The KX-3 has the better keyer – by a margin
The IC-7300 has the quieter receiver – by a margin
On 40M – listening to T30L at 0900z – which is normally a fairly quiet time of day – but where this month it has been really noisy – I wanted to just listen to each radio to see its on air S/N response.
Sherwood has the KX-3 ahead of the IC-7300, but there is something wrong with this picture. The IC-7300 has a noise level of S1 – 2. The KX-3 is S7 – 9, and the 7300 is LOT more enjoyable to listen to in this environment.
I wanted to find out why – and it took just a minute to see that it is the pre-amp. In the IC-7300, I can hear the signal clearly with less noise, but on the KX-3, without the preamp (which is much better noise wise), the signal also drops too much. It just isn’t as clear as the 7300. With the preamp in on the 7300 – the noise level jumps up to S5 – 7 – closer to the KX-3, but still not quite as bad. The point is – I seem to need the preamp in on the KX-3 and on the 7300 – I don’t at all. Signal loss on the KX-3 seems to be a problem where it is not on the 7300. It sure seems to be a signal to noise ratio difference as far as direct sampling vs. superhet designs are concerned.
This presentation confirms my findings. All of this also answers the question “If I were to get the Elecraft K4, which flavor would I buy?”. Its easy – the Direct Sampling, basic stock version. Maybe with the Dual Diversity receive option – IF I were still into having a nice NCC-2 with 2 Wellbrook ALA-1530LNP receiving loops.
But I am not at all interested in 160 or 80M DXing any more – 40M and above is it for me. This means there is NO reason for me to drool over the Elecraft K4. However, like I have mentioned before – if the KX-4 were to be a direct sampling receiver, then Elecraft would beat the IC-7300 and whatever the IC-705 ends up being.
I have to say, ICOM really disrupted things with the IC-7300. For the money, nothing else comes close – it really is an amazing DX rig – and if you don’t need the bells and whistles of say the IC-7610, or the new K4, I just don’t see any other radio offering so much for such a price. In fact, if you don’t care about size or power consumption – the 7300 is the better radio (receiver wise) in my book. You can listen a lot longer without getting the “noise fatigue” that you get with the KX-3.
Sherwood lists the KX-3 higher, and in the slide presentation, the author intimates that the 7300 does as well as legacy superhet receivers (like the KX-3). Personally, I think the 7300 and direct sampling is better – in noisy conditions.
When I saw a demo with Wayne, N6KR, he did discuss how you can add a superhet option to the K4 so you can better block out close in signals. Since I don’t care anymore about DXCC or big DXpedition pileups – this is not of interest to me. Here is a line from the Elecraft K4 product website page:
The K4 and K4D, like other “pure” direct-sampling radios, do not require crystal roofing filters. Digital signal processing is used to provide advanced demodulation, filtering, and signal display. The K4HD can operate either in direct-sampling or superhet mode. Typically the latter is only needed in the presence of extreme signals.
I will continue testing – and will try the close in dynamic range test (by ear) between the two rigs some day. I will also see if in less noisy conditions, how the two rigs compare.
For now – in this simple “Part 1” test – the IC-7300 wins this round for ease of listening in noisy conditions – but the KX-3 keyer is a LOT better than the clunky 7300 keyer.
I do expect that the K4 will be a GREAT radio – since its stock version is a direct sampling receiver. But at $4000, that is too much for my FREQ 300 pursuit.