My preferred mode of operation is portable HF radio and, like many operators, I like trying new rigs. The radio intelligentsia often speak highly of the Elecraft KX2 but up until now I haven’t been able to bring myself to buy one on account of cost and perceived lack of ruggedness. A couple of things have caused me to change my mind and give the KX2 a second look.
My main reason for giving the KX2 a try is I’ve been working on building a lightweight HF radio kit and the KX2 is exceptionally lightweight. Besides being inherently lightweight with its stamped sheet metal exoskeleton, the KX2 is capable of accepting a 2.5 AH internal lithium ion battery and an internal tuner. This saves the extra weight and bulk of carrying these items separately. Earlier this year, Elecraft released an add on board that allows for internal charging so it is even more convenient. It sips power so the internal battery is reasonably useful. I haven’t weighed this rig yet but it is remarkably light and compact.
At this point it is worth pointing out the importance of a tuner. No portable military HF radio made in the last 60 years lacks a built in tuner. Even with a resonant antenna, the portable HF operator can’t always prevent ground conditions or some other confounder from making your antenna less resonant than it should be. A built in tuner is simply common sense and good insurance and the amateur radio manufacturers are remiss in not providing this feature on their radios.
Moving on, I do have a Lab599 TX-500 also and have been exploring a lightweight kit with that rig as well. The TX-500 is such an interesting rig but it its not flawless. That takes me to my secondary reason for wanting a KX2. Namely, my TX-500 been sent into service twice for repairs and I question its long term reliability. The TX-500 deserves its own review so I’ll save further elaboration for another time.
I’ve had the KX2 now for about two weeks. Initially, I had some frustration with making sense of the controls but the manual is quite well written and easy to follow. For instance, the first time I used it on SSB I found a strangely distorted sound played back from the speaker. I thought this was RFI and was immediately concerned my used rig had a problem but I realized that there might be a monitor function left on by the prior owner. Sure enough, I quickly found the setting to check and was able to fix it with just a few minutes skimming the manual.
The Digirig I purchased for the KX2 also had issues. Since it was a new rig, I wasn’t sure if I had a settings issue on the KX2 or a bad cable. It turns out the Digirig itself had its jumper settings misconfigured. A few minutes with a soldering iron had serial rig control working just as it does with any of my other radios. After a couple of days of troubleshooting software and rig settings I’m glad it was a simple fix.
It is said the KX2 has digital modes as an afterthought. While true for a couple of reasons, I have found it usable so far and not too much of a hinderance. One thing I realized early on is this rig doesn’t have a full set of memory settings for data mode operation. For instance, the mic gain setting is shared by the hand mic and your data mode interface. This could be a serious problem but, in practice, I was able to set the computer audio out settings such that the mic gain can stay where it is with both voice and data modes. No issues there.
There is one other odd consequence to the way the KX2 handles data. Namely, the lack of receive audio monitoring when a data mode interface is connected. Since the Digirig connects through the headphone jack, plugging it in interrupts the speaker output. I’m accustomed to listening to ensure the channel is clear before transmitting but with the KX2 I’ve had to learn to monitor the waterfall display on whatever app I’m using. Time will tell if this is a real issue or not. What I will say is, like we did back in the 90s with telephone modems, I can tell if a VARA HF session is performing correctly just by listening to it. Without jury rigging an audio splitter, that won’t be possible with the KX2. The KX2 even uses pin diode switching for TX so there isn’t even a relay click during data operation. It is completely silent.
More work needs to be done to flesh out the TX/RX EQ and voice compression settings as these are critical to getting the most out of voice operations and 10W. It will be interesting to see if it is as good as the TX-500. Spoiler; the TX-500 has excellent voice performance when correctly configured.
In summary, here are the pros and cons of this rig as I see them after two weeks of use.
Pro:
– Very lightweight and compact
– Internal battery and tuner reduces the need for additional external devices
– Great documentation
– Aftermarket support mitigates some concern about lack of ruggedness
– Rapidly deployable
Cons:
– Data mode operation behavior is a significant departure from other rigs
– MARS mod cannot be accomplished without factory coordination
– Potentially more fragile than other comparable rigs such as the FT-817/818 or TX-500
– Internal speaker has lower sound quality than comparable radios
Time will tell how it shakes out and whether the new rig excitement will fade. For now, I’m happy to have the rig and will continue giving it a thorough shakedown.
Padre
The Orderwire 