MFJ-1026 Noise canceller Modification Plan

After some research on the Internet. I concluded this.

MFJ-1026 Noise Canceller modification Plan

1. Reduce Low frequency attenuation (increase gain at 1.8 MHz) 

 - Change C8, C16 (680pF) with 1.6nF   for Better high pass filtering  

 - Change  C18 (680pF) with 1.6nF  for better pass through 

 - May Change L3, L4, L5, L6 (5.6 uH) with 10 uH  ==> No need to change (Just Increase Cap to decrease attenuation at 1.8 Mhz)

2. Better IM Dynamic range

 - Remove Diodes D6, D9, D10, D11

3. Better Gain

 - Add 4:1 transformer to the output of  Q4 (C1)

4. Better control of Phase range (Swap inputs)

 - ADD DPDT SW & Coax to swap  the inputs of  Q8 and Q5

 -  Q8  ->   SW  ->  R20;  Q5  ->  SW  -> R9

5. Getting Better phase range and control

 - Change C13 (120pF) with (47pF  => 68pF)  - Increased range for high band position

 - Change C12 (470pF) with 680pF   - Better phase control for low band position

6. Protect Aux Antenna FET from high power operation

 - Install an AUX antenna input grounding Relay. 

 - Connect Relay (+) to (C2-Q1 junction pad) and  Relay (-) to  (R5-Q2 junction pad), -Install a diode

 - Install a protection diode

 - Need a 12V relay for isolation and a Diode for protection (NA1S TQ2-12V, Single side stable)