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#1
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Dipole question
Are there any advantages and/or disadvantages to having a dipole where
the legs are at a 90-degree angle instead of straight (i.e., one leg oriented north-south; the other east/west)? -- "The graveyards are full of indispensible men." -- Charles DeGaulle |
#2
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Dipole question
On Jul 1, 7:26*am, (Padraigh ProAmerica) wrote:
Are there any advantages and/or disadvantages to having a dipole where the legs are at a 90-degree angle instead of straight (i.e., one leg oriented north-south; the other east/west)? -- "The graveyards are full of indispensible men." -- Charles DeGaulle I am a newbie in EZNEC (eznec.com) antenna modeling, but I tried it with a known-functional arrangement, a 20m dipole at 30 feet. When I rotated one leg as you described, the feed point impedance came down from 75 ohms, the resonant freq went up slightly out-of-band and the pattern was nearly circular. I dropped the antenna to 25 feet and the resonant freq came down into the band and the impedance hit 50 ohms almost on the nose. For all practical purposes, your change is close to an omni. One issue: It has a fairly high take-off angle at 48 degrees. Some people do not worry about take-off angle, the elevation angle of maximum radiation. This is because the differences are only a few dB. It takes 6 dB to make a one s-unit change, so you're not totally ruining your chances for a QSO if you're down a few. "Sal" stretching my limits |
#3
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Dipole question
On 7/1/2011 10:09 PM, Sal M. Onella wrote:
For all practical purposes, your change is close to an omni. One issue: It has a fairly high take-off angle at 48 degrees. Some people do not worry about take-off angle, the elevation angle of maximum radiation. This is because the differences are only a few dB. It takes 6 dB to make a one s-unit change, so you're not totally ruining your chances for a QSO if you're down a few. "Sal" stretching my limits Sal I can't resist. Ever been in a pileup? tom K0TAR |
#4
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Dipole question
On Jul 2, 5:38*pm, tom wrote:
On 7/1/2011 10:09 PM, Sal M. Onella wrote: For all practical purposes, your change is close to an omni. *One issue: *It has a fairly high take-off angle at 48 degrees. *Some people do not worry about take-off angle, the elevation angle of maximum radiation. *This is because the differences are only a few dB. *It takes 6 dB to make a one s-unit change, so you're not totally ruining your chances for a QSO if you're down a few. "Sal" stretching my limits Sal I can't resist. Ever been in a pileup? tom K0TAR Why, yes. I usually get crushed. I have occasionally been lucky. Do tell why you ask. Dare I guess it has something to do with an ignorant comment or two I've (probably) made about antennas and/or takeoff angle? ;-) I did mean "down a few dB," by the way, not "down a few s-units." http://www.eham.net/articles/23758 is interesting. "Sal" |
#5
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Dipole question
On 7/2/2011 9:24 PM, Sal M. Onella wrote:
Why, yes. I usually get crushed. I have occasionally been lucky. Do tell why you ask. Dare I guess it has something to do with an ignorant comment or two I've (probably) made about antennas and/or takeoff angle? ;-) I did mean "down a few dB," by the way, not "down a few s-units." http://www.eham.net/articles/23758 is interesting. "Sal" I contest occasionally. Mostly on 6m and usually as part of a team doing the ARRL QSO parties and the similar contests from other sources. It's really fun because of my center of the continent position, one hop from almost everywhere. This year's field day was a ball. I did over 200 Qs on 6m in 8 hours with 80 watts and 8dBd at 25 feet. 55% of the contacts at a 4A contest site at the time 6m finally collapsed (around 10PM local). We had to tear down at 6:30 AM due to thunderstorms. tom K0TAR |
#6
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Dipole question
On 7/2/2011 9:24 PM, Sal M. Onella wrote:
K0TAR Why, yes. I usually get crushed. I have occasionally been lucky. Do tell why you ask. Dare I guess it has something to do with an ignorant comment or two I've (probably) made about antennas and/or takeoff angle? ;-) I did mean "down a few dB," by the way, not "down a few s-units." http://www.eham.net/articles/23758 is interesting. "Sal" Still, couldn't help but ask. tom K0TAR |
#7
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Dipole question
On Jul 2, 8:07*pm, tom wrote:
On 7/2/2011 9:24 PM, Sal M. Onella wrote: K0TAR Why, yes. *I usually get crushed. * I have occasionally been lucky. Do tell why you ask. *Dare I guess it has something to do with an ignorant comment or two I've (probably) made about antennas and/or takeoff angle? *;-) I did mean "down a few dB," by the way, not "down a few s-units." http://www.eham.net/articles/23758is interesting. "Sal" Still, couldn't help but ask. * tom K0TAR No harm, no foul. "Sal" (KD6VKW) |
#8
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Dipole question
The reason I'm asking is that 'm considering putting up a 10 dipole in a
portable location. My first week with my HTX-100 mny years ago was a blast, and I've enjoyed operating ever since. Most frustration: Hearing a French Polyneasia at 10 over S9 and being unable to get through due tyo a couple of hundred Califonians (onw skip zone closed) with beam antennas and kilowatt amplifies. 25W into a dipole just couldn't cut the mustard. -- "The graveyards are full of indispensible men." -- Charles DeGaulle |
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