market Harris 10 KW transmitter, that 
just arrived today. Installation the next few weeks. I took special notice of 
the hot pluggable PA transistor amplifier modules using this transistor. It 
gets 70% efficiency. With stands very high VSWR .......   73 Bruce-K1FZ


 Tom,   I did not find any linear specs also, but did find a blurb saying it 
was quite linear up to a KW.  
Think will try a 900 Watt amp first, time permitting. Thank you for your 
research information. 


Jacques,  FB working with Freescale the manufacturer.. Looking like the device 
over drives at about 1 KW 
producing high harmonics, the third being trouble some.  Thank you for your 
information. 


Although they do not (or did not) publish IMD data, the single device I 
tried was acceptable at 800-900 watts PEP for SSB. They are a bit better 
than 4 x MRF150 in power, but still very similar. I'd say with correct 
heatsinking and airflow, you could make a good 800-watt plus linear 
amplifier from one.  (From Tom W8JI)



with conventional output matching networks the third harmonic distortion is 
extremely high around -7 to -8 dB ( second harmonic is OK because of the 
push pull configuration of the PA)  Jacques F6BKI 
now retired but spend my working life with TRW , MOTOROLA and 
FREESCALE RF semiconductors 



John N4NU Thank you for your email. That old linear must have been fun.
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK

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