Category Archives: AM

1296 kHz: Help Andy identify this 1970s/80s mediumwave broadcaster

Many thanks to SWLing Post contributor, Andy (G0FTD), who writes:

Back in the 1970’s, there was a rather strange medium wave transmitter on
1296Khz. Originally I think it was in Sussex, and then changed to Orfordness
in Suffolk UK.

It was a weird thing.

I think it was “owned” by the UK’s Diplomatic Wireless Service, not the BBC.

It seemed to be fairly random in its transmissions, and often sent the letter
V in a strange bong-bong-bong-BONG! loops for hours.

Programmes were English by Radio, and a seemingly random mix the BBC World
Service, and BBC Radio 1 (I think).

It slso had a creepy signature tune for the English by Radio programme,
and the modulation had an odd tinge to to it, like it was slightly over modulated.

At some time (the 80’s), I think it’s QTH changed, and the pause between the
letter V being sent was shortened from about 3 seconds to 1 second.

I understand that it had a sharp antenna beam, towards easter Europe, and
was not widely heard in the UK. Those of us that lived in the south east
of the UK could of course hear it off the back of it’s beam.

I’ve never ever seen it mentioned on any radio forums, no archive recordings
seem to exist of these creepy English by Radio them tunes or programmes,
or any off air recordings.

Saying that, I did come across a studio copy of the interval signal, but no
details about it. (But I knew what it was).

Click here to download MP3.

Sometime about 1995 I think it might have been mothballed, and lays ready
for possible future use should there be a need to by the DWS.

If you can help Andy identify, or at least provide more information about this station, please comment! I would love to know about this broadcast service myself.

Relive This Day In Radio History: When WJSV recorded an entire broadcast day

Many thanks to SWLing Post contributor, Bill Patalon, who reminds us that 78 years ago today (September 21, 1939) radio station WSJV made an audio recording of its entire 19 hour broadcast day. Bill points to these details from Wikipedia:

This undertaking was a collaboration between the station and the National Archives, and it was the first time that such a comprehensive recording of a radio broadcast had been made. The station then donated its original set of recording discs to the National Archives, giving it a rare and complete artifact from an era frequently called the Golden Age of Radio. Due to their historical significance, the United States Library of Congress has since added these sound recordings to its National Recording Registry.

https://www.radioarchives.com/WJSV_A_Day_in_Radio_History_p/ra140.htm

Let’s travel back in time…

If you would like to relive September 21, 1939, you can listen to all of the WSJV recording segments courtesy of Archive.org. I’ve embedded the full playlist below–simply press play at the top of the player and each segment will load automatically as long as this page is open. Note that in the very first segment, due to a WSJV equipment glitch, there is a period of silence. Enjoy:

Click here to view or download the full set of recordings on Archive.org.

Many thanks for sharing this bit of radio history, Bill! As a radio archivist, this sort of thing makes my day.

Chris reviews the Eton Field BT and an important note about the discontinued Grundig S350DL

The Eton Field BT

Many thanks to SWLing Post contributor, Chris Freitas, who notes that’s he’s published a favorable review of the Eton Field BT on his blog: Chris Freitas on Radio

The Field BT shares the same basic chassis as the Tecsun S-8800 (check out the review published yesterday) and several other receivers including the Grundig S350DLS450DLX, and the C.Crane CCRadio-SW.

Chris and I both agree that one benefit to this type of large portable is the excellent audio fidelity they can provide.

Read Chris’ full review here.

Not all large portables are created equally

The S350DL may look like a digital radio, but it’s actually analog inside and tuning is prone to drift.

Important clarification: The Field BT–just like the S-8800 and S450DLX–does not have the flaky analog tuning of the discontinued Grundig S350DL series.

Since I started publishing videos of the Tecsun S-8800 in action, I’ve received feedback indicating that many assume the S-8800 will drift off frequency like the 2008 era GS350DL.

It’s true that both radios share a common form factor, but that’s where the similarities end.

The S350DL is actually an analog single conversion receiver with a digital frequency display. The S350DL tuning knob has an inner ring for fine tuning and an outer ring for speedy tuning. The big disadvantage of the S350DL is that it drifts off frequency every time the wind blows. At least, that’s how it seems. It’s a little frustrating, and that’s why mine pretty much stays tuned to one station on my kitchen shelf. Even then, it manages to drift off frequency every few days.

The Eton Field BT, Eton Field, Grundig S450DLX, C. Crane CCRadio-SW and Tecsun S-8800, on the other hand, all have a pure digital tuning experience with no drift at all. Most of these are at least double conversion and the S-8800 is even triple conversion.

Chris, thanks again for sharing your review of the Field BT! It sounds like a major improvement over its predecessor, the S450DLX. I understand you’re also evaluating the excellent Grundig Traveller III–we look forward to that review when published!

A review of the Tecsun S-8800 shortwave/LW/AM-MW/FM portable receiver

Earlier this year, Tecsun released its long-awaited newest large portable: the Tecsun S-8800 portable shortwave/LW/AM-MW/FM receiver.

Though I fully intended to buy a Tecsun S-8800 for review, our friendly Hong Kong-based Tecsun retailer, Anon-Co, sent an S-8800 to me before I could. I’ve worked with Anna at Anon-Co for at least a decade and have purchased numerous radios for review, not to mention as gifts for family and friends.  When she insisted to send it as a gift, I decided I would (gratefully) accept the unit.

I received the S-8800 on February 1 and promptly posted unboxing photos here on the SWLing Post.

My new Tecsun S-8800 had a serious problem, though––one that two early S-8800e adopters noticed as well––internally generated noises, also known as birdies. And while most receivers will have a few minor birdies scattered across the bands, this S-8800 hosted a whole chorus of them, overwhelming the bands and making use of the radio difficult.  Read through this post thread for details.

I contacted Anna at Anon-Co and she immediately notified Tecsun; as a result, they halted distribution of the S-8800.

Tecsun took the S-8800 to their engineering team, and I’m happy to report they’ve now eliminated the horrible warbling DSP birdies of the initial unit I received.

On the S-8800s since released, while there are still a few minor birdies across the bands (more on that later), they’re merely what one might expect to find on any receiver. In short, the S-8800 now in production is a functional receiver, and a contender in its class.

I’ve had the S-8800 for a few weeks now and have had time to put it through its paces. What I present now is a review of the re-engineered Tecsun S-8800.

First impressions

Tecsun S-8800 Front Ang

In the spirit of full disclosure, I must note that I’m not as avid a user of large portables like the S-8800. Personally, my preference is for smaller, full-featured travel-friendly portables, or else larger tabletop models.  I travel often and like to pack lightly, so I rarely reach for anything bigger than my trusty Sony ICF-SW7600GR, or Tecsun PL-880, and more often than not, I grab the ultra-compact Sony ICF-SW100 or C. Crane CC Skywave.

But to say that I never reach for large portables would be inaccurate. In fact, I use a Grundig GS350DL daily; it’s my analog kitchen radio. I rarely move the tuning dial (a good thing, since it unfortunately drifts) because it’s locked onto my in-house SSTran AM transmitter on 1570 kHz.

What large format portables like the GS350DL and S-8800 can provide that a small portable cannot is broad, rich, room-filling audio. In my world, good audio is an important factor in overall signal intelligibility.

The S-8800 chassis resembles several other receivers: the Grundig GS350DL, S450DLX, and more recently, the Field BT, just to name a few.

The body is made of a hard plastic (not rubberized) and feels rugged enough. The knobs and buttons also feel tactile and of comparable quality to the previous similar models noted above.  With the rechargeable batteries inserted, it weighs about 3 pounds 4 ounces (1.5 KG).

The backlit display is large and viewable from almost any angle––even at a distance.

The main encoder (tuning knob) has appropriate amount of brake for most listeners. It wobbles very slightly, but functions amazingly well. I prefer it over its large portable predecessors, especially the 350GL. There is no soft mute while tuning, so band-scanning is a fluid, almost analog, process.

Both the “Band Select” and “AM BW” knobs have soft detents that mark steps in selection. In the field, I noticed that these can occasionally skip an increment when the detent only moves one position or the knob is turned very slowly. This doesn’t really affect functionality in any way, but I thought it worth noting nonetheless.

Like previous similar models, the S-8800 lacks a built-in keypad for direct frequency entry. That would be a major negative for a radio in this price class if the S-8800 didn’t come with one invaluable accessory:  an infrared remote control.

Infrared (IR) Remote Control

The Tecsun S-8800 ships with a IR remote control, and as far as I’m concerned, it’s great.

The remote feels durable, fits well in the hand, and the back has a place for it to balance on your index finger when holding…

But more importantly, the remote works quite well.  The controls are intuitive and the labeled buttons are quite easy to read. They’re also tactile and have a muted “click” response when pressed. Indeed, I wish my television’s remote was this well designed.

And the remote is quite useful, especially if you like listening from bed, from a porch, from the kitchen or dining room or den––or, in fact, from any space where you might wish to control the receiver at a distance. I believe its possible that every function of the S-8800 can be controlled with the remote––even the sleep timer!

Perhaps my dream remote for such a purpose would be backlit, but the S-8800’s remote is so simple to use, I’ve already nearly memorized where the buttons are located for nighttime use.

Operation Manual

The S-8800 ships with an informative operational manual, although this radio is intuitive enough that a seasoned radio listener will not need to reference it, save for advanced settings. Still, it’s written in clear language––with comparatively few English grammar errors––and the diagrams for both the radio and the remote are exceptional.

I referenced the manual several times to sort out ATS operation, saving/erasing memories, and to hunt down function shortcuts.

Features

The S-8800 is a feature-packed triple conversion receiver.  Here’s an abridged list of its features, focusing on those most radio enthusiasts seek:

  • Frequency coverage:
    • LW: 100 – 519 kHz (1 kHz & 9 kHz steps)
    • MW: 520 – 1710 kHz (1 kHz, 9 kHz and 10 kHz steps)
    • SW: 1711 – 29,999 kHz (1 kHz & 5 kHz steps)
    • Note in SSB mode on LW, MW and SW, tuning steps are 10 Hz and 1 kHz.
    • FM: 64 – 108 MHz (selectable for various markets: Russia, The Caucasus, Caspian/Black Sea regions, Japan, China/Europe, and North America)
  • Modes: AM, FM, SSB
  • Variable filter widths
    • AM: 6, 4, 3, and 2.3 kHz
    • SSB: 4, 3, 2.3, 1.2, and 0.5 kHz
  • Digital Signal Processing (DSP)
  • Antenna gain selection: DX/Local
  • External antenna connections: both BNC (SW and FM) and a high-impedance port (LW, MW and SW)
  • Both 9 and 10 kHz spacing on mediumwave
  • Dedicated fine-tuning control
  • Auto Tuning Storage (ATS)
  • 650 station memories
  • FM stereo/mono
  • Backlit LCD display
  • Treble and bass tone controls
  • RCA line-out audio
  • Full-featured clock, alarm and sleep timer
  • IR remote control
  • Two 18650 lithium cells (included) that can be safely charged internally via USB

Wishlist? The S-8800 feature set is pretty comprehensive, but my dream large portable would also have synchronous detection and an RF gain control, though the latter is not common in the world of portable radios.  Fortunately, the S-8800 does have a local/DX gain toggle.

I’m sure some enthusiasts would also like to see Bluetooth connectivity as on the Eton Field BT, but I personally don’t miss it. I like to keep my HF portables free from anything that could potentially raise the noise floor.

With the exception of synchronous detection, the S-8800 has a solid, comprehensive tool set.

Performance

Over the past two weeks, I’ve had the S-8800 on the air almost every day. I’ve compared it with a number of receivers, but mainly its smaller sibling, the popular Tecsun PL-880. Below, I break down my notes by band.

FM

As is typical with my shortwave portable reviews, I spent less time evaluating FM performance on the S-8800.

With that said, I did compare the S-8800 with the PL-880, PL-680 and CountyComm GP5-SSB and a few other portables. The S-8800 found my benchmark weaker broadcasters with ease.

Here’s a short video demonstrating FM performance with a broadcaster over 100 miles distant:

Click here to view on YouTube.

AM/Medium Wave

I’ve had more inquiries about S-8800 mediumwave performance than I’ve had about any other radio I’ve recently reviewed. Why?  Well, for one thing, some radios in this particular portable format perform quite well on mediumwave––the C.Crane CCRadio-SW, for example, comes to mind.  Also, the S-8800’s large front-facing speaker lends itself to superb AM audio.

Unfortunately, mediumwave is not the Tecsun S-8800’s strong suit.

I did extensive testing, comparing it with much smaller portables: the Tecsun PL-880, the Sony ICF-SW7600GR, the Digitech AR-1780, the CC Skywave, and even a pre-production CC Skywave SSB. All of these portables had better sensitivity on mediumwave.

I posted the following representative video a couple weeks ago in a post:

To reiterate from my previous post, comparing any modern radio with the Panasonic RF-2200 on mediumwave is hardly fair.  For one, the RF-2200 has been out of production for a few decades.  For another, the RF-2200 has a large rotatable ferrite bar antenna that provides excellent gain. The RF-2200 simply wipes the floor with all of my modern portables, as their ferrite bar antennas are but a fraction of the size.

To my ear, the S-8800’s  mediumwave band seems noisier than its competitors. Perhaps this is why it struggles with marginally weak stations.

Here’s another comparison with the PL-880––this time at a totally different location:

Click here to view on YouTube.

With that said, when tuned to a local AM broadcaster, the S-8800 really shines. It produces rich audio which can be customized with bass/treble tone controls and by changing the AM filter width.

I also hooked up the S-8800 to my large horizontal loop antenna. This certainly did improve MW reception, but not as dramatically as I hoped.  Additionally, it seemed to be very sensitive to RFI in my shack even when hooked up to the external antenna.

If you took the S-8800 to the field, added a decent inductively-coupled magnetic loop antenna, no doubt it would improve mediumwave reception, but I still doubt it would come close to the RF-2200 in performance.  As long as I own the latter, I wouldn’t be motivated to do so.

Due to my schedule over the past few weeks, I’ve had precious little time to test the S-8800 on mediumwave at night, but some quick air checks proved performance was consistent with daytime testing.

I am pleased to report that no receiver overloading was observable during testing.

In short: if you’re only considering the S-8800 for mediumwave DXing, you should look elsewhere. I would suggest a dedicated AM broadcast receiver like the excellent CCradio 2E,  a vintage Panasonic RF-2200, or perhaps a used GE Superadio.

LW – Longwave

I’ve spent less time on longwave than I have on mediumwave and shortwave.

With that said, the S-8800 was able to receive our local airport beacons at night with relative ease. I was not able to catch any transatlantic longwave broadcasters, but that’s no surprise as it’s almost impossible on even my commercial-grade receivers during the summer months here in North America.

As I said regarding the mediumwave band, I suspect there are much better radios out there for the longwave enthusiast.

SW – Shortwave

At the end of the day, I believe the Tecsun S-8800 was designed with the shortwave and amateur HF radio enthusiast in mind.

The S-8800 has gapless HF coverage from 1,711 kHz to 29,999 kHz, can be used both in AM or Single Sideband (selectable LSB/USB), and has adjustable bandwidth filters tailored to AM broadcast and SSB/CW (ham radio/utility/pirate) reception. The filter widths are well-chosen for each mode: 6, 4, 3, and 2.3 kHz on AM; 4, 3, 2.3, 1.2, and 0.5 kHz on SSB.

It also has a dedicated fine-tuning control that adjusts steps based on the mode.

All of these are desired features for the HF radio enthusiast.

I’m happy to report that the S-8800 is a very capable shortwave receiver, perhaps even one of the best portables currently on the market.

In every comparison test I made on shortwave, the S-8800 outperformed each of its competitors.

Check out the videos below and judge for yourself:

Weak signal on the 31 meter band:

Click here to view on YouTube.

Very weak signal and deep fading on 15,200 kHz

Click here to view on YouTube.

SSB: Ham Radio QSO on the 40 meter band

Click here to view on YouTube.

CW on the 20 meter band

Click here to view on YouTube.

I was pleasantly surprised by the audio in SSB mode and by how well the filters seem to work. Note in the video the warbling sound as I adjust the fine-tuning control on the S-8800.  But it’s actually only present as I adjust the fine-tuning control; I noticed no stability issue once on frequency.

External antenna

Since the S-8800 has a handy standard BNC connector and high impedance AM antenna socket on the back, I hooked it up to my large horizontal loop. In my testing, it handled that antenna’s gain very well and I was most impressed with the performance.

The front end seems to be robust, and selectivity––which is excellent––was not compromised by my antenna. I was able to pull apart two broadcasts with only 5 kHz of separation that were both quite strong. The S-8800 locked onto the stronger of the two stations with ease. When tuned to the weaker station, I used SSB reception on the upper sideband to ignore the noisier lower sideband which was buried in the adjacent signal. Once I zero-beated the signal, it sounded quite good.

Final thoughts about shortwave performance

Perhaps what the S-8800 has going for it on shortwave is a combination of very good sensitivity, excellent selectivity, and a feature all too often overlooked: good audio fidelity (via the internal two-watt speaker).

The AGC (auto gain control) is actually fairly stable on the HF bands (less so on mediumwave). Like the Tecsun PL-880, the AGC has a soft hiss response when the signal fades below the AGC threshold. While I’m not crazy about this, I must confess that it is pretty easy on the ears when fading is pervasive.

I did note one quirk that could annoy those wishing to copy narrow SSB or CW. If the filter bandwidth is set to .5 kHz and you’re listening to a marginal CW signal, the AGC sometimes mutes the receiver during CW dead space. It equates to very unstable audio with audio levels jumping around wildly. This happened more often when I was copying moderate to weak CW signals. I’ve even noticed it when listening to SSB ham radio conversations, but mostly in the narrow bandwidths. I usually keep the filter set to 2.3 kHz or higher and it hasn’t been a problem at these settings. It’s worth noting that I have observed the same AGC behavior in my PL-880 at times.

The S-8800 ships with two rechargeable lithium cells which provide hours of listening time from a full charge.

I never encountered overloading from local AM broadcasters on the shortwave bands, with the caveat that I never tested the S-8800 in an RF-rich urban market.

One thing I have noticed in general about the S-8800 is that it seems pretty sensitive to RFI indoors (electrical noise in the home, office, etc)––more so than my Sony ICF-SW7600GR, for example. If you live in a noisy environment and never plan to use an external antenna or take the radio outdoors, you might think twice about the S-8800.

Birdies

I’m pleased to report that Tecsun did properly address the “birdie” issue I mentioned at the beginning of this review. Still, like most receivers, the S-8800 does have some birdies across the bands. These birdies are well within the norm for such rigs:  a relatively stable heterodyne sound. I made a short video to illustrate what I mean when I talk about a birdie:

Click here to view on YouTube.

I spent one afternoon carefully mapping out all of the birdies I could find across the longwave, mediumwave and shortwave bands.

Here’s what I mapped:

As you can see, there are no birdies in the middle of sensitive areas like broadcast bands, amateur radio bands, etc. A good report, in my book.

Note that while tuning through the shortwave bands, I used 5 kHz steps. I suppose there’s a possibility I might have missed very weak birdies doing this, but any strong birdies would have been received and noted within the 5 kHz window. On LW and MW, I tuned in 1 kHz increments.

Summary

Every radio has its pros and cons, of course. When I begin a review of a radio, I take notes from the very beginning so that I don’t forget my initial impressions. Following is the list I formed over the time I’ve been evaluating the Tecsun S-8800:

Pros:

  • Brilliant audio fidelity from built-in speaker
  • Dedicated AM bandwidth and fine tuning controls
  • Excellent, bespoke IR remote control
  • Capable SSB mode
  • Excellent shortwave sensitivity (see con: mediumwave)
  • Excellent shortwave selectivity
  • Excellent FM performance
  • Easy-to-read backlit LCD digital display
  • Remote control beautifully equipped for full radio functionality
  • Included 18650 rechargeable lithium batteries power radio for hours

Cons:

  • Lackluster mediumwave performance (see pro: shortwave)
  • No synchronous detector
  • No direct keypad entry (Pro: Remote control has excellent keypad entry)
  • Can’t charge and listen at the same time–not designed for AC operation
  • No backstand
  • Line-out audio level is a little high (hot)
  • When in narrowest SSB filters, AGC can’t reliably handle audio/signal changes
  • Slight “warbling” sound while using fine tune control in SSB mode
  • No RDS display on the FM band

Conclusion:

As I’ve already mentioned, if your primary use of the S-8800 is for mediumwave or longwave DXing, you should look elsewhere. While the S-8800 will serve you well with local AM stations, it will not dig signals out of the noise like other better-equipped AM receivers.  The GE Super Radio, Panasonic RF-2200, or CCRadio 2E are much better options.

But if you’re primarily a shortwave radio listener––? I think you’ll be pleased with the S-8800.

To my surprise, the S-8800 consistently out-performed my beloved Sony ICF-SW7600GR and my PL-880. I fully intend to compare it with other portables in the coming weeks and post the videos here on the SWLing Post. [I will update this review with any other findings.]

I did not mention this in previous posts, but the first S-8800 I received in January––the one with the birdie-chorus problem––also outperformed my other modern portables on shortwave. In part, I feared that when the Tecsun engineers addressed the birdie issue, it could have a negative impact on overall sensitivity. I’m happy to report that it did not.

What’s more, I realize that larger portables do have a place in my life.  You might have noted that I did all of my review testing and preparation outdoors, mostly in a nearby national park. I do this, in part, to insure I’m far away from any RFI, but also I simply love playing radio outdoors.

And the S-8800 was a pleasure to tune and use in the field. I really like the large encoder and find that the multi-function knobs, tone controls, volume, and other buttons are well-spaced–I believe I could operate most of this receiver’s functions with gloves on in the winter. And again, there’s that excellent remote control…

Is the S-8800 a good value? Let’s talk price

Only yesterday, Anon-Co announced the price of the Tecun S-8800: $268 US with free shipping to the US.

This review was in final draft form two days before I learned the price from Anon-Co. I had assumed the price would not be released for another week or two at least, thus I made a few predictive statements that I’ll now quote here:

I understand that the S-8800e is being sold in Europe for 339 Euro, roughly $400 USD, plus shipping. There is no way I’d pay that price; it’s simply too much.

If the price exceeds $300 US, I’d suggest careful consideration, as the S-8800 price would be venturing into the realm of used Sony and Panasonic benchmark portables.

But.  If this radio should be sold for less than $250, or even $200…?  Being primarily a shortwave radio listener, I would certainly buy this radio for that price.

In the end, the price is $18 higher than the $250 I mentioned in my review draft, but I assumed shipping would be tacked on to that price. So $268 ended up being pretty close to the mark.

So I believe the Tecsun S-8800 hovers at the top price threshold of what most radio enthusiasts would be willing to pay for a portable.  At $268, it’s over $100 more than the excellent PL-880 and only $20 less than the Tecsun S-2000. And for radio enthusiasts outside the US, it sounds like shipping will be added to the $268 price. I expect European consumers will pay a premium due to embedded (and required) sales tax and customs handling fees.

Click here to view at Anon-Co.

Nonetheless, I would still consider purchasing at the $268 US mark because of its shortwave performance, ability to connect external antennas, audio fidelity, and the included IR remote control.

I would like to see the price lower than $268. If the price were nearer the $200 mark, it would be a no-brainer––this radio would likely fly off the shelves, and I’d strongly suggest purchasing.

Perhaps, with time, the S-8800 price will decrease. In the meantime, if you have the budget, I believe the S-8800 would make for a nice field companion, pulling weak DX out of the noise with excellent audio fidelity to boot. It’s already been a great field companion for me…and, I’m sure, will accompany me into the field again.

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.  

EQUIPMENT: 

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. 

BASELINE TESTS 

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.  

THE DAY OF THE ECLIPSE 

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 

REVIEW OF RESULTS 

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!