Drake TR-4 Filter Schmatic Redrawn

Redrawn TR-4 Filter SSB 9M 2100 L

Drake TR-4 Crystal Filters

Drake TR-4 'Blue' Filters removed

Filters from Bottom of TR-4

Filters removed from radio

Measurement of Tedford SSB 9M 2100 U

Model 7970 Crystal Filter from TR-4

(the working filter)

Test conditions 

Heathkit IG-102 set to read 20 over 

Receiver FT-1000MkV

Rx F was set and Signal Gen was tuned for max meter reading on various F's

9.006.00   less than S1

9.002.00   less than S1

9.001.00   S8

9.00.00    S9

8.999.00   10 OVER

8.998.75   15 over

8.998.00   15 over

8.997.00   10 over

8.996.00   10 over

8.995.00   S9

8.994.00   S2

NO FILTER 20 OVER