Last weekend I did some intensive playing with my brand new Fieldtest KX3 Serial Number 00016. It was a quite good situation for testing, because UBA contest blocked 40m with horrible loud signals, 10m was opened so it was possible to try some DX and the QRP Forum was quiet, so I had time enough.
To say it first: All those months of waiting for the KX3 I was much too conservative. In a lot of discussions I had classified the KX3 as " Improved FT-817 with super control unit" This was definitively wrong and short by magnitudes. The Receiver Extreme low noise, extreme clean signals, nor ringing in CW down to the 50Hz DSP filter. No crossover from nearby stations. I could perfect hear S4 signals only 2 kHz below or above a 9 plus 40 signal, in worse case I could eventually hear some key clicks. In SSB thanks t0 High Cut and LowCut I was able to decode signals middle out of a pileup although I am having difficulties in copying SSB normally. (That's the reason to do 99% CW for me) Latency was absolutely no problem. I connected a K2, K3 and the KX3 using a splitter to the same antenna and all 3 haven been absolute synchronic. Intermodulations: That was one of the points, I expected problems due to the well known fact of extreme high sum levels especially in the evening here in Europe. I was more than surprised: I could not find any Intermodulation with or without Preamplifier. The Preamp can be used in 3 steps: +10dB, +20dB and +30dB. Against all experience, and just for fun I switched it to +30dB while using my full size diamond shape loop on 40m. The RX now sounded a little bit nervous, but again I didn´t find IM2 nor IM3 products. But the KX3 several times switched back the Preamp, whilst the display was showing "High Signal" This is a protection circuit which reacts if the sum of all signal voltages is too high. Wayne, N6KR answered to my question "Actual KX3 is analyzing all in band signals, in a further firmware version it will detect out band signals as well." Sensitivity: 1µV Signal gives a noise free, clear tone in the headphone. Empfindlichkeit: ein 1µV Signal erzeugt einen fast rauschfreien Ton. Unwanted Sideband Suppression: After I had adjusted Phase and Gain (easy to do at the KX3) the opposite sideband of a 9+20 signal could no longer be seen in the S-Meter, it was just audible when I listened concentrated. That's much better than most Xtal Filters do. AGC: Critical point for all SDR based designs. Working in the multi crowded 40m Band during the contest I found that AGC Fast was working not optimal. Lyle, who is the designer of the DSP suggested to use AGC Slow at this time. So did and I can say, it works excellent. Lyle is still working on AGC fast, so I am sure this will do it also in future. Current consumption in receive: 200mA The Transmitter: All worked stations stated an excellent sound of the transmitted signal in SSB and in CW. I didn´t yet use the Equalizer, but I played with the compression. Compression between 10dB and 25 dB resulted in "outstanding good modulation" reports. Even when I got reports far above 599, no one could hear any key clicks. I personally do not like full QSK, for me it is ok if I can listen between letters, but I tested it and yes, the KX3 is full QSK. Internal Temperature Control showed after several ragChew QSO < 35 degree C for the PA and 38 degree C for the DSP Unit (This shows, who is eating current :-) The internal ATU is working like a champ. I was able to tune the 40m element of my Trap beam at 30m easily. When I started with the KXPd3 Paddle, I had some problems. In a discussion with Wayne, N6KR we found that my KX3 was missing its front rubber feet. After installing the feet, the paddle works really great. Because it was warm outside at Sunday (+10 C) I opened /p season and did some QSO in the garden and enjoyed the combination KX3 / HFP-1 (The follow up of MP1). A great combination, I know what I will use in spring and summer on my bicycle tours. QSOing: Yes, I am sure good old Mojo found its way from K2 into KX3. I heard W2mm in a Pile Up on ten. She got me at my second call and stayed in a long QSO. Carol was working at her K3 and was enthusiastic to hear a KX3 from Germany. Some type of Elecraft Family Bonus :-) Under the bottom line: Elecraft is fiddling on the firmware, but under the bottom shell just now and as it is the KX3 is one of the best Receivers I know. Due to KX3s smallness and because my Mobil home is one of the smallest you can get, it is absolutely sure what I am using if you hear me on HF if I find time to be on the road again. I have to excuse for my laughing, when a German DXpedition HAM talked about using a KX3 for his next DXpedition. After some days playing with my KX3 I think, it will handle even such use. 73 de Peter, DL2FI www.qrpproject.de ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
