Re: TVI/RFI Reduction. Empirical Results
> Original Poster: "R.E.Burnett" <R.E.Burnett-at-newcastle.ac.uk>
> BTW. It never ceases to amaze me that a TC can radiate significant
> amounts of power at frequencies as high as 900MHz !
> That's nearly 5000 times my coil's resonant frequency.
It might not be radiating at 900 MHz... More likely, a high level
interference is getting into the receiver some other way and affecting a
low level stage. My guess would be coupling through the power line into
the front of the audio amplifier right after the detector. Also, there is
probably an IF at 10.7 MHz in there, at fairly low levels.
Another likely route for interference is through the AGC circuitry. The TC
puts out large pulses of power. The AGC sees these pulses (even though they
are grossly out of band, but it couples around the circuitry) and reduces
the gain intermittently, causing the detector to "static" out.
In short.. there are lots of ways to build a jammer, and lots of them don't
require radiating at the victim frequency.