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Re: Re: EME Sband?



On Mon, 22 Oct 2001, Edward R. Cole wrote:

> but the problem is frequency stability.  A magnetron is a self-controlled
> oscillator so stability is a function of the thermal characteristic of the
> cavity and its Q.  Most efforts attempt to lock freq. by inserting a reference
> signal.  Mags are also notoriously noisy {Fm noise}.  They may be usable with
> wideband or video signals but not nb cw.

Yep, but my approach would not be to tame the beast, but to find a way to
ride it the way it is.  That is, let it be wideband and just think up
the best application to use it.

Since the energy is not coherent but has one heck of a 60 Hz (half wave
rectified) AM component, maybe DSP could just look for this AM component.

Also, for frequency stability, I would add a heater and thermostat to try
to keep it heated to a constant temp (like an XTAL oven).

In my oven I found a perfect schematic (The Maggie only has 2 wires and
ground.  The 2 wires are for the filament (at 3.5 KV above ground also
serving as the HV connection).  These wires were standard #16 appliance
wire passing through a metal hole in the chassis with no special
insulation.  (I was amazed!).

Frequency was stamped as 2450 MHz.  AC input power is rated at 1.5 KW

Has anyone really analyzed what they hear in the shack on 2450 when the
wife is cooking?  Try listening on AM?

de WB4APR, Bob


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