Icom IC-7300 External Keyboard


Endlessly calling CQ during a contest or special call activation can give you a sore throat. Voice keyers were invented for this particular matter. A voice keyer is even built in in the IC-7300, so at first there is no need for an external device.

This voice keyer has 8 presets and can be used as a keyer for voice, CW or RTTY. The only drawback is that this keyer is only accessible when the voice keyer option is visible on the display. And at that time you can’t see any other screen that might me more of an interest to you than the voice keyer buttons such as a largere scope, the audio in- and output and your meters (SWR, ALC, COMP and I). An external keyboard would be of great help.

Strange enough this external keyboard is not provided by Icom, you are forced to buy an aftermarket device, or… build it yourself. The schematics for this are made available by Icom in their manual on page 12-2.

A prerequisit for me was that I could still use the original mic when the keyboard was attached, and that when I don’t use the original mic, I still have the same capabilities as if I’m using the original mic. So both schematics need to be combined.

Gather the needed components


Except for the resistors all I needed was bought on AliExpress. For the enclosure I choose for a aluminum box measuring 122(W) x 66.5(H) x 39.5(L)mm. Guitar enthousiast use these enclosures to make so call stomp boxes or effects units. Manufacturer Hammond brought an enclosure with these dimension to the market as model 125B/1590N1. If you search on AliExpress with these model numbers, you get some options to choose from.



You can choose whatever momentary switch you like for this project. I went for black plastic 12 mm momentary push-buttons.

Microphone connectors

Icom uses a 8-pin microphone connector. These GX16 connectors, sometimes also referred to as circular aviation socket plug, can be found in abundance on AliExpress. Search for GX16 8 male female because we want two male sockets and 2 female sockets. The male sockets are to be place on the enclosure, the female sockets are needed to build the cable to connect the external keyboard to the radio.


Finding a suitable cable that has sufficient inner strands, is not to thick and looks good was not so easy. Mini din 8 pin extension cables can be found easily, but they do often come in an ugly beige color. As we only need 6 inner strands, I figured out a mini din 6 pin cable would do the trick as well. I still had 1 meter of this cable in my stock as I once used it to build a data interface for my trusty Yaesu FT857-D.


We need one 470 Ohm, one 4,7k Ohm, one 2,2k Ohm and two 1,5k Ohm resistors. All 5% and 1/4 Watt.

Audio Jack Sockets

When looking for audio jack sockets, look for those with a screw on the inside of the enclosure. Not only do they look better, I also have the impression the quality is a bit better.

Preparing the enclosure


On the top of the box 7 holes needed to be drilled. 4 on the top row, 3 on the bottom row. Each hole has to be 12mm.


On the left two 20mm holes are drilled for the GX16 connectors and on the front 2 7mm holes were made for the 3.5mm stereo jacks.


On the back, another 7mm hole was drilled for the 3.5mm jack that will be used to connect a foot-pedal for handsfree PTT operation.

Once all holes are drilled and all components are test fitted, you can start sanding the box and give it some layers of spray paint.

Put everything together

First make sure you solder long ends of wire to the GX16 connectors. It would be a real challenge to solder them when they are already mounted in the enclosure.


I opened the original Icom MH-219 to know what color code they use and tried to use the same as much as possible.

Pin 1: Mic input = white
Pin 2: 8V = not used for this project
Pin 3: Frequency up and down = red
Pin 4: Squelch = not used for this project
Pin 5: PTT = brown
Pin 6: PTT Ground = green
Pin 7: Mic Ground = Black
Pin 8: AF output = Blue

Everything wired up.

Now fix a connection cable with two female GX16-8 connectors, using a SP/2 extension cable and some clear tubing as stress relief. The color scheme of this cable is different from that of Icom, but as long as you connect each wire to the same pin on the opposite side of the cable, you’re good to go.


The finished product


In this picture, the original mic and the foot pedal are not connected. I’m using an in-ear Sennheiser and a 1€ condenser boom mic from AliExpress. Maybe not the “best” solution, but for the moment good enough.

Everything works as it should and the magic smoke remained in the components where it belongs 😉

I will put this keyer to the test during the March 2019 CQ WPX contest. Hope to meet you on the band!

73 de ON5IA

Bow Drill Bearing Block

Last weekend I made a bow drill bearing block out of a stone.

Bow Drill Bearing Block

First of all you need to find a flat stone that fits nicely in your hand. The next thing you need to do is to start making a depression in it using some flint. 30 minutes later you’ll end up with a bearing block as shown above.

The advantage of a stone bearing block over a wooden bearing block is less friction. You want as much friction on your fire board, but a less friction as possible in your bearing block. Metal and glass are even better materials as a bearing block, but they don’t look as “natural” as a stone one.

Paracord Lanyard Knot

How to make a lanyard knot: a photo tutorial.

Step 1: form a loop with the working end under the standing end.
Lanyard Knot (1 of 14)

Step 2: take the other end of the cord. To make it easier to understand I used a different color of paracord. Pull the working end of the desert tan paracord under the loop.
Lanyard Knot (2 of 14)

Step 3: Pull the working end of the desert tan paracord over the standing part of the green paracord.
Lanyard Knot (3 of 14)

Step 4: make a bight with the working end of the desert tan paracord and pull it under the working end of the green paracord.
Lanyard Knot (4 of 14)

Step 5: pull the desert tan paracord over the right side of the loop of the green paracord.
Lanyard Knot (5 of 14)

Step 6: pull the working end of the desert tan paracord under it’s own standing part.
Lanyard Knot (6 of 14)

Step 7: continue to pull the working part of the desert tan paracord over the left side of the green paracord loop. You now see a diamond shape in the middle.
Lanyard Knot (7 of 14)

Step 8: with the working end of the green paracord you make a bight to the top and pull it over the standing part of the desert tan paracord.
Lanyard Knot (8 of 14)

Step 9: pull the working end of the green paracord under both loops into the diamond shape.
Lanyard Knot (9 of 14)

Step 10: pull further and make a bight to the right.
Lanyard Knot (10 of 14)

Step 11: take the desert tan paracord and make a bight to the left over the standing part of the green paracord.
Lanyard Knot (11 of 14)

Step 12: pull the desert tan paracord under both loops, trough the diamond shape and make a bight to the left.
Lanyard Knot (12 of 14)

Step 13: tighten everything up.
Lanyard Knot (13 of 14)

Step 14: and we end up with a nicely knotted lanyard knot.
Lanyard Knot (14 of 14)

Gathering Flint

A fellow bushcrafter, Mike – Survivalmike- , was looking for flint. To bad for him, in Austria there are very few sources of flint (if there are any). So he posted a video on youtube to ask for help.

Lucky for me (and for him) I live near an area full of flint (see previous posts). So I decided to help him out, and went gathering some flint to ship to Austria.

Flint & Steel + Horseshoe Amadou = Fire

Today I’m presenting to you a method of fire lighting, using flint, steel and some horseshoe amadou.

Not so far from where I live there’s a marl cave. There is an abundance of flint in those caves.
Marl cave

The firesteel or steel striker is made by Launditch who I met on BushcraftUK.com.

The horseshoe amadou I collected and prepared myself. I’ll explain in detail how I did this in a future post, but in basically you collect the horseshoe fungus, cut out the amadou, cut it into slices, boil it in water with ashes, flatten it with a baton and let it dry.

Broken Fenix LD20

Right after a battery replacement my trusty Fenix LD20 didn’t function anymore. Even after checking the head and tailcap, the LD20 refused to light. A very bad feeling was coming over me…

Maybe the batteries were dead, although the charger told my other ways. Same result with other batteries and since there isn’t much that looks that might go wrong, my only help would be the internet.

Immediately after entering my keywords I stumbled on a site called Light-Reviews.com. There it was mentioned to tighten the retaining ring that sits inside the tail cap.

Fixing tailcap

A twist of the wrist later, using my Leatherman Charge TTi, my Fenix LD20 was working again. Please note to tighten the retaining ring counterclockwise.

Artificial Fatwood

A time ago I was looking for fatwood, but i couldn’t find any. The only thing that I could find was really dry and porous wood. When I came home I decided to make my own fatwood. Fatwood is just wood and fat (resin 🙂 ) so it shouldn’t be so difficult to make it myself.

I took a small saucepan and filled it with paraffin which I saved from all the candles my wife burned the last two years. Once melted I dropped the pieces of wood in the paraffin.


The bubbles you see on the picture is not the paraffin that’s boiling, but the air that’s coming out the dried wood and being replaced by paraffin.

Once all the bubbles were gone I let the pieces of wood cool down, so the paraffin could harden out. A few hours later I tried the first piece of self made fatwood.

The first two times I tried to light the fatwood (and all other attempts after this video) were successful as of the first or second strike. Only in this video (which is uncut) it took me 21 strokes to get the fatwood burning. It just needs that one little hot sparkle…


Today I went on a small trip with my wife and son to collect some new pieces of flint. The previous flint I brought from this cave is broken into way to small pieces to use with steel striker.

Marl cave
On the left of this picture, you can clearly see the flint bank. It’s compressed between two layers of marl. The funny thing about these marl caves is that the flint is only a side product. People who were working in these caves were out for marl to build house and churches or to make cement. But just like our ancestors, the Neanderthalers, it’s the flint that brings me here.

Walking in a cave like this always smells like an adventure. It’s dark and cold, and you’ll never know who or what you’ll come across. The cave we visited is open for public and not very big. You’ll never get really lost in it.

To collect some flint I didn’t cut into the ceiling nor the walls. I prefer not to take the risk the whole cave would collapse. There are plenty of pieces of flint just laying on the ground. What can be easier than just picking them up?

However, I should have taken some precautions, like wearing gloves. I’ve cut my finger just by picking up a piece of flint. Didn’t they used to make knives and axes from silex 😉 ?
Finger cut

Installing Ubuntu 9.10 On An External USB Hard Drive

Last week, I bought myself a new external Iomega Select Portable Hard Drive. I do not have a laptop of my own, but my employer allows me to use the one from my work at home. That’s ok as long as you want to use it for what it’s intended: to work. If you want to surf the net, or want to use it to download pictures from you camera, you’ll face some limitations. You can’t use or install a browser of application of your own choice.

That’s why I got the idea to install Ubuntu 9.10 on an external USB hard drive. It will be my own operating system and I can configure it how I want. I can even install my own applications. Actually you’re not installing them on the laptop, but on the external hard drive. You are only using the laptop’s hardware.

But as I do own a PC, running Windows XP, I didn’t want to use the entire hard drive for Ubuntu. I also wanted to have some free space to make backups. That free space needs to be NTFS formatted, and to get this done, I took me some time.

Good as I’m, I’ll tell you how I did it in a few steps, beginning with downloading the iso file of Ubuntu 9.10 from this location.

When this is done and before burning the iso on a CD, you must do a MD5 checksum to be sure the iso didn’t get corrupted while downloading. I used WinMD5sum from nullriver.com to compare the UbuntuHashes with the one of the iso.


If the checksum is ok, you can burn the iso on a CD. For that I’m using ImgBurn.

When your CD is ready, remove al internal hard drives from you laptop, plug in your external hard drive and boot your laptop from the CD. Be aware your BIOS is properly configured to boot from CD.

As of then I followed the step-by-step instructions found on softpedia.

Like described in the step-by-step instructions I created 3 partitions. A swap partition of 2 GB a ext4 partition of 30 GB with mount point / and a ext4 partition with the rest of the available space with mount point /home.

Be sure to install the boot loader on your external hard drive. This is also the reason why I removed the internal drive from the laptop: less chance to screw it up!

After a while Ubuntu will be installed to your external hard drive. If everything went well, you can boot your laptop now from this external hard drive. But if you’ll plug in this drive into a Windows machine, it won’t recognize any free space as it’s not formatted in NTFS.

To do this I rebooted the laptop with the CD without having the external drive connected. Then I did choose to test Ubuntu without installing it, I plugged in the external drive and opened GParted. I unmounted the last and biggest partition, and reside it to about 30 GB. The newly free space was formatted NTFS.

Now I’m having a bootable external USB hard drive running Ubuntu, which can still be used to backup files created on my Windows XP desktop.