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#1
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20 Meter Dipole - instant DX!!!
Wonderful lesson, thank you! Now I have to learn how to match antennas &
receiving systems! : } "Radio TexMex" wrote in message ... For the last 6 months I've been using a 1/2 wave 40m dipole sloping from an oak tree in the back your to a peach tree in the front. This has worked great for 40. I use this for amateur activity as well as SWL stuff with an MFJ tuner. I always noticed that on some bands, particularly around 20 meters, I couldn't receive as well I thought was possible. The closest thing to DX I've worked was a station in Costa Rica. Well I finally got around to stringing up a simple 1/2 wave dipole with a 4:1 balun, cut just for 20 Meters. I strung one end from the same point the in the oak tree that my 40m dipole uses but I wanted to keep them angled at least 95 degrees away from each other to keep them from interacting. Because of this, I ended up sloping this fella down into the backyard between the oak and another tree and tied it off to a martin house. I was worried about the fact that I couldn't position this dipole any better away from the trees - and/or higher. I finally got a chance to try it out yesterday after all the above ground power line noise dyed down, and wouldn't you know it, ACTIVITY EVERYWHERE on 20!!! Way more than I'm use to hearing with my 40m and the tuner. The 3rd station I worked was in Serbia!!! And I can only squeeze 50 watts out of my Yaesu FT101B on 20m. Moral of this story: I've learned you can only get so much performance out of an unmatched antenna with a tuner. Cheers! - Matt |
#2
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20 Meter Dipole - instant DX!!!
In article ,
"Lisa Simpson" wrote: Wonderful lesson, thank you! Now I have to learn how to match antennas & receiving systems! : } Snip You just have to have the antenna elements the right length. -- Telamon Ventura, California |
#3
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20 Meter Dipole - instant DX!!!
"Telamon" wrote in message
... In article , "Lisa Simpson" wrote: Wonderful lesson, thank you! Now I have to learn how to match antennas & receiving systems! : } Snip You just have to have the antenna elements the right length. Which sorta implies an antenna for each frequency you wish to listen to. I don't have room for an antenna farm, so I have to make do with one (external) antenna that works for as many frequencies as possible. I currently have an Eavesdropper C attached to the side of the house, which seems to be working well, BUT I have a homemade dipole which seems to work just as well! (used with a RadioShack DX-394). So far I've logged over 200 frequencies since Christmas with the dipole, since I just hooked up the Eavesdropper today. So far I've picked up another dozen new (to me) freq's on the Eavesdropper. What I *really* need is the ability to filter receptions; I seem to now be getting a lot of multiple receptions since plugging in the Eavesdropper . . .. |
#4
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20 Meter Dipole - instant DX!!!
In article ,
"Lisa Simpson" wrote: "Telamon" wrote in message .com... In article , "Lisa Simpson" wrote: Wonderful lesson, thank you! Now I have to learn how to match antennas & receiving systems! : } Snip You just have to have the antenna elements the right length. Which sorta implies an antenna for each frequency you wish to listen to. I don't have room for an antenna farm, so I have to make do with one (external) antenna that works for as many frequencies as possible. I currently have an Eavesdropper C attached to the side of the house, which seems to be working well, BUT I have a homemade dipole which seems to work just as well! (used with a RadioShack DX-394). So far I've logged over 200 frequencies since Christmas with the dipole, since I just hooked up the Eavesdropper today. So far I've picked up another dozen new (to me) freq's on the Eavesdropper. What I *really* need is the ability to filter receptions; I seem to now be getting a lot of multiple receptions since plugging in the Eavesdropper . . Depends on the type of antenna as some are more broadband than others but for reception you get the majority of the benefit of a resonate condition for a band of frequencies. For the most part higher bands than what the antenna was cut for will be some multiple of it and still work well so generally you put up the biggest one you have room for. A dipole will not work well on a band that is 2X the one it is cut for so avoid that situation and make sure the bands fall on the odd harmonics. I'm not sure what you mean by multiple receptions? Some transmissions by a station are simulcast on several frequencies or do you mean that your radio is getting false images of some sort? If you have the false image problem than you can use a pre-selector. You tune it to the frequency of interest and other signals above and below it are reduced hopefully to the point the image is not heard. -- Telamon Ventura, California |
#5
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20 Meter Dipole - instant DX!!!
Multiple receptions; I can hear 2 sometimes more stations at a given
frequency; sorta like trying to listen to a room full of women trying to discuss something! "Telamon" wrote in message ... In article , "Lisa Simpson" wrote: "Telamon" wrote in message .com... In article , "Lisa Simpson" wrote: Wonderful lesson, thank you! Now I have to learn how to match antennas & receiving systems! : } Snip You just have to have the antenna elements the right length. Which sorta implies an antenna for each frequency you wish to listen to. I don't have room for an antenna farm, so I have to make do with one (external) antenna that works for as many frequencies as possible. I currently have an Eavesdropper C attached to the side of the house, which seems to be working well, BUT I have a homemade dipole which seems to work just as well! (used with a RadioShack DX-394). So far I've logged over 200 frequencies since Christmas with the dipole, since I just hooked up the Eavesdropper today. So far I've picked up another dozen new (to me) freq's on the Eavesdropper. What I *really* need is the ability to filter receptions; I seem to now be getting a lot of multiple receptions since plugging in the Eavesdropper . . Depends on the type of antenna as some are more broadband than others but for reception you get the majority of the benefit of a resonate condition for a band of frequencies. For the most part higher bands than what the antenna was cut for will be some multiple of it and still work well so generally you put up the biggest one you have room for. A dipole will not work well on a band that is 2X the one it is cut for so avoid that situation and make sure the bands fall on the odd harmonics. I'm not sure what you mean by multiple receptions? Some transmissions by a station are simulcast on several frequencies or do you mean that your radio is getting false images of some sort? If you have the false image problem than you can use a pre-selector. You tune it to the frequency of interest and other signals above and below it are reduced hopefully to the point the image is not heard. -- Telamon Ventura, California |
#6
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20 Meter Dipole - instant DX!!!
In article ,
"Lisa Simpson" wrote: Multiple receptions; I can hear 2 sometimes more stations at a given frequency; sorta like trying to listen to a room full of women trying to discuss something! "Telamon" wrote in message ... In article , "Lisa Simpson" wrote: "Telamon" wrote in message .com... In article , "Lisa Simpson" wrote: Wonderful lesson, thank you! Now I have to learn how to match antennas & receiving systems! : } Snip You just have to have the antenna elements the right length. Which sorta implies an antenna for each frequency you wish to listen to. I don't have room for an antenna farm, so I have to make do with one (external) antenna that works for as many frequencies as possible. I currently have an Eavesdropper C attached to the side of the house, which seems to be working well, BUT I have a homemade dipole which seems to work just as well! (used with a RadioShack DX-394). So far I've logged over 200 frequencies since Christmas with the dipole, since I just hooked up the Eavesdropper today. So far I've picked up another dozen new (to me) freq's on the Eavesdropper. What I *really* need is the ability to filter receptions; I seem to now be getting a lot of multiple receptions since plugging in the Eavesdropper . . Depends on the type of antenna as some are more broadband than others but for reception you get the majority of the benefit of a resonate condition for a band of frequencies. For the most part higher bands than what the antenna was cut for will be some multiple of it and still work well so generally you put up the biggest one you have room for. A dipole will not work well on a band that is 2X the one it is cut for so avoid that situation and make sure the bands fall on the odd harmonics. I'm not sure what you mean by multiple receptions? Some transmissions by a station are simulcast on several frequencies or do you mean that your radio is getting false images of some sort? If you have the false image problem than you can use a pre-selector. You tune it to the frequency of interest and other signals above and below it are reduced hopefully to the point the image is not heard. I think people like to term this co-channel interference when two stations broadcast on the same frequency at the same time. This happens because one station is meant for reception in your area but another station is meant for another region is making it to you at the same time. Only solution to this is a more directional antenna where the other station could be nulled out. -- Telamon Ventura, California |
#7
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20 Meter Dipole - instant DX!!!
I believe Telamon is right.Antenna should be cut to the proper lenght
according to the band you want to use. cuhulin |
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