Re: DDS/VFO output #bitx40


I don't have a scope but I think that would be normal. In the uBitx Farhan drives the diode mixers from the Si5351 (3v output) via a small attentuator pad. In the Bitx40, Q7 to Q9 are left over from the analogue vfo. If you wanted to drive with a cleaner square wave you could rebuild it to be the same as the uBitx. If you want to really clean up the 7Mhz output (and get rid of the 7.2MHz birdie) you need to use the vfo at 19MHz and change the 12 MHz oscillator to be on the low side of the IF.
73 Brian.

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