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#1
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Hello,
I have been using single-band half-wave dipoles for years. I would like to try some multi-band wire antennas and compare performance. I am considering using an Off Center Fed Dipole or a G5RV or a Carolina Windom. Any thoughts or experiences with these antennas as compared to a half-wave dipole? Thanks & 73s, Deane WB2DCF |
#2
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On Thu, 23 Oct 2003 10:38:15 -0400, Deane Charlson
wrote: Hello, I have been using single-band half-wave dipoles for years. I would like to try some multi-band wire antennas and compare performance. I am considering using an Off Center Fed Dipole or a G5RV or a Carolina Windom. Any thoughts or experiences with these antennas as compared to a half-wave dipole? Thanks & 73s, Deane WB2DCF Hi Dean, Keep your dipole and add a tuner. There is nothing magical about other designs if their overall dimension is roughly the same as what you have now. If you want to work a lower band, try driving the shorted transmission line drop against ground (that is, short the transmission line at ground level, and drive that as a top loaded vertical, but make sure you have a modest investment in radials at that drive point for ground). There are only two things of interest with an antenna (beyond aesthetics - if that isn't a contradiction in terms): drive point impedance and launch characteristics. Impedance can often be taken care of with a tuner (with care for Hi-Z issues at half wave intervals) and launch characteristics are a function of physical size and wavelength. When it comes to size, it won't much matter what name the antenna is called (unless you are switching from vertical to horizontal); hence the advice that if those antennas you are considering are not significantly larger/smaller, then they will not be significantly better/worse. 73's Richard Clark, KB7QHC |
#3
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but make sure you have a
modest investment in radials at that drive point for ground. ================================= Good to see, along with other members of the Establishment, you've dropped Marzipan the Magician's magic number of 120 each of 1/4-or 1/2 wavelength. Stop adding radials when the added number of 1/8th or 1/10th wavelength radials produces no further increase in receiving signal strength. You're learning ! |
#4
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![]() "Deane Charlson" wrote in message ... Hello, I have been using single-band half-wave dipoles for years. I would like to try some multi-band wire antennas and compare performance. I am considering using an Off Center Fed Dipole or a G5RV or a Carolina Windom. Any thoughts or experiences with these antennas as compared to a half-wave dipole? Hi, Multiband dipole like G5RV is fine, W3DZZ also. The only difference is the feeder. But both are wires antenna and will give similar results. So think about the feeder ABout G5RV, read this : http://www.astrosurf.com/lombry/qsl-g5rv.htm 73 Thierry ON4SKY, LX3SKY Thanks & 73s, Deane WB2DCF |
#5
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Deane,
All are good antennas. I sold the Fritzel FD-4 80 to 10 OCF dipole in the mid 90's and used one with good results. I would recommend the Carolina Short 80 (previously called the Carolina Beam). This has a leg up on the others if you want both Dx and local skywave results. The comment about keeping the dipole and adding a tuner is a good one too. I would suggest making the dipole 135 feet long and using ladderlime tho. Remember none of these will equal a beam or phased verticals. many of the locals have put up a big loop skywire (either 80 or 160 full wave loops) with good success. I have a 80 meter loop up at my Island second home and can work the world with 100 watts. 73 Dave K4JRB Deane Charlson wrote in message ... Hello, I have been using single-band half-wave dipoles for years. I would like to try some multi-band wire antennas and compare performance. I am considering using an Off Center Fed Dipole or a G5RV or a Carolina Windom. Any thoughts or experiences with these antennas as compared to a half-wave dipole? Thanks & 73s, Deane WB2DCF |
#6
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Richard Clark wrote:
On Thu, 23 Oct 2003 10:38:15 -0400, Deane Charlson wrote: Hello, I have been using single-band half-wave dipoles for years. I would like to try some multi-band wire antennas and compare performance. I am considering using an Off Center Fed Dipole or a G5RV or a Carolina Windom. Any thoughts or experiences with these antennas as compared to a half-wave dipole? -- http://web.wt.net/~nm5k If strictly comparing performance, all three are inferior when compared to the coax fed dipoles. To be honest, I've tried all of the antennas you mention, and I have no use for any of them. I thought overall, they were pathetic. I agree, if you want to run all bands, just feed a dipole of the lowest band you want to run with ladder line. If you use a tuner, use the very least inductance to get a usable match. That will greatly reduce tuner losses. Nothing you try will beat a coax fed dipole for pure efficiency, unless you use a no-tuner method like Cecils no tuner ladder line setup. But careful use if the tuner will leave losses low enough to not really worry about. Well, unless you are like me, and want every last drop....I stick with parallel dipoles fed with a single coax. At the moment I have 80/40/20 dipoles on one line. I can use the tuner on other bands if needed. But those bands I get: no tuner needed, no tuner losses, the advantages of coax, and a normal dipole pattern on those bands. My total system losses are very low. I don't like using a tuner as you can probably tell. :/. I'll avoid it like the plague if possible. The OCF is prone to common mode problems. Same with the windom which is basically the same thing. The average storebought windom and G5RV's suffer from excess feedline losses due to the micky mouse feedline design. IE: coax to balun to ladder line to antenna...Add tuner loss for all band use...What a micky mouse mess... ![]() to both a storebought windom and a storebought G5RV at previous field days. Ate em for lunch. I mean absolutely tore em a new one...You could see a 2 S unit difference just in the efficiency difference. On theirs, everything would drop. Noise, signals, everything. Pattern was not an issue. Was a painful sight for the owners of those antennas. They had no clue they were that inferior until I A/B'ed those puppies using an antenna switch. ![]() better feed system. IE: dump all the garbage, and run ladder line the whole way. MK |
#7
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Mark Keith wrote:
Richard Clark wrote: Oops, actually, this wasn't aimed at Richard, but the original poster...Sorry..I don't have the original post on the server, and missed the proper quote...MK |
#8
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![]() Deane, Give them a try! Don't throw away your present single band antennas, though. You'll want to put them back up after you make the comparisons, unless you're willing to swap performance for simplicity (in some cases). 'Doc |
#9
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Hey guys and gals, Im kind of new on this group...What do you guys think about
full wave horizontal loops?? I was researching my next antenna and wanted to homebrew a wire of some sort...was all set to make a fan dipole for 20, 40 and 80 when someone turned me onto full wave loops..with a tuner it is said that a full wave 80 meter loop can tune most of the higher frequencies (10, 20, 40 and probably the warc bands)..makes sence as 1 wavelenght on 80 is 2 on 40, 4 on 20, etc... Oh well, mine is ready to go up, have to leader lines in the trees, all im waiting for is wire, rope and coax which should be here any day... What do you guys/gals think of the full wave loops? Steve kb8viv |
#10
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On 05 Nov 2003 19:34:50 GMT, (Desmoface) wrote:
What do you guys/gals think of the full wave loops? Steve kb8viv Hi Steve, Your request seems simple enough to resolve with the free version of EZNEC and reduce the risk of over-analysis that abounds here. ;-) Visit: http://www.eznec.com/ 73's Richard Clark, KB7QHC |
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