Re: Topband: beverage on sloping terrain
Thanks Herb and Mike Option a) will be the direction for a new reversible beverage, so hope that this terrain slopes will not affect it very much Thanks! Jorge De: Mike Waters [mailto:mikew...@gmail.com] Enviado el: sábado, 04 de abril de 2015 08:54 p.m. Para: Jorge Diez - CX6VM CC: topband Asunto: Re: Topband: beverage on sloping terrain I think they would all work, Jorge. Just keep the distance between the earth and the wire as constant as you are able to. And, of course, orient the Beverages so that they point within about 35 or 40 degrees either side of the desired DX's compass heading. 73, Mike www.w0btu.com On Sat, Apr 4, 2015 at 5:31 PM, Jorge Diez - CX6VM cx6vm.jo...@gmail.com wrote: How terrain slopes affect the performance of a beverage? For example, a 800 ft long beverage, with different ground conditions: a) ... from a height of 400 feet ASL where beverage start, at half the beverage is at a height of 300 feet ASL and begins climbing to 400 feet ASL at the end of the beverage b) ... rises from a height of 300 feet ASL where the beverage start to 400 feet ASL where the beverage finish c) ... down from a height of 400 feet ASL where the beverage start to 300 feet ASL where the beverage finish Option a) will result in a bad beverage performance? What about options b) and c)? Thanks, Jorge CX6VM/CW5W --- El software de antivirus Avast ha analizado este correo electrónico en busca de virus. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fw: verticals by the sea (long, mostly anecdotal)
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
Topband: beverage on sloping terrain
Hello How terrain slopes affect the performance of a beverage? For example, a 800 ft long beverage, with different ground conditions: a) the land at that distance of 800 feet go down and up, from a height of 400 feet ASL where beverage start, at half the beverage is at a height of 300 feet ASL and begins climbing to 400 feet ASL at the end of the beverage b) the land at that distance of 800 feet rises from a height of 300 feet ASL where the beverage start to 400 feet ASL where the beverage finish c) the land at that distance of 800 feet go down from a height of 400 feet ASL where the beverage start to 300 feet ASL where the beverage finish Option a) will result in a bad beverage performance? What about options b) and c)? Thanks, Jorge CX6VM/CW5W --- El software de antivirus Avast ha analizado este correo electrónico en busca de virus. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Verticals by the sea
This is purely anecdotal. I visited San Andres Providencia Islands twenty times between 1970 and 1990. I always operated 160 during those visits. On three occasions, at three different locations, I set up a 43 foot Minooka Special within 30 feet of the waters edge and had some radials running out into the sea. On the rest of the trips I operated from the QTH of HK0BKX, HK0DMA, HK0COP or one of the other resident Hams. They were all 2000-3000 feet inland from the sea. You can't get much further from the water because San Andres is 7.5 miles long and 1.5 miles wide. The difference in success between waters edge and a half mile inland was like night and day using the same antenna system. The seaside locations usually brought us twenty over nine reports from the US as well as Europe using 100 watts on 160. We even ran phone patches on 160, There was no satellite phone service in the earlier years. On Providencia we used a 130 foot wire from our second story room at the Aury Hotel. It ran over a salt marsh/lagoon to the second story window of a house. We warned the owner to stay away from the end of that wire. We fed it against the hotel plumbing system. It worked surprisingly well. BTW, as an aside, the telephone system between San Andres and Providencia in those days was a couple 100 watt RCA SSB rigs on 5.3 mHz feeding dipoles about 30 feet high. The islands are 50 miles apart. Carrier pidgeons would have worked better. 73, Barry _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: beverage on sloping terrain
Beverages are very forgiving to such circumstances but I would think that C would be the best choice. I have used such a Beverage in the past exactly like this and found the performance on TB to be adequate. Herb Schoenbohm, KV4FZ On 4/4/2015 6:31 PM, Jorge Diez - CX6VM wrote: Hello How terrain slopes affect the performance of a beverage? For example, a 800 ft long beverage, with different ground conditions: a) the land at that distance of 800 feet go down and up, from a height of 400 feet ASL where beverage start, at half the beverage is at a height of 300 feet ASL and begins climbing to 400 feet ASL at the end of the beverage b) the land at that distance of 800 feet rises from a height of 300 feet ASL where the beverage start to 400 feet ASL where the beverage finish c) the land at that distance of 800 feet go down from a height of 400 feet ASL where the beverage start to 300 feet ASL where the beverage finish Option a) will result in a bad beverage performance? What about options b) and c)? Thanks, Jorge CX6VM/CW5W --- El software de antivirus Avast ha analizado este correo electrónico en busca de virus. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Help requested
I know this is a bit off topic but I honestly dont know where else to go with something like this and any help would be appreciated but since it is off topic please respond via email and off reflector. I am looking for any information regarding three amateur call signs from over 100 years ago. 5XB 7ZJ 7CU apparently they are listed to the same (group) of guys Royal Mumford W3CU Bill Mumford W2CU and Hal Mumford W6CU all of whom are SK at this point. it is my goal to write an article about a legendary contact which is apparently still on the books for the longest over land QSO and it is my belief that it was made with the call 5XB. Keep in mind that all of these calls may be have been before licensing of stations which makes it very hard and probably vital that I find the information before it is lost for all times. Thanks for any help you guys may be able to provide To those of you that this message has impacted I am sorry to bring this request to this reflector but I am at a loss. Jim WA3MEJ Long Live Seal Team VI http://www.qsl.net/wa3mej/index.htm _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: beverage on sloping terrain
I think they would all work, Jorge. Just keep the distance between the earth and the wire as constant as you are able to. And, of course, orient the Beverages so that they point within about 35 or 40 degrees either side of the desired DX's compass heading. 73, Mike www.w0btu.com On Sat, Apr 4, 2015 at 5:31 PM, Jorge Diez - CX6VM cx6vm.jo...@gmail.com wrote: How terrain slopes affect the performance of a beverage? For example, a 800 ft long beverage, with different ground conditions: a) ... from a height of 400 feet ASL where beverage start, at half the beverage is at a height of 300 feet ASL and begins climbing to 400 feet ASL at the end of the beverage b) ... rises from a height of 300 feet ASL where the beverage start to 400 feet ASL where the beverage finish c) ... down from a height of 400 feet ASL where the beverage start to 300 feet ASL where the beverage finish Option a) will result in a bad beverage performance? What about options b) and c)? Thanks, Jorge CX6VM/CW5W _ Topband Reflector Archives - http://www.contesting.com/_topband
