Tag Archives: Elecraft KX2

KX2 Digital modes configuration examples

I spent a lot of time working on digital mode configurations with my KX2 this weekend. I got involved in a thread on the Elecraft mailing list regarding FT8 configuration using a SignaLink USB. Even though I had a functioning configuration using a USB soundcard I pulled out my SignaLink USB, the jumper board, and cables in order to put that configuration together for use with my KX2 as well. I got it going for both WSJT-X and Fldigi. One thing led to another and as I was putting together a little document with notes for myself I decided to polish it up a bit and post it.

Here it is:

KX2 Digital Mode Configuration Examples.pdf

It’s hosted in my lutherie domain so don’t worry about the download source.

Understand that there are more than a couple of variables involved in setting this up. Your situation and\or needs may well differ from mine. It’s not an exhaustive document, there are other bits for you to sort out, but it may be useful to get you started. As I said, I was preparing a simple document for myself to keep track of my configurations and it sort of took on a life of its own. I’m early into my experience with these modes and the KX2. Also, I only have a KX2 with which to test but I’m pretty sure that all of this works the same for a KX3. If you find this useful, great. If not, so be it. As they say, YMMV.



Ps – If you find any errors please let me know and I will correct them and re-post.

Fasten your seat belts for FT8 @ camp

Early in the morning of the day that my XYL and I left for our most recent camping trip I was making a quick pass through some of my favorite Amateur Radio blogs and came upon a post by Bas, PE4BAS and another post by John, AE5X regarding the new WSJT protocol\mode, FT8. In John’s post he graciously referenced my recent post on PSK31 with my KX2 as an example of QRP portable digital operation. I had already packed my equipment in order to operate PSK31 from camp but I thought that I may as well try FT8. I pulled out my PC and installed the beta version of WSJT-X. I didn’t have enough time to setup the KX2 to check configuration and test so I figured that I’d just wing it at camp.

The second day at camp dawned bright and beautiful, perfect weather for digital operations. After a nice breakfast I pulled out my equipment to have a go at FT8. I quickly placed one end of my LNR EF-Quad well up in a tall fir tree and setup the KX2 and laptop. When I originally setup for PSK31 with my KX2 I used an older Toshiba laptop however the battery in that laptop would not hold a sufficient charge so I switched over to another old laptop that I purchased a few years ago at a local Hamfest with the intent of setting up a dedicated WSPR station with my IC-718. This never happened and in the face of my new WSPRlite transmitter it’s not likely that it will so I decided to use it as my portable digital PC. It is a bit more compact than the other laptop and as a result the keyboard is a wee bit smaller, but it’s still reasonably serviceable.

In order to confirm that everything was setup correctly as far as the general PC\radio interface I made a quick test with Fldigi and PSK31 using the same USB soundcard I described in an earlier post. This resulted in a couple of very nice QSO’s with N1ZQ who was operating portable in the White Mountains of New Hampshire and KA3OCS in Virginia. Both stations were very considerate of me being new at PSK31.

Fldigi PSK31 @ camp

With general functionality confirmed I shut down Fldigi and started up WSJT-X. Within a minute I had the interface to the radio and audio setup, selected FT8 on the Mode menu, and with a click of the Monitor button WSJT-X was receiving and decoding FT8 on 20m.

WSJT-X FT8 @ camp

WSJT-X configuration was as follows with the KX2:

WSJT-X radio config with KX2

WSJT-X audio config

This was my first experience with WSJT-X having never operated with either JT9 or JT65 in addition to the new FT8 mode. If you’ve not seen FT8 in action before, let me tell you that it moves very very quickly. The Band Activity pane filled quite rapidly and scrolled along at a rather brisk pace. I observed the activity for a wee bit to get a feel for the flow of activity and then attempted to respond to some CQ calls. After a few attempts I was rewarded with my first FT8 QSO, N4ULE. It was over before I knew it!

First FT8 QSO, N4ULE

When it comes to FT8, as Briscoe Darling once said, “Just jump in where you can and hang on…

In fact if there was a theme song for FT8, it may well be Doug Dillard playing “Banjo in the Hollow” as in the video. FT8 moves right along, just like Doug’s pickin’.

The KX performed as expected, flawlessly. The CAT interface with WSJT-X functioned without an issue. The KX2 mode was DATA A. I’ve read a number of threads on the heat sink temperature rise with digital operation with the KX2\KX3. In the KX2 manual Elecraft states to reduce power to 5W so that is where I set the power. Depending upon the ambient temperature and operation my KX2 sits around 21-25 C. It was about 78 F\25 C at camp and I saw the heatsink temp peak at around 34 C after several rounds of transmission. It would quickly rise and as quickly descend at the end of each transmission. I don’t know what the foldback temperature is for the KX2. I will monitor the power output with my OHR WM-2 the next time I operate FT8 and digital modes in general to see if I hit the foldback in normal operation.

Given our position in Cycle 24, recently purchasing a shiny new QRP rig might not have been the best timing but digital modes seem to be on the rise. They mostly certainly provide new opportunities to make contacts and expand the frontiers of Amateur Radio. Like all of the other modes, some old, some new, they are another tool in the toolbox. My initial impression of FT8 is positive and while it will take a little practice to get used to the pace, my guess is that there will be some more operation with FT8 and my KX2 in the future.

UPDATE: Bas, PE4BAS asked a good question in the comments, that being time synchronization for the PC. I forgot to add this into the original post. WSJT-X requires a means for synchronizing the computer clock to UTC within ±1 second. Thankfully my XYL’s cellphone has service when we are at camp so I used that to access the US Naval Observatory time service at http://tycho.usno.navy.mil/simpletime.html. Using this reference I updated the PC clock manually. Lacking a data service I would have used WWV. This Genesis Radio site has a very nice list of time signals around the world. If the PC was connected to the Internet I’d use NISTIME 32 (scroll to the bottom of the page for the download), which is what I use on my home QTH PC.


PSK31 with the Elecraft KX2

One of the items on my seeming endless list of things to do in Amateur Radio has been to sort out a portable digital station. Other than a little WSPRing now and again I’ve only operated with any other digital mode (PSK31) once, just to try it out. That was three years ago with a Signalink USB and my IC-718. I’ve not touched it since however with my growing interest in portable operations I’ve wanted to add digital capability, especially when operating QRP. The portable digital station made its way to the top of the list with the recent acquisition of my KX2.

Even before the radio arrived I began to research digital operations with it. Obviously one way to do it is with the built-in functionality to both decode and send via the key, digital modes like PSK31 and RTTY. While this is a very nice feature and is clearly the lowest profile as it doesn’t require any additional hardware or software I wanted to have the ability to use a keyboard and perhaps a little large display than the scrolling one-line in the KX2.

The first approach that I thought I’d try was that of an Android tablet. We have a 7″ Samsung Galaxy 4 tablet that lies about largely unused in light of other devices. It’s certainly appealing due to its size, that being just a wee bit larger than the radio itself. I did a bit of research on this option and quickly found the DroidPSK app which is developed by Wolphi Solutions who also has have developed a simple tablet\smartphone to radio interface. A few more minutes research found that DroidPSK also can be used with a Signalink USB. The only downsides to this approach are that I’d need to carry a powered USB hub and I’d rather have a reasonable hardware keyboard as opposed to the soft keyboard of an Android app. The plus side was that I already own both the Signalink USB and a few powered USB hubs so other than the small fee for the app and some cables I was largely set. A nicer keyboard was kind of a sticking point though. The only time that I operated PSK31 I quickly found that I really wasn’t all that enamored with macro exchanges. I wanted to have an actual QSO, not just regurgitate canned messages. QSOs actually do occur in PSK31 but in order to facilitate this a half-decent keyboard was going to be a necessity. I realize that small USB and Bluetooth keyboards are available but that’s yet another piece of hardware to cart along and they are small, so I continued my research.

This past week, as I was sitting in my office eating my lunch and perusing QRZ.com I came upon a post by K5ACL entitled, “JT Modes & the Elecraft KX3, a how-to guide!” The post contained a video in which he described the use of a USB soundcard to interface to his KX3 in order to operate digital modes. Within minutes of watching the video I checked Amazon for the device, found it and ordered it, and as is typical, Amazon Primed it into my hands in two days. In between watching the video and ordering the USB soundcard, another dormant piece of hardware came to mind. We have an old Windows XP laptop that was purchased for the kids sometime ago, well before the days of smartphones and Android tablets. It’s small enough to be very portable and has a reasonable keyboard. With the addition of the USB soundcard it will make a nice platform for a portable digital station.

The USB soundcard that I purchased is a Sabrent. It gets very good reviews on Amazon and so for $6.49 it was worth a try. I plugged it into the XP machine and it had no issues. I quickly tested the input and output to make sure that it was working correctly prior to connecting it to the radio. When I purchased the KX2 in anticipation of digital operation I spent a few extra dollars to get their I\O cables, (E980229) Transmit Audio Cable and the (E980230) Receive Audio Cable. They are nicely done, with a right angle connector on one end and shrink-wrap colored labels that match their intended connections. The USB soundcard jacks are colored green for speaker\headphone (audio output from the PC) and red for the mic (audio input from the radio.) These match nicely with the labels on the Elecraft cables. The red plugs into the “phone” jack on the radio (audio output from the radio to the mic on the PC) and the green plugs into the “mic” jack on the radio (audio input to the radio from the speaker\headphone output.) The KX2 USB interface cable is used for radio control so you’ll need two USB ports.

KX2 PSK31 cables

Aside from the cable interface I set the KX2 to the “Data A” mode and dialed the power back to 5W as recommended by Elecraft.

Turning to the software, it seems as if the most popular PSK31 software is Fldigi, by W1HKJ, so I downloaded and installed that on the old laptop. If you are new to Fldigi, K4REF has a bunch of very nice videos on his YouTube channel that are very helpful.

The configuration of the software for my station is as follows. First, use the KX2 utility application to determine which com port is used by the KX2 cable to connect to the radio. In my case it was com7. Once that is complete shut the KX2 utility application down so that it frees the port for use by Fldigi.

KX2 com port

There are a lot of options in Fldigi. The most important ones to get right are the radio controls and the soundcard interface. When you first start Fldigi it will run a wizard which will step you through the settings. For my PC and the USB soundcard the configuration was a follows:

USB soundcard config

It’s possible that this may be different for your computer depending upon the sound devices in your PC. In XP you can check the audio devices by going to the Control Panel, double-clicking “Sound and Audio Devices” clicking the “Audio” tab, and then clicking the drop-downs for Default Device in both Sound playback and Sound recording. When I plugged in the USB soundcard they both defaulted to “USB Audio Device.”

There are several options for control of the radio. I chose to use Hamlib. My configuration was as follows:

Radio interface config

There wasn’t a selection in the rig list for KX2 so I chose the KX3 as they are likely the same for the purposes of rig interface for PSK31 operation. Set “Device” to the com port that the KX2 is on, in my case it was COM7.

Next I set the mode to USB and BPSK31:

Mode config

And finally I entered the Operator settings (Configure\UI\Operator):

Fldigi operator config

As soon as the soundcard settings were complete signals started to appear on the waterfall and be decoded. In order to check my transmission I picked a clear spot on the waterfall and transmitted a test message to check the soundcard levels and adjust the mic gain on the radio to the 4-5 bars of ALC as recommended by Elecraft.

After a quick check of the macros, I looked for someone calling CQ. One of the first signals that I found on 20m was that of VY2PLH. This is a special callsign for lighthouse activations on Prince Edward Island. In this case the operator, Bernie, VE9BGC was operating at Point Prim Lighthouse. According to their site, Point Prim Lighthouse was built in 1845 and is the first and oldest lighthouse on Prince Edward Island. We had a nice exchange with good signal reports. A very nice first QSO with the KX2 digital station.

Thus far I pretty happy with this configuration. The only new piece of equipment I needed was the $6.49 USB soundcard. The laptop is small enough to fit into the small backpack with the KX2 so this should work well. Now I will have some digital capabilities for our next camping trip.


First trip with the KX2

We just returned from another fine camping trip, this time with the KX2, its first trip to the great outdoors. First observation, they ought to out put warning labels on these things. They are very nice radios and you will want to operate them very often. Second, they sip power. I brought along my a Bioenno Power BLF 1209A battery (9 Ah), and used it without recharging, operating for a bit each day for the entire four day trip. No more hauling a trolling motor battery with the obligatory follow-on chiropractor trips for me.

KX2 at Camp

Yes, 10 W isn’t 100 W and given the current conditions 10 w SSB won’t always get the job done but many times it does. I made some good contacts over the period of the trip including some time at Rawley Point Lighthouse, with some especially nice QSO’s with WA0HHX and WR2D with good signal reports. I heard plenty of European DX stations, usually late in the afternoon on 20m but wasn’t able to make any contacts. (I take my TS-480SAT along and run it off the camper house battery or my Samlex 1223-BBM when I need 100 W.) At some point conditions will be such that I’ll get some DX from camp with the KX2.

For this trip the only antenna I used was my  LNR EFT-10/20/40 Trail-Friendly end fed. It’s very easy to toss my throw line up into a tree and pull up the antenna. I can be up and running in maybe 5-10 minutes.

My XYL and I saw a lot of White Pelicans on this trip. We’ve seen a few on occasion in years past but on this trip there were quite a large number of them flying about, swimming, and fishing in Lake Michigan. They are fun to watch and were quite entertaining while waiting for responses to my CQ calls at the lighthouse.

White Pelican

Butterfly’s were out in abundance on the beach as well including a bunch of Pearl Crescents and quite a few Red spotted Purples.

Pearl Crescent and Red spotted Purple

Next up for the KX2 portable station is a linked dipole for camp, the internal battery pack, and sorting out portable digital modes. We have several more camping trips scheduled for the year and there will be some other outdoor operation as well. The KX2 packs a lot of features into a small package and is a joy to operate. I’m as happy as a canary with a new beak!

Happy Camper with a KX2

New VFO knob for my KX2

In the runup to the purchase of my KX2 I read a number of comments in various places regarding the differences in the VFO between the KX2 and KX3. Most of the comments were about the difference in the feel between the two radios. There is an actual, physical difference. The main tuning encoder in the KX2 is “Mechanical, sleeve bearing” and that of the KX3 is “Optical, with ball-bearing shaft and weighted knob.” So the VFO feel is not just in your head, or your fingers, it’s actually both and based upon the fact that the mechanisms in the two radios are different.

The VFO knob may well be the primary piece of the man\machine interface of a radio. It is the knob that an Amateur Radio operator spends the most time touching\moving. It’s the one knob on a radio in which the feel is most important. In a way, Amateur Radio operators have been fiddling about with proprioception and haptic perception without likely even knowing it. The feel of this physical object and the mechanical\electrical linkage to the radio has always been very important to a radio operator and over the years manufacturers have used all manner of various mechanisms in an attempt to perform the necessary functions for the radio while providing the the right feel to the operator. In my observation the notion of this feel is often referred to as “weight.” The feel of a good VFO should not be light or loose. It should move with some reasonable effort and maintain its position when movement stops. To me it should have the feel of a weighted object moving through a reasonably viscous fluid with just the slightest amount of resistance to the imparted motion.

The VFO on my Kenwood TS-590SG has a very nice feel and even has a sliding lever beneath and just behind the VFO knob that can be used to increase the tension to suit the operator. I like mine with a little less tension and W9SIZ, who’s been twirling Collins and Hallicrafters VFO knobs all of his life, likes his with more. It actually was the very first thing that he adjusted when he took his new radio out of the box, before he even powered it up for the first time. “Tim, how do I adjust this VFO?” “Right here Uncle Paul.” Over many years his fingers and in turn his mind have developed a sense of what a VFO should feel like and the Kenwood product developers knew that the feel of this one knob is very important so they included the ability to adjust it.

There are countless examples of this on both new and old radios. For instance, I have a pair of Kenwood TS-830S transceivers. They are identical in every way except one has the highly desired Kenwood KB-1, which is solid aluminum, versus the standard plastic knob on the other. Even though the mechanical portions of the VFO are identical, the feel of the one with KB-1 is better than the one without. To this day a KB-1 is a highly sought after accessory for the TS-830S. I’ve seen them fetch upwards of $100 on eBay. All in the pursuit of improved VFO feel.

Kenwood KB-1

Aside from the actual differences in the VFO mechanism between the KX2 and the KX3 and how this affects the feel, the VFO knob on the KX2 lacks a dimple. This seems like an obvious miss on Elecraft’s part. How much more would a dimple have cost? I’m sure that we all would have happily paid the difference. So in pursuit of a dimple and some improved feel I started to search for a third-party solution. As you may be aware there is a fair cottage industry of accessories for Elecraft radios. I found some vendors that make VFO knobs for their other radios but none for the KX2. As a last resort I searched eBay and found this:

KX2 VFO tuning knob

It is solid aluminum, with straight knurling on the circumference, and as you can see, a dimple.

OEM KX2 VFO knob vs replacement

It is slightly larger than the original VFO knob (1.257 inches vs 1.112 inches) and has a reasonable heft to it. Where the original knob is just pressed onto the shaft of the VFO mechanism, the new one has a set screw (Allen wrench provided.) Installation is obviously simple. One thing of note is that since the new knob is slightly larger you may find that it might contact the display cover. Mine did. To resolve this I simply loosened the display cover screws and there was enough play in the cover to move it up slightly to clear the new VFO knob. The seller describes potential clearance issues in the posting for the item.

New VFO tuning knob

The new knob imparts a much nicer feel to the VFO and the dimple is a welcome addition. It was much less expensive than the third-party VFO knobs for other Elecraft radios and it is a very nice upgrade to my new KX2. The eBay seller was very easy to deal with and shipped the item very quickly.