DXpedition communications technology…

Posted: April 3, 2017 in Uncategorized

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The assortment of communications gear used in addition to HF.

I am often asked how Dxpedition teams communicate with their Pilot stations and upload their logs to Clublog from the far flung and remote locations that we visit.  In this Blog entry, I will describe the data and voice technology available to enable a Dxpedition to communicate with the outside world in addition to the HF radio gear.

When operating from a Fly in/Hotel venue, communications are usually pretty straightforward. We can use a local SIM card in our cell phone for voice communications for the outside world. Most hotels have some form of Internet/Wi-Fi that is available for Skype calls and uploads of logs to Clublog.

Although, as we found in Iraq and Eritrea, the Internet speeds were insufficient to handle daily log uploads and we had to use other means to upload our logs. In Asmara Eritrea, a BGAN was used to upload logs as the hotel internet was too slow to achieve an effective data rate.

Operating on a remote island is much different than a fly in/hotel situation. Voice communications are generally done via an Iridium satellite telephone. Iridium operates a satellite constellation of 95 active satellites used for worldwide voice and data communications. These satellites are in low polar orbits at 485 miles above the earth. Iridium is optimized for voice calls and they work pretty well. Data handling is limited to short text messages. Larger messages and files can be transmitted via BGAN (see below)

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Our Iridium Extreme 9575 satellite phone.

The Intrepid DX Group uses two Iridium phones for extra redundancy.

In addition to Iridium phones for voice calls, we employ a DeLorme In Reach SE for simple text/data communications with our Pilot stations, friends and family. The DeLorme In Reach also uses the Iridium network and has global coverage. The In Reach SE also has a built in GPS and can send coordinates at regular intervals using the beacon function. Our In Reach SE was attached to the antenna structure of the RV Braveheart and provided hourly beacons and map positions of our travels to South Sandwich and South Georgia Islands. Using the DeLorme IPad application, the In Reach SE was my primary means of communications with our VP8 Chief Pilot-Tony EA5RM.

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Our DeLorme InReach SE provided real time text and GPS beaconing.

We also use a Skyroam global Wi-Fi hotspot for our travels to exotic foreign countries that have cellular networks. The Skyroam takes the headaches out of finding and negotiating Wi-Fi networks. In can allow up to five devices to connect as a Wi-Fi hotspot using the local cellular network.

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Our Skyroam global hot spot.

For managing robust data communications such as file transfers, log uploads and email, a pair of Hughes BGAN terminals are deployed for +1 redundancy. BGAN stands for Broadband Global Area Network. This network consists of three Inmarsat satellites in a geo stationary orbit over the earth. This is line of sight technology and is optimized for moving data. Data speeds of half a megabit per second are possible under ideal circumstances. From South Sandwich and South Georgia Islands, we were only able to make limited contact with the satellite based over Tunisia as it travelled in a figure eight pattern throughout the day. We found that we could only make access at the same precise time each day.

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This map shows the coverage “foot print” of the Inmarsat satellite network.

While voice calls are possible over Inmarsat, the quality is poor as compared to Iridium. It’s important for the Dxpedition organizer to understand the limitations for BGAN/Inmarsat as it moves data whereas Iridium is optimized for voice and does a poor job with Data as Iridium’s data rates are about 1/10th that of Inmarsat.

BGAN terminals work in locations where there is no wireless service. They work on land or sea. An external antenna can be coupled to the terminal to use on a ship or to receive signals outside while the terminal is used indoors.

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We use two Hughes BGAN terminals for redundancy.

BGAN service is very expensive with rates of $4 to $7 per Megabyte transferred. The data usage for our VP8STI/VP8SGI Dxpedition was over $1,500 to update our logs once a day to Clublog. BGAN terminals cost from $2,000 to $12,000 or more.

So, to effectively move voice and data, the Dxpedition Leader must acquire Iridium and Inmarsat knowledge and equipment to meet the ever-increasing expectations placed upon the Dxpedition team for daily log uploads and effective communications with Pilots and others.

What do you think?

 

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Comments
  1. Scott Small says:

    Check out the iSavi isathub; $1300 bgan with $3.75/mb data, decent bandwidth, same constellation pattern. Feel free to reach out to me directly in San Jose if you’re curious. 73 Scott AD6YT

    • n6pse says:

      Hi Scott-AD6YT, Thank you for your interest in my Blog.
      I evaluated the iSavi isathub before acquiring the two Hughes units. We were planning to operate from the very ragged edge of the Inmarsat footprint and Inmarsat felt that the Hughes units had a higher gain antenna and the ability to connect an external antenna. We were operating in polar conditions with daily snow, wind and ice conditions and the external antenna feature was really nice to have. The iSavi isathub would be ideal for a fly in location where there is a good path to the satellite.

  2. Roger says:

    Paul:

    Thanks for shedding some light about various methods to communicate from remote locations.

    Would it make sense to ZIP up the log file before sending it via satellete? The cost per megabyte is so high that it would probably be worth the trouble to compress the log file. The webmaster [in NA or EU] would UNZIP the log before making it available for search on the DXpedition’s website.

    Of course, it could be that ZIPPING is already standard operating procedure.

    When we send our logs to LOTW we send them ZIPPED. This is because the ARRL TQSL procedure for sending logs includes ZIPPING up the log prior to sending it.

    73 Roger K5RKS

    • N6PSE's Blog says:

      Hi Roger-K5RKS, Yes, I heavily compressed each days incremental log before providing it to our QSL manager for uploading to Clublog. The cost of satellite usage is too costly not to do so.

      73,

      Paul N6PSE

  3. Gene K5GS says:

    Hi Paul,

    What’s the difference between what we’re using today and iSavi isathub, they both use the Inmarsat-4 (I-4) BGAN system???

    As you well know, the cost of data depends on the selected data plan. For a DX team the most cost effective seems to be a prepaid SIM vs. something with a contract and monthly charge…

    • N6PSE's Blog says:

      Hi Gene,

      Inmarsat told me that the Hughes 9000 series BGANs have a higher gain than the small/compact Isat Isuvi units.
      Last year, my research showed that the pre-paid Blue Cosmo SIM cards were a good deal but that may have changed since then.

  4. Gene K5GS says:

    That’s what we’ve been using, Blue Cosmo prepaid… The 9000 is physically larger and I would assume the antenna is larger, higher gain.

    Cheers,

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