LF: A simple ULF/MF diplexer?

[DK7FC <selberdenken@posteo.de>]

Hi all,

I would like to run some transmissions on MF WSPR but i also like to run 
a longer transmission on 2.97 kHz. In the current ULF TX installation 
i'm using a parallel 2 nF capacitor anyway. This is just -j167 Ohm on 
MF. I could series compensate it with 65 uH (which is just j1.2 Ohm at 
2970 Hz :-) ) to ground. The 65 uH could be parallel compensated for MF, 
using 280 nF. Then i could add a ferrite transformer to apply the MF RF 
across the 65uH/280nF parallel circuit. The large loading coil of 1.3 H 
will be a high impedance, hopefully, as long as there is no internal 
resonance on MF due to its own winding capacity.
The 2 nF capacitor will have to handle the sum current of ULF and MF. 
QRO is not possible on MF i think but it will handle a few watts which 
is fine for WSPR. Hmm, worth a try?
73, Stefan