How to set-up and use the DX Cluster with G2XV's AKD 4001

Daniel M0ERA, Version 7

In short:

  1. Connect:

    1. vertial yagi (bearing: 51 deg from JO02ce and 61 deg from IO92xd)

    2. feeder to tent

    3. AKD 4001

    4. microphone cable from transceiver to TNC

    5. TNC (e.g. my Tiny2)

    6. serial cable from TNC to computer

    7. computer (e. g. 386 laptop labelled "14")

    8. 12 V supply for AKD rig and TNC

  2. Boot the computer.

  3. Start terminal program. Use Minicom for Linux, Kermit for DOS or Hyperterm for Windows.
    (e.g. type "kermit" or "msk315" at DOS prompt)

  4. Settings: 8n1, speed 9600
    E. g. type in kermit window (with the serial cable is in COM1 port):

            set speed 9600
            set port com1         
            set terminal type byte 8
  5. Connect from terminal (kermit) to TNC:

  6. Now switch on the TNC. You will see the boot message of the TNC.

  7. Switch on AKD4001. Settings:

    1. Power low

    2. Channel 06

    3. Squelch control so that LED labelled "DCD" is off.

    4. Volume control slightly less than half level.

  8. Connect to cluster server. Type "c gb7cdx" (you might need to reconnect if the cluster disconnects eventually).

  9. You will be greeted by GB7CDX. DX spot information will come in. The most useful commands:

           sh/dx                                    (Show DX spots)
           sh/filter                                (Show filter settings)
           set/nofilter                             (Deletes all filters)
           set/filter dxbm/pass 2-cw,2-ssb          (Set filter for 2m only)
           dx G2XV/p 144360.0 JO02 beaming DL       (to spot G2XV/P)
           help                                     (if you need it)
           bye                                      (to disconnect)

If the DELETE key is not working, try Control-h.


The cluster connection is not very immune to interference. However, even in the presence of strong interference (i. e. from 1KW linear), the cluster connection does work. Most of the spots will come in during the receive breaks. To send commands, you might need to coordinate the 4 m signal with the 144 MHz station. Do not transmit on 2 m until the GB7CDX has received the command (which takes a few seconds at most).

The long version:

What you need

  1. The AKD4001 FM 4m transceiver

  2. A TNC

    I used my Paccomm Tiny-2 Mk2, which worked very well. Any TNC should work, as long as it gives 1200 baud to the rig and 9600 baud to the computer.

  3. An 4m antenna

    For permanent use in the club shack, the folded Jaybeam dipole (in the shack) will be fine. For contests, there is a Vine 3 ele yagi with a 25dB front/rear ratio in the trailer, giving some protection against breakthrough. Place the yagi between the cluster node in JO02fh and your contest station. The bearing is 51 degrees from JO02ce and 61 degrees from IO92xd. Of course, the antenna needs to be vertically polarized. There is a mounting stub for the yagi available.

  4. A computer

    Any computer will do as long as it can be connected to the TNC. It needs a serial port or a USB-to-serial adapter. However, make sure it doesn't produce RF noise!

    It is a good idea to switch off the screensaver. If you worry about the screen, the laptop isn't suitable for contests anyhow. All the computer needs to do is to run a serial terminal program, like minicom for Linux, Hyperterm for Windows (installed by default) or Kermit for DOS. Kermit can be downloaded from the internet.

    The very old laptop labelled "14" (Opus Technology NB 386SX-20) was donated to the club by G4WSZ (thank you, Steve!). It is very quiet on 144 MHz, as long as it is set to LOW CPU speed (option 1 in the BIOS). It runs under DOS and has Kermit installed.

    The computer used does not need a hard disk. If it can be booted from a floppy disk or a CD-ROM which also has a copy of DOS and Kermit (or Linux and minicom), it will work.

  5. Cable and connectors

    With the ADK 4001 comes a cable with a 4 pin microphone plug, a 3.5mm audio plug for the headphone socket and a 5 pin 180 deg DIN plug, which goes into a Tiny-2 TNC.

    It is important to note that the AKD 4001 has DC voltage on some of the audio pins. If that get shortened out, the rig will break (it is repairable, however). For that reason, only the ground of the microphone plug is wired, but not the ground of the 3.5mm audio plug. Only the tip of the 3.5mm stereo plug is wired (to the RX input of the TNC). You cannot use the audio output of the microphone plug, as that has the wrong impedance (400mV at 47 kOhms, which is not suitable for a Tiny2).

    The microphone plug layout is as follows: Looking at the front of the rig with the U dent on the bottom, bottom left is PTT, bottom right is mic input 60mV at 600 Ohm, top right is mic braid and earth and top left is not connected.

    Also, you need a connection between the TNC and the computer. For a Tiny2, that is a normal serial cable and a gender changer to get two female 9 pin DB9 plugs (a RS232C cable). Look after this cable! If your TNC needs another connector, build it from scratch, or make an adapter, but do not rewire the existing one. You will need it sooner or later!

    The connections are straight-through, but only five lines are needed:

            (2 -> 2, 3 -> 3, 5 -> 5, 7 -> 7, 8 -> 8).

Getting started

GB7CDX is a DX Cluster node in JO02fh, providing a real-time view of DX "spots" and allowing users to report interesting callsigns currently on the air. It is located at the shack of Fred G4BWP, in Red Lodge, Suffolk, and administered by members of the Cambridge University Wireless Society (ie Michael G7VJR). It runs AR Cluster. See for a detailed manual.

When everything is connected, boot the computer, start the terminal progam (settings are 9600 baud, 8N1, hardware handshaking).

Next, switch on the rig. It always boots with channel 16. GB7CDX is on channel 06 (70.325 MHz). Have an eye on the channel display, as every power cut will reset the channel! Turn the volume control fully clockwise and then anticlockwise to slightly less than half level (around 11 o'clock). Set the power level to low (or "Hi", if you feel that this is really necessary).

Switch on the TNC. You should see its boot messages in the terminal window. Watch the LED labelled "DCD". Turn up the squelch control on the transceiver a little bit further than just needed for the LED to go out.

Now we are in business. On the terminal window, there should be a prompt "cmd:". Connect to the node by typing "connect gb7cdx" or just "c gb7cdx". It will ask for your callsign. Use your own callsign or G8EVY (not /P, even if you are portable). The DX spots will come in all the time, but you can type in your commands in the meantime. Just don't get confused. Make sure the 2m station is not transmitting while you send the commands, or GB7CDX might not get them.

Useful commands:

"bye" (or "quit"). Most important, if you don't log off, you might run into trouble during the next log on. Should that happen, try logging on with a -1 behind your callsign (G8EVY-1).

"help". You can use shortcuts such as "HE" or "?". There is a good manual in the system.

"show/dx" (or "sh/dx"). It will give you some of the last spotted DX stations. You may specify how many spots you want ("sh/dx/20") or the band ("sh/dx 14") or both (you guessed it: "sh/dx/20 14"). You can also specify that you are only interested in IOTA "sh/iota"or 4 meters "sh/4mtr".

To spot a station yourself, use "dx frequency callsign (optional comment)". Note that the frequency is given in kHz! Example: "dx G2XV/P 144330.8 strong signal".

You can (should) keep your user information up to date. The commands for G8EVY are:

     set/name Cambrige and District ARC
     set/qth Cambridge
     set/location 52 11 N 0 8 E
     set/homenode gb7cdx

Use "show/name" etc to check your details.

"sh/time", "show/sun" or "show/muf cx5bw" is also good fun to use. Try "show" alone.

By now, you will have realized that there are a lot of DX spots coming up all the time. You can set a filter to narrow it down to the band you are interested in.

For a 2m contest, this would be:

     set/filter dxbandmode/pass 2-cw,2-ssb,2-fm      or  
     set/filter dxbm/pass 2-cw,2-ssb,2-fm  
     sh/filter                                       displays your filter settings.

When you have a filter set, "sh/dx" will only show filtered spots. Use "sh/dx nofilter" to see what else has been spotted.

"set/nofilter" switches off your filter.

The legal stuff:

Is it allowed during the contests? Check the rules:

"General Rules for RSGB VHF/UHF/SHF Contests 2007

The RSGB Contest Committee has revised the VHF General Rules relating to the use of the DX Cluster and other spotting/chat networks (including internet facilities for example ON4KST) in RSGB VHF and UHF contests.

The revised rules are listed below:

4i. The active use (posting messages, arranging skeds, self spotting etc) of the DX Cluster and other spotting networks (including internet facilities for example ON4KST) to assist an entry to a contest on 6m, 4m, 2m and 70cm is banned in all RSGB contests with the exception of three IARU Region 1 co-ordinated contests (50MHz Trophy in June, 144MHz Trophy in September (!) and 432MHz to 248GHz IARU in October) and the 144MHz Marconi contest in November where permitted by the IARU rules for these contests. You may spot a DX station as long as your operating frequency is not given.

4k. All information must be copied off air at the time of the QSO and on the band in use. Databases must not be used to fill in missing information. The DX Cluster, talkback channels etc must not be used for passing or confirming any contest related information.

These revised rules take effect from midnight 30th April 2007.

To help operators understand these revised rules, a list of do's and don't are listed below:


Some HF contests might not allow the use of the cluster. 1