Saturday, April 18, 2020

How's DX?

Given the social isolation imposed by the Covid-19 virus I’ve resumed interest the pursuit of DX. In ham radio jargon DX means distance. In casual conversation hams might ask one another “How’s DX”? Translated for non-hams this means “How’s propagation? Is distant radio communication optimal? A major interest for many hams is the ability to speak to others in far off exotic locations wirelessly. During the 1970’s the sun spot cycle peaked and optimally effected the ionosphere. Radio signals reflected off the upper atmosphere so efficiently that with 100 watts of power or less it was possible to talk with other hams all over the globe. While living in New York I could routinely contact the ham shack at McMurdo station on Antarctica, call sign KC4USV. [1] Both our signals were typically + 20 db over S9, enormously strong considering we were over 9,000 miles distant. We might not think of the frigid south pole as Shangi-La but it qualified as exotic DX, a distant location inaccessible to most excepting our military, well funded explorers and ham radio operators on the air.

As DX communication is challenging during the current solar minimum, innovative hams are constantly testing the ionosphere in search of band openings. Optimal DX propagation can occur suddenly during unpredictable solar flare activity. To test conditions hams will often broadcast a CQ, an invitation/call to others listening to engage in conversation. Hams calling CQ DX are searching for radio contact with distant stations in other countries. Occasionally hams will organize a DXpedition; a group of hams will travel to an exotic location, set up a radio station and become a highly sought contact pursuit by other operators seeking a “Worked All Countries Award”.

Testing DX conditions can be challenging. It’s difficult to evaluate the ionosphere when no signals are present. In this regard, DX beacons are helpful. There are many automated radio stations covering our globe which transmit beacon signals. As “radio light houses” their signals can be heard distantly when atmospheric conditions are optimal. DX conditions can also be determined by monitoring scheduled networks. Hams maintain daily “nets” over a wide rage of frequencies. Net control operators for these nets are volunteer hams operating in shifts. Two popular HF (High Frequency) nets can be heard on 14.300 MHz. During morning hours the Intercon Net is active. The Intercontinental Amateur Traffic Net [2] acts as a check in center for hams monitoring the frequency. Hams can obtain signal reports, weather condition updates and check in to rendezvous with distant friends. At 12:00 PM the Intercon Net closes and the Maritime Net resumes its net activity on 14.300 MHz. Known formally as the Maritime Mobile Service Network, [3] this volunteer group is a valuable resource to licensed hams on sea bound traffic ranging from pleasure craft to large commercial shipping, cruise ships and sometimes military vessels. Similarly, the Maritime Mobile Service Network broadcasts weather conditions to ships at sea and sometimes relays messaging to land based systems. In addition to VHF/UHF I also have an HF radio in my car. While mobile I listen to the nets on 14.300 for propagation conditions and obtain signal reports. Once you’ve checked in you’re logged into their computer system for future reference. It’s often surprising to be greeted by name upon your call sign check in. Both of these nets are very popular and supported by a huge following of the ham radio community.

When mobile, seaborne or in the air (airplanes), hams frequently exchange grid square information. In addition to simple location plotting, grid map information can assist with aiming directional beam antennas and navigation. The ARRL explains the origins of the Maidenhead Locator System. [4] HA8TKS provides an excellent Maidenhead grid location utility on a zoomable map. [5] Such resources and utilities simplify global communication coordination for mobile operators and systems.

Did I mention that ham radio and DX are great fun?

Have a great weekend!

Best regards,
Thomas D. Jay

W4TDJ  Member ARRL
TDJ Technology
Thomas D. Jay YouTube Channel

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References and acknowledgements:

[1] McMurdo station on Antarctica, call sign KC4USV

[2] Intercontinental Amateur Traffic Net

[3] Maritime Mobile Service Network

[4] The ARRL explains the origins of the Maidenhead Locator System

[5] Maidenhead grid location utility  HA8TKS


  1. Newer ham but I've been around the hobby for 50+ years (thanks dad). He always said you never know when the openings will occur. Take this past Saturday evening 5/9/2020 in Maryland. SFI at 67. No sunspots. HF dead. Then about 1400 UTC, 6m, 10m, 12m and 17m started to wake up. Through 01:52 UTC on 5/10, albeit with FT8, I contacted Cuba on 6m, Caribbean on 10m, New Zealand on 10m, 12m and 17m, and Fiji and Japan on 17m. Then propagation gods said enough, and it was gone. But loads of fun! 73 and be safe Cliff W3KKO

    1. BTW I'm using an 80M end fed half wave and a vertical loop, and 50w on FT8. Just wires. Nothing special. It was a blast

    2. Amazing how FT8 propagates when the bands sound closed. Good DX!