 Radio jamming SSTC driver
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Zum Beispiel
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Fri Sept 14 2007, 02:31PM
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Registered Member #514
Joined: Sun Feb 11 2007, 12:27AM
Location: Somewhere in Pirkanmaa, Finland
Posts: 295
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Now this is bizarre one:
I noticed that when I turn my SSTC's gate drive on and the start-up osc kicks in my radio goes silent. When the gate drive is running there is only hiss on the radio. I find this very odd, since the start-up osc is 160kHz, about 1000 times less than what the FM radio is designed to receive. It completely blanks out everything in the FM band. The radio is about 3 meters from the driver.
Has anyone else ever noticed something like this?
What could cause this? The MOSFET gate capacitance resonating with GDT secondary leakage inductance in the 100MHz region? The MOSFETs are IRFP450s, with 2.6nF of gate capacitance. That would need about 1nH of inductance to resonate at those frequencies, right?
Any ideas?
Discuss.
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Sulaiman
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Fri Sept 14 2007, 03:09PM
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Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
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Commonly FM radios will mix the rf down to a (typ) 10.7 MHz if amplifier
and then down again to a (typ.) 455 kHz second if amplifier.
Maybe you're putting out the third harmonic of 151.7 kHz ?
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