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Old November 9th 03, 09:07 PM
Jim Pennell
 
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One additional item to model is using highly reactive antennas.

The Lowpass rolloff point caused by the integrating capacitors is
controlled by the effective antenna impedance.

While one can assume 50 ohms, more or less, for a matched antenna, using
the Tayloe detector in a general coverage system should be calculated to
assume the antenna has massive mismatches at most frequencies.

I did some simplistic modelling and the results were interesting. To
control the detector rolloff, I'd be tempted to use a low gain RF preamp and
perhaps a small attenuator pad feeding the mixer....

Besides, as I recall, the Tayloe detector responds to harmonics of the LO
and so some frequency selective flters in the RF preamp might be useful.

All in all, The Tayloe detector has some benefits, but as with most
detectors, adding some components can enhance the system performance.


Jim Pennell
N6BIU