Daytime salt water DX question

[gar hi]

With all the interesting talk lately about receiving AM stations great distances traveling on the ocean, I was wondering if anyone here could answer a question I've been wondering about when it comes to the high conductivity of salt water.

Let's take New York stations possibly being heard down along the southeast coast. Between Miami and NYC, there's nothing but water. If you go more north along the coast, the line between NYC quickly starts to also cover the land mass of part of North Carolina.

My question is this. Is the salt water conductivity of AM that good that it could possibly circumvent around the above mentioned land areas of North Carolina that aren't too massive or will you only get a signal in a straight line as on land?

 

[Len14043]

The Great Salt Lake is about 4 times as salty as the oceans. In Utah, the graveyard stations in the SLC area can be heard easily to the Nevada border about 150 miles to the west. KSL induces receiver overload about 50 miles from their tower when listening to them across the GSL.

 

[radioman148]

Wow---we need more saltwater

 

[K4WRF]

With all the interesting talk lately about receiving AM stations great distances traveling on the ocean, I was wondering if anyone here could answer a question I've been wondering about when it comes to the high conductivity of salt water.

Let's take New York stations possibly being heard down along the southeast coast. Between Miami and NYC, there's nothing but water. If you go more north along the coast, the line between NYC quickly starts to also cover the land mass of part of North Carolina.

My question is this. Is the salt water conductivity of AM that good that it could possibly circumvent around the above mentioned land areas of North Carolina that aren't too massive or will you only get a signal in a straight line as on land?

Traveling in a straight line or ray from the signal source, the medium frequency signal will diminish according to inverse square law, frequency and a level dictated by the soil conductivity in the area. Is it a linear curve fit? Not usually unless you are in a region with where the soil conductivity is constant over a wide area like some areas of the Midwest and west.

As you pass over a land mass along the ray, the signal will drop dramatically and might even disappear, then return to greater levels than measured over land as you pass back over the sea water. Many times I have actually seen the signal strength increase over land going away from the source as a conductivity rift is crossed. In any case, the signal direction will always be back towards the source, if I understand the question.

 

[BRNout]

The Great Salt Lake is about 4 times as salty as the oceans. In Utah, the graveyard stations in the SLC area can be heard easily to the Nevada border about 150 miles to the west. KSL induces receiver overload about 50 miles from their tower when listening to them across the GSL.

I can confirm Len's statement. KSL's signal is unbelievable in that part of the Great Basin. And, beyond the lake itself, the number of dry lake beds west of the Wasatch Range permit KSL to come in quite well all day as far south as Cedar City and Enterprise; a good 260 miles from their transmitter site. I don't mean that you lose the station there, I mean that it's semi-local at that point!

As for the "graveyarders," they do come in well out to Wendover; but it's also helpful that most have little or no shared or co-channel competition during the day. So, you get a pure measure as to how far they can travel. Quite unlike most of the US, where "graveyarders" are often tightly spaced.

 

[gar hi]

As you pass over a land mass along the ray, the signal will drop dramatically and might even disappear, then return to greater levels than measured over land as you pass back over the sea water. Many times I have actually seen the signal strength increase over land going away from the source as a conductivity rift is crossed. In any case, the signal direction will always be back towards the source, if I understand the question.

Thanks for the answer. Are you saying that, for example, a signal from NYC passing over the mainland of North Carolina can lose it's strength where you will have no reception if you happen to be located inland in North Carolina but someone else along the coast in Georgia or Florida in the same direct line as the person in NC is positioned may actually be able to hear a signal on the same frequency once it then makes it's pass back out over that large area of open water?

 

[K4WRF]

As you pass over a land mass along the ray, the signal will drop dramatically and might even disappear, then return to greater levels than measured over land as you pass back over the sea water. Many times I have actually seen the signal strength increase over land going away from the source as a conductivity rift is crossed. In any case, the signal direction will always be back towards the source, if I understand the question.

Thanks for the answer. Are you saying that, for example, a signal from NYC passing over the mainland of North Carolina can lose it's strength where you will have no reception if you happen to be located inland in North Carolina but someone else along the coast in Georgia or Florida in the same direct line as the person in NC is positioned may actually be able to hear a signal on the same frequency once it then makes it's pass back out over that large area of open water?

Yes, the signal further out the ray past the land mass can reappear over or near the water.

 

[gar hi]

But if the signal in the same direct path becomes dead over land, how is it possible to become stronger again? Does that not defy the laws of physics? Think about all other kinds of signals, especially the ones traveling by wire. Don't they need a booster of specific power to increase the gain? While I clearly see how salt water is a great conductor of AM waves, I'm failing to see how the salt water itself can increase a signal that's lost power from it's point of origin.

That gets back to my original question. If a person situated just inland in North Carolina can't get a signal from a New York station while someone else in the very same path on the east coast of Florida can pick something up, is it not possible the reason could be because the high conductivity of the salt water could actually pull the signal around the small land area of eastern North Carolina kind of the same way that light can slightly bend around the curvature of the Earth?

 

[radioman148]

The Great Salt Lake is about 4 times as salty as the oceans. In Utah, the graveyard stations in the SLC area can be heard easily to the Nevada border about 150 miles to the west. KSL induces receiver overload about 50 miles from their tower when listening to them across the GSL.

I can confirm Len's statement. KSL's signal is unbelievable in that part of the Great Basin. And, beyond the lake itself, the number of dry lake beds west of the Wasatch Range permit KSL to come in quite well all day as far south as Cedar City and Enterprise; a good 260 miles from their transmitter site. I don't mean that you lose the station there, I mean that it's semi-local at that point!

As for the "graveyarders," they do come in well out to Wendover; but it's also helpful that most have little or no shared or co-channel competition during the day. So, you get a pure measure as to how far they can travel. Quite unlike most of the US, where "graveyarders" are often tightly spaced.

I remember reading that WCBS tower had a salt water ground. I think the same is true for WIOD Miami.
I wonder if the same is true for KSL or is it just their proximity to the lake?

 

[K4WRF]

But if the signal in the same direct path becomes dead over land, how is it possible to become stronger again? Does that not defy the laws of physics? Think about all other kinds of signals, especially the ones traveling by wire. Don't they need a booster of specific power to increase the gain? While I clearly see how salt water is a great conductor of AM waves, I'm failing to see how the salt water itself can increase a signal that's lost power from it's point of origin.

That gets back to my original question. If a person situated just inland in North Carolina can't get a signal from a New York station while someone else in the very same path on the east coast of Florida can pick something up, is it not possible the reason could be because the high conductivity of the salt water could actually pull the signal around the small land area of eastern North Carolina kind of the same way that light can slightly bend around the curvature of the Earth?

Electromagnetic wave propagation does seem to be in direct contravention to the laws of physics in some instances, but in reality it is based on predictable electron behavior. One must consider the source of the signal is constantly tugging at the radio aether which consist of electrons in the air, soil and water. Again, all placed in oscillation by a specific antenna system as a source.

Some medium provide better conductance than others like sea water and that is where the signal will be the strongest as it takes the path of least resistance. The orientation back to the source is fixed even if it is over the water, land path or sky-wave path. Think of it as part of its own signature and it always points back to home.

 

[Len14043]

KSL's stick is located along the SE shore of the Great Salt Lake in a marshy area which provides an excellent ground. I would be interesting to see how 50,000 KALL at 700 Khz. in SLC would do if they had a halfwave tower located in the marshy area along the shore of the GSL. I believe their power is shunted to the east to protect WLW. Interestingly, WLW came through in SLC because KALL reduces their nighttime power and is easily nulled.

 

[Len14043]

More about KSL. I usually find radio-locator's contours fairly accurate, but I believe they underestimate the ground conductivity in the Inter mountain west. In the case of KSL, I believe the purple contour is actually be where the red contour belongs - especially west of SLC. This seems to be the case with most of the Utah stations. I originally though the Utah stations appeared to get out better due to the lack of interference from other stations. However, I was surprised when KSL came in like a local 130 miles west of SLC with a small pocket transistor radio from the 60's. WHAM, fairly close in frequency to KSL was barely audible at about 75 miles from their stick. KNRS at 570 Khz in SLC actually does better than KSL to the north and south.

http://radio-locator.com/cgi-bin/pat?call=KSL&service=AM&status=L&hours=U

 

[K4WRF]

KSL's stick is located along the SE shore of the Great Salt Lake in a marshy area which provides an excellent ground. I would be interesting to see how 50,000 KALL at 700 Khz. in SLC would do if they had a halfwave tower located in the marshy area along the shore of the GSL. I believe their power is shunted to the east to protect WLW. Interestingly, WLW came through in SLC because KALL reduces their nighttime power and is easily nulled.

I wonder if there is a conductivity curve or dielectric constant for GSL? KNRS will be increasing power to 50 kW daytime later this year, that should be interesting before and after.

 

[Len14043]

Will KNRS keep their same pattern? If so, they may be able to be heard nearly border-to-border during the day. As with KSL, the contour map doesn't do their actual signal justice. They can be easily received (at least in the 90's) in Yellowstone Park in Montana, as well as Northern Arizona - well outside their blue contour.

http://radio-locator.com/cgi-bin/pat?call=KNRS&service=AM&status=L&hours=U

 

[nd2023]

So would a 50,000 watt AM station in Montauk, NY cover the entire east coast from Massachusetts to Florida? I think it would. Why hasn't anyone put an AM station there?

 

[radioman148]

So would a 50,000 watt AM station in Montauk, NY cover the entire east coast from Massachusetts to Florida? I think it would. Why hasn't anyone put an AM station there?

What frequency can they use?

 

[gar hi]

Electromagnetic wave propagation does seem to be in direct contravention to the laws of physics in some instances, but in reality it is based on predictable electron behavior. One must consider the source of the signal is constantly tugging at the radio aether which consist of electrons in the air, soil and water. Again, all placed in oscillation by a specific antenna system as a source.

Some medium provide better conductance than others like sea water and that is where the signal will be the strongest as it takes the path of least resistance. The orientation back to the source is fixed even if it is over the water, land path or sky-wave path. Think of it as part of its own signature and it always points back to home.

I guess I find it strange how you can literally get something from nothing. The path of least resistence is understood but that doesn't mean that path will also amplify the signal. The path of least resistance is the reason I wondered in the first place if the salt water could circumvent an AM signal around relatively small areas of land like the very eastern portion of North Carolina. Maybe I'm completely wrong for thinking that would happen but at least it would seem like a better of the two possible explanations, IMO.

 

[BRNout]

Will KNRS keep their same pattern? If so, they may be able to be heard nearly border-to-border during the day. As with KSL, the contour map doesn't do their actual signal justice. They can be easily received (at least in the 90's) in Yellowstone Park in Montana, as well as Northern Arizona - well outside their blue contour.

http://radio-locator.com/cgi-bin/pat?call=KNRS&service=AM&status=L&hours=U

With their low dial position, a 50 kw KNRS will have a killer daytime signal! I agree with the border to border assertion, with the possible exception of SE Utah.

As for KSL, they were about the only station that I could pick up when driving in the east-central Nevada basin and range county, and they hung in quite well. A weakened KSL can be heard during the day around St. George, Littlefield, AZ and Mesquite, NV during the day - or at least that was the case 5 years ago. That's over 300 air miles over land!

Their antenna site is a textbook location for transmission of a MW signal! Marshy, with sandy soil that's high in salt and mineral content. The only bad aspect out there is that Bonneville has to worry a bit when the lake rises during wetter climatic periods. I'll bet that they were sweating back in 1985 or so! Back then, the Tribune noted that Scotland's lake has a monster but Utah's lake IS the monster. With no natural outlet, the GSL rises and falls as the weather patterns change.

So would a 50,000 watt AM station in Montauk, NY cover the entire east coast from Massachusetts to Florida? I think it would. Why hasn't anyone put an AM station there?

Fun question. If it's on the bay side of town, near the water, then theoretically that would be a very good spot. However, Montauk Point itself would not be the best spot because the point is elevated well above the salt water. That would certainly be an interesting spot for a 50 kw clear when speaking theoretically. It certainly would travel a long way along the coast.

However, the lack of available frequencies aside, it would not be good from a business point of view. You're too far from New York City, and the signal has to travel 90 miles over the island to get there - so that market would be out. The Nassau/Suffolk market has most of it's population at the west end of the island, so the theoretical station would be too distant to do well in much of that market either (except for Riverhead and the Hamptons). You're also too far from Hartford, Providence or New Haven to be "local" in any of those markets either. The other thing I could foresee is that such a signal would die quickly inland over mainland New York, New Jersey and New England (aside from SE Conn. and southern RI). So, it would be a coastal blaster - but not so impressive inland. It would be tough to pay the electric bill on such a station.

Does anyone recall the range of WLNG back when they had the 1600 kHz signal? Their tx site wasn't too far from where we're talking about. I seem to recall that it wasn't all that impressive, but I also don't remember the wattage that they were alotted. You could pick them up weakly in Westerly, RI and along the CT coast but they had a much shorter range than 92.1 did/does.

 

[radioman148]

How about a 50KW station on the eastern most tip of Cape Cod? That would have a killer coastal signal & serve the Boston/Providence markets (frequency problem aside).

 

[gar hi]

It would probably get a high share too in places like the Norfolk-Virginia Beach market as well.