Trap question
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| Jan 10th 2018, 11:25 | |
jtabatchTotal Topics: 0 Total Posts: 0 |
do the trap windings , besides resonating at a particular frequency, also add length to the antenna outside the resonant frequency , and if so how much ? Thanks Justin KB2ZVD |
| Jan 12th 2018, 09:54 | |
W1VTSuper Moderator Total Topics: 0 Total Posts: 0 |
No, that is an incorrect way of looking at it. http://hamwaves.com/antennas/inductance.html Assume a 5 turn 37mm diameter coil made out of 2mm diameter wire. With a length of 74mm the inductance is 0.56 uH. With a length of 37mm the inductance is 0.70 uH One would expect the change of inductance to change the effective shortening effect on the antenna. You can see this by making a Variable Frequency Oscillator using an air wound coil as one of the frequency elements and squeezing the turns together. www.eznec.com The demo program may be adequate for designing what you want. https://www.smeter.net/antennas/tuned-trap-antenna.php Zack Lau W1VT ARRL Senior Lab Engineer |
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