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.

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.

Greg,

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.
Not totally true.

We use a THA15/SD1726 (30MHz bi-polar 150w pep) producing 220w in our FM
PA in continuous duty service in the 87.5-108MHz broadcast band.

Yes, it needs plenty of drive and the heat sink require plenty of air
but at $30 USD a hit it's one economical and rugged amp.

Here it is: http://www.transmittersrus.com/shop/powerRF220.htm

I totally agree with you on the antenna.

(((73)))
--
Philip de Cadenet G4ZOW
Transmitters 'R' Us
http://www.transmittersrus.com

Greg,

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.
Not totally true.

We use a THA15/SD1726 (30MHz bi-polar 150w pep) producing 220w in our FM
PA in continuous duty service in the 87.5-108MHz broadcast band.

Yes, it needs plenty of drive and the heat sink require plenty of air
but at $30 USD a hit it's one economical and rugged amp.

Here it is: http://www.transmittersrus.com/shop/powerRF220.htm

I totally agree with you on the antenna.

(((73)))
--
Philip de Cadenet G4ZOW
Transmitters 'R' Us
http://www.transmittersrus.com

"Philip de Cadenet" wrote in message
...
Greg,

We use a THA15/SD1726 (30MHz bi-polar 150w pep) producing 220w in our FM
PA in continuous duty service in the 87.5-108MHz broadcast band.

Yes, it needs plenty of drive and the heat sink require plenty of air
but at $30 USD a hit it's one economical and rugged amp.

Here it is: http://www.transmittersrus.com/shop/powerRF220.htm


That's odd, since the SD1450 specifications were for the commercial FM
broadcast industry (88 - 108 MHz),
and is rated at 150 watts for 18 watts drive. Price is virtually the
ame - maybe its higher for you in UK

Greg
w9gb

"Philip de Cadenet" wrote in message
...
Greg,

We use a THA15/SD1726 (30MHz bi-polar 150w pep) producing 220w in our FM
PA in continuous duty service in the 87.5-108MHz broadcast band.

Yes, it needs plenty of drive and the heat sink require plenty of air
but at $30 USD a hit it's one economical and rugged amp.

Here it is: http://www.transmittersrus.com/shop/powerRF220.htm


That's odd, since the SD1450 specifications were for the commercial FM
broadcast industry (88 - 108 MHz),
and is rated at 150 watts for 18 watts drive. Price is virtually the
ame - maybe its higher for you in UK

Greg
w9gb

Greg,

We use a THA15/SD1726 (30MHz bi-polar 150w pep) producing 220w in our FM
PA in continuous duty service in the 87.5-108MHz broadcast band.

Yes, it needs plenty of drive and the heat sink require plenty of air
but at $30 USD a hit it's one economical and rugged amp.

Here it is: http://www.transmittersrus.com/shop/powerRF220.htm


That's odd, since the SD1450 specifications were for the commercial FM
broadcast industry (88 - 108 MHz),
and is rated at 150 watts for 18 watts drive. Price is virtually the
ame - maybe its higher for you in UK
Where did you get the SD1450 from!

Check out our device he

http://www.angliac.com/st/data_from_st/2846.pdf

Give it a minute to load as it's a PDF page.

(((73)))
--
Philip de Cadenet G4ZOW
Transmitters 'R' Us
http://www.transmittersrus.com

Greg,

We use a THA15/SD1726 (30MHz bi-polar 150w pep) producing 220w in our FM
PA in continuous duty service in the 87.5-108MHz broadcast band.

Yes, it needs plenty of drive and the heat sink require plenty of air
but at $30 USD a hit it's one economical and rugged amp.

Here it is: http://www.transmittersrus.com/shop/powerRF220.htm


That's odd, since the SD1450 specifications were for the commercial FM
broadcast industry (88 - 108 MHz),
and is rated at 150 watts for 18 watts drive. Price is virtually the
ame - maybe its higher for you in UK
Where did you get the SD1450 from!

Check out our device he

http://www.angliac.com/st/data_from_st/2846.pdf

Give it a minute to load as it's a PDF page.

(((73)))
--
Philip de Cadenet G4ZOW
Transmitters 'R' Us
http://www.transmittersrus.com

"Philip de Cadenet" wrote in message
...
Greg,

We use a THA15/SD1726 (30MHz bi-polar 150w pep) producing 220w in our
FM
PA in continuous duty service in the 87.5-108MHz broadcast band.

Yes, it needs plenty of drive and the heat sink require plenty of air
but at $30 USD a hit it's one economical and rugged amp.

Here it is: http://www.transmittersrus.com/shop/powerRF220.htm
Check out our device he

http://www.angliac.com/st/data_from_st/2846.pdf

Give it a minute to load as it's a PDF page.


So you drop from 20 Gp (db) at 30 MHz to 8 Gp (db) at 100 MHz
Would not have been my choice.

BTW, is your equipment FCC type accepted for USA usage on the commercial FM
frequencies (as required)

GB

"Philip de Cadenet" wrote in message
...
Greg,

We use a THA15/SD1726 (30MHz bi-polar 150w pep) producing 220w in our
FM
PA in continuous duty service in the 87.5-108MHz broadcast band.

Yes, it needs plenty of drive and the heat sink require plenty of air
but at $30 USD a hit it's one economical and rugged amp.

Here it is: http://www.transmittersrus.com/shop/powerRF220.htm
Check out our device he

http://www.angliac.com/st/data_from_st/2846.pdf

Give it a minute to load as it's a PDF page.


So you drop from 20 Gp (db) at 30 MHz to 8 Gp (db) at 100 MHz
Would not have been my choice.

BTW, is your equipment FCC type accepted for USA usage on the commercial FM
frequencies (as required)

GB

Hello GB,

So you drop from 20 Gp (db) at 30 MHz to 8 Gp (db) at 100 MHz
Would not have been my choice.

BTW, is your equipment FCC type accepted for USA usage on the commercial FM
frequencies (as required)

Regarding the device choice. I think the designers reason for using the
THA15 is that he found a very inexpensive source for the device and he
already had a 40w exciter in production. It was a suitably inexpensive
device.



FCC approval not required if used outside the US.

We are not based in the US.

My company is a re-seller for NRG products among others.

However frequency stability, harmonic attenuation and spurious products
would probably meet type approval spec in the US. Not sure how tough
your EMC and or electrical safety requirements are but it would probably
meet those to after looking at some of the budget end equipment that has
FCC type acceptance.

I just love those Part-15 Talking House transmitters.

Does the FCC still allow self approval on certain equipment?
--
Philip de Cadenet G4ZOW
Transmitters 'R' Us
http://www.transmittersrus.com

Hello GB,

So you drop from 20 Gp (db) at 30 MHz to 8 Gp (db) at 100 MHz
Would not have been my choice.

BTW, is your equipment FCC type accepted for USA usage on the commercial FM
frequencies (as required)

Regarding the device choice. I think the designers reason for using the
THA15 is that he found a very inexpensive source for the device and he
already had a 40w exciter in production. It was a suitably inexpensive
device.



FCC approval not required if used outside the US.

We are not based in the US.

My company is a re-seller for NRG products among others.

However frequency stability, harmonic attenuation and spurious products
would probably meet type approval spec in the US. Not sure how tough
your EMC and or electrical safety requirements are but it would probably
meet those to after looking at some of the budget end equipment that has
FCC type acceptance.

I just love those Part-15 Talking House transmitters.

Does the FCC still allow self approval on certain equipment?
--
Philip de Cadenet G4ZOW
Transmitters 'R' Us
http://www.transmittersrus.com

"Philip de Cadenet" wrote in message
...
Hello GB,

So you drop from 20 Gp (db) at 30 MHz to 8 Gp (db) at 100 MHz
Would not have been my choice.

BTW, is your equipment FCC type accepted for USA usage on the commercial
FM
frequencies (as required)
-----------------------------------

Regarding the device choice. I think the designer's reason for using the
THA15 is that he found a very inexpensive source for the device and he
already had a 40w exciter in production. It was a suitably inexpensive
device.

FCC approval not required, if product is used outside the US.
We are not based in the US.

My company is a re-seller for NRG products among others.

However frequency stability, harmonic attenuation and spurious products
would probably meet type approval spec in the US. Not sure how tough
your EMC and or electrical safety requirements are but it would probably
meet those to after looking at some of the budget end equipment that has
FCC type acceptance.

I just love those Part-15 Talking House transmitters.

Does the FCC still allow self approval on certain equipment?
--

At one time, you could call the FCC Field Office and approach the situation
like FAA handled
non-commercial built planes. I do remember in the 1970s that the FCC would
provide this
approval from the Field Engineers. Many things changed in the 1980s - in
the
"name of progress and deregulation" - but I believe "self approval" was NOT
one of them.

G. Beat
w9gb

"Philip de Cadenet" wrote in message
...
Hello GB,

So you drop from 20 Gp (db) at 30 MHz to 8 Gp (db) at 100 MHz
Would not have been my choice.

BTW, is your equipment FCC type accepted for USA usage on the commercial
FM
frequencies (as required)
-----------------------------------

Regarding the device choice. I think the designer's reason for using the
THA15 is that he found a very inexpensive source for the device and he
already had a 40w exciter in production. It was a suitably inexpensive
device.

FCC approval not required, if product is used outside the US.
We are not based in the US.

My company is a re-seller for NRG products among others.

However frequency stability, harmonic attenuation and spurious products
would probably meet type approval spec in the US. Not sure how tough
your EMC and or electrical safety requirements are but it would probably
meet those to after looking at some of the budget end equipment that has
FCC type acceptance.

I just love those Part-15 Talking House transmitters.

Does the FCC still allow self approval on certain equipment?
--

At one time, you could call the FCC Field Office and approach the situation
like FAA handled
non-commercial built planes. I do remember in the 1970s that the FCC would
provide this
approval from the Field Engineers. Many things changed in the 1980s - in
the
"name of progress and deregulation" - but I believe "self approval" was NOT
one of them.

G. Beat
w9gb