Dual DAC I+Q Generation and Carrier Modulation

I wanted a simple, easily-interfacable QAM source to test some code I had written for the RTL-SDR, so I put together two small boards: one with two SPI DACs to generate the I and Q inputs, and one board with a single analog QAM modulator on it that takes the carrier, I, and Q signals and outputs the modulated carrier.

First, I made the dual DAC board with two MAX515's - simple, 10-bit, SPI DACs.



Aesthetically the board was not stunning - I used too large a drill for the through holes, and thus my pads were blown out. However, it was salavgable, so I continued putting it together and testing it by bit-banging the DACs with an FT245R dev board:



With that working well, I dead-bugged the modulator, a TRF370417 that will handle carrier freqs of 50 MHz through 6 GHz, to another board:



As pretty as that board turned out, it was unfortunately (and predictably) extremely noisy. Oh well, I suppose I will just have to make a proper board for all 3 chips...