Frank,

Thanks for the advise.

Obviously if it was trivial to modify magnetrons for communications in the
13 cm S band, there would be a lot of high power activity on that band and
fewer dead microwave ovens in landfill sites.

Surely a near KW of radio energy can be used for more than re-warming
left-overs. Maybe not.

Thanks for the advise.

Obviously if it was trivial to modify magnetrons for communications in the
13 cm S band, there would be a lot of high power activity on that band and
fewer dead microwave ovens in landfill sites.

Surely a near KW of radio energy can be used for more than re-warming
left-overs. Maybe not.

No problem, glad to help. It still might be interesting to plug in the
parameters to the free space radar equation, considering receiver noise
figure, and signal BW, etc.. I am sure there is data available on the
reflectivity of the Lunar surface. Of course COHO/STALO will only work if
you are receiving your own signal, so not much use if you are attempting to
work others.

As I suspected, some work has been done on the injection locking of
magnetrons; as in
http://www.lancs.ac.uk/cockcroft-ins...ul04/tahir.pdf
This presentation recommends an injection signal of 2% power, or 20 W in the
case of a 1 kW magnetron. I have no experience on solid state amplifiers at
such a frequency (except for TWTs), but the construction of a single loop
synthesizer using ,a National Semiconductor chip, and a Z-Communications (or
Mini-Circuits etc.) SMT oscillator is trivial. There are lots of eval.
boards available for a nominal cost. I think Z-comm. has one, but have not
priced it recently. I guess such projects are a bit impractical unless you
have a good spectrum analyzer

73,

Frank

Found the following interesting site: http://www.df9cy.de/pathloss.htm
There is a downloadable spread sheet concerning moon-bounce path loss. I
have not verified the accuracy of the spread sheet, but it looks reasonable:

From the spread sheet, if you plug in the following parameters:

Power 1 kW;
BW 3 MHz;
Antenna gain 35 dB;
Frequency 2.4 GHz
and many more, such as noise figure, etc.

The received signal will be 40 dB below the noise.

Reducing the bandwidth to 100 Hz the signal will be about 4 dB above the
noise
-- as 10*log(BW1/BW2) will confirm.

Reduction in bandwidth to between 1 and 10 Hz would seem to be desirable.
Stability required is about 0.0004 ppm, not to mention degradation due to
TCXO 1/f noise.


Frank

One consideration is that Magnetrons are NOT designed, normally for ccs
service-- they are designed for "PULSE" service, even the ovens- (duty
cycle of MUCH less then even .5) and, pulse transmissions arn't looked
favorably on many of the microwave bands any more.


Anchor wrote:
Frank,

Thanks for the advise.

Obviously if it was trivial to modify magnetrons for communications in the
13 cm S band, there would be a lot of high power activity on that band and
fewer dead microwave ovens in landfill sites.

Surely a near KW of radio energy can be used for more than re-warming
left-overs. Maybe not.

"Jim - NN7K" wrote in message
m...
One consideration is that Magnetrons are NOT designed, normally for ccs
service-- they are designed for "PULSE" service, even the ovens- (duty
cycle of MUCH less then even .5) and, pulse transmissions arn't looked
favorably on many of the microwave bands any more.

Sorry if I am repeating stuff that you may have seen before, but I have
noticed things that do not seem to add up. For example the paper at:
http://www-personal.engin.umich.edu/...aes_tps04.pdf;
Shows the CW output of the magnetron spectrum as -10 dBm. Since for the
output is monitored via a 30 dB coupler, and a 30 dB attenuator I would have
expected the amplitude to be 0 dBm. It is hard to imagine such testing
being done with a grossly overheated magnetron. Having observed the output
of a microwave oven on a spectrum analyzer, it did appear to be pulsed,
although the spectrum was more characteristic of a frequency hopping (or
swept) signal.

Frank