It's time again .....
Hurricane Season 2009 is with us, or maybe more correctly, we are with it. It is the way of Nature. "We come meet it and we will go leave it", as the old people have a way of saying. This season means something different to everyone, and I may take the liberty to say, that it may not mean the exact same thing to everyone, something like fingerprint. Some of us look forward to experiencing the high winds blowing, some the water falling and ghauts running, some the calm before and after the storm, and some to the after effect, the mitigation and restoration in the wake. I believe that most of us would prefer that the weather just stayed over the sea and went away early.
There is nothing we can do about storms and hurricane, but Pray before and after. History has shown that praying can work, but it seems that we only pray for storms to come. We provide names which determine the category and intensity, and we even go so far as to suggest to Nature the quantity of storms that we will be happy to experience, and when we want them to begin. However where they begin is not where they end and somewhere in the middle we get lost, and don't know the answers to the what and where of the storms. We seem to be one set of crazy carbon units on this planet.
Now, in relation to ham radio, I believe that this season engenders an increse in ham radio activity. Radios of all brands come out of barrels, boxes, plastic bags, trunks, from under beds, from storage units and other places deemed to be safe. Antennas used to listen for weather nets range from a piece of wire stuck in the antenna socket and poked into a bottle of water on the other side of the table, to a piece of wire hanging outside a window, or running across the yard to a mango tree or a coconut tree. These modern rigs are so sensitive that even a wet finger may pick up stations. This is one group of hams who have perfected this annual routine.
There is another group of hams who take the opportunity to maintain and even replace existing antennas, and get ready to participate in the weather nets and other on-air forum, some local, and others regional, and even international. Most hams seem comfortable in using one antenna on more than one band, in some sort of multiband configuration. In my early years of ham radio I had a Mosley TA33 for 10-15-20 meters, with single band antennas for 40 and 80 meters. I am of the view that an optimized single band antenna is the way to go, especially for those of us who may be considered by others as DX, to help ourselves and those who wish to contact us.
In this part of the world, fortunately for us, even though we may have a space limitation, we do not have a restriction on erecting and installing antenna systems, yet. Some of us even have to borrow real estate from our neighbours, but that is how close we can live in this part of the world. Sometimes a neighbour can get cocky in the face of 'serious' weather with a ham having a TH7 and a 402BA on a 90-foot tower on the other side of his fence. Of course after you show them that the tower can be cranked down to 30 feet, peace reigns supreme.
One antenna per band is cool, but that may not do justice to your station, depending on your operating style, and I am speaking to the low band operation. For 10 to 20 meters the directional antenna you choose will fill your needs for local, regional and international contact, as long as you keep acquaintance with the propagation theory. This knowledge may be more critical for your low band operation, to wit, after sunset and before sunrise or after sunrise and before sunset. I do not beleive that one antenna per band will help you to get the most from your station, if you want to work the world, all the time.
An NVIS type antenna should work well for daytime contact this hurricane season. How the basic NVIS antenna compares with the G5RV, you will have to tell me, but I do not see the military using the G5RV antenna. I am not knocking on putting down the G5RV which many hams seem to have placed their hard earned dollars on. It could be that they need to read what L.B. Cebik [sk] had to say about that antenna, and maybe they could even get the better performance out of it.
Hurricane season or not, I am set up for working DX. The NVIS antenna is not my choice for working DX on 40 and 80. This may be best for local sunrise to sunset contacts up to 500 miles or so, and this covers from the South American coastline in the south to Puerto Rico in the North. DX is sunset to sunrise with contacts into North America, Africa, Europe, Asia and the Pacific, over 2000 miles away. The vertical dipole antenna is the most cost effective DX antenna that can come to a ham's rescue, given the apparent state of the global economy. In V4 we have to be creative and innovative because we do not have access to aluminum tubing in the hardware stores. At best when there is tubing it is the light domestic type and cost one arm and two legs.
So how can we build a vertical dipole for 40 meters or 80 meters without breaking the bank and without a supply of self supporting aluminun tubing? First let us see what height we need. A half wave vertical dipole for 40 meters is 468/7.1= 65.9 feet and for 80 meters is 468/3.8=123.1 feet. To be practical we will build a top and bottom loaded vertical dipole, with a vertical section of 1/8 wavelength. That puts the 40 meter vertical at 984/7.1 = 138.59/8 = 17.32 feet and the 80 meter vertical at 984/3.8 = 258.94/8 = 32.36 feet. The top and bottom loading wire for 40 is 65.9-17.32 = 48.58 feet each, and for 80 it is 123.1-32.36 = 90.64 feet each. You can also experiment with a vertical section height anywhere between 1/8 and 1/4 wavelength.
You notice that we are building a vertical dipole antenna not a grounded monopole antenna which rely on radials for its operation, because we are on a budget or maybe worst yet, we have no budget at all. Having these dimensions all we need do now is to hang that antenna which looks like a capital "I" or more like a capital "H" on the side, from something high enough so that the bottom end is off the ground, 4 feet or more above head height, at your convenience. That is all there is to it? Yes, and NO. Any type of wire can be used, even construction binding wire, but it will melt at under a kilowat. Don't ask!!! 1.5 and 2.5 wire will work great.
For those of us who want to lay out some funds, fence pipe can be substituted for the aluminum tubing. If you don't want to use the fence pipe directly, just make it into a telescoping mast and hang the wire vertical dipole off the top through a rope and pulley sytem. When the pipe is used as the antenna the top load wire is also the guy wire. If the pipe is used as a mast then three [3] guy ropes of 1/4-inch nylon from the top and from the telescoped bottom section, should be attached for support stability. If one is fortunate to have some 2x4 lumber on hand, like me, a wood mast can be fabricated to "antenna length plus 4 to 6 feet". Pretty simple, isn't it?
Even multiples of an electrical half wave at the operating frequency is used for the coax cable feedline. A solenoid balun is made by winding twenty feet of the coax feedline onto a 4.5" pvc waste water pipe, and connecting that end of the coax to the botton end of the vertical element, and the braid to the center point of the bottom load wire, the other cable end goes to the rig. Of course the top end of the vertical element is connected to the center point of the top loading wire, and we are good to go for testing, tuning and pruning, the antennas. First you do a frequency run on the antenna to determine the self resonant frequeny. Then you prune the antenna to your operating frequency if it is any different. You can be on the air in an hour, making DX contact just like anyone else, but you still have your bread in the bank making its 3% pa.
This antenna may work not just for us in V4 but for any ham on the planet. Some hams let pride stand in their way and may never get to taste the real joy. I recall a time when I did not have coax cable and had to use twin lead flex for transmission line. Did it work? Bet your life it had to. I learned how to compute the characteristic impedance of flex wire, and for telephone drop wire too. Some hams will tell you that coax cable is in short supply here. Sorry, but that is a big lie. No supply of RG213 on the island is TRUE, but not of coax cable. The cable TV company here has miles of coax cable. Every now and then they replace spans of external cable, and replace runs of internal cable too. To me coax is coax, and for my 100 watts I believe that tv cable can be a life saver.
Some hams believe that only RG213 and that family of coax cable can work for them. Sorry, they can stay there with that, but I am using my RG59 from the drum until it is finished, and I am still waiting to see anyone get a better signal report out of V4 on 40-meters and 80-meters from their vertical dipole or whatever using only 100 watts. I am not throwing or dropping any words, just making a point that my vertical dipole does not know neither does it care whether it is fed with RG213 or RG59, and I am not passing the RF through any tuner or antenna tuning gizmo. All I need to do is feed my antenna at a 75 ohm point to match my 75 ohm feedline and watch it radiate the best signal that it can.
So much for today. I hope that I may have helped someone in some small way to get closer to realizing their DX operating dream with a low cost or no cost vertical dipole antenna. If you need to talk I am only an email away, and you can also join the discussion group for more information and details on this and other vertical antennas.
So while you string up the NVIS antenna for hurricane season monitoring, remember that you can also work some DX too, with this the right antenna.
There is nothing we can do about storms and hurricane, but Pray before and after. History has shown that praying can work, but it seems that we only pray for storms to come. We provide names which determine the category and intensity, and we even go so far as to suggest to Nature the quantity of storms that we will be happy to experience, and when we want them to begin. However where they begin is not where they end and somewhere in the middle we get lost, and don't know the answers to the what and where of the storms. We seem to be one set of crazy carbon units on this planet.
Now, in relation to ham radio, I believe that this season engenders an increse in ham radio activity. Radios of all brands come out of barrels, boxes, plastic bags, trunks, from under beds, from storage units and other places deemed to be safe. Antennas used to listen for weather nets range from a piece of wire stuck in the antenna socket and poked into a bottle of water on the other side of the table, to a piece of wire hanging outside a window, or running across the yard to a mango tree or a coconut tree. These modern rigs are so sensitive that even a wet finger may pick up stations. This is one group of hams who have perfected this annual routine.
There is another group of hams who take the opportunity to maintain and even replace existing antennas, and get ready to participate in the weather nets and other on-air forum, some local, and others regional, and even international. Most hams seem comfortable in using one antenna on more than one band, in some sort of multiband configuration. In my early years of ham radio I had a Mosley TA33 for 10-15-20 meters, with single band antennas for 40 and 80 meters. I am of the view that an optimized single band antenna is the way to go, especially for those of us who may be considered by others as DX, to help ourselves and those who wish to contact us.
In this part of the world, fortunately for us, even though we may have a space limitation, we do not have a restriction on erecting and installing antenna systems, yet. Some of us even have to borrow real estate from our neighbours, but that is how close we can live in this part of the world. Sometimes a neighbour can get cocky in the face of 'serious' weather with a ham having a TH7 and a 402BA on a 90-foot tower on the other side of his fence. Of course after you show them that the tower can be cranked down to 30 feet, peace reigns supreme.
One antenna per band is cool, but that may not do justice to your station, depending on your operating style, and I am speaking to the low band operation. For 10 to 20 meters the directional antenna you choose will fill your needs for local, regional and international contact, as long as you keep acquaintance with the propagation theory. This knowledge may be more critical for your low band operation, to wit, after sunset and before sunrise or after sunrise and before sunset. I do not beleive that one antenna per band will help you to get the most from your station, if you want to work the world, all the time.
An NVIS type antenna should work well for daytime contact this hurricane season. How the basic NVIS antenna compares with the G5RV, you will have to tell me, but I do not see the military using the G5RV antenna. I am not knocking on putting down the G5RV which many hams seem to have placed their hard earned dollars on. It could be that they need to read what L.B. Cebik [sk] had to say about that antenna, and maybe they could even get the better performance out of it.
Hurricane season or not, I am set up for working DX. The NVIS antenna is not my choice for working DX on 40 and 80. This may be best for local sunrise to sunset contacts up to 500 miles or so, and this covers from the South American coastline in the south to Puerto Rico in the North. DX is sunset to sunrise with contacts into North America, Africa, Europe, Asia and the Pacific, over 2000 miles away. The vertical dipole antenna is the most cost effective DX antenna that can come to a ham's rescue, given the apparent state of the global economy. In V4 we have to be creative and innovative because we do not have access to aluminum tubing in the hardware stores. At best when there is tubing it is the light domestic type and cost one arm and two legs.
So how can we build a vertical dipole for 40 meters or 80 meters without breaking the bank and without a supply of self supporting aluminun tubing? First let us see what height we need. A half wave vertical dipole for 40 meters is 468/7.1= 65.9 feet and for 80 meters is 468/3.8=123.1 feet. To be practical we will build a top and bottom loaded vertical dipole, with a vertical section of 1/8 wavelength. That puts the 40 meter vertical at 984/7.1 = 138.59/8 = 17.32 feet and the 80 meter vertical at 984/3.8 = 258.94/8 = 32.36 feet. The top and bottom loading wire for 40 is 65.9-17.32 = 48.58 feet each, and for 80 it is 123.1-32.36 = 90.64 feet each. You can also experiment with a vertical section height anywhere between 1/8 and 1/4 wavelength.
You notice that we are building a vertical dipole antenna not a grounded monopole antenna which rely on radials for its operation, because we are on a budget or maybe worst yet, we have no budget at all. Having these dimensions all we need do now is to hang that antenna which looks like a capital "I" or more like a capital "H" on the side, from something high enough so that the bottom end is off the ground, 4 feet or more above head height, at your convenience. That is all there is to it? Yes, and NO. Any type of wire can be used, even construction binding wire, but it will melt at under a kilowat. Don't ask!!! 1.5 and 2.5 wire will work great.
For those of us who want to lay out some funds, fence pipe can be substituted for the aluminum tubing. If you don't want to use the fence pipe directly, just make it into a telescoping mast and hang the wire vertical dipole off the top through a rope and pulley sytem. When the pipe is used as the antenna the top load wire is also the guy wire. If the pipe is used as a mast then three [3] guy ropes of 1/4-inch nylon from the top and from the telescoped bottom section, should be attached for support stability. If one is fortunate to have some 2x4 lumber on hand, like me, a wood mast can be fabricated to "antenna length plus 4 to 6 feet". Pretty simple, isn't it?
Even multiples of an electrical half wave at the operating frequency is used for the coax cable feedline. A solenoid balun is made by winding twenty feet of the coax feedline onto a 4.5" pvc waste water pipe, and connecting that end of the coax to the botton end of the vertical element, and the braid to the center point of the bottom load wire, the other cable end goes to the rig. Of course the top end of the vertical element is connected to the center point of the top loading wire, and we are good to go for testing, tuning and pruning, the antennas. First you do a frequency run on the antenna to determine the self resonant frequeny. Then you prune the antenna to your operating frequency if it is any different. You can be on the air in an hour, making DX contact just like anyone else, but you still have your bread in the bank making its 3% pa.
This antenna may work not just for us in V4 but for any ham on the planet. Some hams let pride stand in their way and may never get to taste the real joy. I recall a time when I did not have coax cable and had to use twin lead flex for transmission line. Did it work? Bet your life it had to. I learned how to compute the characteristic impedance of flex wire, and for telephone drop wire too. Some hams will tell you that coax cable is in short supply here. Sorry, but that is a big lie. No supply of RG213 on the island is TRUE, but not of coax cable. The cable TV company here has miles of coax cable. Every now and then they replace spans of external cable, and replace runs of internal cable too. To me coax is coax, and for my 100 watts I believe that tv cable can be a life saver.
Some hams believe that only RG213 and that family of coax cable can work for them. Sorry, they can stay there with that, but I am using my RG59 from the drum until it is finished, and I am still waiting to see anyone get a better signal report out of V4 on 40-meters and 80-meters from their vertical dipole or whatever using only 100 watts. I am not throwing or dropping any words, just making a point that my vertical dipole does not know neither does it care whether it is fed with RG213 or RG59, and I am not passing the RF through any tuner or antenna tuning gizmo. All I need to do is feed my antenna at a 75 ohm point to match my 75 ohm feedline and watch it radiate the best signal that it can.
So much for today. I hope that I may have helped someone in some small way to get closer to realizing their DX operating dream with a low cost or no cost vertical dipole antenna. If you need to talk I am only an email away, and you can also join the discussion group for more information and details on this and other vertical antennas.
So while you string up the NVIS antenna for hurricane season monitoring, remember that you can also work some DX too, with this the right antenna.
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