KD9SV Filters at HC1PF

Solved my severe BCI problems!  

Gary sent me two of his 160 meter bandpass filters with BCI traps on 1.240 and 1.360 KHz, the frequencies of my strongest local AM broadcasting stations.

These are the SDR-IQ receiver screenshots taken without and with the filters inserted:

Freq. 1.240 KHz:  N-NW BOG   = Broadcasting reduced by 44 dB

No Filters: -31 dB                                                                 with Filters: -75 dB

Freq. 1.240 KHz:  East BOG        = Broadcasting reduced by 40 dB

No Filters: - 25 dB (high noise level)                                    with Filters: -65 dB

Freq. 1.240 KHz: Rot. FLAG to N-NW   = Broadcasting reduced by 54 dB

No filters: - 40 dB                                                                 with filters: -94 dB

Freq. 1.360 Khz: N-NW BOG  = Broadcasting reduced by  43 dB

No filters: -38 dB                                                                with filters: - 81 dB

Freq. 1.360 KHz: East BOG  =  Broadcasting reduced by 34 dB

No filters:  - 34 dB (high noise)                                            with filters:  - 68 dB

Freq. 1.3600 KHz: Rot. FLAG to N-NW  = Broadcasting reduced by 50 dB

No filters: -42 dB                                                                  with filters: -93 dB

The BCI filters also reduced the high noise level on the East BOG:

Noise level at noon on 1.830 KHz

                                                           No filters                    with filters

BOG N-NW                          -110 dB                      -114 dB       =  4 dB

BOG East                              -  85 dB                      -114 dB       = 29 dB

FLAG                                    -115 dB                      -115 dB       =   0 dB

Finally the following are the S-meter readings on the TS590 transceiver plus the KD9SV preamplifier in the normal operating set-up:

No filters         BC carrier on 1810              1820                 1830                1840                1850

BOG N-NW                             S 6                 S 7                  S 9+10             S 7                  S 9

BOG East                                 S 7                 S 8                  S 9+15             S 8                  S 9+15

Flag                                           S 4                 S 4                  S 5                   S 4                  S 5

With filters                             1810                1820                1830                1840                1850

BOG N-NW                            S 4                   S 4                  S 4                  S 4                  S 4

BOG East                                S 4                   S 4                  S 4                  S 4                  S 4

Flag                                          S 4                   S 4                  S 4                  S 4                 S 4

What a strange situation: the mixer products of the BCI were terrible when receiving on the BOG antennas, and almost nothing when receiving on the flag. With the filters all disappeared. Hopefully also the AM QRM over the band during some nights will end!