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8640Jr – Band 5 VFO Output Measurements


8640Jr – Band 5 VFO Output Measurements

Band 5 on the 8640 Jr covers approximately 13.6 – 31 Mhz. There are now low pass filters configured for this band, but the output of the VFO has similar performance as the low pass filtered output of the other bands. Here is a photo of it’s waveform at the low end of its range.

Band 5 Waveform - Low End of Range

And another of the upper end of its range…

Band 5 output - Upper end of range

The spectrum shows the harmonics down about 30 db on the low end…

Band 5 spectrum - Low End of Range

And on the high end of the range, the harmonics are down about 30 db, as well…

Band 5 Spectrum - High End of Range

So it looks like if we shoot for around 30 db attenuation of the 3rd harmonic, we should have a pretty good waveform.





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