Tag Archives: Eclipse Propagation

Radio Waves: RIP Phil Erwin, Federal Watchdog Targets Pack, Eclipse Festival of Frequency Measurement, and VOA testing DRM

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Dave Zantow, Michael Guerin, Eric McFadden, and Dan Robinson for the following tips:

The voice of Phil Irwin will be greatly missed (Rappahannock News)

Where wasn’t the presence of Phil Irwin felt in Rappahannock County?

A constant of virtually all proceedings of the Rappahannock County community and government, cherished innkeeper of Caledonia Farm – 1812, founding member of the Rappahannock League for Environmental Protection, regional director of the Virginia Farm Bureau, committee member for both Rappahannock County Farmland Preservation and the Agricultural Forestal District, Rappahannock tourism advisory member — for 25 years chief of morning broadcasts for Voice of America (VOA) — Irwin was found dead Thursday at his working cattle farm north of Washington.

“What a contribution Phil made to our county over his many years here,” Huntly friend Ralph Bates reacted upon learning of Irwin’s death. “He will live in our memories as we drive and see how well our viewshed and environment has been protected because of his commitment and work.”

Former Washington Mayor John Fox Sullivan recalled “a good man and such a part of the Rappahannock fabric. His love for this county, and commitment to it, was unmatched.”[]

Federal watchdog finds ‘substantial likelihood of wrongdoing’ by Trump appointees overseeing Voice of America (NBC News)

The federal watchdog’s findings mark the latest rebuke of the Trump-appointed CEO of the U.S. Agency for Global Media, Michael Pack.

WASHINGTON — A federal watchdog agency has found “a substantial likelihood of wrongdoing” by Trump administration appointees who oversee the Voice of America and other U.S.-funded media outlets.

The finding from the U.S. Office of Special Counsel, an independent government agency charged with safeguarding federal employees’ rights, marks the latest rebuke of Michael Pack, who President Donald Trump appointed to run the U.S. Agency for Global Media, the parent agency to VOA and other broadcasters.

A federal judge last month ordered Pack to stop interfering in the newsrooms of VOA and other media outlets and found that he had jeopardized the First Amendment rights of journalists that his office had targeted for investigation. Lawmakers from both sides of the aisle and press freedom groups have blasted Pack over his actions since he took over in June, accusing him of undermining the broadcasters’ editorial independence and defying congressional authority.

After reviewing allegations from current and recent employees, the Office of Special Counsel wrote to the whistleblowers Wednesday saying it had demanded Pack and the U.S. Agency for Global Media conduct an investigation into the allegations.[]

The December 2020 Eclipse Festival of Frequency Measurement (HamSCI)

Changes in ionospheric electron density caused by space weather and diurnal solar changes are known to cause Doppler shifts on HF ray paths. For example, see Figure 7 in Boitman et al., 1999. HamSCI’s first attempt at a measurement of these Doppler shifts was during the August 2017 total solar eclipse. We plan a careful measurement during the 2024 eclipse. As part of the WWV centennial, 50 stations collected Doppler shift data for the original Festival of Frequency Measurement, demonstrating the value of volunteer participation in collecting this data. During the June 2020 Eclipse Festival, we enlisted participants around the globe and experimented with different data collection protocols. This winter, we request that all amateur radio stations, shortwave listeners, and others capable of making high-quality HF frequency measurements help us collect frequency data for the December 14 total eclipse.[]

USAGM, VOA Testing Innovative Digital Radio Platform (Inside VOA)

A few weeks before the COVID-19 pandemic shut down much of the world, broadcast engineers in Greenville, North Carolina, launched a test of digital radio signals. The U.S. Agency for Global Media began aiming a digital broadcast at Cuba and Latin America, which included Office of Cuba Broadcasting and Voice of America content.

With this 2020 test, VOA embarked on a new phase of global innovation on a platform called Digital Radio Mondiale (DRM), a versatile digital signal not well known in the U.S., but the only one that can cover the entire spectrum: shortwave, mediumwave and longwave, as well as VHF (FM). As digital radio emerged in the 1990s, VOA was among the first broadcasters testing a signal that promised to even out shortwave radio signals that often faded in and out and were marred by static.

VOA tested the DRM signal in the 1990s at the agency’s Morocco transmitter site, one of five facilities opened in a period of expansion in the previous decade. However, other digital signals became the standard in various markets around the world. The U.S. standard audio digital platform is called HD.

Around the world, as other digital radio platforms were adopted, DRM was held back by the marketplace. Nobody was making commercially available receivers.

By the end of the 1990s, VOA innovation focused more on television, the platform that promised larger audiences, even in some places in the world where shortwave dominated. By the early 2010s, the rallying cry became “Digital First,” as VOA strived to attract readers for its language service websites and began tapping into the growing audiences on new social media sites like Facebook, Twitter, Instagram and YouTube.

By 2020, however, DRM had come full circle.

“You’re no longer limited to just reading the news or playing music,” says Gerhard Straub, supervisory director of the USAGM Broadcast Technologies Division.

Straub, along with Gary Koster, Broadcast Radio Technician and transmitter expert and Macon Dail, Chief Engineer at the Greenville Transmitting Station, set up the test broadcast in February of this year, not long before the COVID-19 pandemic grounded global travel. The trio put up a DRM signal with Radio Marti and VOA audio along with scrolling text messages and rotating images.

Engineers have received reports of a clear signal as far south as Brazil.

The USAGM test, says Straub, is “coasting along” in the pandemic, but additional content will be added when technicians can travel again. Straub says the VOA signal was taken off in the initial test to concentrate on the OCB digital content and to keep the signal robust. Now that there is good reception data, he noted, the digital bit rate can be increased and VOA content added back into the test in 2021.

Because DRM operates at lower power, more radio stations and digital signals can be broadcast on a single transmitter. The platform is starting to grow in countries of interest to Western international broadcasters. DRM signals will soon cover all of China, though its government is expected to attempt to control the stations accessed by its citizens. India built 39 transmitters and, more importantly, 2.5 million vehicles already are equipped with DRM radios. Indonesia, Pakistan, Brazil and North Korea all have nascent DRM operations.

Religious broadcasters, who sometimes target audiences similar to those sought by Western governments, are experimenting with the technology. For example, a missionary group, TWR.org, sent the Bible’s Gospel of Mark from Guam to Cambodia via DRM shortwave.

“You have to stop thinking of it as radio, because it’s not,” says USAGM’s Straub. “We are now broadcasting digital data. Just like we broadcast digital data on the internet, we can broadcast digital data over shortwave without being hampered by an internet firewall that maybe limits what we can send to a particular country.”

Reason enough, Straub believes, for VOA to continue leading innovation in a new-again technology.[]

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AM Radio: Ivan compiles 2017 solar eclipse logs

Many thanks to SWLing Post contributor, Ivan Cholakov (NO2CW), who writes:

I never got a chance to summarize my results of the AM scans I did during the 2017 total eclipse.

I used an SDR and a 40 foot end-fed antenna located in a park near the Nashville, TN airport.

On the plus side I did notice a spike of AM signals and amateur radio signals especially on 40 meters. On the negative side, my AM scans were adversely affected by the nearby powerhouse WSM transmitter on 650 kHz.

I’ve attached my results in a spreadsheet [embedded] below.

Click here to view this Google Docs spreadsheet in a new window.

Fantastic, Ivan! Thank you for taking the time to go through your recordings and make these notes. No doubt, this log took a few hours to compile. I’ve yet to go through my eclipse spectrum recordings–!

Again, thanks for sharing!

Click here to view Ivan’s previous post which includes a bandscan of the 2017 Eclipse QSO Party.

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Video: Ivan shares a bandscan from the 2017 Eclipse QSO Party

Many thanks to SWLing Post contributor, Ivan Cholakov (NO2CW) who shares the following:

I finally got around to listening through some of the amateur radio band spectrum captures from the 2017 Solar Eclipse QSO party. I used an SDRPlay receiver with an end fed LNR antenna in portable field setting in Nashville, TN.

About 30 minutes of solar eclipse contacts and chatter:

Click here to view on YouTube.

Thank you, Ivan, for taking the time to put this video together and sharing it. The RSP did a fantastic job capturing this spectrum–I do love the SDRuno application for reviewing spectrum recordings as well. Cheers!

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Guest Post: Eclipse 2017 – Shortwave Propagation Observations

A map of the United States showing the path of totality for the August 21, 2017 total solar eclipse. (Source: NASA)

Many thanks to SWLing Post contributor, Bob LaRose (W6ACU), for the following guest post:

Eclipse 2017 Propagation Observations

by Bob LaRose (W6ACU)

DXers know that the reception of overseas Shortwave Broadcast stations offers one of the best ways to immediately gauge shortwave radio propagation conditions from your location to distant areas of the world. For the eclipse of 2017 I decided to see how reception of SW broadcast stations on lower shortwave  broadcast frequencies (and to a smaller extent medium wave AM) reacted to the short term effects of the eclipse.  

Going into this experiment I suspected that since the eclipse should temporarily reduce ionization to D-layer of the ionosphere, there might be some reduction in corresponding typical D-layer daytime absorption on lower frequencies. The hope was that this would enhance lower frequency propagation, particularly on the path between Asia and Western North America, which is normally totally absorbed at that time of day. I also monitored for propagation on other HF stations such as WWV as well as US-based SW Broadcast Stations in Alaska and Tennessee, and to a lesser extent AM MW broadcast stations. Here are the results of my experiment.  


The Icom -IC-7300

For these tests I was using an ICOM IC-7300 Transceiver as a receiver connected to my standard antenna for lower frequency use – a Carolina Windom with the center about twenty feet off the ground. The antenna works reasonably well over a wide frequency range, including the lower SW and the medium wave AM broadcast bands. Because of my high local electrical noise level and proximity to several local AM broadcast transmitters, I turned off the built-in RF amplifier of the IC-7300 for all the tests. I used the uncalibrated S Meter of the radio to measure relative signal strengths in S units and dB above S-9. 


The day before the eclipse I took baseline measurements at about the time of the eclipse. Because of normal summer daylight absorption, there were no signals present on either the 49 or 41 meter SW broadcast bands. At this time of year signals on those two bands generally fade below the local noise level at my QTH San Diego by about 1500 UTC.  

I also checked the reliable daily beacons on SW at that time are the WWV frequencies of 5 and 10 MHz, The baseline for WWV was a signal strength of S5 on 5 MHz and S7-9 on 10Mhz.  

I also took some baseline measurements of AM broadcast stations in Los Angeles (KFI 640 and KNX 1070). I was not able to receive any of the San Francisco, Sacramento, Las Vegas stations or points further North.  


According the Internet sources the eclipse began in San Diego at 1607 UTC, peaked at 1723 UTC and ended at 1846 UTC. It reached 66% of totality. 

My first observation was at 1550 UTC. The strength of all signals were at the nominal readings from the day before. At 1630 I still did not hear any SW broadcast stations above the local noise level. 

By 1640 the HF broadcast stations had begun to break through the noise. Here is a chart of my reception observations during the observation period:  

Freq KHz  Station and Location  Time in UTC vs. Relative Signal Strength (S Units) 
    1550  1630  1640  1650  1710  1725  1745  1800  1815  1830 
640  KFI Los Angeles  9  9  9  9  9  9  9  9  9  9 
1530  KFBK Sacramento, CA  0  0  0  0  3  6  2  0  0  0 
5000  WWV Ft Collins, CO  5  5  7  9  9  9  6-7  7  5  5 
5845  BBC Singapore (ends at 1700)  0  0  0  9  0  0  0  0  0  0 
5995  Korea – Echo of Hope (presumed)  0  0  0  0  6  0  0  0  0  0 
6015  Korea (presumed)  0  0  0  5  0  0  0  0  0  0 
6045  Korea (presumed)  0  0  0  6  0  0  0  0  0  0 
6125  China National radio  0  0  0  6  0  0  0  0  0  0 
6155  Taiwan (1700-1730)  0  0  0  0  S9+10  5-7  0  0  0  0 
6165  Yamata Japan for Korea (1600-1700)  0  0  6  7-9  0  0  0  0  0  0 
6175  China National Radio  0  0  0  0  5-7  7-9  7-9  0  0  0 
6195  BBC Singapore (open carrier – presumed tune-up for next morning  0  0  0  0  S9+10-20  0  0  0  0  0 
7300  Radio Taiwan  0  0  7  0  0  0  0  0  0  0 
7385  China National Radio  0  0  9  0  0  0  0  0  0  0 
7465  BBC Singapore (ends at 1700)  0  0  S7-8  0  0  0  0  0  0  0 
7485  VOA Thailand (started 1700)  0  0  0  0  7-8  3  0  0  0  0 
7540  VOA Thailand (started at 1700)  0  0  0  0  0  S5-7  0  0  0  0 
9355  Radio Free Asia (Marianas Islds, starts at 1700)  0  0  0  0  5-7  0  0  0  0  0 
9475  WTWW Lebanon, TN  0  0  0  0  0  0  7-9  7  4-6  0 
9655  KLNS Anchor Point, AK  0  0  9  6-7  7-8  0  0  0  0  0 
9965  Radio Free Asia (Marianas Islds, starts at 1700)  0  0  0  0  9  5-7  0  0  0  0 
9980  WWCR Nashville, TN  8  7-9  7-8  7-8  7-8  7-8  7-8  9  7-9  7-8 
10000  WWV Ft Collins, CO  7  S9+10  9  9  9  5-7  9  9  6-8  7-9 
12160  WWCR Nashville, TN  S9+20  S9+10  S9+10  N/R  N/R  N/R  N/R  S9+10  S9+20  N/R 

 N/R = Not recorded 


As the results show, there was a very significant improvement in lower frequency shortwave propagation between San Diego and Asia during the eclipse. The 49 and 41 meter SW broadcast bands in particular went from below the noise level to providing good reception of a number of Asian and Pacific broadcast stations, starting at around 1640 UTC. Stations were received from China, Korea, Mariana islands, Taiwan, and Singapore. All stations fell back below the noise level by 1745UTC. 

Reception of WWV Ft Collins, CO on 5 MHz also greatly improved around 1700 UTC. The 10 MHz signal was not significantly affected. 

As the eclipse moved East, Reception of WTWW on 9475 kHz and WWCR on 9980 kHz from Tennessee peaked at around 1745 UTC. There was no major effect to the WWCR transmission on 12160 kHz. 

On mediumwave AM the only long distance station that I could hear was KFBK Sacramento,1530kHz. The distance is roughly 475 miles. It went from below the noise to an S-6 at peak at 1725 UTC. (Note – I tried the clear channel stations in the Bay Area, Portland, Boise, etc. but none of them were heard. Many of these frequencies have either low power daytime stations or are right next to high power local stations here in Southern California). Reception of KFI 640 kHz Los Angeles (about 90 miles) was unchanged with no sign of typical nighttime selective fading.  

This was an interesting once-in-a-lifetime opportunity for this propagation experiment and the results show that the eclipse conditions can significantly improve certain types of radio propagation over long distances!

Fascinating results! Thank you so much for sharing your report of shortwave radio propagation during the 2017 Solar Eclipse, Bob! 

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