Originally Posted by Pete KE9OA

I have completed the mods to my MFJ 1048 Passive Preselector. Actually, it
isn't too hard to do. This device uses a 6-position double pole bandswitch.
Only one side of this switch is actually used, which means that you have six
extra contacts that you can use for the low frequency ranges.
Inductors with values of 3900uH, 2200uH, 1200uH, 560uH, 220uH, and 100uH
will give you overlapping ranges from 157kHz to 1700kHz. Be sure to use good
quality shielded inductors.
When this preselector is peaked for maximum response, there is no apparent
loss on any of its ranges. Some frequencies actually have a higher signal
strength reading because of matching effects.
Although MFJ didn't have the schematic diagram for this unit on their
website, they were nice enough to e-mail me a scan of the schematic. I will
be glad to forward the schematic, along with my markups as soon as I scan
it. This mod is definetely worth the effort.

Pete