In the USA, we have a fetish for 1 dB noise figure amplifiers for low
frequencies, even though 15 dB NF is more than enough for a very
quiet location.
With a 3 dB noise figure amplifier, even a one foot piece of wire will
hear Europeans on 160! So why use 1 dB NF on much larger
antennas?
> You don't have to believe, just add 6 dB diode mixer loss, 6 dB for a good
> 160m input filter and IF stage with modest 3 dB noise figure and you end
> up with 15 dB RX NF. This is at least 30 dB more then required on 160m
> band polluted with atmospheric and man-made noise.
>
> Modern solid-state HF RX are all over-sensitive with NF as low as 5 dB
> which is good enough even for 2 m band. Heavy price is subsequently paid
> on third order intermodulation immunity.
73, Tom W8JI
w8ji@contesting.com
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