With the 86mhz filter you need 98mhz and 74mhz for downconversion to 12mhz.
Thn you need LO to signal, with 86mhz filter maybe (have to run a spur table)
83 down to 55mhz? (LO below IF) will work.? Could work on first glance.
Or very simple three filters for 15/12/10 and switching to insert them in before?
the power amp, it can be done with diode as the levels are well below -10dbm
at that point.? ?Add a 10-12db mmic after that with max power out of 10dbm
and push for lower gain in the whole strip.? ?To select the filters we can use?
existing lines TXB and TXC mean thing until TXA is switched as there are
unused states there.?
For band pass selection we have the existing Low pass filter selectors.
TXA? ? TXB? ? TXC
---------------------------------------
0? ? ? ? ? 0? ? ? ? ? ?0? ? ? 30mhz LPF
1? ? ? ? ? 0? ? ? ? ? ?0? ? ?20-17m LPF
1? ? ? ? ? 1? ? ? ? ? ?0? ? ?40-30M LPF
1? ? ? ? ? 1? ? ? ? ? ?1? ? ?80-60M LPF
?Unused states 011 and 001
For for over 21mhz we have two control lines to select filters with TXB and TXC.
TXA =0 means the 20-30mhz selection TXA=1 means below 20mhz selection
or no additional band pass filters required.
So we can select up to 4 filters(two lines encoded) as needed with just a bit
more program logic.? Using the two lines raw then? and two of three (15, 12
and 10) can be selected.
And 6M, sure redesign the entire power chain everything, except for the irf510.
What is it about stuffing 7 pounds in a 5 pound box???
Allison
