Elecraft KX3 / KX2
After enjoying numerous little QRP radios, I figured it's time to make a change so I purchased an Elecraft KX3 with the following options:
Roofing filter board
Internal battery charger w/clock
Built in auto tuner
Elecraft screw on CW paddles ( a gift from a good friend )
CW operating tip:
When the KX3 is tilted forward on its rear feet, I found that the CW paddles are a little too low and uncomfortable. When laying the rig flat on its
back I then found the paddles a little too high and again uncomfortable. To resolve this I placed a 3/4" think piece of white pine under the rig.
This places the paddles at a much more confortable and usable operating position.
The picture on the right shows the actual pad that I made out of wood that measures 3/4" x 7-9/16" x 3-3/4".
I cut a small grove on the top front of the pad so the rubber feet on the bottom of the KX3 rests in the slot. This
keeps the radio from sliding off of the pad if you hit the paddles too hard or bump the radio. A radial arm saw,
table saw or router can be used to cut the groove.
Palm Pico Paddles on the KX3
Hannes, DL9SCO and Dieter, DJ6TE have outdone themselves with this setup. The KX3 is a great radio but the Elecraft paddles are very questionable. Every so often the Elecraft paddles will miss a dit or a dah. I tried everything I could think of to resolve this issue and finally gave up. Other’s have had the same problem. After watching a YouTube video on the Pico Paddles I decided to give them a try. I can not put into words how much I like these little paddles. I was concerned about the size, I though they would be too small. I was wrong, they are perfect. They have a great feel, adjustable tension and adjustable contact gaps. When not in use you can swing the paddles to the side and tuck the paddles inside of the little square enclosure. These little guys don’t miss a beat.
The Pico Paddles also have a magnetic base. “Mores Express” sells a metal side panel for the KX3 so you can attach these little paddles to the right hand side of the radio if you don’t want them on the front of the radio. A bonus for me is, my little You Kits / Ten Tec R4020 has a metal enclosure so these little guys will also work with that rig.
Pico Paddle update: May 2020.....I see the Palm Paddles are no longer made. What a shame. I am glad I have three sets of them.
Here's a YouTube video talking about CW paddles, KX3 platform and a note on batteries:
The Ni-Zn batteries (1.6 volt per cell) that are shown in this video can not be charged while they are in the radio. You MUST use the special charger that is designed for these batteries.
The KX2 is my, "Go To Radio" for portable operating. Shown below is my complete KX2 portable setup.
Everything except the nylon cord, coax and antenna fit in the little camera carry bag. Take note to the little computer mic plugged into the left hand side of the KX2. There is a mic that is built into the radio but I like the little plug in mic's.
The following is what all fits inside of the camera case.
KX2 with built in ATU, clock and LiPo battery. A set of Palm Pico Paddles are attached to the bottom of the radio along with the little computer mic on the left hand side.
Tablet, mini log book, pen, 6" long RG316 jumper cable with BNC's on both ends along with an adapter to connect to a PL 259. Power cable with Anderson Power Poles.
One extra LiPo battery. Ear buds and a BNC to banana jack adapter.
Not in the carry bag are the following items.
Home brew 40 meter half wave end fed antenna with a 64 to 1 twenty five watt UnUn. The wire for the antenna is #22 teflon insulated wire 65' 5" long. The antenna and UnUn will fit into my shirt pocket. The coax is a 25 foot length of RG 174 with three wraps of coax wound around a #43 clip on ferrite bead. The choke IS NOT on the antenna end of the coax but on the other end, close to the radio. From that point I attach a 10 foot length of RG 174 which goes to the radio.On each band (10, 15, 20 and 40 meters) I get an SWR of less than 1.3 to 1 somewhere in each band. Even though the KX2 has a built in ATU, I always keep the tuner in the bypass position. Why use a tuner if it's not needed?
I also carry along 25 feet of 1/8" nylon cord for holding up the far end of the antenna. I can put the nylon cord and coax in pants pocket.
The camera bag is a Case Logic SLRC 208 Slim Action Camera Case. I purchased it on Amazon. It sells for about $25.
When it it comes to trimming an antenna, I found that the little MFJ-223 antenna analyzer does a great job. I needed a simple antenna analyzer that would fit in my shirt pocket and the 223 fits the bill. The frequency range is 160 to 6 meters. I also use other antenna analyzers, but I did not want to carry around a large antenna analyzer, like the Rig Expert AA-230 Zoom.
If you'd like to see how the MFJ-223 works, first hand, you may find the video below very interesting.
12 foot long 20 meter micro antenna construction details
I like using very small resonant antennas when operating portable. The following YouTube video will give you instructions on how to make a very compact resontant 20 meter dipole that will handle up
to 100 watts of RF.
The coax I used in the video is a 15 foot length of RG 174. The maximum length I would use of this coax would be no more than 25 feet.
A word on coaxial cable
It's always nice to be able to use low loss coaxial cable, like RG 213, but it is really not practical to use this type of coax when operating portable. I feel RG 8X is great cable for portable operations. RG 58 is a little smaller in diameter but I always had issues when using PL 259 connectors on this cable. It seemed they had a very high failure rate. The center conductor would always fail inside of the connector. Having a coax fail when in the field makes for a bad day. Since the KX3 and my Ten Tec R4020 both use BNC's, I figured it’s time to make the change. Installing BNC's on RG 58 cable is not a fun job. First you must make sure your purchase the correct connector. I decided it would be a lot easier and, in this case, much better to look for assemblies already made. Amphenol Cables on Demand had just what I needed. They use low loss RG 58 cable and BNC's that are molded to the cable. I purchased two each pre made 25 foot lengths and one each pre made 50 foot length. You will also need to carry a BNC female coupler if longer lengths are needed.
I started to use RG-174 coax with BNC's on both ends. It's much smaller and easier to carry. The losses of a 25 foot run of RG-174 are very low.
Shown on the left is a pre made 25 foot length of RG 58 coax, with BNC molded connectors. The double female connector is shown laying in the middle.
The labels on the coax were made using the Brady BMP 21 wire label maker. Since I bought the Brady I've labeled all of the cables in the shack. The Brother P-Touch has its place but there is nothing like a label maker designed for putting labels on wires and cables.
I have since changed to using RG 174 with BNC's on both ends. I only us it for runs under 35 feet. I like to keep my complete portable QRP go package as small and light as possible and RG 174 makes the package a lot smaller. I can actually put a small antenna in one pants pocket and the RG 174 in my other pocket.
11.1 Volts @ 5 AH LiPo battery
Battery size: 5-1/2" x 1-1/4" x 1-5/8"
The LiPo battery, pictured right, is a great addition to my KX3 package. The fully charged three cell LiPo battery is around 12.2 volts. You can run the KX3 at 10 watts output power with this battery. Since I only run my KX3 at the 5 watt level, I can use this battery for a very long time when set up portable.
The four cell pack will product too high of a voltage for the KX3, 16 volts fully charged. The Nickel Metal Hydride Battery, I have used on the Icom IC 703, is almost twice the size of this LiPo and only delivers 4200 mha. Nickel Metal Hydride Battery will also self discharge in a few weeks while just sitting on the shelf. The LiPo batteries will hold their charge, on the shelf, for an extened period of time. I added the fuse holder and the Anderson Power Poles to the battery.
15 Watt power output trick:
I've seen in a YouTube video where a ham used a 4 cell LiPo plugged directly into his KX2. A fully charged 4 cell LiPo is over 16 volts and that is way too high of a voltage to apply to these little radios.
To get the full 15 watts out of your KX3, you need a higher voltage than the 3 cell LiPo can supply. So here's a trick to use so you can get your full 15 watts
out. Use a 4 cell Lipo but put four each 6 amp diodes in series to drop the voltage to the 14 volt range. These little diodes only cost 54 cents each. Cover
the diode string in shrink tubing. I would put the fuse and diode string in an adapter type configuration.
First put Anderson Power Poles on the battery leads. Then build an adapter with the fuse and diode string with power poles on the input side and the output
side. By removing the adapter you will be able to full charge the battery. Put your radio's power cord from the inline adaptor to the radio and now you have more than enough
voltage to run your full 15 watts of output power.
This is the best bag for the buck battery that I have found so far. This is a three cell 11.1 volt battery rated at 6.4 amps.
It is compact and very reasonably priced at $34.75, as of May 2020.
Just put a fuse and Anderson Power Poles on the power leads and you are ready to go.
The fuse holder was purchased from: Marlin P. Jones
Anderson Power poles are also needed. All of my 12 volt equipment use: Anderson Power Poles
Venom Has a great selection of LiPo batteries at a very resonable price.
Hobby King Is a great place to purchase LiPo batteries. They seem to have the best price. They now have a stateside location so shipping is a lot faster.
Hobby Zone is another great place to purchase LiPo batteries.
Power Hobby Is yet another great place to purchase LiPo batteries.
The needed charger, purchased from Hobby Partz, was only $19.
These batteries are also a great choice for other rigs like the Icom 703, Yaesu FT 817 and the You Kits / Ten Tec QRP rigs.
New technology Graphene batteries as of August 2019
Keep an eye on, "Graphene Batteries." This is a new technology and offers 45% more current capacity as compared to the same size LiPo battery.
Samsung is starting to use them in cell phones but in the next year or two you are going to see a nice selection of them for RC equipment that can double
for ham radio service.