Tag Archives: Eclipse

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!

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! 

Dan shares solar eclipse spectrum files

(Source: The K2DLS blog)

Solar Eclipse Data Collection Project

Between 1600 – 2015 UTC on August 21, 2017, as the solar eclipse swept across the nation, I captured much of the lower 2 MHz of the radio frequency spectrum.  I used a Microtelecom Perseus SDR, a 130? inverted L with four radials, and lots of disk space.  In doing so, I have created a permanent record of this portion of the RF spectrum during the solar eclipse.

I am making the spectrum capture files available for your analysis and research.  Each file contains a 5 minute segment.  If you download a group of files, they will play in succession.

You can use the demo version of the Perseus software or any other software that can read the Perseus data, such as Linrad or HDSDR.  You cannot use just an audio player to play the files, even though they have .wav extentions.

Should you perform any analysis or otherwise make use of the files, I’d like to hear from you in the comments below.

Special thanks to Jav, K4JH, for donating the bandwidth for this effort.

Many thanks, Dan and Jav for making these files available for download! Someday, if I can find the bandwidth and space to upload them, I’ll also share the spectrum recordings I made.

Click here to check out K2DLS’ blog.

Tom’s AM broadcast band recordings during eclipse totality

Many thanks to SWLing Post contributor, TomL, for sharing the following guest post:

August 21, 2017: Individual Recordings of MW During Totality

by TomL

I setup flimsy “Backpack Shack” loop antenna and preselector to my Sony ICF-2010 to listen to any propagation of MW signals as each transmitter experienced Totality. My location was a picnic area facing southwest with only a small hill to the east at Ferne Clyffe State Park near Goreville, IL.

I did not bring a DSP radio and computer which would have been better in hindsight. My observations were generally as follows:

Anything west of my location, except for local St. Louis stations were not identifiable.
Noise levels were somewhat elevated because of thunderstorms that had just moved through the area during the evening.

Anything east of my location experienced dramatic increases in signal along the path of totality.
Since large signal increases were seen with the Umbra moving AWAY from me, it would be more beneficial to use a DSP receiver with good outdoor antenna than a single frequency radio and preselector like my setup. The loop antenna sitting on a picnic table acted great and was usable to get strongest signal for each station.

It is still unknown why I could not identify any stations west of me with the Umbra moving TOWARDS my location and needs further study. I thought I heard KTWO in Casper WY, but upon listening to the recording, it was a male announcer buried in the noise and unintelligible.
A transmitter being IN the path of Totality has a better chance of lasting longer with a strong signal than one that is just outside of Totality. Compare behavior of WSB vs. WBT.

If this happens again, make sure to make multiple hotel reservations and cancel the ones not needed. Traffic was horrible and had to stay in a hotel half way from home and I aggravated an achillies heel problem in the stop and go traffic (YUK).

So, it was quite disappointing to not hear anything special west of my location. As Totality neared my site, I just left the radio tuned to KNOX for the people around me to hear. Its signal did become about 25% stronger and near the end of the recording you can hear other weaker stations trying to break in.

Click here to download 1120 KMOX recording.

As soon as totality was over, and my picture taking was done, I returned to the radio and found 1510 khz WLAC Nashville, TN was moderately strong! And this was seconds after their Totality had already ended. A baseline reading beforehand showed this station coming in very very faintly. Subjective SINPO rating beforehand=15452, just after Totality=34433.

Click here to download 1510 WLAC recording.

The next surprise was tuning to 750 WSB Atlanta GA was BOOMING in! They were very clever and had no announcers. Instead they were playing snippets of songs about sun, moon, dark themes. Very entertaining! Baseline beforehand was just moderate noise, no signals. During recording, SINPO=55444 with propagation getting slightly worse near the end of the recording.

Click here to download 750 WSB recording.

Final surprise was 1110 WBT Charlotte, NC, which was not in the path of Totality but just north of it also booming in but not as strongly. Also, near the end of the recording, the signal dropped off very sharply, unlike the WSB signal which stayed strong throughout the 5+ minute recording. Baseline beforehand was low noise and no signals. During recording, SINPO=43434 at 14:40 ET, then approximately 1½ minutes after their maximum eclipse (14:43 ET), SINPO=33423, then at 14:46 ET a SINPO=22422 with another unidentified station breaking through playing a Johnny Cash song.

Click here to download 1110 WBT recording.

Tom, thank you for taking the time to share your recordings and listening experiences with us! Snagging a daytime MW broadcast from the Atlanta, GA and Charlotte, NC regions is most impressive. I reckon they were about 400-500 miles (as the crow flies) from your Ferne Clyffe, IL location.

Sounds like you had an amazing experience, despite the stop-and-go traffic! 

WNAH’s solar eclipse propagation test

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

If you ever loved AM radio you will love this.

Thank you WNAH for recognizing there’s more to radio than plugging into a programming network and walking away!

Click here to view on YouTube.

Very cool! Many thanks, Ivan!

As I mentioned in a previous post, I recorded the entire mediumwave (AM broadcast) band from my North Carolina home with a WinRadio Excalibur on August 21 (day of the eclipse). After receiving Ivan’s message last night, I played back my recording and moved the time forward to around the moment of totality.

The mediumwave band was hopping! Several stations were competing for 1360 kHz with eclipse-enhanced propagation. There were two large signals flanking 1360 as well.

I thought I would never hear WNAH, but as I listened, their ID in CW (Morse Code) popped out of the signal mix. Here’s a short recording of the first station ID I received around 2:26 PM EDT (1826 UTC):

Click here to download the audio.

True: this is rough audio, but it always amazes me how CW can so effectively punch through noise. Nice touch, WNAH!

WNAH’s signal strength increased with time, but so did the competing signals on 1360 kHz. Within 10 minutes, about the time of totality in western North Carolina, WNAH was 40% stronger.

I did submit my recording and notes to WNAH last night.

Due to my schedule, I haven’t had any meaningful time to go over my eclipse spectrum recordings. Indeed, I think I’ll need several dedicated days to review them. While searching for WNAH’s signal, I could see a significant difference in propagation on the waterfall display within a 26 minute span of time:

 14:15 EDT

14:41 EDT

Note that local time of totality was 14:36 EDT.

I made spectrum recordings spanning 0-2 MHz, 6-8 MHz and 13.5-15 MHz.

Post readers: Did anyone else log WNAH? Log any other shortwave or mediumwave DX? Please comment!