DXpedition IT Notes 2015

Dxpedition IT 2015


It’s about the logs! A DXpedition, Field Day event, county expedition, all share one thing in common. The logs! Way back in the “last” century, we used paper logs, then, at the end of the century we used simple computer logs with flakey point-to-point connections. By the beginning of this century we were all pretty used to networked logging computers with lots of rs232 wires running between operating positions (picking up lots of RF on the way). We finally modernized to ‘wifi’ and are taking our first steps toward ‘logs in the cloud’.

Connecting a set of operating positions t.ogether and to the Internet cloud requires a bit more than a ‘second thought’ for any kind of multi-multi operation being set up in the field. This can be very hard if the team has not properly prepared their IT or can be very easy if the complete system has been tested end to end before departure.


This paper will cover network routers/repeaters for connecting a set of logging positions to each other and the Internet. We will also cover specific N1MM networking features. We will cover how to connect your logging network to ClubLog with the automatic batch and real-time capabilities of the ClubPi Raspberry Pi appliance. Finally we will cover experiences with the iSavi INMARSAT wifi connection.


Connecting logging stations

Getting connected at a remote location means having your own router, wired or wireless. It is tempting to use what ever infrastructure may be locally available, such as the hotel’s wifi connection, your own cell phone hotspot or a satcom wifi bridge. Doing so means you lose control over your network, exposing your logging computers to un-controlled environments, potentially being charged excessively for connections and a high likely hood of ‘network down’ conditions that are out of your control. By introducing your own router you control the logging network and can keep it running with or without an external connection to your router.

Logging programs

There are numerous logging programs to choose from when setting up dxpedition IT and the basic Murphy’s rules will apply to your selection. Any field expedition logging system will face challenges with automatic synchronization between logging systems, log status communications, an assignable master that communicates with outside applications/ appliances and robust recovery after disconnects. This list continues to grow as we demand more and more of our logging environments.

Cloud Logging

Clublog has created a new level of DX competition that is thriving in the community. The ability to ‘upload’ dxpeditions log ‘while the expedition is still in progress’ has improved the Dxer’s ability to make the contact and move on, and has helped reduce the pileup DQRM. ‘I’m in the log’ has taken on a whole new meaning. This capability has also introduced a new level of tasks for the operators of the Dxpedition. When and how often should the log be uploaded. What kind of Internet capabilities can be used. Can this be automated. For the really remote operations, the question, how much will this cost? Becomes an important part of the budgeting process.

Internet Connections

There are a number of ways to get an Internet connection. When configured properly, the repeater/router can be used as the gateway/firewall to an Internet connection. In the field we may have a 4G connection on our cell phone and can configure a hot spot. There may be an ‘open’ wifi connection or a ‘pay for connection’ at a Hotel. For really remote operations, some sort of sat link bridge to wifi/ethernet will be required.

If you are hoteling it, you may be able to buy a single connection by the hour or by the week. Configure your hotel connection so only your router is ‘seen’ by the hotel wifi.

You could make arrangements with your cell phone service provider for overseas/remote data usage. Depending on the cost and availability of a broadband network, using your cell phone as a hotspot could be an alternative to the hotel Internet.

When there is nothing available you will need a satcom connection. There are several vendors that provide an Internet bridge. Not all will allow you to use ‘your’ router to connect. All are very expensive. On the order of 1,000 times the price of your wireless broadband provider (4G) . When using such high priced connections, it is extremely important to control the amount of ‘data’ flowing to/from the satcom bridge.


Uploading ADI files or individual QSO’s requires moving data. If you are lucky enough to have low cost Internet access at your expedition site, then, there is no need to worry about how much data will get move. Indeed, even sending a single QSO at a time is a fraction of what gets moved during an email update. However, if you are using a SATCOM interface and paying for every ‘bit’ that gets transferred then you may want to estimate how much data you will be moving!

A typical QSO is about 100 bytes of data. 100 QSO’s is 10K, 1000 QSO’s is 100K 10,000 QSO’s in 1M etc. For a large, remote Dxpedtion planing on 100K QSO’s, over 10M of data will need to be moved. If the Dxpedition has optimized to upload/merge with automation and the Clublog API, I should cost aproximately $50 in data. If done through the Clublog web page and uploading full logs every day, it could cost 10 times as much.

The Internet is inherently inefficient for small data sets. To move one QSO of 100 bytes, there is 7K of overhead. The overhead consists of DNS requests, request and response headers and how well the TCP packets are packed. Interestingly, for 100 QSO’s, the overhead is exactly_the_same! Even 1,000QSO’s has an overhead of about 8K. The bad news is ‘real_time’ ClubLog QSO’s for SATCOM links is pretty much out of the question, however, upload/merge every hour or 100Q’s, 1000Q’s etc can be quite efficient.

An even better strategy is to ‘compress’ the adi files before uploading. Adi files compress up to 90% (so a 1000Q, 100K file would be about 10K of actual data to move. Currently ClubLog only supports zip files through the web page interface (sadely, the web page interface adds 100K or more of data just to get the page to display). Perhaps in the future ClubLog will support zip files through the api.

By incorporating automation for generating adi files and upload/mergeing the files on a regular inerval, it is possible to minimize the costs of keeping ClubLog updated in near real time.



Routers and subnet

Separating the logging computer network from the rest of the Internet is essential to ensuring a durable local network capable of supporting your logging programs capabilies and ensuring that there is no interference from outside sources.

Building a logging computer subnet using a wifi router will accomplish this. The names of the computers are known only by the router subnet and the other computers on that subnet. In this simple form, any commercial router will do.

Connecting the router to an available Internet wifi connection requires one more step which should be done with care, We do not want to expose our logging computers to outside routers. This kind of Internet connection is called bridging.

By configuring a router to be a router/repeater we retain control over our subnet and expose only the router/repeater address to the outside. Sadely, most comercial router software does not support this mode. But all is not lost.

There are many low cost routers that can be configured (burned,imaged etc) to run open source router software called Gargoyle. This extraordinary software is a very clean user interface built on top of the well supported OpenWRT platform. With just a few clicks you can configure Gargoyle for your subnet and the Internet wifi connection of your choice. With a bit more IT work, the Gargoyle router can be configured as a ‘firewall’ restricting Internet access to a single machine and/or a specific Internet Adress (ClubLog for instance). This firewall capability allows your Dxpedition It person the ability to control how much data makes it to the expensive (satcom) connection.

The Gargoyle website provides an list of compatible routers and router technology. When choosing a router be sure to purchase one with 1 or 2 removable antenna’s so you can hook a 15 foot piece of coax up and remote the antenna. This could be necessary to find a ‘hot’ location for the router antenna while protecting the router from the elements. An example router that has been used successfully is the TP-Link TL-WR741ND ($23.99) or TL-WR841ND (25.47). The list of Gargoyle supported routers grows by the day.


I admit it. I’m an N1MM fan. Everyone seems to know how to log with it, fairly easy to learn if you don’t, is very robust during computer and network crashes, has the ability to self sync across all the networked logging stations and knows when stations are out-of-sync. This is ideal for the ups and downs of dx or field expeditions. As a multi-multi logging system, N1MM provides ample operator to operator connections and statistics making ‘run rates’ an interesting sub competition!

ClubLog connection

With few exceptions, Dxpedtions have been uploading their logs to ClubLog. Sometimes it may take days before the first QSO’s show up and days may pass before another upload. Othertimes you may have discovered QSO’s showing up immediately after you have made your contact! Not uploading to ClubLog can impact a Dxpedtion in adverse ways. Primarily from big gun Dxers making duplicate contacts as ‘insurance’. Done broadly, this type of activity indirectly creates DQRM, hostilities and a general lack of the DX code of conduct. In contrast, a Dxpedition capable of real-time ClubLog provides immediate gratification to the Dxer who has completed a contact and even more important to the Dxer who has completed a nealy telpathic contact!. Seeing that “I’m in the log” gets the big guns out of the way quickly and anyone else who is able to confirm that they are ‘In the log”.

The majority of Dxpeditions use ClubLog but perform manual uploads of their log on an intermittent basis. This is slightly better than no ClubLog at all but just barely. Dupes and insurance contacts persist and indirectly promote DQRM.

Is there a better way?

Smaller Dxpeditions that have access to reasonably priced Internet should seriously consider integrating real-time QSO updates to ClubLog into their logging system. Larger expeditions that rely on satcom should automate small-batch ‘updates’ of QSO’s on a planned and announced time table.

Both of these approaches are possible today using an open source network appliance called ClubPi. Opensource means the software is free. Appliance means it is a stand alone network device. ClubPi is a bridge that consumes broadcasted QSO’s from N1MM, transforms the QSO’s into ClubLog ADIF format and sends those QSO’s in batch or real-time to ClubLog automatically.

ClubPi is a network appliance based on the Raspberry Pi Linux computer technology. A Raspberry Pi is a small (deck of cards size),inexpensive ($35) computer capable of being a Linux server. By downloading the ClubPi image, loading it on an SD card and plugging that SD card into the Raspberry Pi, you have a ready-to-go ClubPi

With the addition of a ClubPi appliance configured for the Dxpedtions logging network, both small and large expeditions can have automated ClubLog capabilities.

Internet Hotspot, Hotel, and iSavi/INMARSAT connections

Getting the dxpedition/multi-multi field operation connected often is a challenging task. Well laid plans that include Internet access can easily be way-laid by poor or over priced hotel connectivity, lack of cell phone bars or poor sky location.

Cell phone Hotspot

Typically this is not an option when Dxpeditioning in 3rd world countries. It is worth checkin with your carrier to see if there is a ‘1 month’ option you can buy that gives you unlimited data at your destination. For field day and county expeditions, the cell phone hotspot can easily be your Interenet connection.

In any scenario, you will want to use a separate router/repeater with your hotspot. Having the ability to locate your repeater/router strategically for your cell phone hotspot and provide firewall/isolation for your logging network will provide lots of ‘field flexibility’. You may need to locate your cell phone where you get ‘bars’ and a decent bandwidth connection. Having a separate repeater/router provides addition location flexibility that you will likely need while getting your logging stations connected and your router connected to the Internet.

Hotel wifi

For lots of Dxpedtion vacations and small scale Dxpedtions, there is a high probability that you will have access to hotel wifi. When this works, it is fantastic. Getting it to work can be challenging. Most hotels, even in 3rd world countries, will have wifi for a price. How much it costs, how good it is, how well the coverage is, are all open questions.

Specifically there are two challenges:

  1. Can you get your repeater/router antenna within range of the hotel wifi?
  2. Can you connect and log into the hotel wifi through your router?

Question 1 is very hard to answer until you are on site. If possible, locate other hams that have been to the hotel and ask how good the connection is. You can call the hotel and attempt to get information out of the hotel operations but good data about the wifi capabilities is unlikely. Murphy’s law will be hard at work here when you arrive at the hotel. Being well prepared for different situations will pay off. Here are some useful items that will improve your odds of connecting to the hotel wifi:

  • Get a copy of inSSIDer. It is available for your android, iphone and pc and its cheap. This app will give you a clear indication of the wifi SSID’s available and their signal strength. Use it to find the best possible spot (location to your logging systems and hotel wifi) to position your wifi router/repeater antenna. This little software tool eliminates any questions regarding hotel Internet connectivity.
  • Extend your wifi/router range. This may or may not be legal at your location. Low cost wifi broadband amplifier/pre-ams are available. If you have chosen a router that has a detachable antenna, you can place one of these devices between your router ant the remote antenna. With the additional range you may find the hotel wifi is accessible. You also have the option of moving your router/repeater to a hotter hotel wifi location and keep the logging system subnet in range.

Question 2. There is good news here. For the time being, most hotel wifi connections have open SSID but require a separate ‘special’ login. The hotel login maps some code that you purchased from the hotel desk to your MAC address (the physical address of your device). The good news here is you can configure your wifi/router to connect to the hotel wifi, than, using one of your pc’s, attempt to connect to the Internet (yahoo for instance) through your wifi router (eg connect your pc to the router/repeater wifi NOT the hotel wifi). This will bring up the hotel login screen, enter your magic number. The hotel system will associate your account to the router/repeater MAC address! Now, any number of devices can be connected to your router/repeater and they will have Internet access!

Not to many people in the world do this, so,we may enjoy this little back door for many years to come.

Isavi and INMARSAT

There are other SATCOM options, however, iSavi is the only option that provides a wifi bridge to a SATCOM Internet connection at a price that does not require a mortgage. Iridium iintroduced a low priced device that required a ‘special’ browser (which means we cannot connect our router/repeater) and they charge for ‘air time’ and ‘data’.

ISAVI is a laptop sized device that acts as a bridge between INMARSAT SATCOM data services and a local wifi. It is farily easy to configure. It must be located with a clear shot at the sky. ISAVI provides a simple ‘led’ tool to help line the device up with the geosynchronous INMARSAT in your region. It actually has a built in GPS to figure out what satalite to line up with. Once connected, ISAVI provides medium speed Internet capabilities.

The ISAVI device costs $1,400 plus a one time connection fee.

That’s the good news. The bad news is you are charged $4 per MB, that’s mega byte, not giga byte. For comparison, you typical 4G LTE data prices are $5 per GB. To be clear, INMARSAT charges 1,000 times more for data.

INMARSAT does not charge for being connected. They do charge for every single byte that moves across the connection.

At first, this sounds like an easy thing to manage. Just send data across when you need to. Unfortunately the Internet doesn’t work that way! (and you thought you had control ove your data!). There are dozens of applications on your PC that want to ‘phone home’ for updates, status, virus protection. Cleaning your PC up to eliminate all the data ‘noise’ is daunting. Fortunately, with our wifi router/repeater, we can block most of this traffic. Even after blocking all traffic between the phone-home applications on your PC/tablet/MAC/smartphone, there is a devious little service that continues to hammer away at your connection. It is called DNS (Dynamic Name Service). One of the functions of a wifi router is to provide a bridge to the DNS service. When a request (blocked or not) comes to your wifi router/repeater, the router/repeater DNS service will attempt to map the URL domain to an IP address. If not found locally (or timed out), the router/repeater will ask the Internet. This happense EVEN WHEN you have blocked access to the address. Think of it as a low level function that always occurs. A typical PC will generated 4 to 5 MB of DNS requests per hour! (remember, $4 per hour). So, just idling an ISAVI connection can cost your $100’s per day.

All is not lost. There is no reason to enable DNS in your router/repeater/firewall that is between the ISAVI wifi and your loggins system subnet. Shutting DNS down on your router will kee those queries from happening, however, you will not be able to contact anything on the Internet without first knowing the IP addresses.

The whole reason there is a SATCOM conections is probably to send or check emails and to send QSO data to ClubLog. With some preperation, you can configure your repeater router with the correct IP addresses for the few services you want to access. Once configured in this way, your router/repeater will be quiet as a mouse, your ISAVI connection will be on but not transferring data, and your automatic ClubPi set up will keep uploads data sets to a minimum.



For a router, I recommend something low cost, one or two ‘removable’ antenna, Gargoyle compatible 15 feet of coax and a high gain rubber ducky antenna (or two)


For the logging program I recommend N1MM. It is a proven muti-station logging system, servives computer crashes, network crashes and has automatic synchronization and recovery. N1MM also provides a ‘broadcast’ capability that can be enabled on the assigned master machine that can communicate with external programs or external appliances like ClubPi

By isolating your logging network from ‘what ever’ Internet connection you may have available, you can control the Internet connection count and Internet traffic. In the case of Hoteling, remote locations often charge ‘by the connection, by the hour’ If you do not isolate your network, you will pay for every machine you want to connect and the time those machines are connected. By just exposing your router to the Hotel’s network, the hotel see’s only one connection so you only pay for one connections. In the case of a iSavi INMARSAT device, you can the connection to a single machine behind your network and can optimize the INMARSAT traffic to reduce the total bandwidth consumed.


There are several SATCOM providers but only one with unrestricted wifi, global access.

  • Globalstar: Dont’ plan on Pacific, Africa, parts of Asia/South America, Antarctic or much above the arctic circle. Globalstar has limited world wide coverage.If you fit into Globalstar coverage, than it will cost you $800 for a wifi bridge box and antenna. You will get 9600 baud data rates and will be required to sign a contract for minutes. The contracts are based on minutes per month and do not seem to be flexible (eg 75 minutes for one month, 275 minutes for 6 months, 700 minutes for 12 months. At $1.00 per minute of data, 1MB of data will cost about $20 (9600 baud is about 50KB/minute, 20 minutes to transfer 1MB)
  • Irridium: Irridium has the oldest satcom service. It was/is based on voice communications. It has good coverage except for the extreme polar regions. You can get an Iridium Go! Package for $800 not including contract. You will get 2500 baud data rates. Irridium has the most flexible contract purchases. You can purchase ‘pre paid’ data minutes. Irridium Go! Limits the kind of web applications you can use. You must use their specially configured browser. Unclear if Irridium Go! Allows uploads (to ClubLog) or automated acess (ClubPi)
  • BGAN: BGAN is the high end INMARSAT connection. At $7 per megabyte and a $2,400 box investiment you get speeds up ti 464Kbps. A monthly service charge of $70 per month applies. In addition you can purchase pre-paid data sim cards ranging from 100MBs ($525) to 1200MB ($5,639). This is a full access wifi connection. Unless you have very deep pockets you will want to control the access to your SATCOM link
  • IsatHub iSavi: This is another INMARSAT connection. INMARSAT price ranges for data applie although the contract arrangements are different. The box costs $1,345 and provideds data rates up 384Kbps. The plans are monthly and do not roll over. Monthly plans range from 25MB at $89/month to 2.5GB at $6,975 per month. This is a full Internet service. There are no limitations. As with BGAN, it is very important to control the amount of data being transferred.

No matter what package you choose, SATCOM is expensive to set up and expensive to use. Google/SpaceX and Virgin both are hoping to change this in coming years. Don’t hold your breath! We probably will not see these entries until well into the next decade.

In the mean time, it could be possible for Dxpedition sponsering groups to create a ‘pool’ of BGAN boxes and prepaid sim cards for use by Dxpedtions. This shared cost model, combined with ClubLog/email optimization firewalls (ClubPi/Gargoyle) could dramatically reduce the cost of a Dxpedtion Internet connection, provide real-time or near realtime ClubLog updates and actively reduce DQRM.


Laying out your logging network architecture, separating your logging network to it’s own subnet, managing the Internet connection and automating your ClubLog activity will benefit both sides of the Dxpedtion equation. Your operators will stay focused on operating, the up-to-date ClubLog will reduce the pileups/DQRM and the DX chasing experience will be more rewarding (and less stressful!).

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