[Amps] SD1460 BJT TSPA

[John T. M. Lyles]

We used both the TRW Bordeaux TP9383 and the Thomson SD1460 in the 
250 watt IPA stage for the Broadcast Electronics FM transmitters in 
the early 1980s. Both parts are rated for narrow band operation, over 
88 - 108 in 'class C' common emitter operation. They have emitter 
ballasting which is characterized over that range. All of the data 
sheets only included RF characteristics from 88 - 108. If you try to 
use them at lower freuquency, and also in linear operation, you are 
totally on your own, as that wasn't their intended market. There are 
no designs that I know of that used them at 6 m. I thought 70 MHz was 
middle of band I VHF analogue television?

These were early bipolar parts, with 16 amp collector current and 150 
watt output. Wouldn't it seem beneficial to use some more recent 
devices for a new design, using either VMOS or LDMOS transistors? 
Taking them out of their intended band and trying to get the matching 
right, is like shooting in the dark. Of course, if one had a trimmer 
capacitor on each element, you could eventually find a workable 
setting, but it will be narrow tuned, and possibly you will melt a 
bond wire or fry the transistor before finding the optimal spot for 
high power.

73
John
K5PRO

>Message: 4
>Date: Sat, 8 Jul 2006 07:47:13 +0200
>From: "Dick" <knaap159 at zonnet.nl>
>Subject: [Amps] TP9383 (SD1460) used in SSB amplifiers?
>To: <amps at contesting.com>
>Message-ID: <002401c6a251$f7a0d080$2102000a at ibm>
>Content-Type: text/plain;	charset="iso-8859-1"
>
>Hello,
>
>Anyone tried the TP9383 or SD1460 transistor in a class AB amplifier?
>Originally it's a 28V transistor , 150Watt max in FM-band 88-108MHz.
>
>I think it can work well on 50 and 70MHz, but can't find any
>schematics/designs with it.
>
>Anyone?
>
>73
>
>Dick, pa4vhf