Wifi inside a KX3
While browsing info on the ‘Piglet’ on Nick Garner’s Pignology web site the thought struck me, I wonder if I could install a version of the Piglet inside my KX3. I built my KX3 from a kit and never installed the battery holders or the internal charger. I’ve always operated the rig from an external supply; either Lipo batteries or from a 12 VDC supply in the shack. Looking at the size of the Piglet I thought there might be room enough to fit it inside the KX3.
A few emails back and forth with Nick/N3WG, (the guy behind the pig) confirmed the possibility. Nick suggested a through-hole version of the board, minus the DB9 and Power Poles connectors, for experimentation. A few days later the parts showed up and it was off to the races – another first for Muppet Labs. Actually It turned out to be an easy project and enables logging with Pignology’s Hamlog app without having to deal with wires.
The first ‘trial by fire’ was on top of Cascade Mountain in the Adirondacks. I brought along pencil and paper as backup but Nick’s Hamlog software and the built in Piglet worked perfectly. I logged 22 contacts without a hitch. I was using the Android version of the app which unfortunately does not export a SOTA compatible .csv file, hopefully Nick may add that in the future. I experienced intermittent cell service while on Cascade which let Hamlog look up callers in QRZ while I was logging. Very cool to be able to answer someone with a ‘Thanks Barry, you’re 599 72”, making a personable, but quick QSO. The photo shows the ‘shack’ on top of Cascade (3880’) but not the phone I was using for logging because??? You guessed it I was using the same phone to take the photo!
What you get is a really cool, KX3/W – not everyone has one of those, right?
This mod isn’t for everyone. You should be comfortable with soldering in tight places and not afraid to damage a $1000 radio. Battery drain is increased as the Piglet draws 70 ma, and you have to disconnect it if you want to use the ACC1 jack to update firmware or use a different logging program. For my use this is perfectly acceptable. The ease of logging and (hopefully) log upload to the SOTA database make it perfect. As always YMMV, follow along for a detailed, step by step, article.
- You will have to remove the battery holders in your KX3. This was not an issue for me as I never installed them in the first place. On summits I power the rig with an external Lipo battery, at home with a 12v supply. If you’re OK with this then read on!
- You also need access to P3, so the KXBC3 can’t be installed. Since the battery holder isn’t installed you probably don’t have the charger anyway!
- Mounted inside the KX3 without its antenna exposed the Piglet’s wifi range is short, somewhere around 8 to 15’. I don’t see this as an issue as most people will be much closer than that when logging but figured I should point it out.
- The method I used to power it is unswitched, whenever there is power at the 9-15 VDC plug on the KX3 the Piglet is powered on. There is a spot on the circuit board with ‘switched’ 12 volts that could be used. This solves the always on when battery is connected problem but still means the Piglet is always on when the rig is turned on, and this presents the last caveat.
- Wired as shown the ACC1 jack is no longer usable with the KXUSB (or KXSER) cable when the Piglet is powered on. You must power off the Piglet in order to regain the use of ACC1 for firmware upgrades or using other logging programs.
If you can live with the above then here’s how you do it, including pictures!
This mod isn’t for everyone. You need to be comfortable with soldering in tight places. If you damage your KX3 I’m sure it won’t be fixed under warranty and you lose your internal battery holder.
Installing a Piglet inside an Elecraft KX3
- Obtain the Piglet board, minus the DB9 and Power Poles from Pignology
- Power up your KX3 and set the RS232 baud rate to 4800
- It’s easier to do this now than when the rig is apart for testing.
- Open up the KX3 for surgery
- I found it easier to work on the rig if I disconnected the flex cable and worked on the front half of the rig (the control panel side) without having the back half in my way.
- Remove the battery compartment shield board and battery holders if still installed. Don’t lose the screws holding the battery retainer and shield as It will be replaced.
- Prepare a small three conductor, 6” long, color coded cable.
- On one end strip 1/8” of insulation and tin the wires.
- Solder the ends to the ACC1 jack as shown
- Make note of the color code so you can connect them to the correct lands on the Piglet circuit board.
- Leave the other end of the cable free for the moment.
- Replace the battery compartment shield board (you didn’t lose the screws, correct?
- Prepare the Piglet (Figure x)
- Solder a jumper between pins 4 and 8 of the DB9 connector traces.
- Solder a (+) and (-) 2” jumper with jacks to the appropriate locations (where the Power Poles should connect) on the board. See the parts list for the jumpers/jacks I used.
- Roughly locate the Piglet where it belongs
- Cut the wires from ACC1 to a comfortable length and solder them to connections 2, 3 and 5 of the DB9 connector traces. You did remember your color code, right?
- Use double stick foam tape to mount the Piglet as shown.
- Clean the shield and bottom of the Piglet board with alcohol, it really helps the tape stick better.
- Connect the power jumpers you installed to pins 1 and 10 to the KX3’s plug P3
- Positive (+) goes to pin #1
- Negative (-) goes to pin #10
- P3 is the plug for the KXBC3
- Reconnect the KX3’s flex cable
- Plug a known power source into the KX3’s 9-15V power jack. You should see LED’s start to flash on the Piglet
- Verify you can see the Piglet in your mobile device’s Wifi list.
- Turn on the KX3
- Start your Hamlog app and follow Nick’s instructions for setup.
- If everything is correct you should now be able to control your KX3 with your mobile device
- Congratulations – you now have a KX3/W (Wifi)!
- Piglet board w/o DB9 and Power Pole connectors: Pignology
- Small, flexible wire with push on connectors. I used product number 826 from Adafruit for both the ACC1 wiring and the power connections: http://www.adafruit.com/products/826
- Double stick foam tape. I used servo tape available from any R/C hobby store. Something similar to this should work fine: http://www.sigmfg.com/IndexText/SIGSH119.html
1. Elecraft KX3 Schematic KX3 Control Panel Connectors: http://www.elecraft.com/manual/KX3SchematicDiagramDec2012.pdf
2. KXSER Schematic the cable schematic is on the last page: http://www.elecraft.com/manual/KXPA100%20Owner’s%20Manual.pdf
Don’t forget to disconnect the battery when you’re not using the KX3 or the Piglet will deplete it. The Piglet shows approximately 70ma of current when running. Considering the KX3 can draw up to 3A on transmit it isn’t going to reduce your battery life significantly.
Remember! If you need to use the ACC1 jack with the KXUSB (or KXSER) cable you will have to turn off the Piglet. What I do is open up the rig and remove the (+) connection to the Piglet. I’m sure some craftier folks could find a way to add a switch but I’m OK with this simple approach. The KX3 is usually used portable and the frequency of firmware updates doesn’t make it a burden to stay with the simple approach.
There doesn’t appear to be any negative impact on the KX3’s performance, either RX or TX, since the modification. I don’t have access to sophisticated test equipment but A/B comparisons to an Icom IC756-2 with weak signals, before and after the mod, didn’t show any RX degradation from the mod.
Ideas, questions, suggestions, corrections? Feel free to drop me an email!
’73 and enjoy your KX3/W