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K3 vs KX3 on 6m
24 July 2013 | by There was a good opening on 6m this morning which lasted until early afternoon. I’d just been reading some list traffic on how good the KX3 receiver is so I thought I would plug it in to the antenna and see what I could do. After all, Six is the magic band, who needs 100 watts?
Listening on the two receivers was like night and day. On the KX3 the band sounded much more lively. Stations that were only peaking an S7 on the K3 were S9 plus.
On the KX3 with just 10 watts, just because a station was loud it didn’t mean I could work them. I got some 59 reports but with several stations they didn’t hear me even if I had no competition. The loudest stations had a lot of callers and they just didn’t hear me over the crowd. You wouldn’t think 9dB would make all that much difference but it does!
I’ve seen comments about the K3 being deaf on 6m, or even 10m, but I had never really bothered about it until now. If I can hear them on the K3 I can usually work them even though I generally limit the power to 80 watts.
But I ended up a bit dissatisfied with the K3’s receive performance on one of my favourite bands. The simple solution – fit a preamp between RX IN and RX OUT – isn’t an option for me as I need those ports to plumb in the MFJ noise cancelling device. It’s a pity no-one has come up with a mod to boost the K3’s fairly useless internal preamp on 50MHz.
2 Responses to “K3 vs KX3 on 6m”
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Are you saying that KX3 isn’t worth the the $999.00. I was planning on getting a KX3.
A few thoughts on this—the S-meter reading on two different radios doesn’t mean a thing in my mind, even if they are “calibrated.” It’s the weakest signals that matter for a preamp. My dead-band ambient noise level on 6m and 10m is enough to just blink the first bar on the K3 S-meter when the preamp is engaged. And, I hear a noticeable increase in noise when I connect an antenna. To first order, that’s a better test of whether a preamp is needed. That is, does the band noise overcome the receiver thermal noise? Yes, I know that feedline loss, etc, adds to the thermal noise, but it’s a basic test that works.
The K3 is not particularly sensitive because sensitivity is often the enemy of good strong-signal handling. Apparently with the KX3, they’ve been able to make the receiver a little “punchier” without loosing the strong-signal capability. All of that is very impressive when you think about it.
Six meters is a tantalizing band. Often, at least in the U.S., the CQing stations have an opening to a wide area (this happens due to the skew of population density in the U.S., with the south and west usually CQing for callers in the Northeast and Midwest). I have experienced very loud stations working other stations at a completely different beam heading from me. So, even though they are loud, I’m in a sidelobe at best.
Ten watts to a non-optimized 3- or 5-el Yagi used to be an average station. But, today the average rig puts out 100 watts on 6 and there are some really good antenna designs with real gain. Plus, power is easy to get on 6, too. The Larcan TV amps (when available) are very inexpensive, as well as the 3-500Z conversions. I don’t recall what the power limits are in Europe on 6 meters, but at least in some countries, it’s well-known that “limits” are seen as “recommendations” anyways.
To KF7FEF, I think the KX3 is neat little radio if you’re fine with the joy and limitation of the low power output.