Convert Astro 11 m amp to 6 AM?
 

I have a couple of Astro Little Devil 11 meter amps that came out of
an estate.

Wondering of anyone ever succesfully converted one of these to 6
meters?

I'm using a Ten Tec 6 meter Transverter on my Kenwood TS-450S and
could use a little more "UMPH".

I could use a schematic showing which trim caps are input and which
are output if anyone might have one.

Terry

WB0VQP

wrote in message
...
I have a couple of Astro Little Devil 11 meter amps that came out of
an estate.

Wondering of anyone ever succesfully converted one of these to 6
meters?

I'm using a Ten Tec 6 meter Transverter on my Kenwood TS-450S and
could use a little more "UMPH".

I could use a schematic showing which trim caps are input and which
are output if anyone might have one.


Terry -

10 meters is 28 to 30 MHz and 6 meters is 50 to 54 MHz.

IF this is the Astro that uses the sweep tubes that are now $ 40 to $ 50
each ... Don't bother.
That is a money pit solution ... and sweep tubes if they do operate at 50
MHz have low output.
Most 11 meter amps were built fast and cheap for a quick buck.
At best - it may be a candidate for parts.

You have probably heard that there are suitable CB amp candidates for six
meter conversion;
the problem is, this will be very model-specific and NO general statement
really applies.

If the original design was truly linear (not just by virtue of a label, but
by virtue of correct electronic bias
and stabilization circuitry) and used devices rated for operation ABOVE 50
MHz,
chances are it can be converted by changing the input and output tuned
networks,
and possibly the RF decoupling circuitry (DC power to devices).

For solid state amplifiers that I see everywhere now that the sunspot cycle
is again down,
when suitable 50+ MHz transistors are used, simply looking those devices up
in their manufacturer's
data book (or application notes such as Motorola's) will reveal an actual,
tested and proven
50 MHz amplifier circuit which would be easy to copy.

IF the only circuit published by the device manufacturer is for an amplifier
operating below 30 MHz,
that's a pretty good sign the devices won't provide any gain at 50 MHz...

BTW, a good 6 meter yagi (which is very easy to build and much smaller than
10 meter beams)
will yield more dB increase for less dollars than the amplifier.

Greg
w9gb

wrote in message
...
I have a couple of Astro Little Devil 11 meter amps that came out of
an estate.

Wondering of anyone ever succesfully converted one of these to 6
meters?

I'm using a Ten Tec 6 meter Transverter on my Kenwood TS-450S and
could use a little more "UMPH".

I could use a schematic showing which trim caps are input and which
are output if anyone might have one.


Terry -

10 meters is 28 to 30 MHz and 6 meters is 50 to 54 MHz.

IF this is the Astro that uses the sweep tubes that are now $ 40 to $ 50
each ... Don't bother.
That is a money pit solution ... and sweep tubes if they do operate at 50
MHz have low output.
Most 11 meter amps were built fast and cheap for a quick buck.
At best - it may be a candidate for parts.

You have probably heard that there are suitable CB amp candidates for six
meter conversion;
the problem is, this will be very model-specific and NO general statement
really applies.

If the original design was truly linear (not just by virtue of a label, but
by virtue of correct electronic bias
and stabilization circuitry) and used devices rated for operation ABOVE 50
MHz,
chances are it can be converted by changing the input and output tuned
networks,
and possibly the RF decoupling circuitry (DC power to devices).

For solid state amplifiers that I see everywhere now that the sunspot cycle
is again down,
when suitable 50+ MHz transistors are used, simply looking those devices up
in their manufacturer's
data book (or application notes such as Motorola's) will reveal an actual,
tested and proven
50 MHz amplifier circuit which would be easy to copy.

IF the only circuit published by the device manufacturer is for an amplifier
operating below 30 MHz,
that's a pretty good sign the devices won't provide any gain at 50 MHz...

BTW, a good 6 meter yagi (which is very easy to build and much smaller than
10 meter beams)
will yield more dB increase for less dollars than the amplifier.

Greg
w9gb

wrote in message
...
I have a couple of Astro Little Devil 11 meter amps that came out of
an estate.

Wondering of anyone ever succesfully converted one of these to 6
meters?

I'm using a Ten Tec 6 meter Transverter on my Kenwood TS-450S and
could use a little more "UMPH".

I could use a schematic showing which trim caps are input and which
are output if anyone might have one.

Terry

WB0VQP

Here is the web link for parts

http://www.kenselectronics.com/charles/linear.htm

w9gb

wrote in message
...
I have a couple of Astro Little Devil 11 meter amps that came out of
an estate.

Wondering of anyone ever succesfully converted one of these to 6
meters?

IF you wanted to use this, I would change the tubes to the Russian GI-7B
Triode (which is rated up into the microwaves / 1 GHz)

http://www.nd2x.net/gi7b.html

http://www.nd2x.net/gi7-socket.html

http://www.nd2x.net/W4EMF.html

http://www.geocities.com/ko4nrbs/gi7bconversionrev1.doc

http://www.geocities.com/ko4nrbs/

http://www.uksmg.org/archive.htm

wrote in message
...
I have a couple of Astro Little Devil 11 meter amps that came out of
an estate.

Wondering of anyone ever succesfully converted one of these to 6
meters?

I'm using a Ten Tec 6 meter Transverter on my Kenwood TS-450S and
could use a little more "UMPH".

I could use a schematic showing which trim caps are input and which
are output if anyone might have one.

Terry

WB0VQP

Here is the web link for parts

http://www.kenselectronics.com/charles/linear.htm

w9gb

wrote in message
...
I have a couple of Astro Little Devil 11 meter amps that came out of
an estate.

Wondering of anyone ever succesfully converted one of these to 6
meters?

IF you wanted to use this, I would change the tubes to the Russian GI-7B
Triode (which is rated up into the microwaves / 1 GHz)

http://www.nd2x.net/gi7b.html

http://www.nd2x.net/gi7-socket.html

http://www.nd2x.net/W4EMF.html

http://www.geocities.com/ko4nrbs/gi7bconversionrev1.doc

http://www.geocities.com/ko4nrbs/

http://www.uksmg.org/archive.htm

wrote:

I have a couple of Astro Little Devil 11 meter amps that came out of
an estate.

Wondering of anyone ever succesfully converted one of these to 6
meters?

I'm using a Ten Tec 6 meter Transverter on my Kenwood TS-450S and
could use a little more "UMPH".

I could use a schematic showing which trim caps are input and which
are output if anyone might have one.

Terry

WB0VQP

It's a non-starter, Terry. It could be done, but it is not
likely worth the effort and $. It is likely that the output
transistor(s) in the Astro won't play well at 50 mHz, and
the stray capacitance and inductance that posed no problem
at 27 mHz may drive you to distraction at 50.

Essentially, you'll need to change the input and output
tuned circuits. You won't be able to use the components
that are there now in those circuits, and you'll probably
need to change the transistor(s). And if you need to
change the transistors, you may well need to change the
"support" components that establish bias and stage
input levels.