Topband: HMC580 instead of W7IUV preamp

[Richard (Rick) Karlquist]

On 9/9/2015 4:04 AM, Andrew Ikin wrote:

> 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

It would not be hard to use two HMC-580's in push pull with
input and output transformers.  The output transformer could
be used to feed in the DC, eliminating the RF chokes.  This
should improve second order IMD by 20 to 40 dB, depending
on how well matched the amplifiers are.  It would also increase
3rd order intercept by 3 dB.

Rick N6Rk