The chief designer said we would save the VFO to last. Build the test bed and give it a trial first. Using the scheme we can use any available Xtals for the filter and second mixer then adjust the VFO to fit.
The basic scheme relies on the image being removed by the input filters. So we feed one filter to ground to bypass the image and one to the receiver. (RF amp or 1st mixer)
The high pass filter passing 40 Meters to its destination according to which band is selected.
The low pass filter passing 80 Meters to its destination according to which band is selected.
So one band is rejected and one is received.
I left the credits for the program I'm using. It would be worthwhile to download it if you have need for filters.
You may have noticed it says manual entry. I ran the analysis and then manually adjusted the components to see the response with values available.
We plan to use the BF2040W RF amps and they are 50 Ohm devices so I ran the numbers at 50 Ohm.
The BF2040W is a high gain stable amp rated up to 1 Ghz. It could be used for the RF amp,IF amp and mixer.
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