Jack, and all...
As you know, I'm in the process of putting together a very detailed construction manual for the radio which will be handed out to everyone who takes on the project as part of the class in our club. I wanted to ask you about the voltage adjustment of R1.?
I've been putting my prototype of the radio through some serious testing the past few days. My goal is to also use the DDS VFO to drive some of the older transmitters I have in my collection. But for the 49-er, I see that you indicate that J3 should be used to connect the 49-er to the DDS board at J6. If I'm understanding your instructions correctly, J3 is supposed to have a 4v peak-to-peak voltage on it via the buffer amp on the DDS board. This voltage can be adjusted with R1.?
As it stands now, I'm not seeing any difference in the performance of the 49-er both in receive and transmit by using either J2 or J3 on the DDS board. According to the schematic, J2 is coming directly from pin 20 on the DDS through C2, while J3 goes through the buffer amp and supplies the 4 volts voltage. I attempted to view the output voltage at J3 but saw absolutely no difference when I adjusted R1. In fact, with either J2 or J3 feeding the 49-er, I still had 5 watts output power on the radio.
Can you please clarify exactly where this voltage measurement would be taken? I simply took it directly from J3 and ground but saw nothing but a few milliwatts of DC voltage regardless of the rotation of R1.
Thank you and best 73s.
