Coronal Mass Ejection Causes Storm -- But I Still Hear DX in Hi7

 

So the A index is 27 and the K is 7.  That's pretty bad right? See below.  Lots of red.  Well maybe not so bad in the tropics.  This morning I could hear EA5JZ working a VK on 20 meter SSB.  And yesterday morning I worked a very strong VK3XXY, also on 20 meter SSB.  I note that the Space Weather Center warns (above) of "HF communication degradation at higher latitudes."  So maybe my location at 18 degrees north explains the openings. 

Maybe it is Tropospheric Ducting After All -- 99.5 FM WIDI Puerto Rico Received in the Dominican Republic

 

Invest 94L moved arcoss the Mona Passage yesterday, lowering temperatures, bringing lots of rain and relatively high winds to the area.   I happened to check on reception in the DR of WIDI 99.5 FM (near Mayaguez, Puerto Rico), and was surprised to find that the signal had weakened considerably.  This morning, after the storm passed, signal levels were back to their normal full quieting. This would support the idea that tropospheric ducting is playing a big role in bring this signal into the Dominican Republic.  I had been surprised by the persistence of the signal -- for weeks it had been full quieting here.  I thought that perhaps I was just receiving it directly, line-of-sight, without the benefit of tropo ducting.  But Invest 94L has made me question this idea. 

I asked Google Gemini AI about the persistence of tropospheric ducting on FM broadcast signals in the tropics.  Here is what it said: 

AI Overview

In the tropics, tropospheric ducting is a frequent, persistent, and often strong phenomenon, especially over and around large bodies of water. Unlike mid-latitudes where ducting is a seasonal event, the meteorological conditions in the tropics are favorable year-round.
Why ducting is persistent in the tropicsHigh temperatures and humidity: Tropical climates are characterized by consistently high temperatures and abundant moisture. These conditions are the primary drivers of atmospheric ducting.

Temperature inversions: Stable high-pressure systems common in the tropics can create temperature inversions, where a layer of warm, moist air sits above cooler air. The sharp change in temperature and humidity with altitude creates the "duct" that traps and bends radio waves over long distances.

Dominance of water paths: Large tropical ocean regions are ideal for ducting. A common ducting phenomenon called the "evaporation duct" is ever-present over the sea surface due to a sharp humidity gradient and is particularly effective for trapping frequencies above 3 GHz. While the FM broadcast band (87.5–108 MHz) is at a lower frequency, coastal areas and islands frequently experience ducting over sea paths.

Atmospheric stability: The general stability of high-pressure systems in the tropics allows ducting conditions to persist for many months at a time. This is observed in areas like the Caribbean and the Persian Gulf, where long-distance radio reception is a common occurrence.

Impact on the FM broadcast band (VHF Band II)Favorable frequencies: The FM broadcast band (VHF Band II) is particularly susceptible to tropospheric ducting. While ducting can occur across a range of frequencies, signals above 90 MHz generally propagate more favorably during ducting events than lower frequencies.

Signal interference: The most noticeable effect of this regular ducting is co-channel interference, where distant stations can override local ones. During an event, a listener may pick up two different stations on the same frequency, or experience temporary loss of reception from a nearby transmitter.

Extended reception: For radio hobbyists, this high frequency of ducting means that signals from FM stations hundreds or even thousands of kilometers away can be received clearly.

Diurnal cycle: Ducting events in the tropics often peak during the evening and overnight hours when surface cooling creates a stable nocturnal boundary layer. Conditions may "burn off" after sunrise, but ducting is common throughout the day during periods of stable weather.

In summary, the specific meteorological and geographical conditions found in tropical regions—consistent heat, humidity, and the presence of large bodies of water—make persistent tropospheric ducting on the FM broadcast band not just possible, but highly probable throughout the year.

50 Things to Do with an SDR -- The International Beacon Network

 https://blinry.org/50-things-with-sdr/

Lots of good ideas from blinry's site.  It reminded me of the International Beacon Project:  https://www.ncdxf.org/beacon/  I can receive the 20 meter CW signal on my homebrew rig here in the Dominican Republic.  On 17 September before dawn I could hear the station in Madeira (CS3B) and the one at the UN in New York (4U1UN).  This will be a useful way to monitor the band for openings to the South Pacific. 

Do I really NEED Tropo to hear the Puerto Rican FM Broadcast Station? Or are we just close enough to do this line-of-site?

 

WIDI 99.5 FM from western Puerto Rico continues to put a full quieting signal into the eastern Dominican Republic.   The station is so regularly strong that this made me wonder if I am really using tropospheric ducting to hear it.  If I was using tropo ducting, I think there should be some variation in signal strength over the course of 24 hours right?  But it is always strong.  Why?  

I checked the distance:  97 miles.   With its antenna at 2800 feet, its visual horizon will be 64.8 miles away.  I am about 98 feet above the ocean.  This means my horizon is 12.22 miles away.  There appears to be a gap, right?  I mean 64.8 + 12.22 = 77.02 miles.   So it looks like there is a gap of about 20 miles.  

But wait!  Mike WN2A reminded me that there is a difference between radio line of sight and visual line of sight.   Radio line of sight = 4/3 of visual line of sight. 

AI explains where the 4/3 factor comes from: 

The radio horizon appears longer than the visual horizon by a factor of about 4/3 due to atmospheric refraction, which bends radio waves slightly downward. To simplify calculations, this effect is modeled by treating radio waves as if they travel in a straight line over a larger, "effective" Earth with a radius 4/3 times the actual radius. This increased effective radius allows radio waves to "see" further over the Earth's curvature, extending the line-of-sight range compared to what is seen by the human eye, which is not affected by atmospheric bending to the same degree. 

So that puts WIDI's radio horizon at 86.4 miles.  My radio horizon is 16.16 miles.   86.4 + 16.16 =  102.56 miles No gap.  We should be able to hear WIDI, even without tropospheric ducting.   

Puerto Rico -- Dominican Republic Tropo on 99.5 FM? Yes, probably

 

Our friend Todd K7TFC in Portland found this in the 1950 ARRL Handbook at an, uh, opportune moment.  TRGHS.  This seems to describe what a I am hearing, especially that "airmass boundary" in the lower left of the diagram above.  

I'm not a VHF guy, and I am a bit surprised at the persistence of this propagation path.  It is 4:30 am here and the adult contemporary rock from Puerto Rico (Kokomo by the Beach Boys!) is full quieting here in the Dominican Republic.  And it is of the same strength during daylight hours. I don't remember this from the winter months, but I may have just missed it. 

Here is what AI (Gemini) says about this: 

https://share.google/aimode/M1HvC7Y893eE5gAcn\

One other factor to consider:   The island of Mona is about halfway across the path.  There are few people there, and there is almost certainly not a repeater of any kind.  But there may be a metal tower or two... 

Gianfranco IU1DZZ and Mike WN2A  both support the tropo hypothesis.  Mike mentions the Hepburn Index.  I will have to read up on that.  Hamilton is also looking at this propagation path.  Thanks guys.  

Puerto Rico FM Broadcast Station Heard in the Dominican Republic -- But How? WIDI 99.5 FM

WIDI 99.5 FM. Booming in during daylight here on the eastern tip of the Dominican Republic. Their antenna is about 2100 feet above average surrounding terrain. That would put the horizon at about 56 miles. But the path is about 100 miles. What do you folks think is the likely propagation mode?

https://en.wikipedia.org/wiki/WIDI

A = 97 K = 9

 

Around the World Twice (and maybe more) on 15 meters

 

John EI7GL has a great blog post about some experiments recently done by Salvador EA5Y.  Salvador was aiming his 4 element yagi in one direction, sending dits, and watching for the signal to come around the other side.  You can see the results in the display above.  I commented that this might be the time for one of those antennas with which you can instantly reverse the pattern. Or, probably better, have some other hams aim their antennas in the opposite direction so that they can catch the circumnavigating signals. 

Check it out: 

https://ei7gl.blogspot.com/2023/12/twice-around-globe-on-21-mhz-and.html

Two trips around is 80,000 km or about 50,000 miles!  That's quite a trip.  But how about 3 times around?  Or more? 

Thanks to John EI7GL and to Salvador EA5Y.  

You have heard of the International Geophysical Year (IGY). But have you heard of the IQSY?

 

International Quiet Sun Year.  1964-1965.  Yes, that was a thing.  

"Ham Radio Ireland" June 2023 edition (and Free Propagation Guide)

 

Get the latest edition here: 

 https://www.docdroid.net/VlSXkrD/crnews0623-pdf

Thanks to Steve Wright EI5DD.  I had the great good fortune of running into my friend Michael EI0CL on the 17 meter band recently.  Mike mentioned that he had been talking to Steve.  So Steve is in good company.   

Steve also sent me a useful Solar Indices Data Card, suitable for lamination.  You can download it here: 

http://soldersmoke.com/Solar Indices Data Card.pdf

Coffee with Farhan VU2ESE (video)

Early morning in the N2CQR shack, May 16, 2023

-- Propagation

-- Web sites (RBN, PSK Reporter, others)

-- CW

-- Homebrew rigs

-- VFOs

WIRED on the Dangers of another Carrington Event, Solar Cycle 25, Capacitors Could Save Us All

This Wired article has some really interesting info on competing theories about the solar cycle, about the danger to the Earth from solar flares, and about what a flare like that of the Carrington event could do to the transformers we are currently using.  The article points out that large capacitors could protect these transformers from the effects of the flare.  But the power companies are not installing the capacitors. 

I think one of the scientists Pete mentioned in SolderSmoke podcast #238 is mentioned here: 

https://www.wired.com/story/sun-storm-end-civilization/?redirectURL=https://www.wired.com/story/sun-storm-end-civilization/

Summer Solstice -- EITs. Solar Tsunamis. Strange Falcon 9 Spirals Seen in New Zealand

 

Forbes has an interesting article that may help explain the poor Cycle 25 propagation that were talking about in SolderSmoke podcast #238: https://www.forbes.com/sites/ericmack/2022/03/28/an-increasingly-active-sun-is-now-producing-solar-tsunamis-and-sending-flares-our-way/?sh=613e1dd1fbfd 

And Space Weather website has an interesting piece about some really strange SpaceX Falcon 9-related phenonmenon: 

https://spaceweather.com/archive.php?view=1&day=20&month=06&year=2022

SolderSmoke Podcast #238 -- SolderSmoke Shack South, Cycle 25, Chiquita Banana Radio, RCA, HQ-100, Mate Mighty Midget, Sony SWL RX , Mailbag

SolderSmoke Podcast #238 is available:  http://soldersmoke.com/soldersmoke238.mp3

TRAVELOGUE:  

Cathartic decluttering:  Bill preparing for future winter travel to Dominican Republic.  Will build SolderSmoke Shack South.  Dividing everything up:  Rigs, parts, tools, supplies, antennas, test gear.  Everything.  

OUR SPONSOR:  Parts Candy.  

https://www.ebay.com/usr/partscandy  Premium quality test leads! Hand cut, hand crimped, hand soldered, these will become your new favorite test leads GUARANTEED!

PETE'S BENCH:

-- Cycle 25 better? – Out here on the left coast – it is not evident

-- Chiquita Banana and the US Navy in early ‘wireless” operations.  Why RCA was created by the US Navy in 1919.

-- Update on the MAX2870 –someone has written the code to make it work with the Raspberry Pi and the QUISK SDR software

-- Field Day prep

SHAMELESS COMMERCE DIVISION:

 

Bill needs your help:  

-- Please watch his YouTube videos.  The longer the better!  Success based on hours watched. Great to have on while you are working in the shack. Just go to YouTube and search for the SolderSmoke channel. Or:  SolderSmoke - YouTube

-- Please put links to the SolderSmoke blog on your websites and blogs. 

-- How to USE the SolderSmoke Blog: Propagation, shopping, other sites... 

-- Please put comments under the articles on the SolderSmoke blog.  We like comments and dialogue. 

BILL'S BENCH:

-- Repair of the Sony ICF SW1 shortwave receiver.  Bad electrolytics.  Number Station receiving device? 

-- HQ-100   Q-Multiplier. BFO Switch. AVC.  Noise Limiter limitations.  Dave K8WPE: Old Radio Lessons.

-- MMMRX: Detector circuit. Alignment. Muting. On the air (40 AM with DX-100) 

MAILBAG: 

-- Bob Crane W8SX -- Great interviews at FDIM. On the SolderSmoke Blog. Thanks Bob! 

-- Dave Bamford W2DAB -- Stickers on the Upper East Side of Manhattan.  FB Dave! 

-- Farhan VU2ESE:  LADPAC software now available through W7ZOI' site.  

-- Lex PH2LB: Stickers in a Netherlands pub.  

-- Dave K8WPE Michigan Mighty Mite links.  Old Smoke idea. On the SolderSmoke blog. 

-- Rich WB4TLM was in the electronics class of CF Rockey W9SCH. FB. 

-- Dean KK4DAS Working on  his dad's HQ-170A. VWS maker group on mixers. 

-- Grayson KJ7UM -- Mixology article in ER. 

-- Pete Eaton -- Farhan's new analog rig: Daylight again!  Standby for more info from Farhan. 

-- Will KI4POV New HB Al Fresco single conversion superhet.  FB. 

-- Alvin N5VZH. Shep's "I Libertine."  Yes.  I laughed, I cried,  It changed me. 

-- Chuck KF8TI.  Mr. Wizard!  

-- Steve N8NM on the mend after some routine maintenance. 

-- Ben AB4EN is listening and likes the podcast -- Thanks Ben. 

May 1939 QST

The First Commercial SSB Trans-Atlantic Radiotelephone System

These guys didn't just complain about QSB -- they DID SOMETHING about it!  

Thanks to AWA and Hack-A-Day for disseminating this great video.  

The NCDXF/IARU Beacons (very useful website)

 

So there I was, innocently checking the lower end of the tuning range on my now 17 meter SSB Barebones Barbados W4OP receiver.  I had it tuned to the bottom of the 17 meter phone band.  All of a sudden I hear YV5B in CW.  It was obviously a beacon transmission. 

I had forgotten about these beacons.  Some quick Googling brought me to a very up-dated web site: 

https://www.ncdxf.org/beacon/

The site shows exactly which station is transmitting at any given moment.  There is also a very handy map display giving beam headings and distance from your location.  

So far, I'm only hearing YV5B and VE8AT.  I hope to hear more once the Coronal Mass Ejection is behind us. 

Check it out.  Leave your receiver on 18.110 MHz.  Let us know what you are hearing.  

Three cheers for the NCDXF and the IARU! 

1BCG -- The 100th Anniversary of the Trans-Atlantic Test

Thanks to the Antique Wireless Association for this really wonderful video, and for their involvement in the 100th anniversary event.  Special thanks to Ed K2MP. 

On December 11, 2021, the 1BCG team in Connecticut had some technical difficulties.  As we all know, that is part of being a radio amateur. Details of the problems are presented here: 

http://1bcg.org/1BCG/the-special-event-transmitter/

Phil W1PJE managed to hear and record some of the 2021 transmission (Thanks Phil).  Listen here: 

https://drive.google.com/file/d/1uPvD9Qh-VJTnyDzOPPSrYfbksks8sQsx/view?usp=sharing

Phil also sent this spectrogram of the signal. 

Good thing Paul Godley ran into Harold Beverage on the ship going over. 

And imagine me complaining about having to step out into the carport to adjust my antenna -- Godley had to trek one mile THROUGH SEA-WEED to adjust his.  Respect.   

Where is Sunspot Cycle 25?

The other day I was complaining to Pete N6QW that 17 meters still seems to be in very poor shape.  I can hear 6Y6Y around mid day, but I don't often hear Europeans.  I did year my friend Mike EI0CL yesterday on 17, but conditions were not good.  Pete asked, "Where is Cycle 25?"  Good question. The Space Weather Center has the answer.  

Their Solar Cycle Progression page is up-to-date.  With the slider below each chart you can go back as far as 1750.  Check out Cycle 19.  I was born near the peak (TRGHS).  Pete was on the air during that cycle. Cycle 23 also looked pretty good. I was out in the Azores then (2000-2003) -- no wonder I could work VK and ZL with a 5 watt DSB rig.  

I like the little solar conditions widget that has appeared in the left hand column of this page, and I am grateful to the provider,  but the widget just doesn't update regularly.  So I think I'm going to switch to a link from the Space Weather Prediction Center that shows the numbers we really need: Solar Flux Index (SFI), Sunspot Number (SN), A index, K index.  (Please let me know what you think about this change.) 

Here is the link to the Solar Cycle Progression Charts (be sure to use the sliders):  

https://www.swpc.noaa.gov/products/solar-cycle-progression

Cosmic Rays, Bit Flips, and Computer Vulnerability

Here is a very interesting video about a problem that many of us have been blissfully unaware. 

You can see the role played by the solar cycle.  This is the subject of some on-going research by the folks who put out the SpaceWeather.com web site.  They have been flying balloons to measure high altitude cosmic rays: 

I've been meaning to build a cloud chamber for a long time.  I recently discovered that my local 

supermarket sells dry ice... 

Thanks to Dave, K8WPE for alerting us to this video.  

SolderSmoke Podcast #232 -- Mythbuster, Pete's Tube CW Rig, Pete's DC RX and Simple SSB Rig, NanoVNA and TinySA, Very FB Mailbag

SolderSmoke Podcast #232 is available -- Crank it in Robert!

http://soldersmoke.com/soldersmoke232.mp3

Featuring a guitar intro by Pete "Bluesman" Juliano,  playing his own composition: "Juliano Blues." 

Upcoming GQRP convention and the N6QW rig
Frank Jones and the FMLA -- Possible Victory?
IBEW Stickers:  NASA, Johns Hopkins APL....
Cycle 25 Lookin Better Today:  SFI 93   SN 47
 
Pete's Bench:
Toobular!  A Tube Transmitter
SR-160
Simple SSB rigs around the world! 
KI7NSS's Pacific 40
 
Bill's Bench
The Mythbuster and the Struggle Against the Urban Legend
W2EWL's Cheap and Easy SSB
W4IMP's IMP. Articles in ER by Jim Musgrove K5BZH and Jim Hanlon W8KGI
The Spirit of Homebrew SSB. From Electric Radio K5BZH December 1991
Reduced Front End Gain on the DIGITIA
Back on 17!  HP3SS sells HBR receiver to Joe Walsh
Maybe another Moxon?
 
SHAMELESS COMMERCE DIVISION
 
Test Gear
NanoVNA -- Alan W2AEW helped solve mystery of why NanoVNA not providing accurate readout of circuit impedance.  Over driving.  Need attenuator. 
TinySA -- Limited Resolution Bandwidth.  But you can listen with it!  See video on blog.
 
MAILBAG
-- Google Feedburner to end e-mails from the blog :-(
-- Paul VK3HN -- TIA AGC? Farhan and Paul looking into options 
-- Ciprian's Romanian Mighty Mite
-- Dino KL0S SolderSmoke GIF and graphical presentation on sideband inversion
-- Allison KB1GMX helped me on 24 volts to IRF 510 issue.
-- Dave K8WPE Wabi Sabi and Martha Stewart. And thanks for parts!  40673s!
-- Steve N8NM building a 17 meter rig with 22.1184 crystals in a SuperVXO and a 4 MHz filter.  
-- Dean KK4DAS restoring an old Zenith.  One hand behind your back OM. 
-- Pete Eaton debating SSB or DSB for 17.  Go DSB Pete!
-- Richard KN7FSZ a FB HBer.  Asked about my solid-stating of Galaxy V VFO.  
-- Walter KA4KXX on benefits of no-tune BP filters like Farhan's   FB. 
-- Jack 5B4APL on Time Crystals and Homebrewing in the 4th dimension.  FB OM!  
-- Moses K8TIY listens to the podcast with his young son Robert.  Crank it in Robert! 
-- Farhan and the SBitx on Hack-A-Day
-- Also Tom's receiver from junked satellite rig on Hack-A-Day
-- Todd K7TFC sent in beautiful message about the spirit of homebrewing. On the blog.
-- Grayson KJ7UM was on Ham Radio Workbench with George Zaf
-- AAron K5ATG running a uBitx with a  homebrew tuner and antenna.  Hope I can work him 
-- Heard Mike WA3O last night on 40 DIGITIA.  Water cooled amplifier