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This might be of interest to the group, so I published it on my web site:

www.w3jdr.com

W3JDR
Joe

On Sun, Aug 12, 2018 at 03:23 PM, W3JDR wrote:

Pretty picture nothing else, looks slick and tiny.? A schematic might be useful.

Allison

Hi Allison,
Thanks for the compliment on the picture.

It's a pretty straight-forward Breune bridge, but I'll put up the schematic when I get a chance to edit it with actual values...maybe today. The novelty, if any, is mountIng it right on the connector and using the center pin as the transformer primary.

When I do these things from my tablet, I tend to take shortcuts and fill in details later. Mea Culpa.

W3JDR
Joe

FYI, I posted the LTSpice schematic, so you can analyze if you wish.If there's interest, I can post the whole LTSpice package if anyone requests it.

Joe

Joe,

I suspected its a Brune bridge.? Most of the other forms tend to be larger.

All the ones I've built C3 has to be variable or hand picked as its hard to
predict due to parasitic circuit elements.? One being the inconsistency
of FR4/G10 at high hf and? up.

Allison

I wanted simple, small and easy to build. Only needs to drive A-D input, so no buffering required and linearization can be done in software if desired. I'm only interested in 30 mHz and 10W QRP max, so hoping the reproducability of fixed components holds up. First article built looks good.