This summer I built a ground mounted part 15 AM system as described here and have begun to accumulate data on its operation as reported here. It is a bit early to draw firm conclusions from the measurements but some things of interest have been observed.
Instrumentation
The amount of “freight carried” is shown by the field strength produced by the system and to measure this I decided to use my base coil loaded antenna in my basement as the receive antenna and the Yeasu FRG-100 receiver and a DVM for signal strength measurement. The signal derived from the field strength and which drives the S meter circuits was brought out from the receiver for display on a DVM. The DVM reading was correlated to the RF voltage at the receiver antenna input by use of a RF source where the voltage can be set to known levels. From these data a calibration curve of DVM voltage vs RF voltage input was drawn and an equation was derived from this curve which allows for calculation of the RF signal voltage input from the DVM voltage reading. With the receiver connected to the indoor antenna it is possible to measure relative field strength produced by the transmission system without weather effects previously associated with the outdoor receive antenna. Concurrent measurement of the antenna system parameters is provided by use of a current transformer and oscilloscope as described in this post.
Field Strength Change With Rain
The antenna field strength decreased by as much as 3.7 dB after two days of heavy rainfall. It is not yet possible to explain this decrease lacking more data points but it was observed that the decrease in FS was slow after the beginning of the rain. During and after 1 inch of rain on the first day there was no decrease in FS and the decrease seen began on the second day about one half of the way through the day which produced another 1.08 inches of rain. The largest decrease in FS occurred on the following day with no rainfall with the maximum decrease of 3.7 dB. The FS began slowly increasing on the second dry day and is still increasing on this third dry day and presently is -1.3 dB relative to the FS before the rain.
Ground Resistance Change with Rain
The antenna system feed point R was measured at the end of an unusually dry month of July to be 57 ohms. Using a model that this resistance is the sum of the ground resistance and the loading coil effective resistance, the ground resistance is calculated as Rg = Rfp – Rcoil = 38 ohms. The measured (on the second dry day) Rg after 2.08 inches of rain in two days was 17 ohms. Paradoxically, this halving of Rg was accompanied by a decrease in the measured FS. Measurements of the antenna voltage, current, and input power show little change from those taken before and after the rain except for the v to i phase angle. This change in angle only explains 9% of the reduction which amounts to -0.8 dB. It was noted that there was an increase in the feedpoint power of 0.25 dB after the rain which is probably due to the transmitter’s response to the lowered feedpoint resistance, but the second dry day data reported above were taken after the phase angle was set to 0 and the antenna power restored to the before rain value of 82 mW in an effort to factor out the changes due to antenna tuning and changes due to antenna system input power. This technique of separating effects by normalizing the tuning and power is intended to show the changes due to other effects. These “other effects” dominate the decrease observed and are not yet explainable pending gathering more data.
There is a saying used when I was involved with medical research that states “With the data you do not have we can establish what you do not know.” Well, gathering data thus far has established some things which I know but has also illustrated that there are things which I do not know. For research inclined people such as I this is exciting because there is more to be discovered. For those who just want the answers this is frustrating but such is the nature of the beast. I hope as this progresses to be able to provide some reliable answers with confidence and will keep you updated.
Neil
.
Interesting
That’s interesting. I get opposite results from rain or snow on the ground with my antenna system. The field strengths increase by about 3db and even more with a layer of snow.
After a day or two of rain soaking into the ground, or snow melting into the ground, the resistance decrease also increases the field strength by a couple db and so does the range.
When it’s bone dry is when the system is at it’s worst and is when I “irrigate” the system and surrounding ground where they ground plane is. This restores the range and field strength to what it would be if after a good rain or layer of snow on the ground.
I think the reason why your getting reverse results are the surrounding shrubs and growth. When it gets rained on, it’s absorbing all your signal! 😀
RFB
Foliage Theory
This is one of my speculations but lacking data I didn’t mention it in the first post. But now that it is on the table here’s a possibility. The delay of 24 to 36 hours after the start of heavy rain to the decrease in FS plus the continued decrease on the first dry day would support a theory that this is due to the time it takes for the water to be pulled into the plant tissue via transpiration and that this water is causing signal absorption. I am logging a slow increase over time in the field strength and this could be due to evaporation of water from the leaves due to normal transpiration so as the water leaves the foliage the effect of absorbing the signal decreases. The test of this is to take data after the leaves fall (end of Nov.) during and after rain.
Is there anything else anyone suggests which could cause this or something else to watch for?
Neil
I hesitate to make any
I hesitate to make any comment since my engineering knowledge is nill. But the contradiction to the expected results is so intriguing that I can’t help but to armchair speculate..
Is it possible that the rainfall which should be increasing your FS is perhaps increasing a FS of another larger (or multiples) radiator in your general area, which inturn is overpowering your signal? – much like skywave will enable distance stations to overpower local station signals?
I’m not sure if I’m conveying my thought clearly, or if I’m sounding ridiculous.
But again.. maybe the rain is increasing the FS of multiple radiators in your frequency, which with their increased reach are (in essence) competing for new space, which is resulting in you losing some reach.
??
I hope this doesn’t sound like complete nonsense.. I hope someone gets the gist of what I mean!
Maybe I should have heeded my hesitation to comment
I’ll Add 2 Pennies Worth..
I’m sure that the living green things around the antenna is having an impact. My first set-up was surrounded by trees. The clearing was ~60′ in diameter. I moved everything out into an open field and my range increased by double. That proved to me that green things eat signal..
Your coil is still open to the atmosphere. Humidity and temperature variances could be an issue..
Rain water is distilled water, which is a very poor conductor of electrons. Could it be possible that the rain is diluting the minerals in the dirt?
Just peekin’ outside of the box..
The big problem is that there
The big problem is that there are many things in the environment that affect a Part 15 radio signal.
Most of my measurements were with FM. I found that early morning on a cool, clear day gave me the greatest FS (and best range). Rainy days and/or humid days gave me the least – I assumed that moisture in the air absorbed the signal. And as the day wore on, more particulates were released into the air and held there (particularly as the temperature rose), again absorbing the signal.
I know that AM is at the opposite end of the radio spectrum, but perhaps it’s the humidity after the rain that is affecting the signal, because moisture should improve ground efficiency. I wonder if you would achieve the same results if you just watered your ground (thus keeping the humidity constant)?
Near and Far
Previously I only skimmed the opening notes about the many system measurements that are being observed in radio8z’s laboratory transmitter installation. Tonight I took the time to carefully read every word.
What a valuable collection of documentation this will become. All things near are being considered as possible contributors to the results.
What about things not so near, such as clouds above, or weather factors not mentioned, such as relative air humidity and barometric pressure?
Are there any other earth changes that are less well known to the average person, perhaps magnetic fluxes or those “things we don’t know we don’t know”, which was referred to with different wording.
It seems to me also, and RFB might have touched on this, but as your signals are being influenced by surrounding elements, so are the signals of other broadcasters, and their changing signals might also play a part in bumping your signal, so to speak; possibly putting more or less radiation into your antenna/coil, in addition to your own RF.
Other causes of FS variation?
Neil,
Your indoor tuned antenna and Yeasu receiver seem to be a good solution for providing a stable FS measurement. But, I wonder if there may be other reasons for your observed drop of 3.7 dB attributed to the heavy rain.
Just as the on/off state of various home electrical branches effect an in-home transmitter signal, I suspect the same may be true for received signals inside the house.
I think a day or two of heavy rain could cause the received signal level in the basement of a house to change.
Due to the non-intuitive vagaries of the dB scale, a -3.7 dB change in FS could be huge or minuscule depending on the absolute value of the base FS. Examples:
-100 dBv = 10uV, -103.7 dBv = 6.53 uV.
-80 dBv = 100uV, -83.7 dBv = 65.3 uV.
-60 dBv = 1000uV, -63.7 dBv = 653.1 uV.
Phil
Reply to Phil
I have read and do appreciate all of the comments and will get to them as I can but for now I want to provide some data on the FS measurements in response to Phil’s post.
The dB measurements are all relative to the maximum observed FS 1 day after a light rain. The RF voltage at the receiver input for 0 dB reference is 656 uV (0 dB by definition) on 9/22 with no rain. The lowest reading occurred on 9/28 and was 428 uV (-3.7 dB). The heavy rain ended around midnight 9/26. The current reading at 1 AM 10/1 is 639 uV (-0.2 dB).
The data are incomplete but there is a trend. Here is the set of data so far:
date dB and comments
9/14 -2.5 dry no rain in previous week
9/17 -1.6 light rain
9/22 -0.0 one day after 1/4 inch rain
9/26 -0.1 during light rain
9/26 -0.7 during moderate rain
9/26 -0.7 during heavy rain
9/26 -1.2 after end of rain total 2.08 inches
9/28 -2.7 no rain
9/28 -3.7 later in day
9/30 -0.1 no rain
10/1 -0.2 no rain
So another way to view this using the 9/14 reading as 0 dB is that the first light rain increased the FS to 0.9 dB followed by another increase up to 1.5 dB after rain then after the heavy rain it fell to -1 dB from the starting FS but then increased to 1.4 db. The -1 dB reading may be within the error of measurement which has yet to be determined.
There appears to be two effects here, the first is an increase in FS with rain and a second effect produces a delayed drop in FS two days after the rain followed by an increase by the forth day.
This is very important!
The original purpose of monitoring the FS was to watch for changes due to rain and it was thought that the effect would be due to water on the antenna system components or the surrounding vegetation so the data were taken looking for short term effects. Now that it is recognized that there is a delayed effect the data monitoring needs to be changed to be sensitive to this. Thus it is too early to draw conclusions from a data set which is not designed to study the delayed changes.
This is not unusual in science where an unexpected effect is seen but statistical and experimental honesty requires that the data gathering be redesigned to be appropriate for what is being sought and begun anew and this is what I will do. So, what is here now is interesting but not conclusive.
Back to Phil’s point about other factors which may affect the readings, this is true and the instrumentation may be one of these. The graph of the receiver input voltage vs. the S meter signal shows a small slope which means that a small change in the DVM measured S meter voltage represents a large change in the input voltage as well as the FS derived from this. The effect is to increase the error of measurement and I am seeking a number for this but a preliminary check of the random short term variability of an on the air measurement shows this be about +/- 0.2 dB. I will check the long term error from the original calibration data so this can be ruled out as a cause.
Much more needs to be done to make this project reliable but I am working on it.
Neil
I’ll have to read all of this over again, but…
My AMT-3000 outside 3 meter stick
and 16 radial set-up was surrounded
by foliage. There was nothing I
could do about that.
The set-up worked best when the sun
was shining, and when everything was hot
and dry. On one particular day with
that weather, I heard “DOGRADIO/MICRO1690”
clearly on the car radio in my doctor’s
office parking lot. It was weak but it
was a perfectly readable signal. And
I was almost exactly 2 miles from home.
I’ll never forget this: I went back a week
later on a rainy day to the same parking lot
at the same doctor’s office in the same car
with the same radio. We even parked in the
same spot. I heard nothing. Nothing at all.
The system performance definitely
degraded when it was wet outside.
The signal strength improved
as things dried out. I have no written data
to support this, but I do know that it
happened that way. I took me most of a
summer to notice the pattern. I was pretty
puzzled for a while.
However, in 1969, experiments with a Lafayette
KT-195 in my parent’s cellar showed the direct opposite.
When it rained, the signal went further down the
street. When it was dry, the signal covered
less area. However, the whole set-up was in my
parent’s cellar. Studio, transmitter, and
antenna. So it was a very different kind of
set-up.
I guess that’s why we should keep logs. I wish
I had. If I ever do this again, I guess I will.
Bruce, SLUG 88.3
Wet loading coil degradation
Bruce,
Your experience with a base loaded antenna working best in dry conditions seems to be typical.
One customer who built the in-line version where the antenna pipe is mounted on the PVC top cap found his range was steadily decreasing over months. He found that the entire 3″ PVC coil pipe was full to the top with water! He drilled a drain hole in the bottom cap. He subsequently placed an inverted plastic bucket over the coil and transmitter which reduced the temporary degradation during a rain.
The temporary degradation during a rain seems to be caused by the coil being wet. When it drys, original performance returns.
It is best to place the transmitter and coil inside a nonconductive water shield, such as an inverted plastic bucket, and seal the protruding antenna with silicone caulk to prevent seepage inside. This is what Neil has done successfully with his coil.
Neil’s ongoing measurements are quite interesting and promise to shed light on other effects of rain.
Hi Phil!
Yes, Neil’s measurements are
something new here and I am
enjoying reading about his
findings. Very much, actually.
I did have a soda
bottle over the top of my
copper pipe 3 meter antenna.
The bottom of the pipe was open.
There were some unusual things
about my set-up. You might
remember this, but some might
not have read about these.
It was attached to the side of
a children’s playhouse. The
transmitter and coil were inside.
The antenna was on the outside.
1690 kHz was empty during the day
but busy at night. 1700 kHz had
a pirate station from Hartford, CT
during the day, but I couldn’t hear
the pirate at night. So I ran 1690
during daylight hours. At sunset
the system automatically switched to
1700. At sunrise it automatically
switched back to 1690. This was done
with a power supply on a timer in the
house. A wire went out to a relay I
had wired into the AMT-3000. The relay
was across the dip switches. (I don’t
remember which ones.)
Also, having severe vision problems, I
could never get to the hardware store
to build the 3 meter antenna and loading
coil on your website. So I made another large
coil. I broke a connection on the circuit
board inside the AMT-3000 and attached the
external coil there. (All of the internal
conductors were switched out.)
It worked very well. I am 1/2 mile from West
Hartford Center. My good friend could drive
all over downtown and listen to my station
on his car radio. Granted, he had a GREAT car
radio.
But it was a lot of fun.
Best Wishes to you, Phil.
Bruce, SLUG 88.3
Update on Rain Effects
My previously reported association of field strength with rain showed a marked drop in FS after rain but this was suspect since the experiment wasn’t designed to show this. I have recently completed a 210 hour period of measurement with both heavy and light rain occurring during this time. I also switched the FS measurement to use the outdoor antenna since the indoor antenna was giving variable readings which appear to be due to electrical noise. The readings from the outdoor antenna are steady from moment to moment and there is less audible noise on the audio as compared to the the indoor antenna.
Generally the FS did not drop much during or after rain. The largest drop was 0.8 dB during a heavy rain which totaled 0.66 inches. Immediately after rain the FS returned to the reference value of 0 dB and then peaked by 1 dB 7 hours after the rain stopped. The FS slowly returned to the normal 0 dB level 84 hours after the rain stopped. This pattern was seen with two other rain episodes but the peak rise was less.
The extreme dip in FS after rain was not observed but this could be due to the foliage going dormant and not taking up water or it could be due to a measurement problem with the initial data taken with the indoor antenna. Measurements will need to be made next spring when the leaves come out again.
It is encouraging that there is not a large change in FS under changing conditions of rain. The ground moisture is recharged compared to the drought conditions existing just before the previous measurements were made. Now that the receive system appears to be stable with low noise it will be interesting to track the FS changes with other weather effects.
Neil
Effects on Monitoring
It seems that while evaluating the performance of the transmitting system in the weather you are discovering as much need to study the monitoring gear since it’s performance is also subject to external influences.
Ultimately you may have to have yourself evaluated by a subjective scientist who specializes in calibrating other scientists.
“I think I know, but if I don’t, I don’t know it yet.”
There’s the speed of rain as it falls, the angle of descent, some rain might be wetter than others, water drops have a mineral content…
Monitoring the Monitoring
Carl,
The instrumentation can be equivalent to using a rubber ruler to measure things if one is not careful.
With peer reviewed scientific journals it is common practice during the review process to examine the methods and measurement devices used to gather and analyze data. With the instant internet peer review is not usually done and the possibility for junk science is open.
One set of papers I reviewed involved correlating cancer incidence to house proximity to high tension power lines. Two articles (as I recall from Denver and Baltimore) stood out since they reached opposite conclusions and both used a sensing instrument from the same manufacturer. I contacted the manufacturer and was told that the device was not suitable for measuring that type of EM field and that such data would be suspect. Unfortunately both articles had already been published but I recommended against the publication of a third. So, there are techniques in place which check this if used properly. Phil raised some valid questions about my first report and in a sense served as a reviewer. It has been said that criticism is vital to advancing good science.
The physicist Richard Feynman said to the effect “the easiest one to fool is the researcher himself”. If one goes into an experiment with a pre-conceived idea then it can easily bias the investigation. This is why I wanted to back up and start anew with the data and instrumentation.
Neil
The Sub Conscious
We may know things we don’t know we know, according to Swiss psychologist Carl Jung, famous for theories about the collective unconscious of the human mind.
I was reminded of this in a dream in which I was both aboard and also an outside observer of a high speed train taking sharp curves and switches, in which I began to dwell on track maintenance.
I noticed a kind of hump in one of the two tracks, and as the train went over it I was attentive to whether I could feel it, but the train absorbed it very nicely.
There’s a hidden message in there which very well could be applied to the next antenna.
Time Advances and so does Signal Strength
Going into the first week of December the monitored field strength has remained almost constant at the late summer reading with the disappearance of the leaves from the trees and bushes. But in the second week of the month we received two inches of rain and this time of the year the ground remains saturated and after this rain the field strength has been up by 1.2 dB. The ground has not frozen and this will be the next “big event” to log here. For the record, the total antenna system feedpoint impedance measured the day after the rain was 28 <1 degree ohms. Subtracting the coil loss the ground resistance is 9 ohms.
Neil
Snow Effects
There is now about 3 inches of snow on the ground and the loading coil cover is topped with a cone of snow. The field strength is down by 0.8 dB from the “normal” reading.
The soil is not yet frozen and this will be the subject of the next update.
Neil
More Snow
In the previous post I reported the decrease in field strength with the loading coil partially covered with snow. There has been additional snow and now the coil is almost buried and has snow coned on the top of the coil cover. The field strength is now down 2.7 dB below the “normal” reading.
Two possible effects of the snow can account for this loss, one being the snow detunes the antenna system, and the other being that the snow increases the loss due to energy dissipation. From monitoring the DC supply current to the transmitter it is seen that this current has decreased which supports the theory that the antenna has been detuned rather than increased dissipative loss.
Neil
Weather Elsewhere
Radio8Z is up in snowy Ohio and this message is being sent from less snowy mid-Missouri, where I just changed the ground on the AMT3000 Wintenna system, from an indoor baseboard dipole to a clamp on the basement I-beam.
Previously the signal outdoors 100′ down on the street was almost totally swallowed in noise. day and night regardless of the weather.
But now, with the new ground-clamp, the reading down there is 55dBu with a topped-off signal/noise ratio of 25, meaning full quieting!
Since the antenna faces the outdoors but isn’t exposed to the snow, I expect the range is probably greatly improved out to the far field, but I’m not volunteering to go out there and find out.
Look to the ground. I found $5 on the street two days ago!
Found the Lost dBs
The snow had “coned” quite high on the coil cover and was in contact with the radiator but removing the snow atop and around the coil cover brought the field strength back to 1.8 dB above the nominal.
Perhaps the snow on the ground has a positive effect but now is not the time to measure the ground resistance so I will just speculate.
The soil is not frozen but tonight we expect temps. in the teens so in a few days I’ll probably be able to get a frozen soil reading.
Note to Carl, It is good to have quantified,even if relative, field strength measurements since this allows an assessment of changes to the system. Even a receiver with a FS indicator such as you use provides good information and is much better than “guessineering”.
Neil
Sense of Control
Yes for sure having measuring equipment gives the thrill of “semi-psuedo-near-engineering” which I find very self-impressive.
Yet the day will come when I add more sophisticated monitoring devices such as you’ve invented, and I hope all our projects excite newcomers to the greatest unknown hobby in the world, part 15 radio broadcasting.
Frozen Ground Plane Antenna
After several days of cold wx. and a low last night of 8 degrees the soil is now frozen (I am surprised the air isn’t frozen also).
At this moment the field strength is reading 2.35 dB above the “nominal” reference established last fall. There is a lot of moisture in the frozen soil but I can make no conclusion yet whether the freeze has an effect so this datum is just here for the record.
It was nice to note that despite the ambient being 8 degrees the outdoor transmitter and antenna are working as expected. The frequency has pulled a bit off but only by 4 Hz.
Neil
Lost in the Cold
Your weather observations are most appreciated, Radio8Z.
It is my inclination during severe weather to look out the window and hope for the best.
Today we had an unforecast snowfall close to 1-inch, and I am IMAGINING that the signals from my transmitters are slamming out farther than usual, but I am not putting footprints in the snow to find out.
As far as air is concerned, what is it again? A gas? Why is it invisible? Can it be frozen at any temperature? Can it be made visible at a certain temperature? What impedance does it have to radio frequencies? Does it have a resonant frequency of its own? Is it alive?
Coldness is another interesting thing. What is it made out of?
Unknown Variances
Since obtaining a spectrum analyzer (SA) to view the signal peaks of the various transmitters, one thing has tended to be true.
As long as nothing is physically changed or moved, the spectrum peaks of each signal tend to remain constant regardless of day, night, cold or warm.
That is until the past few days when I noticed the AMT5000 peak, which had been steady at 50dBm on the spectrum analyzer (SA), was suddenly very low at 36dBm.
The transmitter is 36-feet apart from the SA.
The antenna consists of a 2.5-foot wire from the inside baseboard vertically to the aluminum window, the length of the window, and an attached wire on top outdoors for a total of 10-feet.
There had been a strong rain, then a dip to 8-degrees Fahrenheit, about the time the signal strength appeared to be down.
Yet outside driving around the signal seemed the same as usual.
Over two days the signal on the SA returned to 50dBm where it’s remained.
Now I’m trying to understand what took place.
Signal Down
My guess is that the ice that formed was a factor. Maybe, in the past when it rained followed by a freeze the water on the window/wire outside might not have frozen due to heat leaking from inside the house but with the dip to 8 degrees it perhaps did.
It is hard to assess the signal with a car radio as being “usual” due to the AVC in the radio. If you can assess the signal to noise ratio by ear this might work.
Lowest Field Strength Yet
Overnight a heavy, wet snow fell and accumulated 6 inches on top of the loading coil cover and stuck to the antenna. The snow was piled around the base of the radiator. The signal strength is down by 5.5 dB from nominal.
I have been monitoring the gross current going to the transmitter and it usually is around 117 mA but with the snow it has fallen to 83 mA. This is rather encouraging since the current meter can be used to tell if something has gone wrong with the antenna. This current includes the draw from the PLL which is about as much as the final amplifier current but despite this the decrease was easily noticed.
Fortunately, this being a ground mounted system, it is easy to clear the snow to restore the signal.
Neil
Heaters
There are heaters that some FM stations install up on their antenna “bays” to keep ice and snow from wrecking the signal, but do we part 15 AM stations have a comparable sort of heating element that might be added to automatically deal with a snow event such as the one experienced by Radio8Z?
Another Update…High Field Strength
For the past two days the AM field strength has been relatively high reading 2.3 dB above nominal. We have had over two inches of rain in the last week and the soil is saturated and is, at present, partially frozen after an overnight temp of 21 degrees (typical March weather in Ohio).
To gather more information, the transmitter and antenna system were checked and the power into the antenna system was 86.6 mW which is fairly typical for this installation. The total antenna system impedance was measured to be 27.5 ohms <6 degrees. The loading coil resistance for RF is 18 ohms so the ground resistance is presently 9.5 ohms. Most likely it is this low ground resistance which gives the high field strength.
More to come if Spring ever gets here and the leaves come out.
Neil
Spring 13 Update
The leaves are now out on the bushes near the tx. antenna and the ground is saturated with water. A decrease in the DC current to the transmitter was noted and the antenna system performance was measured.
The phase angle between V and I has drifted to -28 degrees compared to the winter reading near zero and the power into the antenna measured 58 mW which is lower than expected.
Adjusting the L to bring the phase angle to 0 degrees raised the power to 88 mW which has been the norm for this system. The field strength is now at the nominal 0 dB reference value.
Unless there is some other factor involved it seems that the appearance of the leaves on the bushes near the antenna had a significant impact on the antenna tuning. Tuning the antenna system restored normal operation.
Neil
One Thing
I learn from Neil’s experience that as these weather related changes come and go, there is possibly a benfit to re-tuning the RF output, something I have not tended to do.
It’s time to start keeping more detailed records of transmitter performance.
Some Numbers
Based on Neil’s posts in this thread, below is a link to a table of values showing the effects of the varying amount of loss in the r-f ground connection, due to weather.
http://i62.photobucket.com/albums/h85/rfry-100/Radio8z_Antenna_Params_zps0fb365ec.jpg
Rain water is distilled water, which is a very poor conductor of
Not necessarily. Acid rain comes to mind.
Weather Influence
My three antenna systems float around quite a bit as weather conditions change.
Two of them are facing both indoors and out, using metal window frames as a major part of the radiating element, and the peaks seen on the spectrum analyzer go high and low over periods of time as the conditions change.
Much the same thing happens with the carrier current system, although the components are different, amounting to grounding rods, electric lines and the big transformer on the pole.
As of yet I’ve made not attempt to understand what is taking place, but seeing the changes does open the door on more critical observation in the future.
Today we got a deep carpet of wet snow which may still be in progress.
Wow. This is really interesting.
I seem to remember a similar
study done long long ago – with
the long wave Part 15 people on
160 to 190 kHz…
Bruce, The Dog Radio Group