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This is my first DIY antenna...
Actually... it's just some sort of ... "mess" production. I made it up out from zero knowledge in head.
I was planning to build a "上下 18 寸" antenna with this coaxial cable and 13A power cord. However, I was too smart to build an antenna with 1 wavelength. So, the VSWR in VHF side just fly high to 1:5. However surprisingly, the VSWR for UHF could be lowered to as low as 1:1.7. So I just move on with the antenna's shape, hoping that I can get a even better VSWR.
I ended up with rolling the two cables together and twisted it into somekind of awkward shape. This lowers the VSWR of UHF to <1:1.1 and <1:1.3 for VHF. The sensitivity is not really high for this.. how should I call it? coxical antenna?.. coxical antenna. As seen, it is not really big in size..
I'm now wondering if there will be any problem with this antenna, as you can see, high p.d. could be induced on the shield coil. (Brown: connected to centre core, green/yellow: connected to shield) Anyone knows if there is gonna be any potential risk in using THIS awkward antenna? You're welcome to leave me a comment.
Source: http://www.sec.noaa.gov/SolarCycle/ ==============================================================......
share trekking on Sai Kung + radio testing... (FT-7R & VR2ZYB 天線) 我很幸運，加入一個好的隊和......
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VR2UIX 2008-05-12 22:28
Try this bazooka antenna for UHF band then. Although the bazooka is a mono-bander, however, it's simple and easy to build. My 20M, 15M and 6M bazooka all work amazingly and always give me good DXing results.
Source: http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=12959
Oliver VR2UIX de 73'