.:: HERF001 ::.
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Purpose:
The purpose of this lab is to find a way to power a microwave oven magnetron from a portable power supply.
Materials:
- 10kV DC-DC inverter module
- 5kV ~6.67uF oil filled capacitor
- 1kW 2.45 GHz Magnetron
- Horn Antenna w/ built in waveguide
- 6V coil / 600VAC 35A mercury contactor
- 15V voltmeter
- 500mA ammeter
- 3A ammeter
- 250uA ammeter (converted into a 5kV voltmeter with a series 20MOhm resistor)
- 4" PVC pipe
- Indicator bulbs
- On/Off lock switch
- Momentary push buttons
- Heavy duty wire
Procedure:
I will test how much power an MOT feeds the magnetron to both the cathode and the heater. I will then try to replicate the same power by using an automotive battery as a power source that will charge a capacitor. This capacitor will pulse a magnetron for a breif moment transmitting ~1kW of RF power for a breif moment. The heater will be activated before the cathode is pulsed until it reaches nominal temperature.
Results:
7/16/01 - Horn antenna calculations have been made for a 21dB gain for a 2.45GHz megnetron source. I will now need to purchase copper sheet metal and welding supplies. Once tests are done using a continuous 2kW power source then the power supply will be switched to the 12V pulsing supply.
7/25/01 - The pulsed power supply was a great success! I powered the heater using the origional supply. Then, I charged the pulse power supply to 5kV and pulsed it. The needle quickly fell to 3kV - 4kV and stopped. It was then simple to quickly bring up the charge to 5kV again. My conclusion from this was that I need a much more powerful charger and a higher voltage rating storage cap. The reason for a higher volatge than 5kV is because at 5kV the HERF was putting out the most RF power, meaning that I have not yet reached the peak (probably around 6kV - 8kV). My next setup will use 8kV 16uF instead of 5kV 7uF.
8/14/01 - I have gotten very far with the HERF's outer body and its inner workings. It is setup as a hybrid and can run on either wall power or batteries. I already have the fan set up and the digital panel meter for reading the capacitor charge. There will be over 8 switches and 2 lights on the control panel.
![](DSCF0998.JPG)
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9/02/01 - The HERF is practically complete. The following images show my progress in development. The HERF will soon be able to run from a 12V automotive battery when I get my 2kW inverter. For now it runs directly from my home power supply.
![](herftop1025.JPG)
HERF001, top view.
![](herfback1023.JPG)
HERF001, back view.
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HERF001, back view.
![](herftop1026.JPG)
HERF001, top view.
![](herfside1029.JPG)
HERF001, side view.
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Horn antenna front view.
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Horn antenna front view.
![](stanza-herf01.jpg)
Wanted to see what the HERF001 would look like on top of my car. It's a bit bulky and would experience a lot of viscous friction. An actual car mounted HERF would have to use a higher frequency so that the same antenna gain can be accomplished using a much smaller antenna. If the antenna is small enough it can even be placed in a over-head lougage car attachment. It would even be possible to have the horn antenna in the trunk and have it radiate through a fiber glass window. For check-point security, an x-ray or radio camera can be used to spot this.
![](parts1030.JPG)
These are some of the parts used for testing the magnetron before constructing the HERF.
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© Copyright Rostislav Persion 2003
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