Those several words: N6QW and LC VFO's said in the same sentence are much akin to wearing Brown Shoes with a Black Tuxedo.
But if you are so inclined to use Analog VFO's then hunt and find an Analog VFO assembly from one of the early Yaesu Radios, like the FT-101. The unit is small, but more importantly is linear, stable and clean! Yaesu found the magic decoder ring. I have two Yaesu radios (FTdx100 vintage 1967 and a FT-101EE vintage late 1970's) and both VFOs are just as I described.
One of my more successful radio projects was the JABOM* which originally started life as a 17M radio with a homebrew 4.9152 MHz Crystal Filter and VXO. In the Rx Tx Mixer Module, I had two sets of BPF's so with a pin header and Jumper pins I could add in 20M.
That worked OK except I got a critical report from someone I trust who said my LSB component was only down about 25 DB. He is an RF Engineer and could actually look at my signal with test gear he has in his shack.
That did it! I ripped out the homebrew filter, installed an 8.998500 BFO and added a 9 MHz commercial filter and wired everything for 20M. The real plus for this rig was the HyCas IF and AGC. I ditched the VXO and because I had a Crystal BFO the DDS of the day was the AD9850 and that is what went into the radio.
The AD9850 was a predecessor to the Si5351 and was only good to 40MHz and did not have the capability to generate two separate frequencies. Its output needed filtering and could be somewhat tepid.
So, after 15 years I embarked on replacing the AD9850 with the Si5351. The current approach with my Si5351 is to have two frequency ranges and VFO memory. So, the replacement unit boots up on either 14.2 or 14.074. A simple toggle switch enables jumping back and forth. If the SSB part of the band sounds dead, I need only flip the switch to see if there are FT8 signals and usually there are.
Here is a brief snippet of the 1st rough checks to see if we have it working.
Once again building in modules facilitates major changes. It also works well with my limited time available. I had the AD9850 out of the JABOM in about 3 minutes. Luckily, I have a box full of Arduino/Si5351 assemblies wired up and so about the same amount of time to pop in a unit to run some tests. This looks promising.
TYGNYBNT. Don't eat your pet.
* JABOM = Just A Bunch Of Modules.
73's
Pete N6QW
