Notes: MDS, blocking and two-tone IMD measurements made using a 500 Hz wide filter and AM audio measurements made using a 12 kHz wide filter. Description of the system: Perseus SDR > P4/2800 MHz/1G Ram > Delta 44 sound card > Hafler DH-110 preamplifier > Hafler P3000 amplifier.

Perseus SDR software version 2.1c was used for the test. Both standard AM and synchronous AM detectors were tested and little if any difference was noted in the measurements. Blocking dynamic range occured at about the ADC clipping level which is -3 dBm (preamp off) and -6 dBm (preamp on). It's possible that the audio distortion numbers are even better than shown since measurements are likely at the limit of the test equipment in use.

One concern with any receiver, perhaps especially 'digital' receivers, is the ability to hear weak signals at or near the noise floor. Listening to cw DX stations on 160 meters there is no apparent difference between the Perseus and Elecraft K3. The next test will be to compare these two receivers to an old high performance 'analog' receiver.

Final judgement on just how well the Perseus works will be withheld until I've had a chance to use it under battle mode conditions - full on cw and ssb contests. For the moment though, all other receivers have been pushed to the side in favor of the Perseus. It's that good ... especially as an AM receiver. The audio performance betters the previous hot ticket R-390A / Softrock only by a small margin but offers many features that only a direct sampling receiver can.

Sample screen shot using version 2.1c software.