Topband: W7iuv preamp

Michael Tope W4EF at
Sat Feb 17 12:41:03 EST 2007

----- Original Message ----- 
From: "Michael Tope" <W4EF at>

> BTW, cooler is going be slightly better for noise figure, gain,
> and linearity and since you are presumeably not making these
> things en maase to sell commercially where you might care
> about shipping weight, I suggest you err on the cool side
> with a large heat sink (<< 60 degC  TO-39 can temperature).

Note, I may unintentionally propagated some misinformation. 
The above is generally true for FET devices, but not for bipolar 
devices such as the 2N5109. The difference being that device
gain in bipolar devices tends to increase not decrease with 
increasing temperature (hence the need for emitter degeneration
to prevent thermal runaway in BJT circuits). In my work I deal 
almost exclusively with GaAs FET devices, so I am used to 
thinking in terms of low temperature = higher gain and higher 
output power. 

73, Mike W4EF

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