| Roofing filter |
| Podam przykład radia fabrycznego oraz z Roofing Filtrem firmy INRAD, mam w PDF do poczytania w j.angielskim "International Radio Roofing Filters for Yaesu FT-1000MP Series Transceivers" i sytuacja wygląda tak: Yaesu FT-1000MP Mark V, serial number 0K120017 Blocking Dynamic Range, odstęp ------ fabryczny ----- roofing filter 5khz 105db 130db 2khz 102db 105db 1khz 104db 106db IMD Dynamic Range, odstęp ------ fabryczny ----- roofing filter 5khz 76db 89db 2khz 69db 79db 1khz 68db 69db Yaesu FT-1000MP serial number 7J21036 Blocking Dynamic Range, odstęp ------ fabryczny ----- roofing filter 5khz 111db 128db 2khz 106db 108db 1khz 102db 103db IMD Dynamic Range, odstęp ------ fabryczny ----- roofing filter 5khz 76db 90db 2khz 69db 71db 1khz 68db 68db "Tom Frenaye, K1KI Director, ARRL New England Division During the K1KI multioperator-single transmitter effort in the October CQWW SSB Contest, we used one FT-1000MP without and one FT-1000MP Mark-V with the International Radio roofing filter. They were used on several bands during the weekend. For the single operator November ARRL Sweepstakes CW contest an FT-1000MP with the roofing filter was used as the main radio, and one without the roofing filter was used as a second radio. In trying to figure out what could be said about the radio’s performance with the roofing filter, what stands out is what doesn’t happen. In the past when there were very loud signals (S9+20 dB or so) on the band, we’d often hear extra IMD products on our frequency, even if the loud signals were 10 to 20 kHz away. With the roofing filter installed, we just don’t hear them at all, unless they are very close in frequency. Listening to other stations on CW or SSB is less stressful without the extra noises! When looking for a clear spot on 40 meter SSB, the radio with the roofing filter is able to find more “holes” between the S9+40 dB international broadcast stations, and able to copy other stations that would not have been heard in the past. After the first Ten-Tec Orions hit the bands in late 2003, there were several times when good friends with new Orions seemed to start up too close to our frequency. It turned out they couldn’t even hear us. It became clear that the performance of that radio was superior to the FT-1000MPs used here. With the International Radio roofing filter, the situation seems to be back to even again in the never-ending goal to keep up with the competition!" |