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#1
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TX Distance question
Hi Folks
I have limited experience (ok almost none really) with respect to Amateur Radio outside of the 2M band. However I just recently got my code ticket & installed a radio on my sailboat. I am using a TS-50 with an automatic tuner and a long copper wire to the top of the mast (probably 50 feet or so long). My ground plane/counterpoise consists of tying the ground to a large aluminium area in the stern of the boat with a copper foil. My very first contacts were established with 2 land stations on 14300 at 100W that were about 1000 miles away. They both reported that my signal was good and that it sounded like I was "sitting right next to them". I have no idea if this was a good distance, great, or mediocre. I realize that propogation variables prevent anyone from giving a really clear answer to this question, but in general, what sort of distance should I expect to achieve? I'm trying to decide whether I need to improve my antenna ground by adding a dynaplate (costly and requies the boat to be taken from the water for installation) or whether the range I am getting is decent. Can anyone comment? Thanks |
#2
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James wrote:
I have limited experience (ok almost none really) with respect to Amateur Radio outside of the 2M band. However I just recently got my code ticket & installed a radio on my sailboat. I am using a TS-50 with an automatic tuner and a long copper wire to the top of the mast (probably 50 feet or so long). My ground plane/counterpoise consists of tying the ground to a large aluminium area in the stern of the boat with a copper foil. My very first contacts were established with 2 land stations on 14300 at 100W that were about 1000 miles away. They both reported that my signal was good and that it sounded like I was "sitting right next to them". I have no idea if this was a good distance, great, or mediocre. I realize that propogation variables prevent anyone from giving a really clear answer to this question, but in general, what sort of distance should I expect to achieve? I'm trying to decide whether I need to improve my antenna ground by adding a dynaplate (costly and requies the boat to be taken from the water for installation) or whether the range I am getting is decent. Propagation will have a HUGE effect on your distance capability. Under good conditions your station should be able to work any point on earth. On the other hand, when the 14MHz band "goes out" (which at this point in the sunspot cycle will happen pretty much every night) you'll be lucky to work 30 miles. I think the ground you describe should be more than adequate. (many land-based mobiles settle for something MUCH, MUCH worse!) You'll need lower frequencies for nighttime operation. 7MHz and 3.5MHz. The antenna *may* (or may not) be too short for effective operation on these bands. Try it, the worst that can happen is the automatic tuner will refuse to make a match. (I think you'll probably be OK on 7, 3.5 may be a problem) Good luck! -- Doug Smith W9WI Pleasant View (Nashville), TN EM66 http://www.w9wi.com |
#3
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James wrote:
I have limited experience (ok almost none really) with respect to Amateur Radio outside of the 2M band. However I just recently got my code ticket & installed a radio on my sailboat. I am using a TS-50 with an automatic tuner and a long copper wire to the top of the mast (probably 50 feet or so long). My ground plane/counterpoise consists of tying the ground to a large aluminium area in the stern of the boat with a copper foil. My very first contacts were established with 2 land stations on 14300 at 100W that were about 1000 miles away. They both reported that my signal was good and that it sounded like I was "sitting right next to them". I have no idea if this was a good distance, great, or mediocre. I realize that propogation variables prevent anyone from giving a really clear answer to this question, but in general, what sort of distance should I expect to achieve? I'm trying to decide whether I need to improve my antenna ground by adding a dynaplate (costly and requies the boat to be taken from the water for installation) or whether the range I am getting is decent. Propagation will have a HUGE effect on your distance capability. Under good conditions your station should be able to work any point on earth. On the other hand, when the 14MHz band "goes out" (which at this point in the sunspot cycle will happen pretty much every night) you'll be lucky to work 30 miles. I think the ground you describe should be more than adequate. (many land-based mobiles settle for something MUCH, MUCH worse!) You'll need lower frequencies for nighttime operation. 7MHz and 3.5MHz. The antenna *may* (or may not) be too short for effective operation on these bands. Try it, the worst that can happen is the automatic tuner will refuse to make a match. (I think you'll probably be OK on 7, 3.5 may be a problem) Good luck! -- Doug Smith W9WI Pleasant View (Nashville), TN EM66 http://www.w9wi.com |
#4
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"Bill Turner" wrote in message ... On Fri, 26 Nov 2004 10:14:46 -0500, James wrote: I'm trying to decide whether I need to improve my antenna ground by adding a dynaplate (costly and requies the boat to be taken from the water for installation) or whether the range I am getting is decent. __________________________________________________ _______ I'd say your system is working pretty well. 50 feet is too long for a 20 meter antenna, however. Your auto tuner is correcting for it, but a shorter length will actually work better, since the auto tuner won't have to introduce as much correction and therefore will have lower loss in the tuner itself. The vertical part of a ground plane antenna (which is what you have) can be determined by the formula Feet=234/Freq, or for 14.3 MHz, 16.4 feet (rounded off). The exact footage depends on variables in the immediate environment, but that should be close enough. If you have to have a 50 foot overall wire because of the height of the boat's mast, just put an egg insulator at the 16.4 foot length to break it up. For multiple bands, figure the length of each section and put egg insulators where needed, and then to change bands, just connect a jumper wire across various eggs to get the correct length. Neat, huh? :-) Also, you can't have too much ground area, within reason. More aluminum foil or copper is always better. If you have access to an SWR analyzer such as the MFJ 259, so much the better. They are highly recommended for making and troubleshooting antennas. -- 73, Bill W6WRT Bill, 50 foot is only too long if you are sticking with the resonant length situation. Which is not really necessary with his setup. In fact he probably gets better versatility with the longer length. Just an opinion. Dan/W4NTI |
#5
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"Bill Turner" wrote in message ... On Fri, 26 Nov 2004 10:14:46 -0500, James wrote: I'm trying to decide whether I need to improve my antenna ground by adding a dynaplate (costly and requies the boat to be taken from the water for installation) or whether the range I am getting is decent. __________________________________________________ _______ I'd say your system is working pretty well. 50 feet is too long for a 20 meter antenna, however. Your auto tuner is correcting for it, but a shorter length will actually work better, since the auto tuner won't have to introduce as much correction and therefore will have lower loss in the tuner itself. The vertical part of a ground plane antenna (which is what you have) can be determined by the formula Feet=234/Freq, or for 14.3 MHz, 16.4 feet (rounded off). The exact footage depends on variables in the immediate environment, but that should be close enough. If you have to have a 50 foot overall wire because of the height of the boat's mast, just put an egg insulator at the 16.4 foot length to break it up. For multiple bands, figure the length of each section and put egg insulators where needed, and then to change bands, just connect a jumper wire across various eggs to get the correct length. Neat, huh? :-) Also, you can't have too much ground area, within reason. More aluminum foil or copper is always better. If you have access to an SWR analyzer such as the MFJ 259, so much the better. They are highly recommended for making and troubleshooting antennas. -- 73, Bill W6WRT Bill, 50 foot is only too long if you are sticking with the resonant length situation. Which is not really necessary with his setup. In fact he probably gets better versatility with the longer length. Just an opinion. Dan/W4NTI |
#6
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....Keep the 50 feet, use a tuner. Quit wasting good
'worry' on tuner losses, they don't amount to enough to worry about. The 'additional' length (and that tuner) gives you access to other bands. Will it be the 'best' possible antenna? Of course not, but it'll certainly be adequate... 'Doc |
#7
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....Keep the 50 feet, use a tuner. Quit wasting good
'worry' on tuner losses, they don't amount to enough to worry about. The 'additional' length (and that tuner) gives you access to other bands. Will it be the 'best' possible antenna? Of course not, but it'll certainly be adequate... 'Doc |
#8
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'Doc wrote:
...Keep the 50 feet, use a tuner. Quit wasting good 'worry' on tuner losses, they don't amount to enough to worry about. The 'additional' length (and that tuner) gives you access to other bands. Will it be the 'best' possible antenna? Of course not, but it'll certainly be adequate... 'Doc Thanks for the feedback folks. Doc is on the right track. THe tuner works really well (way to go SGC, nice product!) and the antenna length doesn't seem to be impeding transmission distance. Furthermore, the length, although not electrically correct for all frequencies, is convenient physically for a sail boat. Glad to hear that the 1000 mile distance I attained was acceptable performance. My actual planned use is for keeping in touch with other vessels (friends) that are within a couple of thousand miles tops. Hopefully it will do the trick. Thanks for the feedback folks. Muuch appreciated. Jimmy |
#9
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'Doc wrote:
...Keep the 50 feet, use a tuner. Quit wasting good 'worry' on tuner losses, they don't amount to enough to worry about. The 'additional' length (and that tuner) gives you access to other bands. Will it be the 'best' possible antenna? Of course not, but it'll certainly be adequate... 'Doc Thanks for the feedback folks. Doc is on the right track. THe tuner works really well (way to go SGC, nice product!) and the antenna length doesn't seem to be impeding transmission distance. Furthermore, the length, although not electrically correct for all frequencies, is convenient physically for a sail boat. Glad to hear that the 1000 mile distance I attained was acceptable performance. My actual planned use is for keeping in touch with other vessels (friends) that are within a couple of thousand miles tops. Hopefully it will do the trick. Thanks for the feedback folks. Muuch appreciated. Jimmy |
#10
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"Bill Turner" wrote in message ... On Fri, 26 Nov 2004 10:14:46 -0500, James wrote: I'm trying to decide whether I need to improve my antenna ground by adding a dynaplate (costly and requies the boat to be taken from the water for installation) or whether the range I am getting is decent. __________________________________________________ _______ I'd say your system is working pretty well. 50 feet is too long for a 20 meter antenna, however. Your auto tuner is correcting for it, but a shorter length will actually work better, since the auto tuner won't have to introduce as much correction and therefore will have lower loss in the tuner itself. The vertical part of a ground plane antenna (which is what you have) can be determined by the formula Feet=234/Freq, or for 14.3 MHz, 16.4 feet (rounded off). The exact footage depends on variables in the immediate environment, but that should be close enough. If you have to have a 50 foot overall wire because of the height of the boat's mast, just put an egg insulator at the 16.4 foot length to break it up. For multiple bands, figure the length of each section and put egg insulators where needed, and then to change bands, just connect a jumper wire across various eggs to get the correct length. Neat, huh? :-) Exactly what I was going to suggest. This will be easy to do if you have a pully on the top end so you can easily drop the wire to change the shorting straps. With the 50 foot wire, I would be concerned about getting high angle radiation on 10/15/20 metters. Dog bone insulators might put less capacitive loading on the top of the disconnected section. Tam/WB2TT Also, you can't have too much ground area, within reason. More aluminum foil or copper is always better. If you have access to an SWR analyzer such as the MFJ 259, so much the better. They are highly recommended for making and troubleshooting antennas. -- 73, Bill W6WRT |
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