I suppose I should offer some comments on my experiences operating from a coastal Maine QTH.
My contest station is on an island about 5 miles offshore from Portland, ME. The island is 3 miles long, about a half-mile wide, and lies along a line that runs pretty much NE-SW. My house is at the NE end of the island. I do not own the land down to the water, so my antennas are not right on the beach. My 160 antenna is a two-element array of quarter-wave-spaced inverted-Ls, each about 60 feet vertical and the rest sloping up to the 90-foot point on my tower. The center of the array is about 300 feet from a small cliff overlooking the water, and about 400 feet from the water to the east and south. The cliff is 20-30 feet high, depending on the tides, which are about10 feet in Casco Bay. Each vertical has about 30 radials on the ground, not very symmetrical due to the property lines, and varying in length from .1 to .25 wavelengths. I stopped adding radials when the feedpoint impedance of each element stopped changing significantly. The soil is forest muck, and ranges from 0 to 3 feet of depth before hitting rock. The system is fed with a Comtek 2-element phasing box, with the addition of an extra option of 180-degree phasing to yield a bidirectional end-fire pattern. I have had good results with this antenna system and location. I am usually among the first and often the first one through pileups for DX. The Reverse Beacon Network data shows that my 160M signal stacks up well against other Northeast U.S. stations, but is not the rock-crushing 10s-of-dB louder that fans of beachfront locations would suggest. Maybe if I owned the property across the street and could put up the same array with the front element in the water I would get that magic 10s-of-dB enhancement. But I don't, and as has been pointed out, maintenance of antennas right on the water is problematic, so being "close" to the water seems to be sufficient. In the 2013 CQ160 contest, my signal in Europe was about equal to W2GD and K3ZM, (300 and 400 miles south of me and right on the water), and a few dB below VY2ZM (450 miles closer to Europe). In previous contests, K8PO, also in Maine, but 10 miles inland and about 50 miles north of my QTH has a signal that is usually comparable to mine, using a single (real) vertical and a lot more (and longer) radials. He is louder than I am to the West and SW, since I have a bit of a hill behind me and his terrain is flat over a pond in that direction. I do have one secret weapon, and that is my receiving capability. I run a two-wire Beverage back in the woods on a friendly neighbor's land (starting about 700 feet from the water, and running over mostly rocky soil) during the winter months. I very often get reports from DX stations after contests that I was the only USA station that could copy them, and from well-equipped NE USA stations telling me that they could not hear most of the stations I was working. I have a wire 4-square for 80 at about the same distance from the water as the 160 array (which would make it twice as far back in wavelengths), and it also works quite well. Maybe it would work better right on the water, but it works well enough. On 20-10, I have some stacked Yagis, and as many commenters have noted, the only benefits to a salt-water foreground for horizontally-polarized antennas are a uniform surface in the Fresnel zone and lack of obstructions. I agree with them, but those effects can be significant. A few years ago, K0DQ ran an exhaustive analysis of RBN data after the CQWW CW contest, which he operated from the QTH of WW1WW. That station, in central NH about 75 miles inland, is on a hilltop with a very nice sloping foreground towards Europe, and stacks of high antennas. On 20-10M, my Maine station had a 1-2dB advantage over the much bigger antennas at the WW1WW station. That could be due to the antennas being at heights better matched to the optimum takeoff angles that weekend. I have often joked that the tides must have been right that weekend (and conversely, any time I lose a contest, I blame it on the tides). Modeling the 20-10M Yagis with and without the presence of the cliff shows some interesting effects. The higher-angle lobes are no different in the two cases, since the lower parts of the free-space vertical pattern hit the same (average soil) medium. However, the lower-angle lobes are pulled lower by the cliff (since the first reflection point is further away), and the higher efficiency of the salt water seems to add a dB or so to those lower-angle lobes in the far-field pattern in EZNEC. I suspect that for horizontal antennas, a nice sloping foreground towards the ocean would be terrific, even if it is a mile away. I have not yet figured out how to model a sloping foreground in EZNEC, so getting the heights right for the desired angles may require some experimentation. For verticals, getting closer to the water (even if not right ON the water) works quite well, and is a good tradeoff between performance and maintainability. A 160M vertical a mile inland may not be the killer antenna that it would be at the beach, but for W2RE and Remote Ham Radio's purposes, it would be a huge step up for an operator in W6 or even W9 who wants to get a taste of East Coast Top Band operation. Ray and I had this discussion in person last week at the Maine State Convention last weekend. Maine is a good place for contesting most of the time and the low bands are a lot of fun there. At the top of the sunspot cycle, being a little closer to Europe and getting sunrise a bit earlier makes a difference. But at the bottom of the sunspot cycle, it can be frustrating to hear stations 50 miles south running stations on 10 or 15 meters when Maine is shut out. And maintaining a station in coastal Maine is a constant challenge, requiring a lot of attention to detail to contend with wind, ice, and salt corrosion. 73, Doug K1DG _________________ Topband Reflector Archives - http://www.contesting.com/_topband
