Toshiba magnetron specs
Julian Grodzicky
I seek spec/data sheets for a Toshiba magnetron model no. 9M302/E3513.
I have some ballpark figures from taking the magnetron apart, making some
measurements & fudged guesses, then using information gleaned from a
chapter in Atwater 'Introduction to Microwave Theory', (Dover, 1962).
However, I have insufficient experience to guide me in the reliability and
accuracy of my calculations. Whereas I did some labs on the klystron, we
only qualitatively covered theory of magnetrons in my tech course.
I have been kindly sent some typical electrical characteristics for this
device from a local Toshiba distributor (T.E. Australia P/L) which agree
with some of my calcs, but no performance figures or graphs, seem to be
available.
'Oscillating frequency range: 9410+/-30MHz
Pulse output power: 3.5kW
Cathode Heater Voltage: 6.3V
Cathode Heater Current: 0.52A
Typical operation -
Pulse anode voltage: 3.6kV
Pulse anode current: 3A
Average anode current: 3mA
Heaver voltage: 6.3V
Pulse width: 0.5us
Pulse repetition: 2000PPS
Magnetic Field: Permanent magnet
Cooling: natural cooling
Applications and features: x band , flying lead type'
Is this as good as it gets?
Failing that I'd like to ask fellow correspondents for the benefit of
their experience:
1. Pointers to references that may lead me to making my own measurements.
I recall coming across a early 60's reference with a title along the lines
of 'Microwave Electron Tubes' or somesuch. Anyone want to let me know of
their favourite? I do have access Philips/Silvers, HP and GEC-Marconi
guides, but not texts
2. Highlights of your own experience, knowledge, ROTs etc. in relation to
magnetrons. Note that I am concurrently reading the rest of Atwater, and
the RSGB Microwave Handbooks.
3. This device came along with a Furuno Model 2400 marine radar, which I
obtained recently and am restoring, in order to teach myself about radar
systems.
I am not wholly and committed to using the magnetron in my restoration.
However, if I construct a solid-state oscillator, operating at say 1 W
or less, what other characteristics must I imbue it to make it appear to
the radar set as if it was connected to a magnetron?
4. Given the power levels of the original magnetron, are there downstream
components that have some minimum power thresholds that would constrain
my emulation of the magnetron?
5. Would the changes, if any, that I would need to make to the set, be
such that I may as well abandon this set and seek to scrounge newer
technology. I'd prefer to stick with the set that I've got.
Cheers,
Julian
VK1YKP
__________________
JuSu
> I seek spec/data sheets for a Toshiba magnetron model no. 9M302/E3513.
>
> I have been kindly sent some typical electrical characteristics for this
> device from a local Toshiba distributor (T.E. Australia P/L) which agree
> with some of my calcs, but no performance figures or graphs, seem to be
> available.
>
> 'Oscillating frequency range: 9410+/-30MHz
This means that the device is designed to operate at a single
frequency somewhere within the given range. It is not tunable, except
by the "pushing" and "pulling" characteristics typical to magnetrons.
> Pulse output power: 3.5kW
> Cathode Heater Voltage: 6.3V
> Cathode Heater Current: 0.52A
Do note that the heater power should be modulated in inverse
proportion to the average power (input or output, doesn't really
matter) that the device is currently operated at.
>
> Typical operation -
> Pulse anode voltage: 3.6kV
> Pulse anode current: 3A
> Average anode current: 3mA
> Heaver voltage: 6.3V
> Pulse width: 0.5us
> Pulse repetition: 2000PPS
Now take these PW (pulse width) and PRR (pulse repetition rate)
figures and work out the duty ratio (duty cycle?). The device is
probably usable for PW's from 0.1 us to 1.5 us, as long as the same
duty ratio is maintained. High voltage power supply permitting, of
course.
You do know, don't you, that the 3.6 kV cathode voltage is the one you
need to switch on at PRR for the duration of the desired output pulse?
Designing the HV supply is an art.
> Is this as good as it gets?
In the full spec sheet you'd find the pushing and pulling figures,
pulling probably presented on a Smith chart. Not really much more.
> Failing that I'd like to ask fellow correspondents for the benefit of
> their experience:
>
> 1. Pointers to references that may lead me to making my own measurements.
Typically the older the better. Even Skolnik is degrading as the
edition number increases. (Skolnik, Merril I., Introduction to Radar;
Skolnik, Merril I., Radar Handbook)
I did have a really good introductory and hands-on text on microwave
measurements, incl. magnetron handling. Unfortunately I've no idea
where it is now... I'll keep looking.
> 2. Highlights of your own experience, knowledge, ROTs etc. in relation to
> magnetrons. Note that I am concurrently reading the rest of Atwater, and
> the RSGB Microwave Handbooks.
Magnetron is your loyal friend. You can even mistreat him a little and
he still will do everything in his power to serve you. But mistreat
him a little too much and be prepared for a longish rejuvenation -
which the commercial radar transmitters typically don't have the
facilities for.
> 3. This device came along with a Furuno Model 2400 marine radar, which I
> obtained recently and am restoring, in order to teach myself about radar
> systems.
Good. Marine navigation radars tend to be straigthforward and
comprehensible, without unnecessary complications that tend to infest
military radars.
> I am not wholly and committed to using the magnetron in my restoration.
> However, if I construct a solid-state oscillator, operating at say 1 W
> or less, what other characteristics must I imbue it to make it appear to
> the radar set as if it was connected to a magnetron?
Argh. Look up radar equation and see what you need to get about 10 nW
of return echo. In other words...
> 4. Given the power levels of the original magnetron, are there downstream
> components that have some minimum power thresholds that would constrain
> my emulation of the magnetron?
Oh yes! Practically everything in the radar set is predicated on the
signal characteristics and power level of the original transmitter. Of
course, if you are looking for a long, challenging and slightly
illegal project, go right ahead!
> 5. Would the changes, if any, that I would need to make to the set, be
> such that I may as well abandon this set and seek to scrounge newer
> technology. I'd prefer to stick with the set that I've got.
In commercial navigation radars, magnetron transmitter is the current
technology. All that has been modernised in more recent units is video
processing and user interfaces. You'll be better off with a magnetron
transmitter and simple technology.
You do know, of course, that you amateur radio license does not
necessarily cover the operation of a navigation aid like the radar
set? It should, however, be simple to obtain the necessary permission
to operate the navigation radar. In some countries the tiniest models
are excempt from licensing altogether.
Good luck! It is an interesting world...
JuSu
Watson A.Name
100...@supreme.pcug.org.au>, grod...@pcug.org.au says...
The TR tube depends on enough power to ionize the gas and shut off
the receiver from the transmitter. If the power gets back into the
receiver, then it's curtains for the mixer diode.
> 5. Would the changes, if any, that I would need to make to the set, be
> such that I may as well abandon this set and seek to scrounge newer
> technology. I'd prefer to stick with the set that I've got.
Your oscillator would have to be pulsed at high enough power to put
out a pulse that would serve as a facsimile of the magnetron pulse.
Remember thatt he loses round trip from antenna to taarget and back
are very great, so if you use a low power oscillator your range
will be greatly reduced. The radar trainer that we trained on in
the army had a 1W output from a klystron, and it could be barely
felt on the finger, and it might go thru the window and show
something outside. But that was about all.
> Cheers,
>
> Julian
> VK1YKP
>
> __________________
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Joe
note is that you will probably need to build a much more powerful oscillator
than 1 watt. Normally, magnetrons in a radar situation, operate at a prf of
around 1-2000. This is as you have already stated. The AVERAGE power,
because of the pulse width is much less. i.e. 2000 pulses of 0.5uS @ 3.5Kw
is not much. However to get range from the radar, the peak power is needed.
Look up the Radar Range Equation in the text books you talk about. Some of
the power is also used to fire a short circuit device across the input to
the receiver, whilst it is transmitting. This won't happen with your setup
of 1 watt, but unless you make other arrangements, the Tx power will be fed
into the Rx input. This probably wont be a problem, especially if the device
is a valve unit. The other observation I would make, is if you do get a
magnetron to try out, be careful of the radiation, especially near your
eyes. The principle of the microwave oven is much better known now, than
when I remember an old fellow who used to check if the Tx was working by
seeing if his hand got warm when he held it in front of the rotating
antenna!!!
Joe
vk3bki
Julian Grodzicky <grod...@pcug.org.au> wrote in message
news:Pine.GSO.4.21.020425...@supreme.pcug.org.au...
>
>
Raymond Neil Cox
I'm new to Google groups so please be patient with me. Both Joe and
Julian seem on the right track. I will look more closely if I am
successful in posting this. I first learned about radar in 1952 at
White Sands Proving grounds where we put a bigger dish and made some
other improvements to a pair of 584 radar. At some pulse repition
rates the peak power was 250,000 watts. I think radars with more than
10 million watts peak pulse power have been built. The modifed 584
worked good. It could lock onto and follow cars on the highway 6 miles
away, even though there were tall mountains behind the highway. We
were in effect tracking about 10 degrees below the horizon so the echo
was entirely lost in the ground clutter, but the moving target
circuitry cut out the non-moving echos. Neil KG4HIY
ber...@ami.com.au
to work with CW radar. Gunn diodes are very practical ways of making
CW radars at 10GHz. In fact I have a Philips module for this very
purpose. Doppler door openers are ubiquitious and if yo can get your
claws on to one and modulate the gunn diode supply voltage you can get
a remarkable amount of information about the local environement.
Go read a good book on CW radar you will be fascinated.
Rolie Baldock. PEE.
On 3 Jun 2002 02:55:27 -0700, raymo...@yahoo.com (Raymond Neil Cox)
wrote:
aeolus