Crystal filters are known to have a 3rd order intercept
point. Depending on how many AM BCB stations impinge
on your filter, you could get intermods. Switching
in an attenuator ahead of the filter should help,
if you can stand the increase in noise figure.
Rick N6RK
On 12/22/2016 12:41 PM, K1FZ-Bruce wrote:
We know that limiting the noise pick up from more directions of an antenna we
can usually hear better. We also know if we limit the noise from a receiver IF
we can hear less noise, and better yet, if we
have a roofing filter earlier in the receiver we can eliminate even more noise
in relationship to the wanted signals.
What if we take it a step further, could we limit the band-with of the antenna
signal with a crystal lattice for 160 meters before the receiver.
Years ago I played around with a single crystal at the input of an old tube
type receiver. It was remarkable what I could hear on 40 meters, on what seemed
to be one frequency.
73
Bruce-k1fz
http://www.qsl.net/k1fz/beverage_antenna.html
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