RF amplifier
 

Hi Group,

My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I need a
simple circuit to cover HF which will boost this up to 500mW. I would like to
try out the signal generator as a low power CW transmitter.

I have a few CBs around that I could use the RF amp to get me on 10 meter but I
am not sure of the drive level. I am not sure if this amp would work below 24
MHz without re-tuning.

Anyone have a simple wideband circuit that could cover 3.5 to 28 MHz?

de KJ4UO

In article ,
says...

Hi Group,

My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I need a
simple circuit to cover HF which will boost this up to 500mW. I would like to
try out the signal generator as a low power CW transmitter.

This is not something I would recommend. While the theory is that
good RF test equipment should have better spectral purity, and lack of
harmonics, than the radio gear it's testing, my experiences with Wavetek
along these lines have not been good.

Anyone have a simple wideband circuit that could cover 3.5 to 28 MHz?

My gut reaction is that "Simple" and "Wideband" do not go together
in this context as far as a clean signal is concerned. Suggest examining
the 'Radio Amateur's Handbook' and 'RF Design for the Radio Amateur' (I
think that's the title) for design considerations.

I still think that, if you want to just do a simple QRP CW
transmitter, you'd be better off going with one of the existing designs
in one of those two books (or similar such pubs).


--
Dr. Anton Squeegee, Director, Dutch Surrealist Plumbing Institute
(Known to some as Bruce Lane, KC7GR)
kyrrin a/t bluefeathertech d-o=t c&o&m
Motorola Radio Programming & Service Available -
http://www.bluefeathertech.com/rf.html
"Quando Omni Flunkus Moritati" (Red Green)

In article ,
says...

Hi Group,

My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I need a
simple circuit to cover HF which will boost this up to 500mW. I would like to
try out the signal generator as a low power CW transmitter.

This is not something I would recommend. While the theory is that
good RF test equipment should have better spectral purity, and lack of
harmonics, than the radio gear it's testing, my experiences with Wavetek
along these lines have not been good.

Anyone have a simple wideband circuit that could cover 3.5 to 28 MHz?

My gut reaction is that "Simple" and "Wideband" do not go together
in this context as far as a clean signal is concerned. Suggest examining
the 'Radio Amateur's Handbook' and 'RF Design for the Radio Amateur' (I
think that's the title) for design considerations.

I still think that, if you want to just do a simple QRP CW
transmitter, you'd be better off going with one of the existing designs
in one of those two books (or similar such pubs).


--
Dr. Anton Squeegee, Director, Dutch Surrealist Plumbing Institute
(Known to some as Bruce Lane, KC7GR)
kyrrin a/t bluefeathertech d-o=t c&o&m
Motorola Radio Programming & Service Available -
http://www.bluefeathertech.com/rf.html
"Quando Omni Flunkus Moritati" (Red Green)

My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I
need a
simple circuit to cover HF which will boost this up to 500mW. I would
like to
try out the signal generator as a low power CW transmitter.

I did something similar when I first was licenced in 2001, but I would not
recommend it now.

I used my Leader LSG-216 signal generator as a VFO followed by a 1 Watt
amplifier that I put together myself. It worked and I had several QSO's with
it, but after several RST xx8 reports I found that the signal generator had
hum modulation and some jitter. I have later learnt that this is almost
inherent in a synthesizer which covers a large frequency range. It has very
large VCO gain: MHz/Volts - change in frequency per change in voltage in
order to cover the large frequency range. But this also makes it very
sensitive to noise in the control voltage.

As a signal generator, i.e. a tool for aligning circuits and so on, this is
not a problem.


Sverre LA3ZA
www.qsl.net/la3za

My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I
need a
simple circuit to cover HF which will boost this up to 500mW. I would
like to
try out the signal generator as a low power CW transmitter.

I did something similar when I first was licenced in 2001, but I would not
recommend it now.

I used my Leader LSG-216 signal generator as a VFO followed by a 1 Watt
amplifier that I put together myself. It worked and I had several QSO's with
it, but after several RST xx8 reports I found that the signal generator had
hum modulation and some jitter. I have later learnt that this is almost
inherent in a synthesizer which covers a large frequency range. It has very
large VCO gain: MHz/Volts - change in frequency per change in voltage in
order to cover the large frequency range. But this also makes it very
sensitive to noise in the control voltage.

As a signal generator, i.e. a tool for aligning circuits and so on, this is
not a problem.


Sverre LA3ZA
www.qsl.net/la3za

"Sverre Holm" wrote in message
...
My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I
need a
simple circuit to cover HF which will boost this up to 500mW. I would
like to
try out the signal generator as a low power CW transmitter.

I did something similar when I first was licenced in 2001, but I would not
recommend it now.

I used my Leader LSG-216 signal generator as a VFO followed by a 1 Watt
amplifier that I put together myself. It worked and I had several QSO's
with
it, but after several RST xx8 reports I found that the signal generator
had
hum modulation and some jitter. I have later learnt that this is almost
inherent in a synthesizer which covers a large frequency range. It has
very
large VCO gain: MHz/Volts - change in frequency per change in voltage in
order to cover the large frequency range. But this also makes it very
sensitive to noise in the control voltage.

As a signal generator, i.e. a tool for aligning circuits and so on, this
is
not a problem.


Sverre LA3ZA
www.qsl.net/la3za



One must wonder about another "possible" problem as well. If even a fraction
of transmitted RF were to get back into the sig gen, it may upset the
balance as well causing any sort of problems. Much like when RF gets back
into a Power Supply situated close by - creates hum and so on - on the
signal. Some Sig Gens may not have enough shielding to protect from this.
Their shielding may very well prevent signals from leaking OUT when testing
from it's own source, but not designed to fight off Transmitted RF getting
back into it. I'm not saying those things WILL happen, but certainly
possible. Otherwise, the idea is interesting and I'm sure many others
unmentioned have thought of or have actually tried it. I being one.

On another note along these lines, though I didn't see it or hear it, I
heard a ham on 2 meters once who claimed to take a Bearcat scanner - a 250
model I believe.. and used it in much the same manner... I'd love to have
seen and heard it up close. G.W.

"Sverre Holm" wrote in message
...
My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I
need a
simple circuit to cover HF which will boost this up to 500mW. I would
like to
try out the signal generator as a low power CW transmitter.

I did something similar when I first was licenced in 2001, but I would not
recommend it now.

I used my Leader LSG-216 signal generator as a VFO followed by a 1 Watt
amplifier that I put together myself. It worked and I had several QSO's
with
it, but after several RST xx8 reports I found that the signal generator
had
hum modulation and some jitter. I have later learnt that this is almost
inherent in a synthesizer which covers a large frequency range. It has
very
large VCO gain: MHz/Volts - change in frequency per change in voltage in
order to cover the large frequency range. But this also makes it very
sensitive to noise in the control voltage.

As a signal generator, i.e. a tool for aligning circuits and so on, this
is
not a problem.


Sverre LA3ZA
www.qsl.net/la3za



One must wonder about another "possible" problem as well. If even a fraction
of transmitted RF were to get back into the sig gen, it may upset the
balance as well causing any sort of problems. Much like when RF gets back
into a Power Supply situated close by - creates hum and so on - on the
signal. Some Sig Gens may not have enough shielding to protect from this.
Their shielding may very well prevent signals from leaking OUT when testing
from it's own source, but not designed to fight off Transmitted RF getting
back into it. I'm not saying those things WILL happen, but certainly
possible. Otherwise, the idea is interesting and I'm sure many others
unmentioned have thought of or have actually tried it. I being one.

On another note along these lines, though I didn't see it or hear it, I
heard a ham on 2 meters once who claimed to take a Bearcat scanner - a 250
model I believe.. and used it in much the same manner... I'd love to have
seen and heard it up close. G.W.

I thought the Leader Sig Gens were free running and not very stable. Maybe
it is a new model.
If you simply want a CW TX, why not build the VFO as well?
There are plenty of designs around.
If you do want to use the RF gen , you could always follow it with a low
pass filter.

Richard


Sverre Holm wrote in message
...
My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I
need a
simple circuit to cover HF which will boost this up to 500mW. I would
like to
try out the signal generator as a low power CW transmitter.

I did something similar when I first was licenced in 2001, but I would not
recommend it now.

I used my Leader LSG-216 signal generator as a VFO followed by a 1 Watt
amplifier that I put together myself. It worked and I had several QSO's
with
it, but after several RST xx8 reports I found that the signal generator
had
hum modulation and some jitter. I have later learnt that this is almost
inherent in a synthesizer which covers a large frequency range. It has
very
large VCO gain: MHz/Volts - change in frequency per change in voltage in
order to cover the large frequency range. But this also makes it very
sensitive to noise in the control voltage.

As a signal generator, i.e. a tool for aligning circuits and so on, this
is
not a problem.


Sverre LA3ZA
www.qsl.net/la3za

I thought the Leader Sig Gens were free running and not very stable. Maybe
it is a new model.
If you simply want a CW TX, why not build the VFO as well?
There are plenty of designs around.
If you do want to use the RF gen , you could always follow it with a low
pass filter.

Richard


Sverre Holm wrote in message
...
My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I
need a
simple circuit to cover HF which will boost this up to 500mW. I would
like to
try out the signal generator as a low power CW transmitter.

I did something similar when I first was licenced in 2001, but I would not
recommend it now.

I used my Leader LSG-216 signal generator as a VFO followed by a 1 Watt
amplifier that I put together myself. It worked and I had several QSO's
with
it, but after several RST xx8 reports I found that the signal generator
had
hum modulation and some jitter. I have later learnt that this is almost
inherent in a synthesizer which covers a large frequency range. It has
very
large VCO gain: MHz/Volts - change in frequency per change in voltage in
order to cover the large frequency range. But this also makes it very
sensitive to noise in the control voltage.

As a signal generator, i.e. a tool for aligning circuits and so on, this
is
not a problem.


Sverre LA3ZA
www.qsl.net/la3za

On 04 Dec 2003 03:55:19 GMT, (PDRUNEN) wrote:

Hi Group,

My wavetek sig gen covers 100KHz to 512 MHz and puts out about 10mW. I need a
simple circuit to cover HF which will boost this up to 500mW. I would like to
try out the signal generator as a low power CW transmitter.

I'm not familiar with this particular model, but my own experiences
with other signal generators lead me to believe that they are very
poor singal sources for this type of application. The main problem
AISI is freqency drift. You may get some reasonable stability after an
hour-or-so's settling down, but many people with whom you wish to
communicate via CW will be using *very* narrow filtering and will
constantly lose your signal if they don't repeatedly re-tune.
--

"I expect history will be kind to me, since I intend to write it."
- Winston Churchill