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.

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.

Radio amateurs do this all the time. In most countries, for it to be
legal you need a radio amateur license.

Today it actually is not very difficult to receive moon bounce reflections,
because we can make very sensitive receivers and detect signals that are
below the noise, using a computer.

However, to do that you need to transmit a signal at a very stable
frequency, so that you know beforehand what will be coming back.
A microwave oven magnetron cannot really do that. It transmits a
big blob of RF at a woblling output frequency, rather than a well
defined frequency.

You also don't need that power, really. It is better to spend your
effort on a good antenna, because it helps both during transmit and
during receive, doubling the outcome of your effort.

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:

http://en.wikipedia.org/wiki/EME_%28communications%29

http://www.electronics-radio.com/art...r-propagation/
moonbounce-propagation-eme.php

etc. Google is your friend.

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.

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.

"JIMMIE" wrote in message
...
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.

As long as you can keep the microwave in the ham band it would be legal. A
number of years ago in the 73 Magazine there was an artical on converting a
microwave to a ham transmitter. Some microwaves, if not all operate
somewhere aroung 2 to 3 Ghz. You just need to make sure it is tuned to the
ham band that is somewhere in that range and you have a license above the
novice level.

There might be a number of technical resons it may or may not work.

Instead of telling you how stupid your question is - I will refer you to the FCC web site - Part 97.....

Part 97 says - no unauthroized transmissions - hence if you cannot ID your signal, you cannot transmit anywhere except 11 meters.
11 meters you are limited to no more then 3 watts AM or 12 watts PEP SSB..
No digital modes and no repeaters on 11 meters.

Second off - if licensed as an amateur - you have to follow the band plan.
You can't just pick a frequency that sounds quiet and start operating.
One amateur recently was fined for operating on 350 Mhz band, I think his fine was around $12,000.00

Third - you would need to limit your transmit power to no more then 1500 watts PEP, and you would have to have the equipment no only to measure the transmit power, but also to do a field survey - since if you had neighbors, you would have to test the exposure limits in the neighborhood.

Your records would have to be kept of when you operated and available for review by the FCC - should they come knocking on your door.
Most of the band specturm is being used for one thing or another and just because you think that it is high enough that no one would hear you, doesn't mean that someone isn't using it for something legally / commercially..

http://www.arrl.org/part-97-amateur-radio

http://www.ntia.doc.gov/files/ntia/p...3-allochrt.pdf

Channel Jumper wrote:

Instead of telling you how stupid your question is - I will refer you to
the FCC web site - Part 97.....

Part 97 says - no unauthroized transmissions - hence if you cannot ID
your signal, you cannot transmit anywhere except 11 meters.
11 meters you are limited to no more then 3 watts AM or 12 watts PEP
SSB..
No digital modes and no repeaters on 11 meters.

11 meters has nothing what so ever to do with the question.

There are many ways to ID a signal, and "unauthorized transmissions" has
little to noting to do with IDing.

Second off - if licensed as an amateur - you have to follow the band
plan.

No, you don't; band plans are voluntary.

You have to follow the FCC frequency allocations.

You can't just pick a frequency that sounds quiet and start operating.
One amateur recently was fined for operating on 350 Mhz band, I think
his fine was around $12,000.00

Irrelevant.

Microwave ovens operate at 2.45 GHz.

There is an amateur band at 2.39 to 2.45 GHz. One should probably
force the frequency down a little to be safe.

Third - you would need to limit your transmit power to no more then 1500
watts PEP, and you would have to have the equipment no only to measure
the transmit power, but also to do a field survey - since if you had
neighbors, you would have to test the exposure limits in the
neighborhood.

Not quite.

First, there are few, if any, microwave magnetrons capable of 1.5 KW so
the requirement to measure output is moot; just pick one that puts out
less than 1.5 Kw.

Second, a field survey is not appropriate nor needed for a directional
antenna pointing into the sky.

Your records would have to be kept of when you operated and available
for review by the FCC - should they come knocking on your door.

Nonsense; the US requirement for ham logging went away a long time ago.

Most of the band specturm is being used for one thing or another and
just because you think that it is high enough that no one would hear
you, doesn't mean that someone isn't using it for something legally /
commercially..

Again, nonsense as there is a ham band where microwave oven magnetrons
operate.

http://www.arrl.org/part-97-amateur-radio

http://www.ntia.doc.gov/files/ntia/p...3-allochrt.pdf

Read your own links and note the 2.39 to 2.45 GHz ham band.