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The Very First DX – December 12, 1901

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History of the very first DX

Marconi first contact December  12th, 1901 is certainly a date with a historical relevance in radio transmissions. In fact, at 04.30 GMT of that day, Guglielmo Marconi succeeds in sending the first transatlantic wireless communication. Succeeding in this contact, Marconi demonstrate that radio waves transmissions could be transmitted even across the Atlantic ocean. With this success Marconi, in addition, disproved detractors who told him, that the curvature of the earth would limit transmission to 200 miles or less.

The Facts

The Italian inventor received in St. John’s, Newfoundland, Canada, the letter S in morse code (three dots) transmitted from Poldhu, Cornwall, in England.
Marconi first contact
Signal Hill, Newfoundland Canada, to Poldhu, Cornwall, England.
Marconi set up a specially designed wireless receiver in Newfoundland, Canada, using a coherer (a glass tube filled with iron filings) to conduct radio waves, and balloons and kites to lift the antenna as high as possible. Marconi AntennaThe station in Cornwall, England instead was composed by a twenty-four ships’ masts each 200 feet high, and the transmitter was powered by a 32 brake horsepower engine driving a 25 kilowatt alternator. the very first dxHistory says that detractors were correct when they declared that radio waves would not follow the curvature of the earth. In fact today we know that radio waves had been headed into space from England when they were reflected off the ionosphere and finally bounced back down toward Canada. Science demonstrated and explained this contact, made thanks to Radio wave propagation, just a few years later. Therefore thinking in terms of amateur radio logic, we should consider this experiment as the first DX contact ever. If you are interested in Marconi’s experiments and history, probably you can find interesting arguments and further details about this story here:

What is a DX?

If you are not an amateur radio operator, DX could be considered a funny term. In the amateur radio lingo: DX is the telegraphic shorthand for distance or distant DXing is the hobby of receiving and identifying distant radio signals.

Marconi and the very first DX on YouTube

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WSJT-X 2.7.0 Release Candidate 4 available

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WSJT-X version 2.7.0 RC-4  can be downloaded from the sourceforge.net repository.

WSJT-X 2.7.0 RC4, released on March 11 2024, brings improvements primarily aimed at Fox-mode operators and enhancements to the QMAP companion program. Notable updates include QMAP’s ability to decode Q65 submodes with varying T/R sequence lengths, automatic adjustments of dial frequency and submode when clicking on stations in the Active Stations window, and a more compact file format for wideband data files. Users can now export a 3 kHz portion of a wideband data file as a standard WSJT-X *.wav file and send integer kHz dial frequency requests to WSJT-X with CTRL+click on QMAP’s waterfall. Minor User Interface enhancements have also been implemented. Additionally, WSJT-X now supports the decoding of MSK144 from the jt9[.exe] executable and includes modifications to handle issues arising from short callsign hashes in standard FT4/FT8 sub-bands. These updates streamline operations and improve the overall user experience for amateur radio enthusiasts.

 

WSJT-X 2.7.0-rc4  Release notes

Marc 11, 2024

WSJT-X 2.7.0 Release Candidate 4 brings some improvements for Fox-mode operators, new features for companion program QMAP, and a number of relatively minor enhancements and bug fixes.

QMAP enhancements — of particular interest to EME operators:

– QMAP now decodes Q65 submodes with both 60-second and 30-second T/R sequence lengths. Clicking on a resulting line in the WSJT-X Active Stations window automatically sets dial frequency and working submode as needed to call that station.

– QMAP operates in 60-second receive sequences, and its Q65 decoder starts at t=19.5, 30.0, 49.5, and 58.5 s into the sequence. Most decoded messages are displayed well before the end of the relevant time slot.

– A new, more compact file format is now used for wideband data files. A “Save decoded” option has been added to the Save menu.

– An option has been added to allow exporting a 3 kHz portion of a wideband data file as a standard WSJT-X *.wav file.

– CTRL+click on QMAP’s upper waterfall sends an integer kHz dial frequency request to WSJT-X.

– With focus on the WSJT-X main window, hit Alt+A on the keyboard to clear the Active Stations window.

– Many minor enhancements to the User Interface.

WSJT-X: – Enable decoding of MSK144 from the jt9[.exe] executable.

– Several changes to reduce problems experienced when (contrary to our recommendations) messages with short (10-bit) callsign hashes are used in standard FT4/FT8 sub-bands.

About Release Candidate versions

A release candidate (RC) version is a pre-release version of a software product that is considered to be feature-complete and relatively stable but may still undergo further testing before the final release. Release candidates are typically made available to a wider audience, including beta testers and the general public, to gather feedback and identify any remaining issues or bugs.

About WSJT-X

WSJT-X is a computer program designed to facilitate basic amateur radio communication using very weak signals. The first four letters in the program name stand for “Weak Signal communication by K1JT,” while the suffix “-X” indicates that WSJT-X started as an extended branch of an earlier program, WSJT, first released in 2001. Bill Somerville, G4WJS, Steve Franke, K9AN, and Nico Palermo, IV3NWV, have been major contributors to development of WSJT-X since 2013, 2015, and 2016, respectively.

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Ham Radio Frequencies

Navigating the Airwaves: A Comprehensive Guide to Amateur Radio Bands

Amateur radio, also known as ham radio, is a popular hobby that allows individuals to communicate with others around the world using their own radios using specific radio waves.

One of the key aspects of amateur radio is the use of specific frequency bands for communication.

These bands are allocated by national telecommunication authorities and overseen globally by the International Telecommunication Union (ITU).

In this article, we will explore the different amateur radio bands, their characteristics, propagation, and usage.

Understanding Amateur Radio Bands

Amateur radio bands are expressed in meters, representing the wavelength of the radio waves used for communication. The length of a wave is inversely proportional to its frequency, so longer waves have lower frequencies, and shorter waves have higher frequencies. The wavelength in meters can be calculated by dividing the speed of light (299,792,458 meters per second) by the frequency in hertz.

The customary band names provided below are primarily nominal wavelengths, not representing exact values. For instance, in the western hemisphere, the nominal 80-meter band spans approximately 85.7–74.9 meters, with an international portion from 85.7–83.3 meters. The so-called “17-meter” band actually covers 16.6–16.5 meters, while the nominal “15-meter” band ranges from 14.28–13.98 meters. It would be logically labeled as the “14-meter” band, but the established nomenclature has persisted due to historical usage in a shortwave broadcast band.

Frequency Allocations

The allocation of frequency bands for amateur radio varies from country to country and between ITU regions.

The International Telecommunication Union, in its international radio regulations, divides the world into three ITU regions for the purpose of managing the global radio spectrum.

Region 1 encompasses Europe, Africa, the Commonwealth of Independent States, Mongolia, and the Middle East west of the Persian Gulf, including Iraq.

Region 2 encompasses North and South America, including Greenland, the Caribbean, and a small number of the eastern Pacific Islands.

Region 3 comprises Asia east of and including Iran, and most of Oceania. The region excludes Central Asian and Eurasian countries formerly members of the Soviet Union.

Each  ITU region establishes the authorized frequency ranges, and individual amateur stations are free to use any frequency within these ranges, depending on their class of station license. The allocation of bands and specific frequencies within each band is determined by international agreements and national regulations.

ITU allocation of frequencies for each region is made available for radio amateurs worldwide throught the IARU web site, where all band plans are published.

The Bands

The ham radio bands span a wide spectrum of frequencies, from low-frequency bands like LF and MF to high-frequency bands like HF, VHF, and UHF.

Each band has unique propagation characteristics, usage patterns, and regulations, facilitating diverse forms of communication among amateur radio enthusiasts worldwide

Below, for each band, we offer concise descriptions highlighting key characteristics, primary usage, and any applicable emission mode restrictions. Additionally, we provide links to real-time band monitoring through web SDR platforms, modern web based radio receivers, enabling users to listen in on these frequencies.

LF – Low Frequency Bands

2200 meters (135.7 – 137.8 kHz)

The 2200 meters band is just below the Asian and European longwave broadcast band and far below the commercial AM broadcast band. It is often used as a technical challenge due to the difficulty of long-distance (DX) propagation caused by higher D layer ionospheric absorption. It was formally allocated to amateurs at the 2007 on a secondary basis. Available on all ITU Zones, but not in all countries, this band is known to be notoriously noisy, particularly in the summer months.

Propagation characteristics:

  • Ducting might be possible on 2200-Meters in D region bite-outs.
  • Negative ions may help propagation
  • Groundwave propagation can be a big factor

MF – Medium Frequency Bands

630 meters (472 – 479 kHz)

The 630 meters band is just below the commercial AM broadcast band and the maritime radio band. It is also known as the “top band” and was formerly shared with the largely defunct Loran-A radionavigation system. Allocations in this band vary widely from country to country.

Propagation characteristics:

  • Propagation around sunrise and sunset can give good results
  • Ducting might be possible on 630-Meters in the nighttime electron density valley and in D region bite-outs.
  • Negative ions may help propagation

160 meters (1.800 – 2.000 MHz)

The 160 meters band is located just above the commercial AM broadcast band. It is often taken up as a technical challenge due to the difficulty of long-distance (DX) propagation caused by higher D layer ionospheric absorption. This band is known as the “top band” and is notorious for its noise, particularly during the summer months. This band is usable mostly during night time and during weak solar activities.

Propagation characteristics:

  • Ground waves to about 25 miles
  • Day sky waves to about 200 miles
  • Night sky waves to about 2500 miles

HF – High Frequency Bands

80 meters (3.500 – 4.000 kHz)

The 80 meters band is considered the most reliable all-season long-distance (DX) band. It is popular for DX contacts at night and reliable for medium-distance contacts during the day. In the US and Canada, a portion of this band allows for single-sideband voice and AM voice transmissions.

The 80 metes band goes from 3.5 to 4.0 MHz in ITU Region 2; generally 3.5–3.8 MHz in ITU Region 1, and 3.5–3.9 MHz in Region 3.

Upper part of the 80 meters Band in ITU Region 2 countries, is commonly named as 75 meters band.

This band is good for local communications during the day, and hardly ever good for communications over intercontinental distances during daylight hours. During late afternoon and night , when noise decreases, it can be effective even for worldwide communications.

Propagation characteristics:

  • Ground waves to about 20 miles
  • Day sky waves to about 250 miles
  • Night sky waves to about 2500 miles

60 meters (around 5 MHz)

The 60 meters band is a relatively new allocation and was originally only available in a small number of countries. It is now expanding, and in most countries, the allocation is broken into channels and may require a special licensing request. The 2015 ITU World Radiocommunications Conference approved a new worldwide frequency allocation for amateurs on a secondary basis.

Propagation characteristics:

  • Short and medium distances, day and night.

40 meters (7.000 – 7.300 MHz)

The 40 meters band is considered the most reliable all-season long-distance (DX) band. It is popular for DX contacts at night and reliable for medium-distance contacts during the day. This band is now free of other users due to the shutdown of many shortwave broadcasting services. ITU Region 1 and Region 3 40 meters band range is from 7.000 to 7.200 MHz.

Propagation characteristics:

  • Ground wave to about 20 miles
  • Day sky waves to about 750 miles
  • Night sky waves to about 10,000 miles

30 meters (10.100 – 10.150 MHz)

The 30 meters band is a very narrow band shared with non-amateur services. It is recommended for Morse code and data transmissions, and in some countries, amateur voice transmission is prohibited. It provides significant opportunities for long-distance communication at all points of the solar cycle. . WARC Band, contest free.

Propagation characteristics:

  • Day sky waves to about 750 miles
  • Night sky waves to about 10,000 miles

20 meters (14.000 – 14.350 MHz)

The 20 meters band is considered the most popular DX band and is usually most active during the daytime. It is commonly used for DX operations in all modes. This band permits long distance contacts, even when other bands are closed, and this is the reason why it is particularly crowded during contests.

Propagation characteristics:

  • Ground waves to about 20 miles
  • Day sky waves with worldwide communications extending from dawn to dusk
  • Excellent night sky waves during high sunspot activity
  • Virtually no sky waves during minimum sunspot activity

17 meters (18.068 – 18.168 MHz)

The 17 meters band is similar to the 20 meters band but more sensitive to solar propagation minima and maxima. It is a very narrow band, just 100 kHz wide. It is also a WARC band, allocated to amateur radio use during the 1979 World Administrative Radio Conference.

Band is open at daytime and it usually opens before the others. . WARC Band, contest free.

Propagation characteristics:

  • Day sky waves to about 700 miles
  • Very sensible to solar maximun

15 meters (21.000 – 21.450 MHz)

The 15 meters band is most useful during solar maximum and generally a daytime band. Daytime sporadic E propagation occasionally occurs on this band, allowing for communication over distances of up to 1,500 km (1,000 miles).

Propagation characteristics:

  • Ground waves to about 20 miles
  • Worldwide day and night sky waves during high sunspot activity
  • No night sky waves and only occasional day sky waves during minimum sunspot activity

12 meters (24.890 – 24.990 MHz)

The 12 meters band is mostly useful during the daytime but can open up for DX activity at night during solar maximum. It propagates via sporadic E and F2 propagation. WARC Band, contest free.

Propagation characteristics:

  • Propagates via Sporadic E and F2 layer
  • Skip distances about 1000 miles
  • Open at daytime

10 meters (28.000 – 29.700 MHz)

The 10 meters band is best for long-distance communication, especially during solar maximum. It offers short to medium-range groundwave propagation day or night. This band is also known for sporadic E propagation during the late spring and summer, allowing for short band openings into small geographic areas.

Propagation characteristics:

  • Ground waves to about 20 miles
  • Worldwide sky waves in daytime and early evening hours during high sunspot activity
  • Very little day sky waves and virtually no night sky waves during minimum sunspot activity.

VHF Very-High Frequencies and UHF Ultra-High Frequencies

Frequencies above 30 MHz are referred to as Very High Frequency (VHF) and those above 300 MHz are called Ultra High Frequency (UHF). These bands have wider allocations, allowing for high-fidelity audio transmission modes and fast data transmission modes.

Propagation characteristics:

  • No ground wave propagation in sense of MF and HF ground waves.
  • (Beginning with 50–54 MHz) Direct and reflected waves describe line-of-sight radiation for these frequencies.
  • Only 6-meter band exhibits fairly constant propagation at distances of about 75 to 100 miles. Some ionospheric conditions permit propagation paths up to 2500 miles.
  • Frequencies at 144 MHz and above exhibit primarily line-of-sight communications with little ionospheric effects on this propagation. However, unusual propagation modes, such as ducting, will allow limited long-range communications.

Ham Radio Frequency Chart

US Amateur Radio Bands

Recommended Frequencies and Calling Frequencies

The table below provides guidance on recommended frequencies for specific modes of communication and special activities, including the calling frequencies.

This helps operators avoid interference and promotes responsible use of the radio spectrum, fostering a cooperative and respectful environment among radio operators.

The specified frequencies are generally associated with specific modes or activities (all frequencies in MHz) under normal conditions. These aren’t strict regulations, and increased activity, like during emergencies, DXpeditions, or contests, may lead to operations outside these ranges. No entity or individual has exclusive privileges to a frequency, as per Rule 97.101(b), emphasizing cooperation in channel selection and shared use.

It’s advisable, and common sense, for radio operators to check for existing usage before transmitting. If you’re the first to occupy a frequency, fellow operators should make efforts to minimize interference, acknowledging the challenge of achieving complete interference-free operation in today’s crowded bands.

Single Side Band Mode

Traditionally, 20 meters and above use Upper Sideband (USB), while 40 meters and below use Lower Sideband (LSB). However, the 60 meter band is an exception, employing Upper Sideband. This convention arose for convenience in early Single Sideband (SSB) transceiver design and persists. Where phone communication is allowed, Ham radio operators are legally permitted to use both sidebands.

FrequencyModes / Activites
160 Meters
1.800-2.000CW
1.800-1.810Digital Modes
1.810CW QRP Calling Frequency
1.825SSB QRP Calling Frequency
1.843-2.000SSB, SSTV and other wideband modes
1.910SSB QRP calling frequency
1.995-2.000Experimental
1.999-2.000Beacons
80 Meters
3.500-3.510CW DX window
3.560CW QRP Calling Frequency
3.570-3.600RTTY/Data
3.585-3.600Automatically controlled data stations
3.590RTTY/Data DX
3.790-3.800DX window
3.845SSTV
3.885AM calling frequency
3.985SSB QRP Calling Frequency
40 Meters
7.030CW QRP Calling Frequency
7.040RTTY/Data DX
7.070-7.125RTTY/Data
7.100-7.105Automatically controlled data stations
7.171SSTV
7.173D-SSTV
7.285SSB QRP Calling Frequency
7.290AM calling frequency
30 Meters
10.106CW QRP Calling Frequency
10.130-10.140RTTY/Data
10.140-10.150Automatically controlled data stations
20 Meters
14.060CW QRP calling frequency
14.070-14.095RTTY/Data
14.095-14.0995Automatically controlled data stations
14.100IBP/NCDXF beacons
14.1005-14.112Automatically controlled data stations
14.230SSTV
14.233D-SSTV
14.236Digital Voice
14.285SSB QRP Calling Frequency
14.286AM calling frequency
17 Meters
18.080CW QRP Calling frequency
18.100-18.105RTTY/Data
18.105-18.110Automatically controlled data stations
18.110IBP/NCDXF beacons
18.130SSB QRP Calling Frequency
18.162Digital Voice
15 Meters
21.060CW QRP calling frequency
21.070-21.110RTTY/Data
21.090-21.100Automatically controlled data station
21.150IBP/NCDXF beacons
21.340SSTV
21.385SSB QRP Calling Frequency
12 Meters
24.910CW QRP Calling Frequency
24.920-24.925RTTY/Data
24.925-24.930Automatically controlled data stations
24.930IBP/NCDXF beacons
24.950SSB QRP Calling Frequency
10 Meters
28.060CW QRP Calling Frequency
28.070-28.120RTTY/Data
28.120-28.189Automatically controlled data stations
28.190-28.225Beacons
28.200IBP/NCDXF beacons
28.385SSB QRP Calling Frequency
28.680SSTV
29.000-29.200AM
29.300-29.510Satellite downlinks
29.520-29.580Repeater inputs
29.600FM simplex
29.620-29.680Repeater outputs
6 Meters
50.060CW QRP Calling Frequency
50.090CW Calling Frequency
50.100 to 50.130SSB DX Window
50.125US National SSB Calling Frequency
50.885SSB QRP Calling Frequency

About WARC Bands

The WARC bands, an abbreviation for “World Administrative Radio Conference” bands, are specific frequency allocations reserved for amateur radio usage. Established during te 1979 ITU Conference, these bands provide additional spectrum exclusively for amateur radio enthusiasts. WARC bands offer opportunities for experimentation, communication, and global connectivity, contributing to the diversity and vibrancy of the amateur radio community. WARC bands include 12 meters (24.890 – 24.990 MHz), 17 meters (18.068 – 18.168 MHz), and 30 meters (10.100 – 10.150 MHz).

By common agreement among ham radio operators, the WARC bands are not to be used for contesting.

Related Links

Final notes

Amateur radio bands play a crucial role in enabling communication among ham radio operators worldwide. From the low-frequency bands to the very-high and ultra-high frequencies, each band offers unique characteristics, propagation conditions, and usage patterns.

The information provided in this article is based on general knowledge of amateur radio bands. It is important to consult the specific regulations and band plans for your country or region before operating your radios on any amateur radio frequency.

We recommend to check band plans published either from IARU or national organizations.