Re: Topband: Salt-Water QTH
Congrats! On Fri, May 8, 2015 at 5:58 PM, Ray Higgins (W2RE) < w...@hudsonvalleytowers.com> wrote: > Update: > > Thanks to all the input and suggestions regarding my Salt-Water QTH post > on April 1. Your input was very valuable in making the final decision. We > had several options to choose from, since land is readily available in > Maine. After some debate with my partners on the venture, we decided to > pull the trigger on the 60+ Acre parcel with a small home, 3000’ x 1000’ > lot, located on the Ocean near the most northeast corner of the state of > Maine and Ideally nearby a small airport which will be the method of > traveling via a single engine aircraft. The deal went into contract today > and we hope to start breaking ground sometime in June/July. > > Thanks, > > Ray > W2RE.com > > > > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water QTH
I should have been more specific, the airport is several miles away. Sent from my iPhone > On May 8, 2015, at 6:25 PM, wrote: > > No issues with a tall 160m near the airport? I have both > here and had to get a permit from the FAA. My tower > is now on their air nav charts! :D) > > 73, > Charlie, N0TT > > On Fri, 8 May 2015 17:58:30 -0400 "Ray Higgins (W2RE)" > writes: >> Update: >> >> Thanks to all the input and suggestions regarding my Salt-Water QTH >> post on April 1. Your input was very valuable in making the final >> decision. We had several options to choose from, since land is >> readily available in Maine. After some debate with my partners on >> the venture, we decided to pull the trigger on the 60+ Acre parcel >> with a small home, 3000’ x 1000’ lot, located on the Ocean near >> the most northeast corner of the state of Maine and Ideally nearby a >> small airport which will be the method of traveling via a single >> engine aircraft. The deal went into contract today and we hope to >> start breaking ground sometime in June/July. >> >> Thanks, >> >> Ray >> W2RE.com >> >> >> To:topband@contesting.com >> Subject:Topband: Salt-Water Qth! >> From:HVT >> Date:Wed, 1 Apr 2015 07:47:23 -0400 >> List-post: > mailto:topband@contesting.com> >> This is my first post to the Top-Band Reflector, so please excuse my >> ignorance >> if this topic has been discussed in the past. >> >> Is there any scientific data in print to prove the theory that ocean >> front >> property is better than a location inland about a mile or so on a >> ridge >> overlooking salt water for HF. I had this heated debate over the >> weekend with >> two ham friends of mine while we traveled to Maine looking at >> real-estate along >> the coast. I understand the theory that verticals literally in or on >> the water >> have a huge advantage. The debate was about how far away from the >> water does it >> become a diminishing effect. I made the claim that the Ocean-Front >> property >> would be a better location than anything inland including a location >> on a ridge >> within a mile. This heated debate went on for about 500 miles while >> we were >> driving back to NY. It was a very interesting conversation and made >> the long >> drive back much quicker! :) >> >> Additional information about the debate: >> >> In the State of Maine there is a setback regulation on shoreline >> property >> regarding structures including radio towers. To play it safe with >> the shoreline >> protective rules, the proposed array system would be setback minimum >> 500’ from >> the water or as far back as 2000'. At these distances on 80/160 >> meter will a >> vertical antenna system see any positive effects with additional >> gain from the >> salt water? >> >> What about horizontal antennas? Do they see any effects from >> Salt-Water? >> >> I'm sure I can use HFTA to model the terrain, which I have done in >> the past >> with great accuracy. However, I'm not sure if it calculates >> Salt-Water. Maybe >> it does. >> >> We are anxious to start building in Maine ASAP. Any input would be >> appreciated. >> >> Thanks, >> >> Ray W2RE >> W2RE.com >> >> _ >> Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water QTH
Update: Thanks to all the input and suggestions regarding my Salt-Water QTH post on April 1. Your input was very valuable in making the final decision. We had several options to choose from, since land is readily available in Maine. After some debate with my partners on the venture, we decided to pull the trigger on the 60+ Acre parcel with a small home, 3000’ x 1000’ lot, located on the Ocean near the most northeast corner of the state of Maine and Ideally nearby a small airport which will be the method of traveling via a single engine aircraft. The deal went into contract today and we hope to start breaking ground sometime in June/July. Thanks, Ray W2RE.com To: topband@contesting.com Subject:Topband: Salt-Water Qth! From: HVT Date: Wed, 1 Apr 2015 07:47:23 -0400 List-post: mailto:topband@contesting.com> This is my first post to the Top-Band Reflector, so please excuse my ignorance if this topic has been discussed in the past. Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. I had this heated debate over the weekend with two ham friends of mine while we traveled to Maine looking at real-estate along the coast. I understand the theory that verticals literally in or on the water have a huge advantage. The debate was about how far away from the water does it become a diminishing effect. I made the claim that the Ocean-Front property would be a better location than anything inland including a location on a ridge within a mile. This heated debate went on for about 500 miles while we were driving back to NY. It was a very interesting conversation and made the long drive back much quicker! :) Additional information about the debate: In the State of Maine there is a setback regulation on shoreline property regarding structures including radio towers. To play it safe with the shoreline protective rules, the proposed array system would be setback minimum 500’ from the water or as far back as 2000'. At these distances on 80/160 meter will a vertical antenna system see any positive effects with additional gain from the salt water? What about horizontal antennas? Do they see any effects from Salt-Water? I'm sure I can use HFTA to model the terrain, which I have done in the past with great accuracy. However, I'm not sure if it calculates Salt-Water. Maybe it does. We are anxious to start building in Maine ASAP. Any input would be appreciated. Thanks, Ray W2RE W2RE.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
While reading this thread, the concept of purchasing the Radio Caroline ship came to mind several times. It would probably be cheaper than the land, if it is still available. :) 73 Art NK8X On Fri, Apr 3, 2015 at 5:39 PM, N2TK, Tony wrote: > And it is very close to a nice golf course > N2TK, Tony > > -Original Message- > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of > donov...@starpower.net > Sent: Wednesday, April 01, 2015 1:04 PM > To: topband@contesting.com > Subject: Re: Topband: Salt-Water Qth! > > Hi Paul, > > Its the perfect location for a Topband 4-square array! > It would be even better if the array were in the marsh... > > Marshland Road, > Hilton Head Island > > > https://www.google.com/maps/place/32%C2%B012%2701.0%22N+80%C2%B043%2727.0%22 > W/@32.1999078,-80.7241131,234m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0 > <https://www.google.com/maps/place/32%C2%B012%2701.0%22N+80%C2%B043%2727.0%22W/@32.1999078,-80.7241131,234m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0> > > Is there a Marshland Road on the Maine coast? > > 73 > Frank > W3LPL > > - Original Message - > > From: "Paul Christensen" > To: topband@contesting.com > Sent: Wednesday, April 1, 2015 5:32:23 PM > Subject: Re: Topband: Salt-Water Qth! > > Rich, > > Have a look at 1KW 1130 AM on Hilton Head Island, SC (WHHW-AM). At 12 noon > on any day, I can easily ride that signal down the Space Coast of FL and > about 10 miles inland. That's the entire coast of GA, part of SC and half > of > FL. > > Paul, W9AC > > -Original Message- > From: Richard Fry > Sent: Wednesday, April 01, 2015 9:42 AM > To: HVT ; topband@contesting.com > Subject: Re: Topband: Salt-Water Qth! > > Below is a link to the groundwave field of a 1 kW non-directional AM > broadcast station located about 1 mile from the Atlantic, in Florida. > > The groundwave field shown is based on the FCC M3 conductivity map, and > their GW propagation charts for this frequency and power. > > The space wave fields radiated by vertical monopoles are related to their > groundwave fields, so space wave fields radiated over (mostly) salt-water > paths are much greater in magnitude than over terra firma (other things > equal). > > Maybe this will give a rough idea of what to expect from a sea-coast QTH in > Maine. > > R. Fry > > http://s20.postimg.org/ylw4y5vn1/WMFJ_1_k_W_1450_k_Hz_Pt_Orange_FL.jpg > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
And it is very close to a nice golf course N2TK, Tony -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of donov...@starpower.net Sent: Wednesday, April 01, 2015 1:04 PM To: topband@contesting.com Subject: Re: Topband: Salt-Water Qth! Hi Paul, Its the perfect location for a Topband 4-square array! It would be even better if the array were in the marsh... Marshland Road, Hilton Head Island https://www.google.com/maps/place/32%C2%B012%2701.0%22N+80%C2%B043%2727.0%22 W/@32.1999078,-80.7241131,234m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0 Is there a Marshland Road on the Maine coast? 73 Frank W3LPL - Original Message - From: "Paul Christensen" To: topband@contesting.com Sent: Wednesday, April 1, 2015 5:32:23 PM Subject: Re: Topband: Salt-Water Qth! Rich, Have a look at 1KW 1130 AM on Hilton Head Island, SC (WHHW-AM). At 12 noon on any day, I can easily ride that signal down the Space Coast of FL and about 10 miles inland. That's the entire coast of GA, part of SC and half of FL. Paul, W9AC -Original Message- From: Richard Fry Sent: Wednesday, April 01, 2015 9:42 AM To: HVT ; topband@contesting.com Subject: Re: Topband: Salt-Water Qth! Below is a link to the groundwave field of a 1 kW non-directional AM broadcast station located about 1 mile from the Atlantic, in Florida. The groundwave field shown is based on the FCC M3 conductivity map, and their GW propagation charts for this frequency and power. The space wave fields radiated by vertical monopoles are related to their groundwave fields, so space wave fields radiated over (mostly) salt-water paths are much greater in magnitude than over terra firma (other things equal). Maybe this will give a rough idea of what to expect from a sea-coast QTH in Maine. R. Fry http://s20.postimg.org/ylw4y5vn1/WMFJ_1_k_W_1450_k_Hz_Pt_Orange_FL.jpg _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
W3RE : Apparently you missed the references I cited for BBC Engineering reports.Apparently everyone else did also, as they've not been mentioned since. And as for only hams being aware of seaside gain, the entire MW DX community has taken that as a matter of course for a hundred years. It seems to me there has always been little cross-pollination between the MW and 160 DXers, which is a shame. MW DXers have a lot of knowledge based on the plethora of high powered transmitters all around the world operating 24 hours a day with non-changing (almost) antenna systems. Chuck > Also w...@hudsonvalleytowers.com wrote: > > >>... "Is there any scientific data in print to prove the theory that ocean > front property is better than a location inland about a mile or so on a > ridge overlooking salt water for HF. ... I understand the theory that > verticals literally in or on the water have a huge advantage."... > >> > > It is not a theory that there is a remarkable increase in MF transmission > when closely approaching saltwater waterline. It has been observed over at > least a half century by what must now be millions of observers, certainly > the vast majority not hams, observed at least since inexpensive > transistorized portable radios were available around 1960. > > > These and millions of others took these radios everywhere with them, and it > was soon common knowledge that you could hear the New York AM stations all > day long if you took the radio out over the salt water at east coast ocean > beaches as far south as Cape Hatteras. Not a bit of theory involved, just > undeniable observation. > > The wow factor of this has severely diminished since the internet, and > nobody except hams thinks that hearing NYC AM stations during the day down > the east coast is the least interesting. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
"A LID operating QRO at an excellent northeastern US sea view site with excellent antennas -- is still only a *loud* LID, who is able to cause a lot more interference and consternation than a weak LID." The above is an excellent example of "confrontational interoperability," and close to the examples of "good" and "bad' interoperability I share with my students, Guy!!! 😊 72, Jim Rodenkirch K9JWV > From: k2av@gmail.com > Date: Fri, 3 Apr 2015 15:59:39 -0400 > To: donov...@starpower.net > CC: topband@contesting.com > Subject: Topband: Salt-Water Qth! > > On Wed, Apr 1, 2015 at 12:17 PM, wrote: > > > > Its not practical to place a vertical closer than 1/4 > > wavelength of an ocean beachfront except in a temporary installation > > such as a DXpedition. > > Also w...@hudsonvalleytowers.com wrote: > > >>... "Is there any scientific data in print to prove the theory that ocean > front property is better than a location inland about a mile or so on a > ridge overlooking salt water for HF. ... I understand the theory that > verticals literally in or on the water have a huge advantage."... > >> > > It is not a theory that there is a remarkable increase in MF transmission > when closely approaching saltwater waterline. It has been observed over at > least a half century by what must now be millions of observers, certainly > the vast majority not hams, observed at least since inexpensive > transistorized portable radios were available around 1960. > > The 1960 date sticks in my mind because of a story that circulates among > Berea College alumni to this day about transistor radios scattered among > 1200 students stuck in a terribly boring required general assembly lecture. > Some 15 or 20 of these new all-the-rage radios were scattered all over the > assembly hall, and were tuned in to the 7th game of the 1960 world series > between Pittsburgh and the Yankees. Back then there were no earbuds to go > stealth. Volumes were low, but loud enough to hear without the giveaway of > the radio resting upon the ear. The winning run in the bottom of the ninth > resulted in barely suppressed cheers and moans and the cumulative uproar of > whispers mercifully brought the lecturer to a bewildered halt. We received > an outraged dressing down from the college president who, to his credit, > was the first up on the stage to figure out what was going on, and who > apparently was not a baseball fan. I won't get into why I know it was > terribly boring. But I digress... > > These and millions of others took these radios everywhere with them, and it > was soon common knowledge that you could hear the New York AM stations all > day long if you took the radio out over the salt water at east coast ocean > beaches as far south as Cape Hatteras. Not a bit of theory involved, just > undeniable observation. > > The wow factor of this has severely diminished since the internet, and > nobody except hams thinks that hearing NYC AM stations during the day down > the east coast is the least interesting. The question now is why can't the > complainer text high definition video to anywhere in the world over the > internet in five seconds or less. But transistor radios were really neat > new affordable stuff in 1960. > > The depth of the drop off walking away from the beach, the inverse of the > improvement walking toward it, exposes the answer to your question. > Whatever the theory, the fact remains of an often reported sharp change in > signals across several hundred meters, sometimes in significantly less > distance. > > The "mysteries" of near-to-ocean propagation or losses become less foggy if > one always carefully considers ground media loss in discussions. Ground > losses continue to be the "undiscovered country" of top band transmitting > antenna discussions, remarkably ignored in many discussions about 160 meter > antennas that require a counterpoise. These ignored counterpoise issues can > take back expensive amplifier gain with losses as large. > > Models depend on a monolithic uniform ground all the way to and beyond the > horizon and uniform to deep depth. Models need this to simplify computer > computations so they can run on ordinary PC's in times that are measured in > minutes rather than months or years. Accurate 160m modeling of what goes on > from 100 meters out in the water, across a sandy beach to 10 kilometers > inland cannot be accomplished with available resources and program code. > Some investigators have set up carefully at a site with antenna and serious > commercial measuring equipment, and have simply been unable to get > measurements to match a model, regardless of the ground characteristics > specified in the model. > > At the water line, the remaining difficulty at this point would be support > of a vertical. An FCP above and parallel to the water line or out over the > water would be a very efficient counterpoise and quite easy to erect with > inexpensive materials. A shortened aluminum
Re: Topband: Salt-Water Qth!
This is fascinating stuff. My 160 meter vertical is less than 2 wavelengths away from the Great Pond Bay and the salt water lagoon inside which includes a floodplain of very brackish water. This is proven my taste and by the fact that there are plenty of mangroves there. Before I knew any better I ran 1000' coax and then a 600' Beverage from on side of the salt flat muck to a post on the other using an existing series of fence posts. The results were horrible and my inland Beverages over a former hay field worked but the salt pond beverage did not. All I can say that to a moral certainty that whatever that proves it proves. Herb Schoenbohm, KV4FZ On 4/2/2015 3:59 PM, Grant Saviers wrote: Since this thread continues, I thought I would share some EZNEC Pro/4 modeling results I have submitted for publication to QEX, with a focus on "verticals on the beach" for DXpeditions. EZNEC Pro4 can segment ground along a line into two arbitrary ground properties, in my modeling 4 S/m, 80 for salt water and 0.005 S/m,13 for land. W3LPL's and other's guidance is roughly consistent my modeling of a vertical at various separations from the tide line. The brief summary of modeling results is there is significant benefit at elevation angles <20 degrees towards the salt water IF the antenna is less than 0.7 wavelengths (WL) from the tide line. The pattern is asymmetrical in azimuth as a result, favoring the salt water. The -2db azimuth pattern at 5 degrees elevation is 140 degrees wide at peak 4.5dbi gain towards the water when the vertical is 0.3 WL from the tide line, with 2 radials elevated 0.025 WL. In this case the F/B is 11 db. Around 0.45 WL from the tide line the elevation gain -2db point starts to fall below 20 degrees and continues to fall as separation is increased. Since my objective was to better understand the tradeoffs for DXpeditions, only 1 or 2 elevated radials were modeled and additional radials did not enhance seaward performance. In this case, elevating the radials helps the peak gain, about 0.15 WL is optimal.Further than 1 WL from the tide line, there is essentially no low angle gain benefit from the sea and the vertical pattern is whatever you have as ground + radials. The results for azimuth and elevation gain and pattern showed no fractional wavelength peaking, the values all smoothly trend out to more than 1 wavelength from the tideline. These are only gain results, so the seaward path may have much lower skip and/or ground wave losses. Grant KZ1W _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
On Thu, Apr 2, 2015 at 12:51 PM, Kenneth Silverman wrote: > One time in Jamaica I ran a test between two 10m verticals: one right on > the sea wall, and another 100' back and spaced about 200' apart (enough > that they shouldn't have much interaction at 10m). The vertical on the sea > wall was at least 2 S-units better than the one 100' back, and often much > more. These kinds of results are like my walkabout-on-the-beach results with my Elecraft K2/10/battery plus short antenna. I was listening during the IOTA (lots of stations) to 40m CW signals which should be low angle: Europe in early afternoon. Kenny was talking about a 10-12 dB differential. In my case, I saw variation on a given station from "569" or "559" to uncopyable in the noise. While that is as quantifiable as jello, it is a LOT of loss however fuzzy the number may be. Quite adequate to inform antenna placement decisions. If someone offered me a bucket of gold coins that someone loosely estimated at 50 to 70 pounds, I'd take it regardless of the lack of precision measurement :>) The big gorilla in the room remains invoked losses in the "ground" media, whatever it is, however close or far from the antenna, however invoked, and how to avoid same. At the beach, sand is a terrible ground media, thus transiting wonderful to awful walking out of the water up the beach. This still applies to an ocean view "cliff-side" QTH. To minimize ground loss directly underneath, push a cliff-side antenna as close to the cliff as it may be supported. For counterpoise, erect an FCP parallel to the cliff edge. The point is to get the sea water reflection, with as little ground loss penalty as possible. You can still screw up the advantage of a cliff-side QTH by not paying attention to the gorilla. A friend who has a saltwater fronting house in Florida has tried a multiband vertical at his low sea-facing wall, back ten feet from the water, and out at the end of the pier. The pier location is a clear all around winner. There is still dirt below the antenna at the wall location. Eliminate the gorilla. 73, Guy _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Below, KK9A took a snip from my web page. When I wrote that, I missed one very important point: simple trigonometry. Let's imagine a perfectly straight coastline, and we place a 160 vertical 1/2 WL back(520' for this discussion) to try and get that potential of 3 dB of gain. That "gain" is only seen for the point directly in front of the vertical - i.e. 520' away. Let's call this azimuth 0 (zero) If your target destination is 45 degrees off zero azimuth, the distance over land is 735'. Based on or tests, that could be in the -3 dB zone! If the destination is 75 degrees off zero, the distance over land is +2000'. One quickly realizes that the distance over land varies, meaning the first reflection point over water is farther away at any azimuth other than zero. And the enhancement of the salt water reflecting plane is quickly diminished. In hindsight, having the vertical as close to the water as possible (or over it), will give you better overall performance in multiple directions. And that's been the secret to our success. One time in Jamaica I ran a test between two 10m verticals: one right on the sea wall, and another 100' back and spaced about 200' apart (enough that they shouldn't have much interaction at 10m). The vertical on the sea wall was at least 2 S-units better than the one 100' back, and often much more. Going back to W3LPL';s comments, he was right on. When placing a vertical near the water, the goal is to minimize the near field loss (maximize current return), while maximizing the far field reflecting surface in multiple directions. Going to an elevated site 1 mile from the shore line will have unknown benefits. But the vertical is likely to work better than a horizontal antenna regardless. 73, Kenny K2KW Team Vertical --- I did not recall seeing tests for verticals a wavelength or more way from the sea so I checked the team vertical website and found the following: John KK9A While field testing the verticals this past summer, we decided to test the effect of the land-water boundary on the pseudo Brewster angle. Since our receive site was elevated less than 1 degree across the bay, we could see any change in the low angle energy. To our knowledge, there has not been any published tests of this kind. The goal was to see how far from the water the vertical would loose the benefit of the salt water on the pseudo Brewster angle. The tests were done with a 20m ZR vertical, and we moved the antenna away from the water in 5' steps. The water's edge was considered the reference point. As the vertical was moved back from the water, there was little change until we came close to 1/4 wavelength from the water. At that point there was a 3 dB increase in signal level! Moving farther, the received signal level dropped, indicating a loss of low angle energy. This was most significant at 1/2 wavelength from the boundary, being down about 3dB from the waters edge. Moving farther back to 3/4 wavelength, the signal picked up again, to more than 2dB enhancement from the water's edge. We could not move the antenna farther due to obstructions. During the tests, we did not believe the data, and reran the test. We also observed the same results on the second test. At the time we only had 20m antennas, so we could not confirm that enhancement was truly frequency dependent. But based on these results, more testing is warranted. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
The problem John, with that experiment is it does not tell you what is happening just above the very lowest angle. By modelling you can see that the last lobe to reduce is that contained down near the horizon. We are also interested in the content between 2 degrees up to 20+ degrees. By moving the antenna away from the sea the energy contained in that sector reduces. For example on HF the content between 3-10 degrees is all important. 73 Clive GM3POI -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of j...@kk9a.com Sent: 02 April 2015 15:00 To: topband@contesting.com Subject: Re: Topband: Salt-Water Qth! I did not recall seeing tests for verticals a wavelength or more way from the sea so I checked the team vertical website and found the following: John KK9A While field testing the verticals this past summer, we decided to test the effect of the land-water boundary on the pseudo Brewster angle. Since our receive site was elevated less than 1 degree across the bay, we could see any change in the low angle energy. To our knowledge, there has not been any published tests of this kind. The goal was to see how far from the water the vertical would loose the benefit of the salt water on the pseudo Brewster angle. The tests were done with a 20m ZR vertical, and we moved the antenna away from the water in 5' steps. The water's edge was considered the reference point. As the vertical was moved back from the water, there was little change until we came close to 1/4 wavelength from the water. At that point there was a 3 dB increase in signal level! Moving farther, the received signal level dropped, indicating a loss of low angle energy. This was most significant at 1/2 wavelength from the boundary, being down about 3dB from the waters edge. Moving farther back to 3/4 wavelength, the signal picked up again, to more than 2dB enhancement from the water's edge. We could not move the antenna farther due to obstructions. During the tests, we did not believe the data, and reran the test. We also observed the same results on the second test. At the time we only had 20m antennas, so we could not confirm that enhancement was truly frequency dependent. But based on these results, more testing is warranted. To: Subject: Re: Topband: Salt-Water Qth! From: "Ed Sawyer" Reply-to: sawye...@earthlink.net Date: Wed, 1 Apr 2015 13:13:17 -0400 The best write up and data I have seen on this subject was the "team vertical" report on test done in Jamaica back about 10 or more years ago. As I recall, the vertical signal strength to low angle DX went up "dramatically" within 2 or less wavelengths of the edge of the high water mark and maybe leveled off as "fantastic" from within 0.5 wavelength. But further and further away past 2 wavelengths, the signal strengths dropped away and had very diminishing effects. I don't recall how far back before the benefits were disappointing but that article has the answers you need. Just scale it for 160 or 80M vs their 40 - 10M data. By the way, I used a vertical as 9M6/N1UR at Layang Layang island in the Spratlys in 1998. 40 and 30M performance was "amazing" but 20 - 10 was good but not great. The vertical was placed about 100 feet from the edge of the water. So it would have been just under a wavelength on 40, just over on 30, and 2 - 3 wavelengths on 20 - 10. Ed N1UR _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
I did not recall seeing tests for verticals a wavelength or more way from the sea so I checked the team vertical website and found the following: John KK9A While field testing the verticals this past summer, we decided to test the effect of the land-water boundary on the pseudo Brewster angle. Since our receive site was elevated less than 1 degree across the bay, we could see any change in the low angle energy. To our knowledge, there has not been any published tests of this kind. The goal was to see how far from the water the vertical would loose the benefit of the salt water on the pseudo Brewster angle. The tests were done with a 20m ZR vertical, and we moved the antenna away from the water in 5' steps. The water's edge was considered the reference point. As the vertical was moved back from the water, there was little change until we came close to 1/4 wavelength from the water. At that point there was a 3 dB increase in signal level! Moving farther, the received signal level dropped, indicating a loss of low angle energy. This was most significant at 1/2 wavelength from the boundary, being down about 3dB from the waters edge. Moving farther back to 3/4 wavelength, the signal picked up again, to more than 2dB enhancement from the water's edge. We could not move the antenna farther due to obstructions. During the tests, we did not believe the data, and reran the test. We also observed the same results on the second test. At the time we only had 20m antennas, so we could not confirm that enhancement was truly frequency dependent. But based on these results, more testing is warranted. To: Subject: Re: Topband: Salt-Water Qth! From: "Ed Sawyer" Reply-to: sawye...@earthlink.net Date: Wed, 1 Apr 2015 13:13:17 -0400 The best write up and data I have seen on this subject was the "team vertical" report on test done in Jamaica back about 10 or more years ago. As I recall, the vertical signal strength to low angle DX went up "dramatically" within 2 or less wavelengths of the edge of the high water mark and maybe leveled off as "fantastic" from within 0.5 wavelength. But further and further away past 2 wavelengths, the signal strengths dropped away and had very diminishing effects. I don't recall how far back before the benefits were disappointing but that article has the answers you need. Just scale it for 160 or 80M vs their 40 - 10M data. By the way, I used a vertical as 9M6/N1UR at Layang Layang island in the Spratlys in 1998. 40 and 30M performance was "amazing" but 20 - 10 was good but not great. The vertical was placed about 100 feet from the edge of the water. So it would have been just under a wavelength on 40, just over on 30, and 2 - 3 wavelengths on 20 - 10. Ed N1UR _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Please see the articles on sea gain (from technical reports of the BBC Engineering Department), referenced by Chuck Hutton, which I believe addresses this very phenomenon. 73, Nick At 17:13 01-04-15, you wrote: As I recall, the vertical signal strength to low angle DX went up "dramatically" within 2 or less wavelengths of the edge of the high water mark and maybe leveled off as "fantastic" from within 0.5 wavelength. But further and further away past 2 wavelengths, the signal strengths dropped away and had very diminishing effects. I don't recall how far back before the benefits were disappointing but that article has the answers you need. Just scale it for 160 or 80M vs their 40 - 10M data. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Now-a-days I'm just 90% an appliance operator; lack of EE knowledge other than reading all the handbooks back in the late 70's give me today & that puts me at a disadvantage when it comes to salient salt water detail... I'm on a salt marsh, running QRP I hear 599 from people I'm in a QSO with, not a 2000's version of a QSO being: 599 73, & then onto the next call coming in where they give 599 73, ad nauseum... Actual salt water is 400' from me. I'm here to say my Tx is incredibly better than my Rx is. Gary KA1J --- This email has been checked for viruses by Avast antivirus software. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Tom, Received a lot of valuable information from very smart people today that know a lot more about this stuff than I. We can move forward with an intelligent game plan to add a well equipped station for contesting on the coast of Maine. Hope to break ground sooner than later, keep you posted as the project progresses. Thank you, Ray Higgins (W2RE) On Apr 1, 2015, at 3:35 PM, Tom W8JI wrote: >> If you're back five wavelengths from salt water or salt marsh, almost the >> entire Fresnel zone will be over land and the salt water will make >> essentially >> no improvement . That's okay if the land is salt marsh, but its very bad if >> it poor sandy soil... For a take off angle of ten degrees, the near edge of >> the Fresnel Zone is about 0.1 wavelengths from the feed point and the far >> edge is about three wavelengths away. For lower angles the far edge of >> the Fresnel Zone extends out the 5 wavelengths or more. > > For horizontally polarized antennas high above earth, typical for Yagi's and > such, saltwater under and around the antenna does not mean all that much. The > primary benefit is an unobstructed horizon and antenna height. > > As for ground conductivity, unless it is terrible, what happens out at the > first bounce back from the ionosphere has more meaning. The 40 meter signal > from here is evidence of that. > > Verticals on groundwave are a different story, as are verticals on bands with > very low wave angle propagation, where the Fresnel region phase change can > hurt low angles. > > I would worry more about the path, and especially local noise. Things that > happen very close to the antenna can be handled with copper. > > Of course if the goal is to broadcast on groundwave with vertical > polarization (the only mode that supports groundwave), a saltwater path is a > major improvement. > > 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Frank: Correct, the old house's soil was sandy on top of clay. The salt marsh has soil that is your usual black muck and is ALWAYS wet. During extreme high tides the bottom of the element actually goes below the water line. Luckily that hasn't happened often or when I need to be qrv. BUT, it means lots of maintenance keeping everything clean and no matter how much liquid insulation compound and silicon gasket maker I coat things with, they tend to corrode down there. At one point I bought a DXE 4 SQ rx system. It lasted two seasons before the insides just corroded away. I now have a K9AY that is way away from the salt marsh and tends to last longer between having to open the control box and cleaning away the salt. Don N1DG At 03:09 PM 4/1/2015, donov...@starpower.net wrote: Don's email nicely describes the lack of salt water advantage when you're just 2500 feet from the ocean or salt marsh. Perhaps Don can describe the soil characteristics at his site 1/2 mile from the ocean and at his newer ocean front QTH. I suspect his old QTH had poor sandy soil and his oceanfront QTH has soil similar to a salt marsh. 73 Frank W3LPL -- From: "Don Greenbaum" To: "Top Band Reflector" Sent: Wednesday, April 1, 2015 7:26:50 PM Subject: Re: Topband: Salt-Water Qth! In 1997 I moved from a home about 1/2 mile from the ocean to oceanfront property (I live on an inlet). I put up a hytower with a 160 wire (inverted L). This was the same antenna I had inland that I was struggling with. I just could NOT believe the difference. Instead of fighting pileups I was in and out with a contact.In 2005, I bought Titanex Vertical and my dxcc 160 total has now gone from 106 to 261. And, my Titanex has only 2 radials on it. The hytower inland had 32 radials. On 80 long path I had never heard a JA from my old QTH. I now work South East Asia easily during the winter and am at 335 countries with WAZ there. One downside, any antenna this close to the salt water CONSTANTLY needs attention due to the salt. Here are two views of it. The first view faces South. The second faces North: http://www.nookhill.com/lookingout.jpg http://www.nookhill.com/inthewoods.jpg Don N1DG >On 4/1/2015 7:47 AM, HVT wrote: > This is my first post to the Top-Band >Reflector, so please excuse my ignorance if this topic has been discussed >in the past. > > Is there any scientific data in print to prove the theory >that ocean front property is better than a location inland about a mile or >so on a ridge overlooking salt water for HF. I had this heated debate over >the weekend with two ham friends of mine while we traveled to Maine >looking at real-estate along the coast. I understand the theory that >verticals literally in or on the water have a huge advantage. The debate >was about how far away from the water does it become a diminishing effect. >I made the claim that the Ocean-Front property would be a better location >than anything inland including a location on a ridge within a mile. This >heated debate went on for about 500 miles while we were driving back to >NY. It was a very interesting conversation and made the long drive back >much quicker! :) > > Additional information about the debate: > > In the >State of Maine there is a setback regulation on shoreline property >regarding structures including radio towers. To play it safe with the >shoreline protective rules, the proposed array system would be setback >minimum 500â⢠from the water or as far back as 2000'. At these distances >on 80/160 meter will a vertical antenna system see any positive effects >with additional gain from the salt water? > > What about horizontal >antennas? Do they see any effects from Salt-Water? > > I'm sure I can use >HFTA to model the terrain, which I have done in the past with great >accuracy. However, I'm not sure if it calculates Salt-Water. Maybe it >does. > > We are anxious to start building in Maine ASAP. Any input would >be appreciated. > > Thanks, > > Ray W2RE > W2RE.com > > > Sent from my >iPhone > _ > Topband Reflector Archives - >http://www.contesting.com/_topband _ Topband Reflector >Archives - http://www.contesting.com/_topband - N1DG--Licensed since 1962 EX-WB2DND, A61AD (GUEST OP, QSL MGR), A52DG, C92DG, /VP8O, /KH4, / KH9, /BV, /VS6, /4X, /9V /A7 Webmaster: VP8O, K4M, BS7H, 3Y0X, K5K, A52A, VK0IR, 9M0C, ZK1XXP, WB2DND/KH9, BQ9P, ZL9CI 2006 inductee into the CQ Magazine DX Hall of Fame Member: NCDXF, CWops, ARRL, DDXA, YCCC AIM SKYPE: aurumtel Please consider the environment before printing this email _ Topband Reflector Archives - http://www.contesting.com/_topband -
Re: Topband: Salt-Water Qth!
If you're back five wavelengths from salt water or salt marsh, almost the entire Fresnel zone will be over land and the salt water will make essentially no improvement . That's okay if the land is salt marsh, but its very bad if it poor sandy soil... For a take off angle of ten degrees, the near edge of the Fresnel Zone is about 0.1 wavelengths from the feed point and the far edge is about three wavelengths away. For lower angles the far edge of the Fresnel Zone extends out the 5 wavelengths or more. For horizontally polarized antennas high above earth, typical for Yagi's and such, saltwater under and around the antenna does not mean all that much. The primary benefit is an unobstructed horizon and antenna height. As for ground conductivity, unless it is terrible, what happens out at the first bounce back from the ionosphere has more meaning. The 40 meter signal from here is evidence of that. Verticals on groundwave are a different story, as are verticals on bands with very low wave angle propagation, where the Fresnel region phase change can hurt low angles. I would worry more about the path, and especially local noise. Things that happen very close to the antenna can be handled with copper. Of course if the goal is to broadcast on groundwave with vertical polarization (the only mode that supports groundwave), a saltwater path is a major improvement. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Don's email nicely describes the lack of salt water advantage when you're just 2500 feet from the ocean or salt marsh. Perhaps Don can describe the soil characteristics at his site 1/2 mile from the ocean and at his newer ocean front QTH. I suspect his old QTH had poor sandy soil and his oceanfront QTH has soil similar to a salt marsh. 73 Frank W3LPL - Original Message - From: "Don Greenbaum" To: "Top Band Reflector" Sent: Wednesday, April 1, 2015 7:26:50 PM Subject: Re: Topband: Salt-Water Qth! In 1997 I moved from a home about 1/2 mile from the ocean to oceanfront property (I live on an inlet). I put up a hytower with a 160 wire (inverted L). This was the same antenna I had inland that I was struggling with. I just could NOT believe the difference. Instead of fighting pileups I was in and out with a contact. In 2005, I bought Titanex Vertical and my dxcc 160 total has now gone from 106 to 261. And, my Titanex has only 2 radials on it. The hytower inland had 32 radials. On 80 long path I had never heard a JA from my old QTH. I now work South East Asia easily during the winter and am at 335 countries with WAZ there. One downside, any antenna this close to the salt water CONSTANTLY needs attention due to the salt. Here are two views of it. The first view faces South. The second faces North: http://www.nookhill.com/lookingout.jpg http://www.nookhill.com/inthewoods.jpg Don N1DG >On 4/1/2015 7:47 AM, HVT wrote: > This is my first post to the Top-Band >Reflector, so please excuse my ignorance if this topic has been discussed >in the past. > > Is there any scientific data in print to prove the theory >that ocean front property is better than a location inland about a mile or >so on a ridge overlooking salt water for HF. I had this heated debate over >the weekend with two ham friends of mine while we traveled to Maine >looking at real-estate along the coast. I understand the theory that >verticals literally in or on the water have a huge advantage. The debate >was about how far away from the water does it become a diminishing effect. >I made the claim that the Ocean-Front property would be a better location >than anything inland including a location on a ridge within a mile. This >heated debate went on for about 500 miles while we were driving back to >NY. It was a very interesting conversation and made the long drive back >much quicker! :) > > Additional information about the debate: > > In the >State of Maine there is a setback regulation on shoreline property >regarding structures including radio towers. To play it safe with the >shoreline protective rules, the proposed array system would be setback >minimum 500’ from the water or as far back as 2000'. At these distances >on 80/160 meter will a vertical antenna system see any positive effects >with additional gain from the salt water? > > What about horizontal >antennas? Do they see any effects from Salt-Water? > > I'm sure I can use >HFTA to model the terrain, which I have done in the past with great >accuracy. However, I'm not sure if it calculates Salt-Water. Maybe it >does. > > We are anxious to start building in Maine ASAP. Any input would >be appreciated. > > Thanks, > > Ray W2RE > W2RE.com > > > Sent from my >iPhone > _ > Topband Reflector Archives - >http://www.contesting.com/_topband _ Topband Reflector >Archives - http://www.contesting.com/_topband - N1DG--Licensed since 1962 EX-WB2DND, A61AD (GUEST OP, QSL MGR), A52DG, C92DG, /VP8O, /KH4, / KH9, /BV, /VS6, /4X, /9V /A7 Webmaster: VP8O, K4M, BS7H, 3Y0X, K5K, A52A, VK0IR, 9M0C, ZK1XXP, WB2DND/KH9, BQ9P, ZL9CI 2006 inductee into the CQ Magazine DX Hall of Fame Member: NCDXF, CWops, ARRL, DDXA, YCCC AIM SKYPE: aurumtel Please consider the environment before printing this email _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Hi Ray, If you're back five wavelengths from salt water or salt marsh, almost the entire Fresnel zone will be over land and the salt water will make essentially no improvement. That's okay if the land is salt marsh, but its very bad if it poor sandy soil... For a take off angle of ten degrees, the near edge of the Fresnel Zone is about 0.1 wavelengths from the feed point and the far edge is about three wavelengths away. For lower angles the far edge of the Fresnel Zone extends out the 5 wavelengths or more. By far the best reference I've ever seen on this topic is NBS Technical Note 139 "Siting Criteria for HF Communications Centers" William F Utlaut. http://babel.hathitrust.org/cgi/pt?id=uiug.30112106608711;view=1up;seq=29 73 Frank W3LPL - Original Message - - Original Message - From: "Ray Higgins (W2RE)" To: donov...@starpower.net Cc: topband@contesting.com Sent: Wednesday, April 1, 2015 6:10:46 PM Subject: Re: Topband: Salt-Water Qth! Hi Frank, Thank you for your detailed answer. I appreciate your valuable time in responding. After a few emails and a phone call it looks like we need to be within the fresnel zone, which is five wavelengths according to the ON4UN book. Yes! I know Peter K3ZM location all too well. We put up his 190’ R25 support for his 4SQ in 30+ mph winds a few years back. Great location on a marsh about 1/4 mile from the Ocean. Thanks for the input, we looking forward to start building the contest station! :) 73, Ray W2RE On Apr 1, 2015, at 12:17 PM, donov...@starpower.net wrote: Hi Ray, Two primary factors affect sky wave signal strength from Topband verticals close to salt water: 1. ground loss in the immediate vicinity of the feed point. The feed point must be much closer than 1/4 wavelength from salt water or a salt marsh to significantly reduce ground loss. 2. ground reflection loss, especially close to the near edge of the Fresnel Zone Perhaps the most practical solution to achieving very low ground loss is to place the base of the vertical in a salt marsh such as at W1KM. There is an AM broadcast tower on a pier extending well into San Francisco Bay but this would be exceptionally difficult to duplicate in a ham installation. Its not practical to place a vertical closer than 1/4 wavelength of an ocean beachfront except in a temporary installation such as a DXpedition. Most ground reflection loss within the Fresnel Zone of a vertical with the feed point at ground level occurs within one wavelength of the feed point for low angle sky wave signals. This requires that a Topband vertical be located within several hundred feet of salt water or a salt marsh. For horizontally polarized antennas, the only significant factors are ground reflection efficiency within the Fresnel zone and blockage of the horizon by terrain. For very tall towers and very low angles, the Fresnel Zone extends out at least several miles but much closer than the horizon except in mountainous terrain that blocks the visual line of sight to the distant horizon. For horizontally polarized antennas, salt water isn't significantly more efficient for Fresnel Zone reflection than average soil on very flat terrain. Perhaps the biggest improvement for horizontal polarization at an ocean front location derives from its exceptionally flat Fresnel Zone, especially for VHF EME where the full 6 dB ground gain is very difficult to achieve over typical urban and densely populated suburban location. An exceptionally flat Fresnel Zone can be a significant improvement compared to locations where the Fresnel Zone encompasses many large buildings or any location with sharp elevation changes (greater than 1/4 wavelength) close to the near edge of the Fresnel Zone. Don't forget to consider the many serious maintenance problems of an ocean front location, not only antenna maintenance but also resolution of RFI from power lines for many miles around. K3ZM had serious RFI very efficiently propagated across the Chesapeake Bay from power lines nearly 20 miles away. This could be a significant problem in an area with power lines near the ocean. 73 Frank W3LPL - Original Message - From: "HVT" < w...@hudsonvalleytowers.com > To: topband@contesting.com Sent: Wednesday, April 1, 2015 12:47:23 PM Subject: Topband: Salt-Water Qth! This is my first post to the Top-Band Reflector, so please excuse my ignorance if this topic has been discussed in the past. Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. I had this heated debate over the weekend with two ham friends of mine while we traveled to Maine looking at real-estate along the coast. I understand the theory that verticals literally in or
Re: Topband: Salt-Water Qth!
Hi Ray, If you're back five wavelengths from salt water or salt marsh, almost the entire Fresnel zone will be over land and the salt water will make essentially no improvement . That's okay if the land is salt marsh, but its very bad if it poor sandy soil... For a take off angle of ten degrees, the near edge of the Fresnel Zone is about 0.1 wavelengths from the feed point and the far edge is about three wavelengths away. For lower angles the far edge of the Fresnel Zone extends out the 5 wavelengths or more. By far the best reference I've ever seen on this topic is 73 Frank W3LPL - Original Message - From: "Ray Higgins (W2RE)" To: donov...@starpower.net Cc: topband@contesting.com Sent: Wednesday, April 1, 2015 6:10:46 PM Subject: Re: Topband: Salt-Water Qth! Hi Frank, Thank you for your detailed answer. I appreciate your valuable time in responding. After a few emails and a phone call it looks like we need to be within the fresnel zone, which is five wavelengths according to the ON4UN book. Yes! I know Peter K3ZM location all too well. We put up his 190’ R25 support for his 4SQ in 30+ mph winds a few years back. Great location on a marsh about 1/4 mile from the Ocean. Thanks for the input, we looking forward to start building the contest station! :) 73, Ray W2RE On Apr 1, 2015, at 12:17 PM, donov...@starpower.net wrote: Hi Ray, Two primary factors affect sky wave signal strength from Topband verticals close to salt water: 1. ground loss in the immediate vicinity of the feed point. The feed point must be much closer than 1/4 wavelength from salt water or a salt marsh to significantly reduce ground loss. 2. ground reflection loss, especially close to the near edge of the Fresnel Zone Perhaps the most practical solution to achieving very low ground loss is to place the base of the vertical in a salt marsh such as at W1KM. There is an AM broadcast tower on a pier extending well into San Francisco Bay but this would be exceptionally difficult to duplicate in a ham installation. Its not practical to place a vertical closer than 1/4 wavelength of an ocean beachfront except in a temporary installation such as a DXpedition. Most ground reflection loss within the Fresnel Zone of a vertical with the feed point at ground level occurs within one wavelength of the feed point for low angle sky wave signals. This requires that a Topband vertical be located within several hundred feet of salt water or a salt marsh. For horizontally polarized antennas, the only significant factors are ground reflection efficiency within the Fresnel zone and blockage of the horizon by terrain. For very tall towers and very low angles, the Fresnel Zone extends out at least several miles but much closer than the horizon except in mountainous terrain that blocks the visual line of sight to the distant horizon. For horizontally polarized antennas, salt water isn't significantly more efficient for Fresnel Zone reflection than average soil on very flat terrain. Perhaps the biggest improvement for horizontal polarization at an ocean front location derives from its exceptionally flat Fresnel Zone, especially for VHF EME where the full 6 dB ground gain is very difficult to achieve over typical urban and densely populated suburban location. An exceptionally flat Fresnel Zone can be a significant improvement compared to locations where the Fresnel Zone encompasses many large buildings or any location with sharp elevation changes (greater than 1/4 wavelength) close to the near edge of the Fresnel Zone. Don't forget to consider the many serious maintenance problems of an ocean front location, not only antenna maintenance but also resolution of RFI from power lines for many miles around. K3ZM had serious RFI very efficiently propagated across the Chesapeake Bay from power lines nearly 20 miles away. This could be a significant problem in an area with power lines near the ocean. 73 Frank W3LPL - Original Message - From: "HVT" < w...@hudsonvalleytowers.com > To: topband@contesting.com Sent: Wednesday, April 1, 2015 12:47:23 PM Subject: Topband: Salt-Water Qth! This is my first post to the Top-Band Reflector, so please excuse my ignorance if this topic has been discussed in the past. Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. I had this heated debate over the weekend with two ham friends of mine while we traveled to Maine looking at real-estate along the coast. I understand the theory that verticals literally in or on the water have a huge advantage. The debate was about how far away from the water does it become a diminishing effect. I made the claim that the Ocean-Front property would be a better location than anythi
Re: Topband: Salt-Water Qth!
In 1997 I moved from a home about 1/2 mile from the ocean to oceanfront property (I live on an inlet). I put up a hytower with a 160 wire (inverted L). This was the same antenna I had inland that I was struggling with. I just could NOT believe the difference. Instead of fighting pileups I was in and out with a contact.In 2005, I bought Titanex Vertical and my dxcc 160 total has now gone from 106 to 261. And, my Titanex has only 2 radials on it. The hytower inland had 32 radials. On 80 long path I had never heard a JA from my old QTH. I now work South East Asia easily during the winter and am at 335 countries with WAZ there. One downside, any antenna this close to the salt water CONSTANTLY needs attention due to the salt. Here are two views of it. The first view faces South. The second faces North: http://www.nookhill.com/lookingout.jpg http://www.nookhill.com/inthewoods.jpg Don N1DG On 4/1/2015 7:47 AM, HVT wrote: > This is my first post to the Top-Band Reflector, so please excuse my ignorance if this topic has been discussed in the past. > > Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. I had this heated debate over the weekend with two ham friends of mine while we traveled to Maine looking at real-estate along the coast. I understand the theory that verticals literally in or on the water have a huge advantage. The debate was about how far away from the water does it become a diminishing effect. I made the claim that the Ocean-Front property would be a better location than anything inland including a location on a ridge within a mile. This heated debate went on for about 500 miles while we were driving back to NY. It was a very interesting conversation and made the long drive back much quicker! :) > > Additional information about the debate: > > In the State of Maine there is a setback regulation on shoreline property regarding structures including radio towers. To play it safe with the shoreline protective rules, the proposed array system would be setback minimum 500â from the water or as far back as 2000'. At these distances on 80/160 meter will a vertical antenna system see any positive effects with additional gain from the salt water? > > What about horizontal antennas? Do they see any effects from Salt-Water? > > I'm sure I can use HFTA to model the terrain, which I have done in the past with great accuracy. However, I'm not sure if it calculates Salt-Water. Maybe it does. > > We are anxious to start building in Maine ASAP. Any input would be appreciated. > > Thanks, > > Ray W2RE > W2RE.com > > > Sent from my iPhone > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband - N1DG--Licensed since 1962 EX-WB2DND, A61AD (GUEST OP, QSL MGR), A52DG, C92DG, /VP8O, /KH4, / KH9, /BV, /VS6, /4X, /9V /A7 Webmaster: VP8O, K4M, BS7H, 3Y0X, K5K, A52A, VK0IR, 9M0C, ZK1XXP, WB2DND/KH9, BQ9P, ZL9CI 2006 inductee into the CQ Magazine DX Hall of Fame Member: NCDXF, CWops, ARRL, DDXA, YCCC AIM SKYPE: aurumtel Please consider the environment before printing this email _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Some may wonder why I posted the groundwave coverage contour of an AM broadcast station as being relevant to this thread. Hams are mostly interested in the space wave radiated by an antenna system. The NEC4.2 plots linked below show how the space wave and ground wave fields launched by a vertical monopole are related to each other, over a range of r-f loss in the buried radial systems used with that monopole. Loss in that r-f ground connection directly affects the fields a vertical monopole radiates at all elevation angles below the zenith, including the horizontal plane. Space wave fields decay at a 1/r rate. Ground wave fields decay at greater than a 1/r rate due to the added propagation loss where the radiated field encounters a lossy ground plane (the Earth). The plots linked below show the fields close to the radiator, where propagation loss for the ground wave is very nearly the same as for the space wave. For long propagation paths the magnitude of the ground wave field is so low as to have no practical use. This is the condition shown by NEC and other MoM software when plotting the far-field (only) patterns of a vertical monopole over real earth, for infinitely long paths over a flat ground plane. This relationship between the space wave and ground wave fields is the reason that such ground wave field analyses are (or should be) valuable to hams. Also note that the greatest field launched by each of the systems in the graphic below always occurs in the horizontal plane -- not at some "takeoff angle" above it. R. Fry, CPBE http://s20.postimg.org/4sp4pk6zx/Elpat_Compare.jpg _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Have a look at 1KW 1130 AM on Hilton Head Island, SC (WHHW-AM). At 12 noon on any day, I can easily ride that signal down the Space Coast of FL and about 10 miles inland. That's the entire coast of GA, part of SC and half of FL. That's pretty much as shown for them (link below). Nice signal for just 1 kW. http://s20.postimg.org/3udd10j1p/WHHW_Groundwave.png R. Fry _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
You might want to take a look at some technical reports from the BBC Engineering Department. Two in particular: RA-25 titled "Influence of Ground and Sea on MF Propagation" and 1975-32 titled "LF and MF propagation : An Approximate Formula for Estimating Sea Gain". Both (and many more very interesting papers on Beverages, propagation, etc) are available online at http://www.bbc.co.uk/rd/search?Type=Publications Chuck > From: w...@hudsonvalleytowers.com > Date: Wed, 1 Apr 2015 07:47:23 -0400 > To: topband@contesting.com > Subject: Topband: Salt-Water Qth! > > This is my first post to the Top-Band Reflector, so please excuse my > ignorance if this topic has been discussed in the past. > > Is there any scientific data in print to prove the theory that ocean front > property is better than a location inland about a mile or so on a ridge > overlooking salt water for HF. I had this heated debate over the weekend with > two ham friends of mine while we traveled to Maine looking at real-estate > along the coast. I understand the theory that verticals literally in or on > the water have a huge advantage. The debate was about how far away from the > water does it become a diminishing effect. I made the claim that the > Ocean-Front property would be a better location than anything inland > including a location on a ridge within a mile. This heated debate went on for > about 500 miles while we were driving back to NY. It was a very interesting > conversation and made the long drive back much quicker! :) > > Additional information about the debate: > > In the State of Maine there is a setback regulation on shoreline property > regarding structures including radio towers. To play it safe with the > shoreline protective rules, the proposed array system would be setback > minimum 500’ from the water or as far back as 2000'. At these distances on > 80/160 meter will a vertical antenna system see any positive effects with > additional gain from the salt water? > > What about horizontal antennas? Do they see any effects from Salt-Water? > > I'm sure I can use HFTA to model the terrain, which I have done in the past > with great accuracy. However, I'm not sure if it calculates Salt-Water. Maybe > it does. > > We are anxious to start building in Maine ASAP. Any input would be > appreciated. > > Thanks, > > Ray W2RE > W2RE.com > > > Sent from my iPhone > _ > Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
The best write up and data I have seen on this subject was the "team vertical" report on test done in Jamaica back about 10 or more years ago. As I recall, the vertical signal strength to low angle DX went up "dramatically" within 2 or less wavelengths of the edge of the high water mark and maybe leveled off as "fantastic" from within 0.5 wavelength. But further and further away past 2 wavelengths, the signal strengths dropped away and had very diminishing effects. I don't recall how far back before the benefits were disappointing but that article has the answers you need. Just scale it for 160 or 80M vs their 40 - 10M data. By the way, I used a vertical as 9M6/N1UR at Layang Layang island in the Spratlys in 1998. 40 and 30M performance was "amazing" but 20 - 10 was good but not great. The vertical was placed about 100 feet from the edge of the water. So it would have been just under a wavelength on 40, just over on 30, and 2 - 3 wavelengths on 20 - 10. Ed N1UR _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Hi Frank, Thank you for your detailed answer. I appreciate your valuable time in responding. After a few emails and a phone call it looks like we need to be within the fresnel zone, which is five wavelengths according to the ON4UN book. Yes! I know Peter K3ZM location all too well. We put up his 190’ R25 support for his 4SQ in 30+ mph winds a few years back. Great location on a marsh about 1/4 mile from the Ocean. Thanks for the input, we looking forward to start building the contest station! :) 73, Ray W2RE On Apr 1, 2015, at 12:17 PM, donov...@starpower.net wrote: > Hi Ray, > > Two primary factors affect sky wave signal strength from Topband > verticals close to salt water: > > 1. ground loss in the immediate vicinity of the feed point. The feed > point must be much closer than 1/4 wavelength from salt water > or a salt marsh to significantly reduce ground loss. > > 2. ground reflection loss, especially close to the near edge of the > Fresnel Zone > > Perhaps the most practical solution to achieving very low ground loss > is to place the base of the vertical in a salt marsh such as at W1KM. > There is an AM broadcast tower on a pier extending well into San > Francisco Bay but this would be exceptionally difficult to duplicate in > a ham installation. Its not practical to place a vertical closer than 1/4 > wavelength of an ocean beachfront except in a temporary installation > such as a DXpedition. > > Most ground reflection loss within the Fresnel Zone of a vertical with > the feed point at ground level occurs within one wavelength of the feed > point for low angle sky wave signals. This requires that a Topband > vertical be located within several hundred feet of salt water or a salt > marsh. > > For horizontally polarized antennas, the only significant factors are > ground reflection efficiency within the Fresnel zone and blockage > of the horizon by terrain. For very tall towers and very low angles, > the Fresnel Zone extends out at least several miles but much closer > than the horizon except in mountainous terrain that blocks the visual > line of sight to the distant horizon. For horizontally polarized antennas, > salt water isn't significantly more efficient for Fresnel Zone reflection > than average soil on very flat terrain. > > Perhaps the biggest improvement for horizontal polarization at an ocean > front location derives from its exceptionally flat Fresnel Zone, especially > for VHF EME where the full 6 dB ground gain is very difficult to achieve > over typical urban and densely populated suburban location. An > exceptionally flat Fresnel Zone can be a significant improvement compared > to locations where the Fresnel Zone encompasses many large buildings or > any location with sharp elevation changes (greater than 1/4 wavelength) > close to the near edge of the Fresnel Zone. > > Don't forget to consider the many serious maintenance problems of an > ocean front location, not only antenna maintenance but also resolution of > RFI from power lines for many miles around. K3ZM had serious RFI > very efficiently propagated across the Chesapeake Bay from power lines > nearly 20 miles away. This could be a significant problem in an area with > power lines near the ocean. > > 73 > Frank > W3LPL > > > > > > > > > > From: "HVT" > To: topband@contesting.com > Sent: Wednesday, April 1, 2015 12:47:23 PM > Subject: Topband: Salt-Water Qth! > > This is my first post to the Top-Band Reflector, so please excuse my > ignorance if this topic has been discussed in the past. > > Is there any scientific data in print to prove the theory that ocean front > property is better than a location inland about a mile or so on a ridge > overlooking salt water for HF. I had this heated debate over the weekend with > two ham friends of mine while we traveled to Maine looking at real-estate > along the coast. I understand the theory that verticals literally in or on > the water have a huge advantage. The debate was about how far away from the > water does it become a diminishing effect. I made the claim that the > Ocean-Front property would be a better location than anything inland > including a location on a ridge within a mile. This heated debate went on for > about 500 miles while we were driving back to NY. It was a very interesting > conversation and made the long drive back much quicker! :) > > Additional information about the debate: > > In the State of Maine there is a setback regulation on shoreline property > regarding structures including radio towers. To play it safe with the > shoreline protective rules, the proposed array system would be setback > minimum 500’ from the water or as far back as 2000'. At these distances on > 80/160 meter will a vertical antenna system see any positive effects with > additional gain from the salt water? > > What about horizontal antennas? Do they see any effects from Salt-Water? > > I'm sure I
Re: Topband: Salt-Water Qth!
Hi Paul, Its the perfect location for a Topband 4-square array! It would be even better if the array were in the marsh... Marshland Road, Hilton Head Island https://www.google.com/maps/place/32%C2%B012%2701.0%22N+80%C2%B043%2727.0%22W/@32.1999078,-80.7241131,234m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0 Is there a Marshland Road on the Maine coast? 73 Frank W3LPL - Original Message - From: "Paul Christensen" To: topband@contesting.com Sent: Wednesday, April 1, 2015 5:32:23 PM Subject: Re: Topband: Salt-Water Qth! Rich, Have a look at 1KW 1130 AM on Hilton Head Island, SC (WHHW-AM). At 12 noon on any day, I can easily ride that signal down the Space Coast of FL and about 10 miles inland. That's the entire coast of GA, part of SC and half of FL. Paul, W9AC -Original Message- From: Richard Fry Sent: Wednesday, April 01, 2015 9:42 AM To: HVT ; topband@contesting.com Subject: Re: Topband: Salt-Water Qth! Below is a link to the groundwave field of a 1 kW non-directional AM broadcast station located about 1 mile from the Atlantic, in Florida. The groundwave field shown is based on the FCC M3 conductivity map, and their GW propagation charts for this frequency and power. The space wave fields radiated by vertical monopoles are related to their groundwave fields, so space wave fields radiated over (mostly) salt-water paths are much greater in magnitude than over terra firma (other things equal). Maybe this will give a rough idea of what to expect from a sea-coast QTH in Maine. R. Fry http://s20.postimg.org/ylw4y5vn1/WMFJ_1_k_W_1450_k_Hz_Pt_Orange_FL.jpg _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Rich, Have a look at 1KW 1130 AM on Hilton Head Island, SC (WHHW-AM). At 12 noon on any day, I can easily ride that signal down the Space Coast of FL and about 10 miles inland. That's the entire coast of GA, part of SC and half of FL. Paul, W9AC -Original Message- From: Richard Fry Sent: Wednesday, April 01, 2015 9:42 AM To: HVT ; topband@contesting.com Subject: Re: Topband: Salt-Water Qth! Below is a link to the groundwave field of a 1 kW non-directional AM broadcast station located about 1 mile from the Atlantic, in Florida. The groundwave field shown is based on the FCC M3 conductivity map, and their GW propagation charts for this frequency and power. The space wave fields radiated by vertical monopoles are related to their groundwave fields, so space wave fields radiated over (mostly) salt-water paths are much greater in magnitude than over terra firma (other things equal). Maybe this will give a rough idea of what to expect from a sea-coast QTH in Maine. R. Fry http://s20.postimg.org/ylw4y5vn1/WMFJ_1_k_W_1450_k_Hz_Pt_Orange_FL.jpg _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Hi Ray, Two primary factors affect sky wave signal strength from Topband verticals close to salt water: 1. ground loss in the immediate vicinity of the feed point. The feed point must be much closer than 1/4 wavelength from salt water or a salt marsh to significantly reduce ground loss. 2. ground reflection loss, especially close to the near edge of the Fresnel Zone Perhaps the most practical solution to achieving very low ground loss is to place the base of the vertical in a salt marsh such as at W1KM. There is an AM broadcast tower on a pier extending well into San Francisco Bay but this would be exceptionally difficult to duplicate in a ham installation. Its not practical to place a vertical closer than 1/4 wavelength of an ocean beachfront except in a temporary installation such as a DXpedition. Most ground reflection loss within the Fresnel Zone of a vertical with the feed point at ground level occurs within one wavelength of the feed point for low angle sky wave signals. This requires that a Topband vertical be located within several hundred feet of salt water or a salt marsh. For horizontally polarized antennas, the only significant factors are ground reflection efficiency within the Fresnel zone and blockage of the horizon by terrain. For very tall towers and very low angles, the Fresnel Zone extends out at least several miles but much closer than the horizon except in mountainous terrain that blocks the visual line of sight to the distant horizon. For horizontally polarized antennas, salt water isn't significantly more efficient for Fresnel Zone reflection than average soil on very flat terrain. Perhaps the biggest improvement for horizontal polarization at an ocean front location derives from its exceptionally flat Fresnel Zone, especially for VHF EME where the full 6 dB ground gain is very difficult to achieve over typical urban and densely populated suburban location. An exceptionally flat Fresnel Zone can be a significant improvement compared to locations where the Fresnel Zone encompasses many large buildings or any location with sharp elevation changes (greater than 1/4 wavelength) close to the near edge of the Fresnel Zone. Don't forget to consider the many serious maintenance problems of an ocean front location, not only antenna maintenance but also resolution of RFI from power lines for many miles around. K3ZM had serious RFI very efficiently propagated across the Chesapeake Bay from power lines nearly 20 miles away. This could be a significant problem in an area with power lines near the ocean. 73 Frank W3LPL - Original Message - From: "HVT" To: topband@contesting.com Sent: Wednesday, April 1, 2015 12:47:23 PM Subject: Topband: Salt-Water Qth! This is my first post to the Top-Band Reflector, so please excuse my ignorance if this topic has been discussed in the past. Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. I had this heated debate over the weekend with two ham friends of mine while we traveled to Maine looking at real-estate along the coast. I understand the theory that verticals literally in or on the water have a huge advantage. The debate was about how far away from the water does it become a diminishing effect. I made the claim that the Ocean-Front property would be a better location than anything inland including a location on a ridge within a mile. This heated debate went on for about 500 miles while we were driving back to NY. It was a very interesting conversation and made the long drive back much quicker! :) Additional information about the debate: In the State of Maine there is a setback regulation on shoreline property regarding structures including radio towers. To play it safe with the shoreline protective rules, the proposed array system would be setback minimum 500’ from the water or as far back as 2000'. At these distances on 80/160 meter will a vertical antenna system see any positive effects with additional gain from the salt water? What about horizontal antennas? Do they see any effects from Salt-Water? I'm sure I can use HFTA to model the terrain, which I have done in the past with great accuracy. However, I'm not sure if it calculates Salt-Water. Maybe it does. We are anxious to start building in Maine ASAP. Any input would be appreciated. Thanks, Ray W2RE W2RE.com Sent from my iPhone _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
"The RHR team is also expanding to the State of Maine with multiple Ocean Front Properties…. more details to follow." More local QRM from clueless remote operators. Why don't you expand on the west coast? Can anyone save us from this plague? Roger On 4/1/2015 7:47 AM, HVT wrote: This is my first post to the Top-Band Reflector, so please excuse my ignorance if this topic has been discussed in the past. Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. I had this heated debate over the weekend with two ham friends of mine while we traveled to Maine looking at real-estate along the coast. I understand the theory that verticals literally in or on the water have a huge advantage. The debate was about how far away from the water does it become a diminishing effect. I made the claim that the Ocean-Front property would be a better location than anything inland including a location on a ridge within a mile. This heated debate went on for about 500 miles while we were driving back to NY. It was a very interesting conversation and made the long drive back much quicker! :) Additional information about the debate: In the State of Maine there is a setback regulation on shoreline property regarding structures including radio towers. To play it safe with the shoreline protective rules, the proposed array system would be setback minimum 500’ from the water or as far back as 2000'. At these distances on 80/160 meter will a vertical antenna system see any positive effects with additional gain from the salt water? What about horizontal antennas? Do they see any effects from Salt-Water? I'm sure I can use HFTA to model the terrain, which I have done in the past with great accuracy. However, I'm not sure if it calculates Salt-Water. Maybe it does. We are anxious to start building in Maine ASAP. Any input would be appreciated. Thanks, Ray W2RE W2RE.com Sent from my iPhone _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
"The RHR team is also expanding to the State of Maine with multiple Ocean Front Properties…. more details to follow." More local QRM from clueless remote operators. Why don't you expand on the west coast? Can anyone save us from this plague? Roger On 4/1/2015 7:47 AM, HVT wrote: This is my first post to the Top-Band Reflector, so please excuse my ignorance if this topic has been discussed in the past. Is there any scientific data in print to prove the theory that ocean front property is better than a location inland about a mile or so on a ridge overlooking salt water for HF. I had this heated debate over the weekend with two ham friends of mine while we traveled to Maine looking at real-estate along the coast. I understand the theory that verticals literally in or on the water have a huge advantage. The debate was about how far away from the water does it become a diminishing effect. I made the claim that the Ocean-Front property would be a better location than anything inland including a location on a ridge within a mile. This heated debate went on for about 500 miles while we were driving back to NY. It was a very interesting conversation and made the long drive back much quicker! :) Additional information about the debate: In the State of Maine there is a setback regulation on shoreline property regarding structures including radio towers. To play it safe with the shoreline protective rules, the proposed array system would be setback minimum 500’ from the water or as far back as 2000'. At these distances on 80/160 meter will a vertical antenna system see any positive effects with additional gain from the salt water? What about horizontal antennas? Do they see any effects from Salt-Water? I'm sure I can use HFTA to model the terrain, which I have done in the past with great accuracy. However, I'm not sure if it calculates Salt-Water. Maybe it does. We are anxious to start building in Maine ASAP. Any input would be appreciated. Thanks, Ray W2RE W2RE.com Sent from my iPhone _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Salt-Water Qth!
Below is a link to the groundwave field of a 1 kW non-directional AM broadcast station located about 1 mile from the Atlantic, in Florida. The groundwave field shown is based on the FCC M3 conductivity map, and their GW propagation charts for this frequency and power. The space wave fields radiated by vertical monopoles are related to their groundwave fields, so space wave fields radiated over (mostly) salt-water paths are much greater in magnitude than over terra firma (other things equal). Maybe this will give a rough idea of what to expect from a sea-coast QTH in Maine. R. Fry http://s20.postimg.org/ylw4y5vn1/WMFJ_1_k_W_1450_k_Hz_Pt_Orange_FL.jpg _ Topband Reflector Archives - http://www.contesting.com/_topband
