| AEROCOMM MODEL HF 1000+6 |
| W6PQL The amplifier BLF188XR A is a push-pull design, using a dual-LDMOS device; by nature, this type of amplifier does a good job of suppressing even harmonics, but the odd harmonics are monsters, so be sure to use a good low pass filter. Just look at this spectrum analyzer display of the unfiltered output on 40 meters: http://obrazki.elektroda.pl/9354175900_1435522049.gif After passing through the LPF, the spectrum is much more reasonable, and in compliance with FCC regs. http://obrazki.elektroda.pl/9254083500_1435522411.gif |