[Lowfer] LORAN Antenna Couplers

[JJ]

  Hi all,

So with the demise of the LORAN system, there's a lot of junk out 
there.  I picked up 2 Northstar Avionics M1-A LORAN antenna couplers for 
cheap cheap money.
One is a model #1010.  Half the board is an amp and the other is a 
filter on the input.  All components are leaded.  The amp uses a pair of 
MPS 6571's.
The second unit is a #2011.  It's the same size as the other and half 
the board is a filter.  The amp uses surface mount components and is a 
small board mounted at a right angle to the main board.  This 
daughterboard has white silicone sealant around it do I can't find what 
the active device is.
These things are built pretty well and should be usable even if I have 
to bypass the input filter.

Are there any avionics gurus here on the list?  Before I try a smoke 
test, I was wondering what the input voltage might be.  I can't find 
anything on the net.

Thanks,
Jon
W1JHJ