There are several prototype versions of the 9BFC in operation, and they work just fine when connected to a decent multiband antenna.

BUT – when connected to a high SWR antenna (as is sometimes necessary in the field) the internal surface mount inductors can get disturbingly warm. The prototype 9BFC used a mix of surface mount and toroid inductors.

So, I am announcing the brand new all-toroid version of the 9BFC!

The 9BFC covers the 80, 40, 30, 20, 17, 15, 12, 10, 10 and 6-meter ham bands. This design has demonstrated its resilience and performance under all load conditions, and so has become the production version of the 9BFC.

So when you want to get a signal out, even when working with too-short or otherwise mismatched antennas, the 9BFC is now available: https://turnislandsystems.com/product/nine-band-filter-combiner/

And of course it works great with a well-tuned multiband antenna!