[Elecraft] IF feed for spectrum display

[Philip Theis]

Eric put out a discussion of "using an extra
high impedance input buffer stage taking its signal from the output of the
2N5109" to properly isolate the external IF device.
Does anyone have a simple circuit already worked out for this?  If so, will
they share it?
I was contemplating a 2N5179 but would happily use something that is already
engineered.
I have one of the new SDR-IQ's and it is perfect to put behind the K2, gives
190KHz of bandwidth readout.  See RFSPACE.COM
Thanks
Phil K3TUF