Yes, my last iteration was for - well I didn't print and file it... I was looking at 500Hz and it had some reasonable components at that frequency. The PL-259 chassis plates came in today and still looking for a small metal project box to put it in. One of those To-Do list items. I have a selection of inductors but they gap between 6.8 & 10mH and if memory serves me I was looking at ~8mH and didn't find one cheap from china. Anyway still on the to-do list but not a priority since there is not a whole lot being transmitted at that low a frequency that I have an urgent need for. Something to play with. Also on the list is a Farraday Cage to experiment with and this would be a good project for it once I put it together. That I have all the parts ready to do...

 

I don't like the idea of the uF caps and nH mH choke in that filter. I suspect that you will get equal or better performance with a simple series 15n cap, this will give you around 60dB attenuation at 120Hz and insignificant attenuation above 1MHz.

edit - changed my nH typo to mH

 

Not nH, mH. 10mH = 10000000nH or 10000uH. Since this is for a receive-only radio, all I need is to attenuate/choke the antenna signal. I'm sure it is already filtered but not for what I am experiencing from being so close to a noisy distribution feeder. Instead of the typical Bournes small spool radial inductor, maybe I can get away with using one of the resistor look-alike through-hole axial devices. Never tried this before so it is all supposition without any experience. Anyway a back burner priority at this time. I will resurrect it after I build my Farraday Cage experiment box. Almost have all of my antenna inputs lightning suppressed and still some antenna switching and installing my dummy load still to-do also. I recently relocated my workbench/ham shack and still putting it all back together.