Rick N6RK Wrote Sept 9.
Snip<I've characterized this device and can tell you that the 1/f
corner is well below 2 MHz, because it is based on HBT
technology. The devices that are good at VHF and noisy
at 2 MHz use MOSFET, GaAsFET, or ephemt technology.
JFET devices are also low noise at 2 MHz if they have a sufficiently
low channel resistance.>
Both amps, being single ended are likely to be susceptible to second order
IMD from BC AM band Tx. Whether one would notice much difference with a amp.
with a less than 1dB NF versus the above mentioned types with higher NFs is
debatable. The reason I say this is; is that the Flag has a high NF due to
its termination resistance. With other antenna types the noise due to the
loss resistance is a minute fraction of the antenna impedance. Hence, this
noise resistance is mismatch to amp. input z. For example a very low noise
JFet amp. (Wellbrook ALA100LN) when terminated with a loop antenna will
provide a 6-8dB lower noise floor compared to the amp. being terminated with
a resistance equal to its input z.
73
Andrew Ikin
G8LUG
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