two specific saltwater AM daytime signal questions

[gar hi]

I know there are those here who know more about signal propagation than I do and I'm wondering if there's a definite answer to a couple questions I've been wondering about.

It's been my experience from my daytime AM DXing here in Florida out on barrier islands that stations within the state of Florida sure seem to have better reception out on the barrier islands than they do inland.

For example, 740 WYGM is barely audible here in Tampa but out on the beach in Dunedin, it has a very listenable signal and shares the frequency with many other stations too. In Tampa, all I get on 640 AM is the Cuban but out on the beach in Dunedin, I can get a listenable signal from WVLG The Villages as well. When I was at Daytona Beach Shores, I could get a barely audible signal from 880 WZAB way down in South Florida (Sweetwater) which is a ways inland. Also, I got a pretty good signam from 660 WORL from Altamonte Springs which is supposed to be strongly nulled in that direction.

There are more examples but what I'm saying is that being out on a barrier island surrounded by saltwater seems to enhance the signals of stations that travel from on the land. The same stations are noticeable weaker when you go back on the mainland.

My first question obviously is does saltwater intensify signals that have traveled on many miles of land like the pattern I've noticed?

To me, it would seem to defy the laws of physics but the pattern like the examples I gave sure suggest otherwise.

I also ask this because I'm determined to make a trip to the east coast of Florida again, this time with an overnight stay so I can have plenty of time for midday DXing on the beach and not be rushed like the time I went to Daytona where I could only spend around 45 minutes and then drive back.

The question I asked also ties in with the fact that between Queens NY (where WCBS and WFAN's sticks are), there's still some land the signals have to travel over (though a lot of it is coastal land with saltwater intrusion) before exiting the eastern part of North Carolina where's there's nothing but about 400 miles of saltwater between there and Daytona Beach.

My second question is if my observations about reception of inland signals from within Florida are true, that the saltwater gives them a boost, could that also apply to the area of water between North Carolina and Florida too?

I'd appreciate any possible input.

 

[davideduardo]

My first question obviously is does saltwater intensify signals that have traveled on many miles of land like the pattern I've noticed?

Saltwater does not intensify AM signals, it just does not attenuate them much.

The conductivity of salt water is 5000, while the best soil is around 30 (I'll skip the unit of measurement, mhos, as what is important is the difference). So, a station that is on land that travels over salt water to you is vastly less attenuated than the same signal traveling over land.

The worst conductivity is below 0.5. Long Island, the Coachella Valley, etc., are some very bad places. They are desert or sandbars. The best is damp loamy organic soil. THink Iowa.

On the south coast of Puerto Rico, during the datytime there are 50 or 60 coastal vicinity venezuelan stations, hundreds of miles away, that come in very clearly. Go 30 miles north over land, and not one comes in daytime. As long as there is lots of salt water, they go on for amazing distances as the signal is not attenuated by the resistence of low conductivity soil, sand or rock.

 

[cyberdad]

My first question obviously is does saltwater intensify signals that have traveled on many miles of land like the pattern I've noticed?

On the south coast of Puerto Rico, during the datytime there are 50 or 60 coastal vicinity venezuelan stations, hundreds of miles away, that come in very clearly. Go 30 miles north over land, and not one comes in daytime. As long as there is lots of salt water, they go on for amazing distances as the signal is not attenuated by the resistence of low conductivity soil, sand or rock.

As posted elsewhere, I'm in our beach getaway location about 22 miles southwest of downtown Pensacola for a couple of weeks. Ground conductivity here is terrible. Between .5 and 1. At this location, the strongest daytime signal is WWL....about 160 miles away via saltwater path. About a half dozen other New Orleans stations are also available here. Almost all of them....even the 1kw stations on 600, 800, and 990...are considerably stronger than the Pensacola stations. And I'm less than 20 miles from most of the sticks.

Yet at the Pensacola airport, about five miles inland....all of the New Orleans stations are gone (except for a substantially weakened WWL).

You can Google "ground conductivity" and be taken to a map of U.S. ground conductivity values provided on the FCC site.

 

[ddsparxx]

If you google "ground conductivity", click on images, and go to where it says "home.att.net", or just go to http://home.att.net/~optcamel/fmradio1.htm and scroll down to the bottom, you can see the ground conductivity map more clearly.

 

[gar hi]

Thanks for the replies.

While I've always understood how a atation will travel much greater distances if it's only on saltwater as compared to land, my experience like I said seemed to suggest that simply being surrounded by saltwater gave me better reception of land path stations too.

Even 560 WQAM from Miami has a noticeably better signal out at the Gulf than it does here in tampa.

If not the saltwater, what then could be the reason for better reception of land path Florida stations out on the barrier islands on the coasts as opposed to inland?

 

[nd2023]

I've been able to get WCBS 880 in Miami Beach during the day.

 

[KR4BD]

Almost all the NYC 50 KW AMers are very clear on the Outer Banks of North Carolina during the day. While vacationing there about a year ago, I was also able to hear WBZ Boston and WOKV from Jacksonville, FL at high noon... Salt water is an amazing conductor of AM band signals.

 

[ddsparxx]

I've heard those plus couple of graveyarders from southern NJ (WCMC 1230, WENJ 1450and I think WBSS 1490 was heard as well) at the Outer Banks last September. WCMC instead of Norfolk's WJOI, right on the shore.

 

[klutch00]

Almost all the NYC 50 KW AMers are very clear on the Outer Banks of North Carolina during the day. While vacationing there about a year ago, I was also able to hear WBZ Boston and WOKV from Jacksonville, FL at high noon... Salt water is an amazing conductor of AM band signals.

I remember back in 1983 going on vacation in Nags Head with my family I was able to get WNBC, WOR, WABC and WCBS. I didn't recall getting either WHN or WNEW, but I may not have been looking for them.

 

[K4WRF]

Thanks for the replies.

While I've always understood how a atation will travel much greater distances if it's only on saltwater as compared to land, my experience like I said seemed to suggest that simply being surrounded by saltwater gave me better reception of land path stations too.

Even 560 WQAM from Miami has a noticeably better signal out at the Gulf than it does here in tampa.

If not the saltwater, what then could be the reason for better reception of land path Florida stations out on the barrier islands on the coasts as opposed to inland?

Don’t think about this too much or you will get a headache.

Signal strength as it propagates from any source attenuates to the inverse of the square of the distance (1/d²), referred to as the inverse-square law. Serially to that argument, conductivity is expressed in terms of admittance (the inverse of impedance) and in units of Siemens in the case of soil or saltwater milliSiemens per meter, specifically in the range of 0.1 all the way to 5000 ms/m. The best admittance encountered over land being 40 mS/m or a little better.

Electrons are being tugged by the source from a hemispherical perspective encountering these admittances. It is easy to wrongly consider this operation from a point-to-point perspective. As the current (as in ampere) field propagates, voltage is produced and is proportionate at any given observation point to the admittance of the soil or seawater at that location. This is why an observer in some instances, may travel away from a source and suddenly see an increase in signal over a region of higher conductivity.

Even though the point source of signal origin may be over a land mass for an intermediate part of the straight-line path; reception is more subject to the admittance at the source and receiving point. Finally, the “inverse-square” law is valid in any specific admittance range 0.1 to 5000.

Okay, I’m going to bed now!

 

[gar hi]

Don’t think about this too much or you will get a headache.

This is why an observer in some instances, may travel away from a source and suddenly see an increase in signal over a region of higher conductivity.

Even though the point source of signal origin may be over a land mass for an intermediate part of the straight-line path; reception is more subject to the admittance at the source and receiving point.

So that confirms my observations of getting better reception from inland distant signals on a barrier island than back on land?




I found something that sounds like some serious DXers talking about ground wave potential.

This person talks about a daytime catch received in Newfoundland of WQAM 560 from Miami.

I had with me a Sony ICF-6500W receiver and at daytime on ground
wave I was able to clearly copy WQAM 560 kc 5 kw in Miami, FL. At the
time WQAM's single tower was out in Biscayne Bay. That was an
approximate distance of 2158 km, 3474 mi. Part of the ground wave path
in NF was over land but the signal probably skewed along and around
the coast to Signal Hill.

http://www.mail-archive.com/[email protected]/msg24696.html

It's interesting how it's mentioned the wave probably skewed along and around the coast as if it went around the land.

I've always wondered if that was the case.

For example a signal from New York that has a direct path that takes it over coastal NJ, Delaware, Virginia, and North Carolina between the transmitter in New York and a point on the east coast of Florida could possibly use the near by salt water to conduct the signal even if it's not exactly in the direct path?

 

[gar hi]

WOW!

Ever wonder what daytime AM from the mainland actually sounds like from Bermuda?

I found these audio clips posted by someone in another forum of some sample daytime DXing from Bermuda.

The first one is WNIS 790 and WTAR 850 from Norfolk, Virginia. That's 720 miles!

And WNIS is a ND 5kw station too.

http://www.wtfda.info/showthread.php?t=3599

This next one is unidentified stations on 1410 and 810.

810 is allegedly from Puerto Rico.

http://www.wtfda.info/showthread.php?t=4087

 

[davideduardo]

810 is allegedly from Puerto Rico.

810 is from Puerto Rico... the format is Oldies, two versions, one on the AM and the other on the FM, WORO.

 

[radiorob2.0]

A saltwater story.....

I purchased a GE Superadio II at a catalog store located in Wilmington, NC. My family lived up the coast along the inter-coastal waterway within view of the ocean. After adding batteries, I fired up the Superadio. At 560, there was music. The back announce was WQAM (circa 1990 they were oldies). I pulled out my other radio, a Realistic DX-440 (Sangean) and entered "560" and there was static and what might have been WQAM in the noise. It was at that point the GE Superadio II was my new favorite radio.

 

[cd637299]

It was me who posted the Bermuda stuff. I just happened to join this board when I saw the posts above. Thank you Mr. Eduardo for ID'ing the 810....dunno what you heard to verify, but I seem to recall the radio facing PR that day. (A 50kW fulltime AM without a website, too.) Anyone wanna try the 1410? Certainly *somebody* has heard this before....and sorry it did not come out better.

I myself have been to Cape Hatteras with GE Superadios II & III + Select-a-Tenna. WBZ to the north & WIOD to the south *in the daytime*, and even WWL over land!

Port Fourchon LA is a great spot too....KVNS Brownsville/XEFW Tampico to the west, WCNZ 1660 to the east (Cuba too IIRC).

cd

 

[gar hi]

I've been so interested in saltwater daytime DXing. Thanks for those audio clips!

It has to be awesome to be able to take a radio and listen for all you can get in the daytime from Bermuda.

I'm surprised you got 810 from San Juan, as their signal doesn't seem to favor that direction but it had to be from Puerto Rico because what else could it be.

How were the New York or Philly stations there?

The AM dial really lights up about 20 miles west of me out at the Gulf in central Florida.

I'm planning another trip to the east coast for some daytime DXing, probably Daytona Beach.

 

[cd637299]

The 50kW NYC's were no problem, except a very very weak WEPN 1050. WMCA as well....no ID but it had to have been them based on the programming.

Amazingly no sign of WPHT 1210, but KYW was there and a very weak WPEN. No WFIL or WIP.

I even got 3 Miami stations--560, 670 & 940, all extremely weak. Even weaker was WFTL 850 under that WTAR.

I definitely bagged WKAQ 580, so WKVM would not have been a big shock. Never heard WKVM here in s FL tho. Whatta pattern they must have.

cd

 

[gar hi]

I've gotten WKAQ 580 here in Tampa at night and that's one of many Puerto Rico stations I'll be looking for in the daytime when I'm on the east coast.

I hope I can null 580 from Orlando, though. 850 WABA looks like a possibility and there are several 5000 kw ND stations from Puerto Rico too that I'll have to make a list of. There's a station on 550 from Ponce, PR which would have been be the best chance to get due to lack of local interference on the same frequency but unfortunately the station has to cross about 50 miles of land in Puerto Rico, as Ponce is on the South side.

In Bermuda, were WCBS and WFAN noticeably any stronger than the other 50 kw stations?

Those two stations are located out in Queens on high Island and the area is surrounded by a lot of water. They are the only two that would have any possibility of making it down to the east coast of Florida in the daytime but then there's also a station on 660 near Orlando and one in South Florida on 880 that made it difficult to hear what was in the background last time I was at Daytona beach. I'm hoping my Terk AM Advantage loop can maybe help this time.

On my first daytime DXing trip at the Gulf on the west coast, I'm pretty much certain I was hearing 1030 KCTA Corpus Christi in the background of a stronger Spanish speaking station. That would be an 890 mile daytime catch.


http://www.youtube.com/watch?v=GsW21MVXM8Q

 

[BobOnTheJob]

A saltwater story.....

I purchased a GE Superadio II at a catalog store located in Wilmington, NC. My family lived up the coast along the inter-coastal waterway within view of the ocean. After adding batteries, I fired up the Superadio. At 560, there was music. The back announce was WQAM (circa 1990 they were oldies). I pulled out my other radio, a Realistic DX-440 (Sangean) and entered "560" and there was static and what might have been WQAM in the noise. It was at that point the GE Superadio II was my new favorite radio.

10-4 on that...I had a GE Superadio II with me in Nassau in 1989. 1400 from Ft Lauderdale was quite listenable there in the hotel at 183 miles. Seems that one is a dead duck about 30 miles west of FTL.

 

[drt]

I've gotten WKAQ 580 here in Tampa at night and that's one of many Puerto Rico stations I'll be looking for in the daytime when I'm on the east coast.

I hope I can null 580 from Orlando, though. 850 WABA looks like a possibility and there are several 5000 kw ND stations from Puerto Rico too that I'll have to make a list of. There's a station on 550 from Ponce, PR which would have been be the best chance to get due to lack of local interference on the same frequency but unfortunately the station has to cross about 50 miles of land in Puerto Rico, as Ponce is on the South side{/quote}

You will need to null the religious station on 550 out of Orange Park/Jacksonville to have a chance of getting the 550 out of Puerto Rico.

Also on 810; don't forget that there a station on that frequency transmittng from the northern Bahamas. Just to make things interesting or more difficult!

drt