On 2/26/2021 7:31 AM, John Kaufmann via Topband wrote:
>
When dealing with narrowband
> coherent signals, this can really make very weak signals become
> visible on the display
That's exactly what I said in my first post.
> when they are virtually invisible in a larger measurement
> bandwidth.
The effect of the bandwidth of bins is to increase the frequency
resolution (and decrease the time resolution) of a measurement. It is a
fundamental property of spectral measurements that we can not know both
frequency and and time with infinite accuracy from the same measurement,
because they are the inverse of each other.
On 2/26/2021 8:46 AM, Richard (Rick) Karlquist wrote:
Averaging is a nice technique that mitigates the poor sensitivity
of the mini-flag, but only for "bright lines" due to power
supplies, etc.
And for signals from ham transmitters.
I would be surprised if it would do anything
to improve DF'ing power line noise, which is clearly a major
application domain.
Of course not -- that noise is not coherent. Averaging is useful for
chasing noise from electronic sources, not the noise generated by arcing
in power systemsn or by lightning, which is impulse noise. Impulse noise
will be displayed by horizontal lines on a waterfall if the time scale
is fast enough.
73, Jim K9YC
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