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75m/30m, 40m/17m Dual Banders
There was a discussion the other day about stub loaded
dipoles. A 30m dipole loaded at each end with a 30m/4 shorted stub is resonant on both 30m and 75m. A 17m dipole loaded at each end with a 17m/4 shorted stub is resonant on both 17m and 40m. The stubs provide inductive loading on the lower bands resulting in "shorty" dipoles, shrunk by about 20%. I've summarized two such antennas on my web site at: http://www.w5dxp.com/dualband.gif -- 73, Cecil http://www.w5dxp.com |
75m/30m, 40m/17m Dual Banders
On May 20, 4:51�pm, Cecil Moore wrote:
There was a discussion the other day about stub loaded dipoles. A 30m dipole loaded at each end with a 30m/4 shorted stub is resonant on both 30m and 75m. A 17m dipole loaded at each end with a 17m/4 shorted stub is resonant on both 17m and 40m. The stubs provide inductive loading on the lower bands resulting in "shorty" dipoles, shrunk by about 20%. I've summarized two such antennas on my web site at: http://www.w5dxp.com/dualband.gif -- 73, Cecil �http://www.w5dxp.com Hi Cecil, How do you model the 1/4wl 3" stubs on the ends of the dipole? I have EZNEC 4.0. Gary N4AST |
75m/30m, 40m/17m Dual Banders
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75m/30m, 40m/17m Dual Banders
Cecil Moore wrote:
It's actually 0.3 ft, i.e. 3.6 inches. The EZNEC file is at: http://www.w5dxp.com/40_17.EZ Dead link? Craig 'Lumpy' Lemke www.n0eq.com |
75m/30m, 40m/17m Dual Banders
Lumpy wrote:
Cecil Moore wrote: It's actually 0.3 ft, i.e. 3.6 inches. The EZNEC file is at: http://www.w5dxp.com/40_17.EZ Dead link? Seems to be OK this morning - and the spacing is 0.25 ft, i.e. 3 inches. -- 73, Cecil http://www.w5dxp.com |
75m/30m, 40m/17m Dual Banders
Cecil Moore wrote:
... The EZNEC file is at: http://www.w5dxp.com/40_17.EZ Lump: Dead link? Cecil: Seems to be OK this morning - and the spacing is 0.25 ft, i.e. 3 inches. Got it now. Thanks. Craig 'Lumpy' Lemke www.n0eq.com |
75m/30m, 40m/17m Dual Banders
"Cecil Moore" wrote in message ... There was a discussion the other day about stub loaded dipoles. A 30m dipole loaded at each end with a 30m/4 shorted stub is resonant on both 30m and 75m. A 17m dipole loaded at each end with a 17m/4 shorted stub is resonant on both 17m and 40m. The stubs provide inductive loading on the lower bands resulting in "shorty" dipoles, shrunk by about 20%. I've summarized two such antennas on my web site at: http://www.w5dxp.com/dualband.gif -- 73, Cecil http://www.w5dxp.com It might be easier to do what I did. I have 17 and 40 meter dipoles connected to a common feedpoint. The 17 m dipole is the supporting element, hung between two trees at about 50 feet. The 40 m dipole is arranged as an inverted V. The trees are not far enough apart to have the 40 m dipole on top. Either way, the 40 m has to be resonated first. Tam/WB2TT |
75m/30m, 40m/17m Dual Banders
Tam wrote:
It might be easier to do what I did. I have 17 and 40 meter dipoles connected to a common feedpoint. Now your challenge is to turn it into a 40m rotatable beam. Have a look at: http://www.w5dxp.com/4017beam.EZ -- 73, Cecil http://www.w5dxp.com |
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