May 1, 2014
   
 

Misc. Information
1. Input filter for 40meter receiver
2.1 Watt CW Tramsmitter
3. 40m Transceiver

 

 

Input filter for 40m receiver

L1, L2, 32t #26, T-50-6, tap 5turns up from ground

This is suitable for input to a NE602/612 mixer.
The output of this filter labeled "to Mixer" connects to pin 1 of the NE602/NE612 and pin 2 of the NE602/NE612 connects to ground through a 0.1uf ceramic cap.
see receiver schematic here . . .
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1 Watt CW Transmitter - QST October 1994, p.64

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40m Receiver by W7JI



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For a better IF filter:

"Designing and Building High-Performance Crystal Ladder Filters", Jacob Makhinson, N6NWP

also "Crystal Characterization and Cystal Filter Design" Nick Kennedy, WA5BDU"

and "Crystal Ladder Filters for All", QEX, Nov - Dec 2009"

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Audio Circuits - might insert audio filter between limiter and power amp.

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Audio Filter Using LTC1060 Universal Dual Filter Building Block