----- Original Message -----
From: "John T. M. Lyles" <jtml@lanl.gov>
To: <amps@contesting.com>
Sent: Monday, July 10, 2006 2:24 PM
Subject: [Amps] SD1460 BJT TSPA
> 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?
>
It is, however the gap at 73-74 something is allocated to radio astronomy
just before the second portion of the tv band at 76. Why on earth ( pun )
would they squeeze a weak signal hole between the two? Could it be
that the tv xmtrs play an unsuspecting yet intentional role?
Mike k1ern
> 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@zonnet.nl>
>>Subject: [Amps] TP9383 (SD1460) used in SSB amplifiers?
>>To: <amps@contesting.com>
>>Message-ID: <002401c6a251$f7a0d080$2102000a@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
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