On 9/24/2019 1:36 PM, jimlux wrote:
On 9/24/19 1:14 PM, Wes wrote:
Why all of the complications? The preamps are unity gain.
Aha.. I was hunting around for a circuit description. Yeah, it looks there's a
noninverting buffer followed by a 1:1 transformer.
So it's more of an impedance buffer. What Z does it present to the element?
(I do a lot of work with HF receivers that use short (2-3 meter) antennas
feeding high Z buffers, so they're more "E-field" probes)
Can't be more than 50K ohm (the parallel combination of the two bias
resistors). I don't know what the 5pF cap is doing, maybe suppressing something
or the other, otherwise, it's contraindicated. IMHO, of course.
Wes N7WS
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