Many people who’ve used an ATS-3 mention the receiver characteristics of this amazing little riglet. The typical refrain is “signals seem to just pop out as I tune the rig”.
That certainly is the case and it is an amazing characteristic, especially given its size. To a lesser extent the same can be said for Wilderness Radio’s SST.
More years ago than it seems, the ARRL made a posting to QRP-L asking if any QRPers would be willing to send their kit-built rigs to their lab so that measurements could be made and reviewed in an upcoming article in QST. You can read/download that article here as a pdf file.
But back to the ATS-3…
A few weeks ago I used Spectran and a signal generator to measure the audio response (for a given change in RF input) of my K3 and figured, as long as I have everything set up for that, why not measure the other QRP rigs I have to see how they compare.
I’m paying more attention to steepness of the skirts rather than overall bandwidth:
As expected, the results agreed with what I hear as I use these rigs – there were no surprises. But it is interesting to note the similarities of this specific characteristic between the tiny little ATS-3A with Elecraft’s flagship.
The results of the other rigs measure can be seen here. I’ll eventually add the KX1…currently awaiting the arrival of a small part to repair its DC connection.