Old posts


so, the website changed. I found only one way of transferring the old blog to the new one: copy & paste. So, I copied everything worth copying. There is one disadvantage: the date is reset to today. For most posts that won’t really matter, but it’s good knowing that I didn’t have my QSO with Rob PA3CNT today.

Web-based remote control

Inspired by things like René, PC7X repeater status page I thought it should be possible to remotely control my FT-817nd (or any CAT-equipped rig for that matter). Of course there are already a few solutions:

  • RemoteRig: a hardware solution for transceivers with a detachable head like the Yaesu FT-8900 or Icom IC-7100
  • HRD: ham radio deluxe can connect to a ‘remote’ HRD, of course this requires 2 PC’s and windows on both
  • Icom’s remote solution, that requires a specific type of RIG with ethernet or a windows PC connected to the RIG at one end, and windows with the Icom software on the other end.

I don’t like MS windows, so that is one issue, one that disqualifies the last to solutions. And the FT-817nd has a fixed head, so that disqualifies the first. And, that is true for so many rigs.

So I started a small project to build a web-based solution. The first steps have been made I can display the FT-817’s frequency and TX/RX status led. It turns out that the FT-817nd has a severely limited CAT interface. But fortunately also a number of undocumented features…

Bias-Tee (PTT via coax insert)

So, the Bulgarian Trasverter supports PTT via Coax, or VTT as they call it. Basically, all you have to do is apply 5 to 15 volt DC offset on the coax coming from the back-end transceiver during transmission. There are plenty of schematics out there to do so, no worries. Basically there is a small (10 nF) capacitor in line and a coil feeding the DC offset.

Nice thing: the Yaesu FT817nd has a PTT output, an open collector NPN transistor and 13 volt readily available on the ACC socket. With a PNP transistor and two resistors this makes for a perfect VTT source. So, all I had to do was:

  • build the Bias-Tee on one side of a PCB
  • build the VTT circuit on the other side
  • Box it up in a tin-plate box
  • Add some connectors

Et voila:

Bias Tee
Bias Tee

Hook it up to the FT-817nd and it looks like:

FT-817nd with Bias Tee
FT-817nd with Bias Tee

13 transverter and amp (2)

So, yesterday another milestone and a small setback. First the setback: my power supply is a meat 28 volt and 320 Watt, which seems to be too little for the transverter and amplifier.

And therein lies the good news: the amp has been powered up, connected to the transverter and put to work. Hans, PE1CKK, was nice enough to assist in the tuning of the amp and we finally measured over 60 Watt of output power. Now, I know that I’ll loose at least one dB of that in the relay and cables. So, if I want to do things right, I have to use better, shorter cables. Semi-rigid coax comes to mind. But, If I replace my current RG-316 coax by 3mm semi-rigid, I’ll have to do it all the way, not just from the amp output to the relay, but also from relay to receiver input. I’ll think about it. For now, let’s just get things working. As you can see from the picture below, the sequencer board is not yet connected and  installed, so that has to go in first. And, I need a bigger PSU!


Korg nanoKONTROL2 and Studio One

I got myself a Korg nanoKONTROL2 to work with Persons Studio One. The nanoKontrol2 was only € 44,- and well, that is not much money for what it is.

Presonus recommends using the nanoKontrol in what they call Mackie mode, the Korg manual refers to this mode as Cubase mode. This works, sort of. The pan pots are bit of a thing, going only from 40% right to 90% left or so, but other than that things work as expected. BTW. the org unit may look cheapish on some pictures, but the faders and knobs, though not very big, do feel nice.

But, I wasn’t quite happy with the setup in Studio One as Persons made it for this tiny controller. I wanted to use the knobs and faders as I see fit. Fortunately, Studio One offers the opportunity to define your own midi control surface the way you like it. Just select “New Control Surface” when adding an external device rather than the Kort nanoKONTROL2 predefined option.

The next step is to set the nanoKONTROL in “CC” mode. This can be done when you plug in the device by holding down ‘set’ and ‘cycle’, but I found the Korg software to be just as useful. You then do have to manually configure the function of each knob, first by selecting ‘MIDI LEARN’ and touching each knob and fader on the device and setting the type of know. From the same panel you can assign a number of buttons statically to a function, but most of the linking to functions you will do from the normal Studio One editor. This allows you to use the faders as usual in the main context, and to adjust the parameters of say a reverb in that context. This is a bit of work, but that is what we wanted.

There are a few things that don’t quite work as I like, but this is a lot better (IMHO) than the default setup.

First in FreeDV

Just now (18:15 UTC) I had a QSO with Rob, PA3CNT, in FreeDV on 433.525 MHz. The audio quality was somewhat suboptimal, but all relevant info could be exchanged. I’m definitely a happy camper today! (This may be a first FreeDV on 70cm in PA country!) All thanks to John, PA0ETE, who posted the movie from my previous blog posting on his website.

Below you see my laptop running FreeDV attached to the IC-7100. It’s a setup on the backrest of my couch because the USB cable is only 1.5m long.


ps. after the first posting of this blog entry Lucas, PD0LVS, installed freeDV too, so that is a second QSO! And this time it’s even a distance worth mentioning: JO22jp <-> JO22lh.

FreeDV on the IC-7100

Inspired by Don Snodgrass K4QKY I decided to try the same with my Icom IC-7100 and my Mac. Should be simple enough, the IC-7100 has a built-in USB serial adapter for rig control using CI-V commands and audio device for analog audio in- and output.


I’m using either the built-in speaker and microphone or an apple headset with integrated microphone for now. Until I’ve made a few QSOs and have some reports on my audio that will have to do.

I did have to install the SI Labs USB to UART driver and reboot but then indeed the two serial devices that are integrated into the IC-7100 did show up. The audio device was already visible in the system preferences and indeed, without much ado I could configure FreeDV to use all of that. A short movie (might take a while to load) shows me setting things up.

All I need now is another station for a first QSO….

About the configuration of the IC-7100. Be sure to select USB and DATA as mode, the display will show ‘USB-D’ on the top left. In the connectors settings menu select USB in the ‘DATA MOD’ configuration item. If you, like I did at first, select normal SSB (USB) operations and select ‘USB’ as the audio source for ‘DATA OFF MOD’ there will be a terrible amount of echo.

Using ‘USB-D’ mode has the added benefit that it’s very easy to switch from the FreeDV modem (laptop) to the normal microphone input, just (de)select the DATA mode.

PS. a longer USB cable would be welcome… 5 meter or so will do.

PS2: John posted the movie on his site as well, for a much faster experience.

PS3: I removed the movie from this blog posting… check YouTube for a new version.

the Kaasplankantenne

Kaasplank(je): a selection of cheeses, usually served on a cutting board.

Based on the design for a 4m antenna by John, PA0ETE, I decided to try for myself. Initially I wanted to stay as close as possible to the original design, but eventually selected different materials.

  • one dirt cheap plastic cutting board ( €0,69 at the budget household store )
  • two 1m lengths of 8mm round aluminium tube ( € 2,39 each at the DIY store )
  • one 1m length of 15mm square aluminium tube ( € 4,00 or so )
  • two m3*16mm screws with nuts ( several cents )
  • two 6mm bolts with wingnuts ( several cents )
  • two faston connectors ( several cents )
  • length of Aircell7 with a N-female connector ( € 10,00 or so )
  • tie wraps (several cents )

I started out by drawing a template on paper. Drew the outline of the cutting board, and two lines at a 120 degree angle from each other (and the center line). Then one centimeter from those lines is drew a few 5mm holes… 2 for each tie wrap one set about 15mm from the center line, the other set at about 1cm from the board edge. Then taped the template to the cutting board and drill the holes for the tie wraps. Turns out that the holes are a bit far from each other… next time I’d prefer to make more of a slit and a bit closer to the radials.

Then I drilled a 3mm hole at about 7mm from the end in of each the round tubes. Through these holes the 3mm screws will be used to connect the coax cable. I attached some simple faston connectors to the coax and then wrapped everything in self-fusing rubber tape. In the picture below you see the details of the connections.


Below you se the entire cutting board. The coil of coax is needed to cancel out the RF signal on the outer shield, I made it 6 turns. The advantage of the cutting board is already obvious: the coil can be positioned very close to the connection. Again a few holes through the cutting board for a few tie wraps to keep the coil in place.


The cutting board is mounted on the square aluminum rod using m6 bolts and wingnuts for easy disassembly. I clamped the aluminium rod to the fencing of my balcony. Below a picture of the whole thing.


The Aircell7 and N connector as well as the 15mm square tube were leftovers from a previous attent at an antenna that failed. Non the less, I prefer N connectors for outdoor use over PL. Yes that doubles the price of the antenna, so be it. RG58 will probably do just as good. Anyway, this is what I had, so why bother with something less…

The only purpose of the square tube is to be able to mount the antenna at some distance from the mast (or balcony).

Initial results

Without any tuning the antenna’s SWR is 1:1 for the entire 4m band. The first QSO (thanks Thijs, PA5TYS) yielded good results given the positioning of the antenna: clamped to the balcony and several high apartment buildings blocking line of sight, including my own.

About the dipole

The antenna is a normal dipole with a twist. The 120º angle helps reduce the impedance of the dipole from 75Ω to 50Ω, Exactly what we want. Normally a dipole requires a symmetric feed, the coil will cancel out any current on the coax outer mantle. Five or six turns will do the job.

QRV on 23cm

After the recent upgrade of the shack it was time to upgrade the antenna collection. Thanks to Mischa for the hint to simply build a ground-plane antenna, I made my first QSO on 23cm just 15 minutes ago. See below for the antenna.


Yes, that’s it… 5 pieces of electrical wire, each about 6cm in length on a N socket, see the close-up below.