DXpedition IT Notes 2014


This is a paper that compliments the Visalia DXpedition IT presentation in 2014

What will be covered?

This is a very high level overview of networking that might be used in moderate to large dxpeditions.  Many of the techniques may also be applied to small dxpedition.

I will be using N1MM as the example logging program.  Most of the networking technology would be common to all multi station logging programs.

Specifically I will cover how N1MM machines are networked.  Why it is important to use a wifi router.  What kind of router should be acquired. And various techniques for setting up the router.

I will move on to Clublog and the importance of using Internet connections to publish your logs in batch, near real time and realtime.

I will also cover connecting to the Internet using a facilities wifi network and will cover my thoughts on connecting to the internet using Global broadband technologies.  (note, I have do have first hand experience with Global broadband)


During this presentation I will be discussing various products.  I have no financial or non financial relationship with the companies producing these products.

Who am I:

I’ve been playing with electronics and computers for my whole life.  I’ve pushed bits and deployed exabytes and just about everything in between.  Putting together the T32 network was an interesting challenge but I crave the unknown!

Logging, the final word of the dxpedition

20th century logging

Ham radio started in the 20th century and so did ham radio logging.  In the final years of the 20 century we go some pretty good logging software which replace our tedious paper logs.  20th century logging programs were difficult to network, often requiring serial ports and lots of wires that would brake, come loose hang our programs.

Often the safest way to log during a dxpedition was to run separate machines and consolidate the logs by hand.  QSLing was still by snail mail and resolving broken calls could take years.

21st century logging

Welcome to the 21st century!  Logging has matured and logging programs take advantage of many standard networking technologies.  Wifi has replaced all those wires and connecting machines is a matter of ‘getting the configuration right’.

Logging is a system of computers which act like a single computer.  Each station can operate stand alone and automatically sync with other stations once network connections are re-established.  All stations have the same log so there is multiple levels of redundancy.

Clublog has grown to be a necessary part of any dxpedition.  Clublog has created a new level of DX competition that is thriving within the community.  As dxpeditioners we have moved from uploading to clublog at the end of the expedition to uploading every few days to uploading daily and finally to realtime posting of QSOs

Other conveniences of 21st century logging include: automatic deduping, LOTW, QSLing through automation or even QSLing services.  QSL requests are automated through services like Clublogs’ OQSL with built in payment technologies like PayPal to help defer QSLing costs.  Resolving broken call correspondence is done through email (mostly) and resolved in a matter of days if not hours.

DXpedition logging network.

The first thing to understand is there is a “physical network” and a “logical network”.  The physical network is the actual hardware you will need and the logical network how the software interacts on the network.

Logically N1MM runs in a ‘master – slave’ mode.  There is one master and many slaves.  Even though the software is identical, one machine has the master and that machine coordinates the activities of the other machines and is the machine used to generate the ‘official log’.  The master is also the machine that will communicate logging information to the outside world.

Physically an N1MM hardware setup looks like any other wifi setup.  There is a wifi router and all machines connect to that router so they they can communicate with the master.  The router is also where the Internet may get connected.

A typical configuration would include slaves for every operating position and a master that could be used in an operating position if there were a failure.  My recommendation is to use the Master as a monitoring station and a station to grab files for upload or provide the real time interface to Clublog.

The lowly router

The key to unlocking the power of a dxpeditions netork is the wifi router.  We are all familiar with this little box that sits quietly gathering dust but keeps ups connected to the new world order.  With proper care and feeding, the wifi router can add flexibility to your dxpedition network while reducing setup and maintenance time giving that poor IT operator a chance to makes some real QSOs!

The first thing to know is not all routers are created equal and the router industry would have you believe that you need to spend a pile of money to get usable routing technologies.

So, what router should you buy?  The router you get should have at least the following capabilities:

  • Detachable antenna.
  • At least 4 wired connections. (which you may need in an emergency)
  • DD-WRT compatible

Your current router may allready fill these requirements!


Enter DD-WRT.  DD-WRT is Open Source routing software.  I has well over a decade of evolution with some of the best router programs on the planet making regular contribution.  Because it is Open Source and FREE, there is no corporate hand waving that cripples a routers capabilites.  Any router that can run DD-WRT has ALL the capabilites of a high end router.

So what?  Specifically we are interested in a router capability called ‘repeating’  This is normally seen in high end routers, not the box that is in your house. DD-WRT has this capability for free!  This capability is just like the repeaters that we all know and love but instead of different frequencies like a 2 meter repeater, the router uses two different subnets.

Subnets are cool!

Everyone uses subnets whether they know it or not.  Your home wifi creates a subnet that all your home computer appliances connect to.  When you select a wifi SSID to connect to, you are selecting a wifi subnet.

The magic happens when you use your wifi router repeater to connect your router to another router or modem that has a connection to the Internet.  The other router sees your router as a single address on its subnet and has no idea that you are a router or that you are managing your own subnet of many machines!

DD-WRT has its own site that provides all the details neccessary to install on your router.  Check the ‘router compatibility list’ to verify your router is on the list.

Internet connections:

The only reason to have a wifi repeater-router is to connect the Internet!  Once connected we can upload to Clublog or even send real time QSO’s to Clublog.  If you are lucky enough to have unlimited data then you can let your entire team connect their pads, phones, personal laptops etc.(don’t do this if you are paying by the byte!)

If you are setting up at a facility that has Internet, then use your wifi repeater-router to make the connection to their router.  To do this we need to know the SSID of the facilities router.  Usually the facility offers a connection a a price and provides you with the SSID and some sort of password for their Internet engry page.  But before you shell out your clams, check to see what the signal looks like and what SSID’s are visible.  Do this with a hand little program for your Android call inSSIDer.  It is basically a spectrum analyzer for wifi frequencies that also interogates the wifi routers for their SSIDs.  The spectrum analyzer shows how strong the wifi signal is.  Use this to verify that the signal is reaching your operating location.  This is where a detachable antenna for your router may be very handy.  You may find a hotspot that is inconvenient for locating the router by easy to locate an antenna!

Once you have a hot locaton for your router antenna, go into your DD-WRT admin screen and change what ever you had configured for the repeater SSID to the facilites SSID.

Subnet magic allows you to use a computer on your subnet to attempt a ‘browse’ to the Internet.  What you will get is the Internet entry screen that the facility provides.  Enter the key they provided.  The facilities router only see’s your repeater-router IP/MAC address and thinks only one connection has been made.  In reality, you have everyone’s cell phones, pads and computers connected!

Classic Clublog

Clublog is great if it contains timely information.  The leader board of contacts creates a whole new way for dxers to compete with their fellow dxers.  To make this work, the dxpedition has to get those logged QSOs into Clublog. The classic way to do this is by creating an ADIF snapshot of the dxpeditions log at intervals during the dxpedition.  This is easy enough and is often done once per day.  Follow the recommended procedures provided by Clublog and all should go well.

Real time Clublog:

But we are ham radio operators and like to push technology right?  The next step in this ‘uploading of QSO’s is to send the QSOs in real time.  Luckily, Clublog provides an api that can be used to send each QSO as they happen.  N1MM provides a facility that ‘broadcasts’ each QSO as they happen.  What is needed is a bridge to transform the broadcasted N1MM QSO into a Clublog api!

Introducing Clubbridge.  Clubbridge is an Internet appliance that uses a tiny linux server to receive N1MM broadcasts and make Clublog web api calls.  It can be preconfigured and tested before the dxpedition.  Once at the dxpedition all that needs to be done is to ‘plug the power in’  The rest of the connections happen automatically.  Just log a test QSO from your N1MM system (master or slave) and watch the QSO show up in Clublog!

What is Clubbridge?  Clubbridge is a Raspberry Pi computer (the size of a deck of cards) a wifi dongle and an SD card imaged with a preconfigured Raspbian linux system.  The image is available on line for free at ???? The actual Clubbridge code is written in Python and all sources can be located in the image.

The Clubbridge image is in the ‘early adopter’ stage and currently should only be used in conjuction with periodic uploads.  I will continue to test (All my contests push QSO’s to my Clublog log) and will add capabilities as time presents itself.  I would like to release under open source but that actually requires a tremendous effort.

How much data are we really talking about?

The more remote the dxpedtion the less likely there will be Internet.  When we must pay for Global Internet we start worrying about how much data will we need to move.  There are a number of conisderations:

  • Will we use classic Clublog and upload every day?
  • Will we attempt an incremental upload? (incremental is not recommended by Clublog)
  • Will be rely on realtime Clublog using Clubbridge
  • What kind of plan can we get?  By the MB? By the connect time?
  • What kind of bandwidth (bps) will we get
  • How much does all this cost.

Lets analyze how much data we will need to use (see slide)

Lets analzye the costs based on three global Inernet providers


Please take away:

  • Use a wifi repeate-router with DD-WRT
  • Yes, you can connect to the Internet
  • Realtime Clublog is here!





4 Responses to DXpedition IT Notes 2014

  1. Pingback: Visalia 2014 talk | Radio Station NX1P

  2. Mike K6EEP says:

    Thanks for the presentation in Visalia.  It helps to hear it from someone who has actually gone through the whole process.  I already have everything in my various junk boxes.  So it will be fun to experiment with all this stuff.  What language did you write the interface to Clublog in?  Just curious. 

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