Topband: HMC580 instead of W7IUV preamp

[Richard (Rick) Karlquist]

On 9/8/2015 7:02 PM, Mike Waters wrote:
> Given the recent discussion about the need for low-noise preamps for the
> Waller Flag, it would be interesting to learn what the NF on 160 for
> this device might be.
>
> It's rated for "DC" up into the GHz range. However, as N4IS pointed out,
> a good NF at VHF does not mean a good or better NF below 2 MHz.
>
> 73, Mike
> www.w0btu.com <http://www.w0btu.com>
>

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.

Rick N6RK