Re: WR90-SMA transition update

Neil Smith G4DBN

I ran a load of simulations in OpenEMS, but I’ll file the probe to length and measure the actual length, then see how repeatable it is. Without a trimming screw, I’ll have to file them all to get them on frequency I’m sure.
I’ll publish the OpenEMS model when I publish the drawings
Neil G4DBN

On 10 Sep 2020, at 06:27, Alex May M1BSX <alexmay@...> wrote:

A thing of beauty! :-)

Very intrigued as to how it was milled and whether you're using an empirical approach to determine the length of the "probe" ? 

73s Alex (M1BSX)

Alexander R. May

On Thu, 10 Sep 2020, 00:01 Neil Smith G4DBN, <neil@...> wrote:

This pic is my first try at machining an SMA coax to WR90 waveguide transition.  Milled it from a lump of 1 3/4 inch aluminium square bar on my ancient Bridgeport.    It needs a bit of trimming to get it bang on frequency as I left the pin a little long. Now I'm waiting for a load of Radiall SMAs to arrive from Mouser.

Neil G4DBN

I modelled it in OpenEMS with a three-inch length of WR90 mated with the oval cavity. Return loss (black) and through loss (red) look promising, I need to check the real thing once I have the probe filed to resonance.

Fusion 360 CAD image


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