Tag Archives: Propagation

Radio propagation may improve soon with region of solar flux

Many thanks to SWLing Post contributor, Mike Hansgen, who shares this latest Space Weather report from Tamitha Skov:

Space Weather jumps into action this week with two weak solar storms en route to Earth. NASA models predict they will hit starting July 9 and they could easily bring aurora to high latitudes, if not mid-latitudes. Amateur radio operators are also in for some fun as a new region rotates into view and brings with it a boost in solar flux, which will help radio propagation just in time for hurricane season. GPS users shouldn’t be affected by the low-level flaring of this region on Earth’s day side, but should stay vigilant near aurora and near the dawn-dusk terminators for glitches in their reception. Low-latitude GPS/GNSS reception might even improve under the influence of these weak solar storms. See details of the coming storms, when this new active region will be in view, catch up on aurora photos, and see what else is in store!

Click here to view on YouTube.

Don’t buy into the doom-and-gloom: Low sunspots are not the end of DXing!

In response to the spaceweather.com article about a lack of sunspots I posted yesterday, SWLing Post contributor, Rob Wagner (VK3BVW), replies:

Oh Thomas! Really?
It’s not all doom-and-gloom, you know! The low-frequency part of the SW spectrum is proving very good value at the moment. And the mediumwave guys are telling me that there’s plenty of DX to be had in that part of the RF spectrum.
And yesterday, I had some FT8 success!
From southeastern Australia on a dipole with 5w getting into Plymouth, Minnesota on 14mHz in the mid-afternoon here. Not bad at all for the bottom of the sunspot cycle!

Ha ha! Thanks for your reply, Rob! Honestly, I wasn’t trying to spread doom-and-gloom, rather I was pointing out how low this sunspot cycle has gone. (Okay, so perhaps I was also shaking my fist at our local star!)

I completely agree with you Rob. It’s not all doom-and-gloom! Here are a few strategies for working DX during sunspot lows:

Go low!

Sunspots really enhance propagation on the higher HF bands:  especially 17 meters and higher. Without supspots, you’re not going to reliably snag serious DX on 10 meters, for example–there will be the occasional opening, but it might not last long. During sunspot cycle peaks, the higher bands provide outstanding DX opportunities even with a modest setup.

During one peak, I’ll never forget sitting in my car in North Carolina, with a RadioShack 10 meter mobile radio connected to a mag mount antenna, and having a three way chat with a ham in Sandiego, CA and one in Glasgow, Scotland.

With that said, even this year I’ve snagged some excellent DX on 17 meters (my favorite HF band). And, as you point out Rob, 20 meters is a great band for snagging serious DX even with no sunspots giving you a boost.

Openings between the US and Australia happen routinely on the 40 meter band as well, although some of us might have to wake up early or go to bed late to participate.

Of course all of this same advice applies for SWLing. Most of the DX I snag these days is found on the 25 meter band and lower. I’ve also been using this opportunity to explore Mediumwave DXing.

Digital Modes

Kim Elliott and I had an exchange about this yesterday on Twitter. Some digital modes are so robust they seem to work regardless of propagation.

Kim knows this well as he receives reception reports from Shortwave Radiogram listeners across the globe each week.

If you’re a ham radio operator, I strongly encourage you to check out the latest “weak signal” digital modes: JT65 and, especially, FT8.

In fact, SWLing Post contributor, Robert Gulley (AK3Q), wrote an excellent introduction to these modes in the June 2017 issue of The Spectrum Monitor magazine.

Robert and I talk about the FT8 mode frequently. Since I discovered this mode at the 2017 W4DXCC conference, I’ve been hooked. Sure–it lacks the nuances of phone and CW, but it’s incredibly fun to watch my flea-powered signal acknowledged by someone on the other side of the planet with a flea-powered signal.

As Robert will tell you, FT8 seems to defy propagation theory. I agree wholeheartedly.

I’ve worked some of my best DX with this mode during the sunspot low and have never used more than 15 watts out of my Elecraft KX3 and KX2.

Don’t give up!

Although propagation was poor, I worked more stations during National Parks On The Air than I had worked the entire time I’ve been a ham radio operator. All in the field with modest portable antennas and 15 watts or less.

Use the sunspot low as an excuse to explore frequencies and modes you’ve never used before. Use this as an opportunity to improve your listening skills and the most important part of your listening post or ham station–your antenna system!

I regularly get email from people who’ve found the SWLing Post and take the time to write a message to me complaining about the death of shortwave radio: the lack of broadcasters, the prevalence of radio interference and the crummy propagation.

My reply?

“Hey…sounds like radio’s not your thing!”

While this same person is moaning and complaining, I’ll be on the radio logging South American, Asian and African broadcast stations.

I’ll be working DX with QRP power, even though everyone tells me that’s not possible right now.

I’ll be improving my skill set and trying new aspects of our vast radio world.

You see: I’ve learned that the complainers aren’t actually on the air. They gave up many moons ago because someone told them it wasn’t worth it, or they simply lost interest. That’s okay…but why waste time complaining? Go find something else that lights your fire!

While these folks are complaining, I’ll be on the air doing all of the things they tell me I can’t do.

Rob, thanks for your comment!

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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(Source: RadioWorld via Sheldon Harvey at the International Radio Report)

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