I have a couple of kits in queue that will probably enhance the performance of the PFR3A.
The first that I will build (probably my next project) will be the AA0ZZ Keyer that the 4 States QRP Group offers. My sister purchased this as a Christmas gift for me after several blatant hints were dropped by yours truly. Well she did ask me what I wanted! It has more memories than the PFR3A has built in; and I'm sure will be easier to program. I have found out that if you don't get the timing of your CW just right as you input it into the PFR3A's memory, that the messages can come out garbled, for lack of a better description.
The other kit that I have in the shack, that will come in useful will be the New England QRP Club's SCAF filter. The PFR3A doesn't offer any on board auxiliary filtering. I bought the SCAF a couple of years ago with no real need for it as both the K1 and K2 have great on board filtering. I was thinking of selling it as it was superfluous to my needs then; but it sure isn't now!
I have a pair of Sony earbuds that seem to work great with the PFR3A. I used to use them on my Palm Tungsten E2 when listening to MP3s; but have transferred them over the yellow box. They are less cumbersome than the "Walkman" headphones I was using and deliver a nice strong signal to my ear bones.
I was playing around with "Ol' Yeller" some more tonight and made a couple more QSOs with it. Even with the above accessories added, I don't think that it will replace my K1 as my "lead off hitter" when it comes to portable field radios; but it will be a nice addition to the lineup.
The one thing I am wondering about, and am sure will get to test in the coming weeks, is how the red LED frequency display is going to be in a sunny environment. I might have to come up with some kind of home brewed temporary shield arrangement to allow it to be read outdoors on sunny days.
72 de Larry W2LJ