On 9/11/2017 12:32 PM, 'Jim Sheldon' @W0EB
I've gotten caught up in a massive SMD building program on an
"Indo-ware" transceiver, the SSB 6.1 that's being sold in partial kit
form on eBay. It just happens to be the rig those little DDS VFO's I've
been posting about was designed for, so I thought I'd build one just as
a receiver (The transmitter portion is only the low level (15 mW) output
from the board and for TX it would need a T/R switch, PA and low pass
filters for each band. It runs 80-10 meters in 6 bands. 10 MHz is
included but the 17 and 12 meter bands are not.
The on board crystal filter is supplied as a handful (7) of 8.000 MHz
crystals and one has to determine the parameters of these crystals and
match them yourself to figure out where to put them in the filter.
A spreadsheet has been provided that uses values derived by testing each
crystal with an AADE L/C meter & some simple homebrew test fixtures and
plugging the values into a free program also from AADE that is no longer
available (that I can find anyway) since Neil Hecht (designer of the
AADE products) passed away in 2015.
Does anyone out there have the install files for that program? If so,
would you kindly send me a zip file of the program?
Jim - W0EB
You can design crystal ladder filters within the AADE Filter program. I'm not aware that Neil ever had any other programs available for doing crystal filters.