A Philips BLV25 transistor power amplifier is shown in their
application report NCO8202, dated 1982 by H. G. van Hees in Nijmegen,
the Netherlands.
It was capable of 300 watts from 88 to 108 MHz, from 28 Volts Vcc.
The driver is BLW86 in the Philips note.
One thing to note is that the BLW25 is a bipolar power transistor and
that there is no data for Zin and Zout above 110 MHz in the
datasheets. The part is internally matched on the input to be optimal
for 88-108 MHz.
Rin rises at 110 and Xin is inductive and rising also. Rout is
falling to under 2 ohms while XL of the output is about 0.5 Ohms at
110 MHz. It is difficult to guess what they would be at 144 MHz.
To move this to 144 Mhz would require changing components and
possibly a new board layout. If yours uses coaxial lines for
transformers on the input and output, they would certainly be too
long to use at the 2 meter band and would require cutting and
shortening.
The FM modules are run in class B or towards class C mixed mode. They
would not be linear enough for SSB on 2 meters, but fine for FM
amplification. I would guess that you might get 150 watts total from
them but that is a wild guess. Good luck on the modifications, they
might be extensive for this change.
73
John
K5PRO
>From: "IT9GSF Fabio Grisafi" <fgrisafi@tin.it>
>To: <Amps@contesting.com>
To: <amps@contesting.com>
>Date: Mon, 8 Apr 2002 12:18:44 +0200
>Subject: [Amps] VHF AMPLI WITH BLV25
>
>I own some VHF FM modules with 3 BLV25 transistors. (2 finals and 1 driver).
>I can share them with some friend that helps me in modifing them to work on
>2 meters (I will send a module free).
>
>I wish to know wich power I can get from those modules and if they are OK
>for class AB operation.
>
>Best 73 de Fabio, IT9GSF.
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