Category Archives: Propagation

Homeopathic Radio Engineering

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Mainstream radio engineering principles hold that the received signal strength of a transmission is proportional to the radiated power. Doubling the transmitter power produces twice the received power, quadrupling the transmitter power produces four times the received power, twice the received voltage, which is 6 dB or one S unit. This has been accepted for over a century.

However, recent experimental results, first reported on the FRN and later in The Journal of Irreproducible Results cast doubt in this basic radio engineering theory.

These results claim that as the transmitter power is reduced to very low levels, the received signal strength actually goes up, not down.

A transmitter location on the east coast of the USA was used. The tests were conducted on HF radio frequencies on and around 6925 kHz, using a state of the art solid state transmitter with a standard off the shelf MOSFET as the RF final amp:

Each monitoring post was equipped with the highest quality HF receiving gear and highly sensitive monopole receiving antennas.

During the trials, it was found that placing a non-conductive fabric, such as a sock, over the receiver produced the strongest signals. While the exact mechanism for this effect is not yet known, it is presumed to be due to the high dielectric constant of the fabric.

The results of the experiment clearly speak for themselves, as transmitter power went down, the signal strength went up:

One way to explain the results is to return to the luminiferous ether theory of radio propagation. Radio waves are propagated by vibrations in the ether. Fewer radio waves means that there is more ether per radio wave, so the vibrations are larger, producing a stronger signal at the receiving site.

There were even reports of radio propagation that cannot be explained by any known laws of physics, such as signals in the daytime traversing from Montana to New Zealand on 6955 khz with a completely sunlit path, even though D layer absorption would make this completely impossible. Yet this was reported many times by longtime radio physicist Dr. Winston: “The signals were always received with as SIO of 555. Even the audio quality was perfect, why it sounded like I was listening to it live in the studio!”.

Several times signals were actually received and logged on the FRN before the transmission began. This suggests that superluminal neutrinos may be involved.

Further research into this new phenomena is required. If homeopathic radio is ever perfected, it would allow listeners to report hearing transmissions that used little, or theoretically even no power. Indeed, reducing the output power to zero watts might produce the best results of all for this type of station.

Boom Box Radio Early Morning Propagation Analysis

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Boom Box Radio had an early morning transmission on March 10, 2013, from 1044 until 1212 UTC. They were trying to reach a listener in Guatemala. The time of this transmission, starting just before to after sunrise, lets us examine the effects of sunrise on reception on the 43 meter band.

This first waterfall shows when Boom Box Radio signed on at 1044 UTC. You can see a very faint trace appear on the waterfall about a quarter of the way up from the bottom, at 6925 kHz. Remember that with a waterfall, time flows or falls down, like with a real waterfall, so the latest information is at the top:

This next waterfall shows what happened at 1107 UTC, when the signal went from just a faint trace of a carrier on the waterfall, and no audio, to a very good S7 to S9:

Note again that the oldest information as at the bottom of the waterfall. At that time, there is just barely a carrier. Then you start to see some modulation, and then finally, in a matter of seconds, the signal shoots up to armchair quality.

Below is a graph showing the signal strength of Boom Box Radio, in dBm, from 1044 UTC sign on, until 1212 UTC sign off. You can click on it to see a larger version:

An S9 signal corresponds to -73 dBm. Every S unit is 6 dBm, so S8 is -79 dBm, S7 is -85 dBm, etc.

I have annotated several important times: The 1044 UTC sign on, 1107 UTC when the signal went up, 1125 UTC which was local sunrise, and 1212 UTC when it went off the air.

You can see that there is a very slow increase in signal level after the sign on, but the signal remains extremely weak. Then suddenly at 1107 UTC, the signal shot up to S9. Then for the rest of the transmission it mostly stayed in a range between S7 and S9.

The sudden increase in signal was caused by the Sun increasing the ionization level of the F layer of the ionosphere. This increase needs to have occurred at the point in the ionosphere where the radio waves are being reflected, most likely roughly midway between the transmitter and receiver locations. Note that in my case, this occurred before my local sunrise. This could be due two at least two factors I can think of. First, the transmitter site could be to my east. Second, the ionosphere is several hundred miles up, so it experiences sunrise before a point directly below it (on the Earth’s surface) does.

I believe this graph shows the importance of selecting the correct time for transmissions, depending on your target area. Just before sunrise is when the ionosphere is the weakest, and is only able to reflect radio waves on 43 meters at low angles. Too early in the morning, and the band is not open for local (NVIS – Near Vertical Incidence Skywave) reception. The band is, however, open for reception to more distant locations, that is, more than many hundreds of miles away (well over 500, perhaps close to 1,000 miles). If you’re trying to get out to DX locations, this is a good time to do it. Sunrise varies throughout the year, so as we move into summer, and it occurs earlier, the band will likewise open up earlier for NVIS. Likewise in the middle of winter in December, it is somewhat later.

For reference, the operator of Boom Box Radio stated that this was a Heathkit DX-60 transmitter putting out 40 watts into a 40 meter band dipole that was about 15 feet high.

I thank Boom Box Radio for conducting this early morning test.

Update: The operator contacted me again to mention that his local sunrise was at exactly 1107 UTC.

WWV and WWVH Via Both Long and Short Path on 15 MHz and I can Hear Russia From My House

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In Measuring The Distance To A Shortwave Radio Station we looked at how the propagation delay in a shortwave signal can be used to estimate the distance to the station.

I ran some more tests the other day:

Below is a recording of 15 MHz, taken at 2300 UTC on December 13, 2012:

The GPS 1 PPS reference is on the top trace, and the audio from the radio is on the lower trace.

You can see the one second tick pulse from WWV in the audio, as well as two pulses from WWVH, the first (weaker) one is the normal (short) path signal, and the second one is via long path. We can confirm this is the case by converting the time delays into distance. We’ll use the same formula as in the previous article, we subtract off the 286 sample delay from the radio, multiply by 22.676 to convert the delay in samples to microseconds, then multiply by 0.186282 (the speed of light in miles per millisecond) to convert the delay into miles.

For WWV, the measured delay from the 1 PPS pulse is 660 samples. (660-286) * 22.676 * 0.186282 = 1580 miles
For WWVH short path, the measured delay was 1516 samples: (1516-286) * 22.676 * 0.186282 = 5196 miles
For WWVH long path, the measured delay was 5080 samples: (5080-286) * 22.676 * 0.186282 = 20250 miles

The distance to WWV is 1480 miles, and to WWVH is 4743. The long path distance to WWVH is 20158 miles.

Remember, the calculated distances can be longer than the great circle distance, due to the signal making one or more (many more in the case of long path) hops between the Earth and the ionosphere. Plus, there is the experimental error.

And here is one more example, this time it is the Russian time station RMW, on 14996 kHz, recorded at 1157 UTC on December 10, 2012:

The delay was 1835 samples: (1835-286) * 22.676 * 0.186282 = 6543 miles.
The great circle distance is 4821 miles.

Measuring The Distance To A Shortwave Radio Station

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In a previous post, I showed how it was possible to crudely measure the speed of light (or at least another type of electromagnetic radiation, radio waves, in this case) by measuring the time delay between two shortwave radio time stations, WWV and WWVH.

I’ve decided to re-do that experiment, but in a slightly different way. Rather than measure the speed of propagation, I will use that speed to determine the distance to the radio station.

Various time stations transmit precise time on several shortwave frequencies. Here in the USA, we have WWV in Ft. Collins, Colorado, which transmits on 2.5, 5, 10, 15, and 20 MHz. We also have WWVH in Kekaha, Hawaii, which transmits on 2.5, 5, 10, and 15 MHz. These stations transmit an audio “tick” at exactly each UTC second. There is also the Canadian station CHU, located near Ottawa, Ontario, which transmits on 3330, 7850, and 14670 kHz.

One way to measure the speed of radio waves (and light) would be to measure how long it takes for the tick to travel a fixed distance. Divide the distance by the time, and we have the speed of light. However, that requires knowing the exact UTC time locally. This can be done with a GPS unit that outputs a 1 PPS (pulse per second) signal.

How to feed these signals into the computer, so they can be measured? The radio audio is easy enough, feed it into the sound card. It turns out the 1 PPS signal can also be fed into the sound card, on the other channel. I used a capacitor to couple it.

The first measurement that is required is one to determine what time delay is added by the radio electronics. In my case, I was using a JRC NRD 545 receiver, which has DSP (Digital Signal Processing) to implement the audio filters. This certainly adds a time delay. I therefore needed to run some baseline measurements, to determine how long this delay was.

I fed the same 1 PPS signal into the antenna jack of the radio. The signal is a short (10 microsecond pulse) that is rich in harmonics, so it produces a noticeable “tick” sound every second. I then recorded the audio from the radio, along with the 1 PPS signal fed into the other channel, and obtained this data (click on the graph to enlarge it):

I measured the time delay between the two ticks, and found it to be 286 samples. At 44.1 kHz, each sound sample is 22.676 microseconds. Multiplication gives us the time delay, namely 6485 microseconds. This delay added by the radio is constant, provided I do not adjust the IF filtering parameters (which were set to USB mode, 4.0 kHz wide, for all tests).

Next, the antenna was reconnected, an the radio tuned to 15 MHz. At this time of the day (about 2100 UTC) it is possible to hear both WWV and WWVH. Here’s the sound recording:

The WWV pulse occurs at about 5.18 seconds on the recording, and WWVH, much weaker and harder to see, at about 5.2 seconds.

The delay for the WWV pulse is 657 samples. Subtracting the radio delay of 286 gives us a delay due to propagation of 371 samples. Multiplying by our conversion factor of 22.676 microseconds per sample gives us 8413 microseconds.

Light (and radio waves) travel at 186,282 miles per second or about 0.186 miles per microsecond. For the metric inclined, that’s 299.792 km/sec or 0.300 km per microsecond. So multiplying our time in microseconds by the distance light travels each microsecond gives us the distance:

8413 * 0.186 = 1567 miles (2522 km)

The actual distance, along the Earth’s surface, from my location to WWV is 1480 miles, or 2382 km. Why the discrepancy? The radio waves do not travel along the Earth’s surface, but instead are reflected from the ionosphere, which is several hundred miles up. This means the actual path they take is longer. We’ll try to take that into account, a little further down.

The delay for the WWVH pulse is 1550 samples. Subtracting the radio delay of 286 gives us a delay due to propagation of 1264 samples. Multiplying by our conversion factor of 22.676 microseconds per sample gives us 28662 microseconds. We’ll do our next multiplication again, to convert to distance:

28662 * 0.186 = 5339 miles (8592 km)

The actual distance from my location to WWVH is 4743 miles, or 7633 km.

Next, here’s a recording from the Canadian time station, CHU:

The delay for the CHU pulse is 401 samples. Subtracting the radio delay of 286 gives us a delay due to propagation of 115 samples. Multiplying by our conversion factor of 22.676 microseconds per sample gives us 2607 microseconds. We’ll do our next multiplication again, to convert to distance:

2607 * 0.186 = 486 miles (782 km)

The actual distance from my location to CHU is 407 miles, or 656 km.

Now let’s try to take into account the actual path of the radio waves, which get reflected off the ionosphere. We need to know the height of the ionosphere, which unfortunately is not constant, nor is it the same over each part of the Earth. Here is a map showing the approximate height, while the above recordings were taken:

In the case of the path to CHU, the height is about 267 km, or 166 miles.

We also need to determine the straight line path between my location and CHU, through the Earth, vs the distance along the Earth’s surface. This can be calculated, and it is 391 miles, or 629 km.

We’ll determine what the actual path length is for a radio signal traveling this distance. It looks like a triangle, with a height of 166 miles, and a base of 391 miles. We need to determine the other two sides to find the total path length. All we need to do is take half of 391 miles, which is 195.5 miles, square it, add to that 166 squared, and take the square root, then double our answer. The result is 513 miles, which is very close to our measured value of 486 miles. We’re off by a little more than 5%.

Next let’s try WWV: The actual distance is 1468 miles or 2362 km. Doing our math, using an approximate FoF2 ionosphere height of 246 km (153 miles): Half of 1468 miles is 734 miles, we square that and add to 153 squared, and take the square root, and double our answer, getting 1500 miles. Our measured distance was 1567 miles, so we’re off by less than 5%.

Next, the case of WWVH. This is more complicated, as the signal probably is making more than one “hop”, that is, it is going up to the ionosphere, reflected down to Earth, and then reflected back up again, and down again. This may possibly occur multiple times.

We’ll try doing the math anyway. The actual distance is 4588 miles or 7383 km. Doing our math, using an approximate FoF2 ionosphere height of 253 km (157 miles): Half of 4588 miles is 2294 miles, we square that and add to 157 squared, and take the square root, and double our answer, getting 4598 miles. Our measured distance was 5339 miles, an error of 16%. But again, we don’t know how many hops there were. Still, not a bad effort.

Does anyone else have a GPS receiver with a 1 PPS output? If so, I’d like to hear from you, I have some additional experiments in mind.

Propagation Gives Away Your Location

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Being as pirate radio is, well, illegal, operators like to stay anonymous. At least ops who want to avoid the FCC. Naturally, most ops consider keeping their location secret very important. Some even go so far as subtly, or not so subtly, providing false clues about their location, in an effort to fool the radio authorities. Unfortunately, basic rules of radio propagation make this futile.

A warning in advance. I’m going to be discussing some basic shortwave radio propagation theory. Nothing here is brand new, or unknown to anyone in the radio field. Certainly not the radio authorities. Some fur… err… feathers are possibly going to be ruffled by what is presented below, possibly with loud protests of “destroying pirate radio” and “releasing the identities of operators”. Nothing could be further from the truth. This is Propagation 101 stuff. If it scares you, then you probably shouldn’t be operating a pirate radio station. The purpose is the educate listeners and operators, so they know exactly what information can be gleaned from observing signal reports. It’s better to know exactly what can be done with this information, than to stick your head in the sand and pretend it doesn’t exist.

As has been discussed on this blog many times before, daytime propagation on the 43 meter band (where 6925 kHz is located) is considered NVIS (Near Vertical Incident Sky Wave). The radio waves go up, and are reflected back to the Earth for a fairly short distance around the transmitter site, usually a few hundred miles at the most. Attenuation by the D layer limits distant reception. At night, it’s almost the opposite reception pattern, as the D layer fades away, allowing distant reception. And the weaker F layer limits or eliminates NVIS reception, resulting in a skip zone around the transmitter, where the signal cannot be heard. The resulting reception area is shaped roughly like a doughnut.

So, for a daytime transmission, if one looks at a set of reception reports (as well as “no reception” reports, which can be equally useful), it becomes very easy to guesstimate about where a transmitter is. Not exactly of course, or even to a particular state, but certainly within a hundred miles or two. There will be a cluster of strong reception reports around the transmitter site, out to a few hundred miles. The maximum reception distance will vary a lot with transmitter level, antennas, and propagation conditions, but is likely under 1,000 miles. Look at where all the reports are coming from, especially the strong ones, find the center, and you have a good guess as to where the transmitter is.

At nighttime, listeners too close to the transmitter site (in the skip zone) will hear nothing, or at best a very weak signal. And during the transition from NVIS to DX propagation (see Going Long and An Interesting Example of a Station Going Long) the received signal will start to peak, and then suddenly cut out. Observing when this happens at a variety of listener sites provides other clues as to the transmitter location. If the F layer height and ionization values are known (and they are available in real time online) the distant to the station can be roughly determined when the station goes long. Do this for several receiver locations, and you can guess about where the transmitter is.

One ruse some operators have used in the past is to give misleading reception reports with a low signal level, using their real name and location, as just a regular listener. This is extremely dangerous, as if anyone is paying attention, their very weak signal report can stand out like a sore thumb if there are reports from others in the same area, with much stronger signal levels. Likewise, if you’re an operator, providing a completely bogus QTH doesn’t fool the FCC one bit. Announcing a QTH out on the Great Plains, while you’re really on the East Coast, doesn’t fool anyone when you’re being heard on the East Coast with an S9 signal at local noon. It just reminds everyone that you failed PROPAGATION 101. While shortwave propagation can be odd at times, there are limits. The laws of physics still must be obeyed.

The FCC and other radio enforcement agencies of course don’t have to rely on crude techniques such as these to locate transmitters. They have modern DFing equipment that can quickly and accurately locate a pirate station. The only reason they haven’t busted a given pirate is because, (as much as this may hurt to hear) that pirate is not important enough to get a visit. For now.

The commercially available WJ-9012 HF Direction Finding System, for example, boasts an error of less than 2 degrees. At a distance of 200 miles, that’s about 7 miles. Presumably the FCC has much better equipment.

While not announcing your location is probably a good idea (if for no other reason than to come across as taunting the FCC), in reality it doesn’t do too much to protect you from the radio authorities. Not interfering with allocated radio services, especially government and military, as well as operating from random remote locations, will go a long way to avoid getting The Knock.

Keep Safe!

Daytime Vs Nighttime Static Levels And The Impact On Reception

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Undercover Radio was on 6925 kHz USB several times on Sunday, May 20, 2012, conducting some transmitter tests in the afternoon, and with a show in the evening. I noticed how, even with a relatively weak signal strength in the afternoon, the overall reception was still good, due to the low daytime noise levels on the 43 meter band. Transmitter power was around 20-30 watts PEP.

Here is a graph showing the signal level of Undercover Radio on 6925 kHz, as well as background noise from an otherwise unoccupied adjacent frequency for 4 minutes, starting at 1700 UTC May 20, 2012:

Undercover Radio’s signal strength was about -92 dBm. Bear in mind that this was a voice only program with Dr. Benway talking, with frequent pauses in speech. Since this was an SSB transmission, the received signal level falls to the background noise level during pauses in speech.

The background static at 6930 kHz was -100 dBm

The net result is a signal to noise ratio of 8 dB, which is certainly adequate for fair to good reception.

Some recordings:
Undercover Radio 6925 kHz USB 1700 UTC
Background noise 6930 kHz USB 1700 UTC

Undercover Radio came back on at around 1900 UTC. Here is another comparison of Undercover’s signal vs background noise on 6932 kHz:

(Sorry, this time the noise is pink and the signal is blue. Just to keep you on your toes)

Eyeballing the graphs, it looks like the signal to noise ratio was about 15 dB, better than before. The quality of the received audio was indeed very good. Here is a recording

Next, Undercover Radio came on again at 0212 UTC.

The noise levels were around -85 dBm. Undercover Radio’s signal started at just around the noise level. At the time, he was running 20-30 watts PEP. Later, around 0245, Dr Benway realized he didn’t have the amp on, and then switched it on, going to 500-600 watts PEP.

One reason for the much higher nighttime noise levels is that not only is 43 meters open to DX from distant stations, but also to distant thunderstorms and other noise sources. Think of every thunderstorm in the world as a transmitter (which it really is). There’s thousands of active thunderstorms at any time, transmitting RF energy over the entire radio spectrum. This energy is received at your location from whatever parts of the world propagation is open to, on a given frequency. So while your signal can get out further at nighttime, it also has to compete with a lot more QRM sources.

During the daytime, the D layer of the ionosphere attenuates low angle radiation on 43 meters, preventing DX reception. You’re limited to just a few hundred miles. This applies both to the signals from radio stations that we want to hear, and distant noise sources.

Also notice how much Undercover Radio’s signal varied after the amp was switched on – by around 30 dB. That’s five S units! This tells us that signal reports, or even recordings, can be very hit or miss. One minute, an op can be at the noise level, a few minutes later, he can be many S units above it.

Two recordings. First, one from 0222 UTC when he was running 20-30 watts PEP, and the SNR was just a few dB. And second, one from 0300 UTC during a signal peak, when he was running 500-600 watts PEP, and the SNR was about 25 dB.

For comparison, here are some plots of WWCR, 6875 kHz, showing their signal level last night:

First, from 2230 to 0100 UTC (sorry for the X axis scaling, showing -100 for 2300 UTC. Blame Excel)

You can see that when their carrier went off the air, the noise level was around -80 dBm. And the signal varies by about 30 dB during the transmission, during nighttime. Earlier in the transmission, while it was still daytime, the signal was slightly weaker, but there was a lot less fading.

And second at 0300 UTC:

Perhaps the main point to take away from this is that while a pirate can be heard much further at nighttime than during the daytime on 43 meters, the lower noise levels and lack of significant fading during the daytime generally make for better quality reception, for those listeners within the several hundred mile NVIS range, and allows reception by listeners with more modest receiver/antenna setups. This is especially true when using lower power (grenade type) transmitters. Nighttime DX reception quality will be poorer, and limited to those with more substantial receiving stations. By selecting the time of day for operation, operators can to some degree select their audience and target area. A pair of transmissions, one in the daytime and one at night, would reach both local and DX listeners.

Signal Levels of Radio True North’s May 14th Transmission on 6950 kHz

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The graph below shows the received signal levels of Radio True North, a pirate radio station from Canada, which transmitted on 6950 kHz on Mary 14, 2012. The signal faded in at around 0200 UTC, and the transmitter was switched off at 0702 UTC – that can plainly be seen on the chart:

You can also see that after the transmitter switched off, the received signal levels were about -85 dBm, that is the background noise level. At peak, the signal was about -75 dBm, just a hair under S9. The signal to noise ratio is the difference between the signal and noise levels, or 10 dB.

Here is a short recording taken at around 0516 UTC, so you can hear what this signal sounds like. Remember, it is around S9, but the signal to noise ratio, which is what really matters, is only 10 dB. We had rain/thunder storms all along the east coast during this time.

Signal to noise ratios were discussed an earlier post, coincidently enough called Signal To Noise Ratios. There’s some simulated SNR recordings there. The 10 dB example sounds very close to the RTN recording above.

RTN was using his “usual power” (we’ll be vague and say a few hundred watts). Had he been using a lower power level, say 10 watts, the signal to noise ratio would have been about 0 dB, if not negative. He’s using a delta loop antenna, and is about 4,000 km (2,500 miles) away from my location.

Here’s a graph of RTN’s carrier frequency, as measured here:

You can observe both the power on drift, and short term cycling (about every 10 minutes) due to most likely to something thermal, perhaps a fan.

GPS Disciplined 10 MHz Reference

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Some time ago, I wrote about the Rubidium reference that I connected to SDR. The reference supplies a very stable and precise 10 MHz reference clock to the SDR, so that the sample rate does not drift. Drift in the sample rate causes drift in the received frequency, much like drift in the various oscillators in a conventional radio causes drift.

Just today, I replaced the Rubidium reference with a GPS disciplined reference.

Here’s what I got:

The reference itself is the box in the center. To the right is the power supply, to the left is the antenna.

A GPS disciplined reference or oscillator uses timing signals from the GPS satellites to control,or “discipline” the oscillator built into the reference using a tracking loop. The 10 MHz output is continuously adjusted to keep it at the correct frequency, usually by making very small adjustments and using long time constants (averaging periods), typically around 100 seconds or more.

The 10 MHz output from the reference connects to an input on the netSDR. Internally, that 10 MHz signal is used to produce an 80 MHz clock that is used to drive the A/D sampling.

Here is what the inside of the reference looks like:

Here’s a plot of WWV on 10 MHz:

I believe the frequency shifts you see are due to doppler effects in the ionosphere.

Now I can figure out exactly what frequency Captain Morgan is on.

Excellent 43 mb Propagation, 10/11 mb Operators Put On Suicide Watch

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Old Sol has been quiet lately. Far too quiet for the 10 and 11 meter band guys. As I’m typing this, the solar flux is back into double digits, at 95. The Sun Spot Number (SSN) is officially 24, but you need to squint real hard to actually see any sunspots:

Sunspot SunSpeck group 1452 has pretty much rotated out of view, taking the meager solar activity we’ve had with it.

The NOAA/NASA/Space Weather prediction boys promise that we’re still a year away from the peak of cycle 24, and activity will increase.

Go up. Yes, it will go up any time now, just you wait. Hey! Look over there! Global Warming!

Meanwhile, back in the real universe, the background x-ray flux is at B1 levels.

So what does all this mean for us DXers? The lower solar activity has several major effects. First, the highest frequencies that can be propagated are lower, in many cases much lower. During a solar cycle maximum with high activity, the higher bands are often open 24 hours a day. With the lower activity we’ve been having, this is not this case. Yes, 10 meters is still open at times, but not nearly as much, or with the good conditions that have been experienced in the past. So operators and listeners need to move down to lower frequencies.

The foF2 frequencies are correspondingly lower, which means that a given band (including 43 meters) will go long earlier in the evening. Operators may want to adjust their schedules accordingly, and consider transmitting a little earlier to reach a semi-local audience. OTOH, they’ll end up reaching more distant listeners earlier in the evening as well.

Second, D-layer absorption is lower, due to decreased x-ray flux from the Sun. This means that lower frequencies are not attenuated as much, which is a good thing, since in many cases that’s all that is propagating. The last few days, I’ve been hearing 48 mb (6 MHz) Europirates fade in as early as 2 hours before local sunset. And once the Sun does set, their signal levels increase to really strong levels. Likewise, US pirates such as Wolverine Radio have been reported across the US and into Europe with incredible signal levels.

Third, the lack of major solar flares and coronal streams affecting the Earth means that geomagnetic conditions have been very stable. No geomagnetic storms means stronger signals, and less fading.

The net result is that reception conditions for 43 meter band pirates has been extremely good lately. Lots of operators and listeners have been taking advantage of the excellent conditions, loggings are way up.

There is a coronal stream expected to start impacting the Earth around the 13th or 14th of April, so we’ll have to see what effect, if any, that has on conditions. Until then, enjoy the great propagation!

Solar Storms (plus Solar Hurricanes, Typhoons, and other ways the Sun will vaporize us or even worse, possibly cause your iPhone to not work)

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Over the past few years, there has been dramatically increased media coverage of solar flares, and the effects they can have on the Earth, primarily on our electrical distribution and communications systems. The emphasis has been on the ability of the flares to cause geomagnetic storms on the Earth, which then can induce currents in our electrical power grids, causing them to go offline from damage. There has been a tremendous amount of fear instilled in the public by the hundreds, if not thousands, of news articles that appear every time there is a solar flare.

Those of us who are shortwave listeners or amateur (ham) radio operators are typically familiar with solar flares, and some of the effects they can cause. To summarize:

A solar flare is a sudden brightening of a portion of the Sun’s surface. A solar flare releases a large amount of energy in the form of ultraviolet light, x-rays and various charged particles, which blast away from the solar surface. The x-rays can have an almost immediate effect on the Earth’s ionosphere, the layer of charged particles above the atmosphere, which allows for distant reception of shortwave radio signals. I discuss the effects of x-rays on the ionosphere this earlier article. Energetic solar flares can cause what are known as radio blackouts, where all of the shortwave spectrum appears to be dead, with few or no stations audible. Other communications bands, such as AM / medium wave (MW between 526-1705 kHz), FM, TV, and cellular phones are not affected. Just shortwave. Also, the portion of the Sun producing the flare must be roughly facing the Earth to have an effect, and only the sunlit portion of the Earth is affected.

The solar flare can also cause a Coronal Mass Ejection (CME), which is a burst of energy, plasma, particles, and magnetic fields. The CME typically takes one to three days to reach the Earth. When it does, it can cause a geomagnetic storm, which is a disruption of the Earth’s magnetosphere. The magnetosphere is a region of space surrounding the Earth, where the magnetic field of the earth interacts with charged particles from the sun and interplanetary space.

The CME can produce very high radiation levels, but only in outer space. If you’re an astronaut on the International Space Station, this could be a concern. If not, you don’t really have much to worry about. High altitude airline flights can result in somewhat higher than usual radiation doses, but high airline flights always result in higher than usual radiation doses, due to less atmosphere protecting you from cosmic radiation. You might just get a little more especially if you fly over the North Pole. Or over the South Pole, but I don’t think there are too many of us who do that.

The effects of a geomagnetic storm:

The Earth’s magnetic fields are disturbed. This can cause compass needles to deviate from their correct direction towards the poles, and has been frequently mentioned in medieval texts.

Communications systems can be impacted. As with solar flares, shortwave radio is most affected. AM can also be affected to some degree. FM TV, and cell phones are not affected.

Back in 1859, there was a large geomagnetic storm, often called the Carrington Event because the solar flare that caused it was seen by British astronomer Richard Carrington. The effects were dramatic. Aurora were seen as far south as the Caribbean. Telegraph lines failed, and some threw sparks that shocked operators. Storms of this magnitude are estimated to occur about every 500 years. Other very large geomagnetic storms occurred in 1921 and 1960, although neither was the magnitude of the 1859 storm. The term “Carrington Event” has now come to mean an extremely large geomagnetic storm that could cause devastating damage to the communications and electrical systems around the world. But these forecasts are often based on the notion that, with more communications and electrical systems in place, we are much more reliant on these systems and vulnerable to disruption, meanwhile ignoring the fact that we better understand how geomagnetic storms cause damage, and what can be done to prevent it. Remember, this was 1859, and very little was even known about how electricity worked, let alone the effects of geomagnetic storms. This was in fact the first time that the relationship between solar flares and geomagnetic storms was established.

Communications satellites can be affected due to the higher radiation levels and unequal currents induced in various parts of the satellites. This could cause the satellites to temporarily malfunction, or even be damaged (which could affect FM, TV, and cell phone calls, which would otherwise be unaffected). As satellites are always in a high radiation environment, they are protected, and it would take very severe conditions to cause extensive damage.

Between 19 October and 5 November 2003 there were 17 solar flares, including the most intense flare ever measured on the GOES x-ray sensor, a huge X28 flare that occurred on November 4. These flares produced what is referred to as the Halloween Storm, causing the loss of one satellite, the Japanese ADEOS-2. Bear in mind that there are almost a thousand active satellites in orbit.

GPS navigation can also be affected, due to variations in the density of different layers of the ionosphere. This can cause navigation errors.

But the effect that, thanks to media hype, everyone is most concerned about is the possibility of a solar flare causing a geomagnetic storm that destroys the entire power grid, leaving virtually the entire United States without power for weeks or even months. The good news is that this is highly unlikely to happen.

Here’s the scenario: The geomagnetic storm causes currents to be induced in the wires that make up the long distance transmission lines that connect the various electrical power plants and users across the United States, aka the power grid. If these currents become large, they can damage equipment such as transformers, leading to widespread power outages.

And indeed this happened, on a much smaller scale, on March 13, 1989. A geomagnetic storm caused ground induced currents that severely damaged seven static compensators (devices that are used to regulate the grid voltage) on the La Grande network in the Hydro-Quebec, Canada power grid, causing them to trip or shut down automatically. The loss of the compensators allowed fluctuations in the grid voltage, causing damaging to other devices. The net result was that over 6 million people in Quebec and the Northeastern United States were without power for about 9 hours. Another million were without power after the 9 hours. Parts of Sweden also had electrical power disruptions.

While being without power for 9 hours, or even several days, sounds dreadful, especially in this age of constant communications, it does happen routinely. Hurricanes and tropical storms often cause millions to lose power outage each year, as do snowstorms, ice storms, and thunderstorms. Even heat waves have caused massive blackouts. I was without power for a week after Hurricane Isabel in 2003. The concern with an extreme geomagnetic storm, such as a repeat of the Carrington Event, is that critical components such as large transformers could be damaged, which can take time to repair or replace. And there’s the fear that widespread damage to the electrical grid could result in more components being damaged than spare parts exist, causing even longer delays until they can be replaced.

In the two decades since the 1989 event, more protective devices have been installed, and electrical transmission line operators are more aware of the damage caused by induced currents from geomagnetic storms. Preventative measures, such as temporary blackouts for several hours until conditions stabilize, can prevent much of the damage from a large geomagnetic storm. The advanced warning of geomagnetic storms now possible due to the satellites that are continuously monitoring the Sun and the Earth’s geomagnetic field can give electrical transmission line operators the advanced warning they need to take preventative measures.

Also, the 1989 event occurred in Quebec, which is at a very northern latitude. Geomagnetic storms tend to be stronger near the poles, and less severe as you move towards the equator (much like how the aurora is commonly seen near the poles, but not elsewhere).

It’s also worth noting that there are actually three electrical grids in the United States: an Easter, Western, and Texas grid. They are not currently connected to each other, although there are discussions to do so.

Finally, while a repeat of the Carrington Event is possible, it is extremely unlikely (remember, they are thought to occur about once every 500 years). There are far more important things to plan for, such as blizzards, hurricanes, tornadoes, and even severe thunderstorms, which routinely do occur. It is certainly more prudent to prepare for events like these, by keeping batteries, portable radios, canned food, and jugs of water on hand, than to worry about an event that probably won’t happen again for several hundred years.

So, why all the media frenzy and public concern over solar storms?

First, the Sun operates on a roughly 11 year solar cycle. Solar activity, including the appearance of sunspots and solar flares, peaks about every 11 years, and then fades until the next solar peak. There’s a solar peak occurring right about now. The last one was in 2001. This was before Facebook, Twitter, and everyone spending several hours a day on the internet, obsessing about the crisis du jour. Or crisis of the year in this case. Back in 2001, very few people even knew there was such a thing as a solar flare, other than space scientists and ham radio operators.

Those of us who have been involved with radio related hobbies for some time are used to the 11 year cycle. As an SWL since 1978, I’ve witnessed several solar cycles. During a solar peak we get many more flares which disrupt reception, although the overall higher level of solar activity is actually beneficial to shortwave propagation. Plus, it’s more likely that we’ll get to see the aurora. Then things calm down for many years, until the next solar peak.

There’s also been a substantial increase in advocacy by scientists and other public officials for increased spending on solar flare / geomagnetic storm research and related programs. Obviously this is justified to some extent, as we are much more reliant upon technology, and even just electricity, than we were decades ago. Still, I wonder if things are being exaggerated just a wee bit. Government officials and those involved in research have a vested interest in increasing their budgets and staffs – it’s job security for them. I’m not suggesting any malice, pretty much everyone thinks their job is important, especially those in the scientific field. It’s human nature.

This increased advocacy has resulted in increased media coverage as well. I’m far less sympathetic here. The motto of many news organizations seems to be “If it bleeds, it leads”. Pretty much every time there’s a solar flare, there’s a flurry of news articles announcing impending doom. The titles are amusing, not only are there SOLAR STORMS, but also SOLAR HURRICANES, SOLAR TYPHOONS, and SOLAR TSUNAMIS. I haven’t heard of any SOLAR TORNADOES, but maybe next month. Invariably the articles describe how a solar flare can wipe out the entire power grid, sending us all back to the stone age. And this might be the one that does it! Of course, a day or two later, when the CME arrives and little happens other than poor shortwave radio listening and some enhanced Northern Lights, there’s no followup article. Although if there was, I’m sure it would state that while we dodged the bullet this time, the next flare will surely fry us all. And our iPhones.

Some examples:

Nasa scientists braced for ‘solar tsunami’ to hit earth

The Daily Telegraph disclosed in June that senior space agency scientists believed the Earth will be hit with unprecedented levels of magnetic energy from solar flares after the Sun wakes “from a deep slumber” sometime around 2013.

Cities blacked out for up to a year, $2 TRILLION of damage – with a 1 in 8 chance of solar ‘megastorm’ by 2014

Imagine large cities without power for a week, a month, or a year. The losses could be $1 to $2 trillion, and the effects could be felt for years.

‘A longer-term outage would likely include, for example, disruption of the transportation, communication, banking, and finance systems, and government services,’ the NRC report said, it was reported on Gizmodo.

‘It could also cause the breakdown of the distribution of water owing to pump failure; and the loss of perishable foods and medications because of lack of refrigeration.’

Solar Flare: What If Biggest Known Sun Storm Hit Today?

Repeat of 1859 space-weather event could paralyze modern life, experts say.

A powerful sun storm—associated with the second biggest solar flare of the current 11-year sun cycle—is now hitting Earth, so far with few consequences. But the potentially “severe geomagnetic storm,” in NASA’s words, could disrupt power grids, radio communications, and GPS as well as spark dazzling auroras.

The storm expected Thursday, though, won’t hold a candle to an 1859 space-weather event, scientists say—and it’s a good thing too.

If a similar sun storm were to occur in the current day—as it well could—modern life could come to a standstill, they add.

The news articles are bad enough, but I suspect the fact that 11 years ago no one saw articles like this, or even knew solar flares existed, has convinced a lot of the public that solar flares (of this magnitude and frequency of occurrence) are a new phenomena. It probably doesn’t help that this is the year 2012, and we’ve had the Mayan 2012 END OF THE WORLD nonsense to deal with for the last decade or so. I wonder if anyone has retconned Mayan history into them having a solar observatory and been aware of the 11 year solar cycle, and how it would peak in 2012, destroying the Earth. Maybe they even had an x-ray satellite in orbit. I bet the aliens that helped them build their pyramids left them one. The grays are helpful, like that.

Perhaps the most ironic part of this entire saga is that the 2012 solar cycle peak is forecast to be extremely low. Here’s the latest forecast and current progress through the cycle, click to enlarge it:

The peak smoothed sunspot number (SSN) is forecast to be about 60, vs the 120 for the previous cycle. The lower peak SSN means lower overall solar activity. That means fewer flares, and they should (overall) be less severe. The peak is also forecast to be in 2013, so I’m not sure how that works out for all the 2012 Doomsayers.

To put this further into context, here’s a graph showing all the previous solar cycles:

The red arrow points to the cycle peaking in 1928, the forecast at the time (2009) was that the cycle we’re in now would be similar to that one, it’s since turned out that activity is even lower.

The largest peak is Cycle 19, from the 1950s. Many older ham radio operators have fond memories of Cycle 19, when radio propagation conditions were excellent. They were hoping for a repeat with Cycle 24, but that is clearly not the case. And Cycle 25 is currently being forecast by some to be even lower than Cycle 24, although it’s not worth putting much, if any, stock into long range solar cycle predictions. Predictions for our current cycle (24) from just a few years ago had it being as strong as, or even stronger than, the previous cycle, which is clearly not the case.

The period marked as the Maunder Minimum on the above graph was a period of extremely low solar activity around the late 17th century. Very few sunspots were noted during this time period.

While we are indeed entering the peak of a solar cycle, which means more solar flares (and more powerful flare), which can have impacts on the Earth, I believe the historical evidence shows that the doomsday scenarios proposed by many alarmists are not warranted. I would suggest checking with various websites such as http://www.spaceweather.com/ to keep track of when a solar flare has occurred. Not to panic that the end is near, but to know when to go outside and look at the Northern Lights. They can be quite beautiful.