Heathkit SB-620 Panadapter IF information

The Heathkit SB-620 Panadapter is compatible with various receiver IF frequencies and connects to the plate lead on the receiver mixer tube socket using a 7.5-12pf capacitor. If the receiver has multiple mixers, use the one which as the variable oscillator attached (VFO/LMO/PTO, etc).

For IF selection options, the SB-620 Panadapter uses a number of different coils, resistors, capacitors, etc. Specific combinations are covered in charts in the manual and here are the Heathkit instructions in ".pdf" format.

IF FrequencyR1R2L1L2L3C3C4RFC1

There are several different capacitor/resistor and wiring changes depending on the IF frequency selected. Refer to the assembly instructions in the manual.

The purpose of this section is to focus on the more popular 455Khz IF and the 3395Khz Heathkit IF coils which are the most difficult items to locate.

Detailed data (measured off my SB-620) about the coils should help you build what's needed:

Good luck ! The osc coils should be the most difficult to make because of tap selection (how many turns from the grounded end of the coil). Don't assume the inductance ratio is the same as the turns ratio on these small criss-cross wound coils. Curiosity got the better of me and I unwound the 40-807 coil. Total number of turns is 18-1/2 and the tap is located 7-1/4 turns from the grounded end. No, I can't afford to unwind any others.