What do you think about this airline vs 5G brouhaha?
jjn at nuge.com
Thu Jan 20 00:04:12 UTC 2022
On Wed, 19 Jan 2022, Masataka Ohta wrote:
> Jay Hennigan wrote:
>> Radar receivers are typically some form of direct conversion with
>> rather good selectivity, synchronized to the frequency of the
>> transmitted pulse.
> No. Direct conversion stage has no inherent frequency
> selectivity and is subject to saturation by noise of
> any frequency unless the noise is removed in advance.
> Selectivity can be enjoyed only after successful
> unsaturated conversion, direct or to IF.
> But, the solution is to put an LC band pass/stop filter
> between an antenna and a receiver, though I have no
> idea on the difficulty to obtain FAA/FCC approval to
> do so.
By adding an LC bandpass filter will add to the propogation delay of
the receiver. When the round-trip time of the echo at 1000 feet is only 2
microseconds, that added delay will throw the RA out of calibration.
Perhaps the calibration circuitry can deal with this added delay.
--- Jay Nugent WB8TKL
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