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#1
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Velocity factor
Does anybody have a velocity factor chart? I need the information for 13
gauge stranded plastic cover? TIA Howard W3CQH |
#2
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Velocity factor??
John Doe wrote:
At the present time - my MFJ Antenna Analyser has it resonating at approx 10.5Mhz, and I am trying to get it to resonate at 1.8Mhz (160M). What length and type of feedline are you using? If ladder- line (or similar) your have a tuned-feeder system and the resonance frequency may not be anywhere near the stand- alone antenna resonant frequency. What does the antenna analyzer say is the resonant frequency closest to 1.8 MHz? With the two above pieces of information, we can estimate what needs to be adjusted to obtain a system resonance of 1.8 MHz. -- 73, Cecil http://www.w5dxp.com |
#3
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Velocity factor??
I have made a indoor/outdoor STEALTH of sorts, a Multiband HF LOOP Antenna, approximately 540ft long (from center connector back around to the other side of the connector). I am using 13 gauge - copper - stranded plastic cover - wire! Does anybody have a velocity factor chart? At the present time - my MFJ Antenna Analyser has it resonating at approx 10.5Mhz, and I am trying to get it to resonate at 1.8Mhz (160M). I need the info to try and figure out how much I need to reduce the overall circumfrence. 73's Howard W3CQH |
#4
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Velocity factor??
On 18 abr, 16:20, "John Doe" wrote:
I have made a indoor/outdoor STEALTH of sorts, a Multiband HF LOOP Antenna, approximately 540ft long (from center connector back around to the other side of the connector). I am using 13 gauge - copper - stranded plastic cover - wire! Does anybody have a velocity factor chart? At the present time - my MFJ Antenna Analyser has it resonating at approx 10.5Mhz, and I am trying to get it to resonate at 1.8Mhz (160M). I need the info to try and figure out how much I need to reduce the overall circumfrence. 73's Howard W3CQH Hello, John, The effect of a 1mm thick PVC coating on 1.8mm diameter of copper on phase velocity is less then 2 percent below that of light. So c is about 0.98...0.99*c0. This is without correction for capacitive fringing at the ends of the wire and without correction for influence of ground. As your wire is about 1 wavelength for 1.8 MHz, your loop should have a low impedance and therefore you should find a point of resonance around 160 m band (assuming you did connect the wire directly to the MJF). Maybe you should use a balun between your MFJ and 1WL loop. You will get resonance at near multiples also. Best Regards, Wim PA3DJS. |
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