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'[EE]: Design for 40W broadband VHF RF no tune Powe'
2002\09\18@074123 by Russell McMahon

Design for 40W broadband VHF RF no tune Power Amplifier

ref sourced by Ken Mardle.

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2002\09\18@114804 by Jim


That is a design for a 40 Watt VHF RF Power Amplifier for
**the FM broadcast band**.

In most countries broadcasting by persons not possessing the
proper license and authorization to do this is illegal.

Don't quite take me at my word? Check out this site where
such notices of violation are posted as action progresses
against illegal/improper broadcasting (as well as other
violations of 'radio law') are posted:

And next time, *please* mention the band/freq range for which
the amplifier/device is intended for.

Incidently, this particular design has been on the web for
quite some time and is linked to from most LPFM and 'pirate
broadcaster' web sites.

RF Jim

{Original Message removed}

2002\09\18@130245 by Dan Larson

I wonder if it can be modified for use on the 6-meter HAM band?
Or, perhaps if the transistors can hack it, the 2-meter HAM band?

Just a thought....


On Wed, 18 Sep 2002 10:46:45 -0500, Jim wrote:

{Quote hidden}

>{Original Message removed}

2002\09\18@151559 by Jim

Let's look at what this design does:

o Designed to amplify the output of an exciter with an output
 power *significantly* under 1 watt
o requires +28 VDC
o capable of 20dB gain (ideally .5 W in would yield 50 W out)
o contains *no* TR relay

Let's look at the "givens" (the usual amateur gear's output
power capability, the DC power usually available and other

o Most amateur gear in the one-watt class are FM hand-held
 portable radios - with a 2 to 5W high power and 1/2 to one
 watt low power capability.
o Most FM *mobile* and even base gear output powers range from 10 W
 to over 45 W
o Any amplifier used with "unit-ized" (integral receiver and
 transmitter in one package) require a companion amplifier
 to contain the function of a TR relay to bypass the Power amp
 during receive
o Most mobile gear utilizes +12VDC/+13.8VDC power input
o Most passenger vehicles manufactured today are equipped
 with "12 V" systems

Now tet's look at what must be 'modified' for use of this amplifier
on the Six Meter amateur band (an octave lower in frequency
than the FM broadcast band - at least here in the former 13

o Complete redesign of the input matching LC network
o Complete redesign of the output matching LC network
o Complete redesign of the low-pass output LC filter (you will
 wind up with an illegal amount of 2nd harmonic coming out of
 this amplifer if this isn't redesigned!)

The bias circuit is probably usable. That's the only upside.

With the list of the above "givens", the list of items required
to be modofied for use on a band nearly an octave lower and in
light of the this design's capabilities - I see a big 'disconnect'
in any moves to simply modify it for amateur service on six ...
there are better designs with different devices that are
better suited for amateur  use.

RF Jim

{Original Message removed}

2002\09\19@091802 by Micro Eng

picon face link to the FCC.  Some major fines...20K for violations?
wow...guess we can buy a few cruise missles when they collect all those...

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