On Mon, 07 Jan 2013 02:15:09 +0000, jimp wrote:

David wrote:
On Sat, 05 Jan 2013 04:02:59 -0800, JIMMIE wrote:

The beer got flowing the other day and some of my friends and I got to
BSing about the possibility of transmitting a microwave pulse and
reciving it reflected off the moon. Plans are to use a microwave oven
magnetron for the transmitter. We were wondering if this would be
legal.

No, it would not be legal to do it as you described. However, there
are lots of ways to do it legally:

And why not in the USA?

Microwave oven mangetrons operate at 2.45 GHz, which is the top of the
2.39 to 2.45 GHz band and should be trivial to pull down a little bit.

All modes are allowed in the band.

All licencess other than Novice can use the band.

Microwave magnetrons would likely have unacceptable spurs and sidelobes,
as the frequency is not very stable.

David wrote:
On Mon, 07 Jan 2013 02:15:09 +0000, jimp wrote:

David wrote:
On Sat, 05 Jan 2013 04:02:59 -0800, JIMMIE wrote:

The beer got flowing the other day and some of my friends and I got to
BSing about the possibility of transmitting a microwave pulse and
reciving it reflected off the moon. Plans are to use a microwave oven
magnetron for the transmitter. We were wondering if this would be
legal.

No, it would not be legal to do it as you described. However, there
are lots of ways to do it legally:

And why not in the USA?

Microwave oven mangetrons operate at 2.45 GHz, which is the top of the
2.39 to 2.45 GHz band and should be trivial to pull down a little bit.

All modes are allowed in the band.

All licencess other than Novice can use the band.

Microwave magnetrons would likely have unacceptable spurs and sidelobes,
as the frequency is not very stable.

Spurs are highly unlikely with a cavity based device like a magnetron.

Sidelobes are an artifact of antennas, not oscillators, unless you are
talking about modulation sidelobes which are pretty trivially dealt with
in a pulse device.

The frequency stability of a magnetron is highly correlated to the
power supply, i.e. the anode voltage.

The power supply and pulse control of an oven would be useless for any
sort of communications, so one would need to build one that pulled
the frequency down into the amateur band and provided for some sort of
modulation scheme.

The simplest modulation would be very high speed CW.

Jef wrote:


Spurs are highly unlikely with a cavity based device like a magnetron.

Sidelobes are an artifact of antennas, not oscillators, unless you are
talking about modulation sidelobes which are pretty trivially dealt with
in a pulse device.

The frequency stability of a magnetron is highly correlated to the
power supply, i.e. the anode voltage.

The power supply and pulse control of an oven would be useless for any
sort of communications, so one would need to build one that pulled
the frequency down into the amateur band and provided for some sort of
modulation scheme.

The simplest modulation would be very high speed CW.


Some years ago a local ham injection locked his microwave oven and
produced a pretty stable source in the 2.4GHZ band.

Jeff

That would be the smart thing to do if one wants frequency stability and
these days it is pretty easy to do.

In message ,
writes
Jef wrote:


Spurs are highly unlikely with a cavity based device like a magnetron.

Sidelobes are an artifact of antennas, not oscillators, unless you are
talking about modulation sidelobes which are pretty trivially dealt with
in a pulse device.

The frequency stability of a magnetron is highly correlated to the
power supply, i.e. the anode voltage.

The power supply and pulse control of an oven would be useless for any
sort of communications, so one would need to build one that pulled
the frequency down into the amateur band and provided for some sort of
modulation scheme.

The simplest modulation would be very high speed CW.


Some years ago a local ham injection locked his microwave oven and
produced a pretty stable source in the 2.4GHZ band.

Jeff

That would be the smart thing to do if one wants frequency stability and
these days it is pretty easy to do.

While these technical discussions are very interesting, I can't help
feeling that most of it will go over the head of the OP. Even if he
knows nothing about amateur radio, he will by now have realised that
moonbounce is quite a specialist subject, and not something that the
ordinary man-in-the-street would be able to suddenly decide to have a go
at. If he does know about amateur radio, he probably knows this already!
--
Ian

Ian Jackson wrote:
While these technical discussions are very interesting, I can't help
feeling that most of it will go over the head of the OP. Even if he
knows nothing about amateur radio, he will by now have realised that
moonbounce is quite a specialist subject, and not something that the
ordinary man-in-the-street would be able to suddenly decide to have a go
at. If he does know about amateur radio, he probably knows this already!

Well, I have not personally used moonbounce but I have visited a moonbounce
station back in the late seventies and I sometimes read about moonbounce
as it is today, and I get the impression that it has become a lot
easier for the average ham to build a moonbounce station.
It may not be for the ordinary man-in-the-street and probably also
not for the ordinary novice radio amateur, but someone who can read
and think and is not without money should be able to assemble a
JT65 moonbounce station. Back in the seventies it required you to
be a lunatic, have a suitable location, and a real lot of money.

Rob wrote:
Ian Jackson wrote:
While these technical discussions are very interesting, I can't help
feeling that most of it will go over the head of the OP. Even if he
knows nothing about amateur radio, he will by now have realised that
moonbounce is quite a specialist subject, and not something that the
ordinary man-in-the-street would be able to suddenly decide to have a go
at. If he does know about amateur radio, he probably knows this already!

Well, I have not personally used moonbounce but I have visited a moonbounce
station back in the late seventies and I sometimes read about moonbounce
as it is today, and I get the impression that it has become a lot
easier for the average ham to build a moonbounce station.
It may not be for the ordinary man-in-the-street and probably also
not for the ordinary novice radio amateur, but someone who can read
and think and is not without money should be able to assemble a
JT65 moonbounce station. Back in the seventies it required you to
be a lunatic, have a suitable location, and a real lot of money.

When I got my Novice many decades ago, my transmitter was a 6AQ5 xtal
oscillator and a superregen receiver, all homebrew down to the power
supplies with parts mostly from salvaged TV sets.

Given all the stuff available today, I would rank building a moonbounce
station of some sort at 2.4 GHz to be about the same order of difficulty.

On 1/10/2013 2:20 PM, Rob wrote:
Ian Jackson wrote:
While these technical discussions are very interesting, I can't help
feeling that most of it will go over the head of the OP. Even if he
knows nothing about amateur radio, he will by now have realised that
moonbounce is quite a specialist subject, and not something that the
ordinary man-in-the-street would be able to suddenly decide to have a go
at. If he does know about amateur radio, he probably knows this already!

Well, I have not personally used moonbounce but I have visited a moonbounce
station back in the late seventies and I sometimes read about moonbounce
as it is today, and I get the impression that it has become a lot
easier for the average ham to build a moonbounce station.
It may not be for the ordinary man-in-the-street and probably also
not for the ordinary novice radio amateur, but someone who can read
and think and is not without money should be able to assemble a
JT65 moonbounce station. Back in the seventies it required you to
be a lunatic, have a suitable location, and a real lot of money.


Yes, there is a program that works for recieved signals below the noise,
does all the work for you, and lets you run as low as 100 watts with a
single decent yagi on 2m.

It also looks up calls from a built in database and is wrong often
enough that most real EMErs with an ounce of respect won't use it. Many
logs submitted show QSOs with people not on the air.

There is nothing like actually hearing the signal.

tom
K0TAR