The trap dipole antenna is impedance matched by a 1:6 balam requirement, a design circuit found on the web is shown below. The 80m band is similar, but the 40m and 20m band equates to a near three wavelengths overall. Each half of the trap dipole relates to a near or more than a full wave, such as on the 10m band, the trap dipole antenna equates to two wavelengths. Increasing "Cshunt" values will reduce the top line SWR values, and stay below SWR = 1 ♵, but the low end frequency span for the trap is the 80m band, at 3MHz the SWR value of 0 ♷9 equates to just under SWR = 1 ♳, but at 4MHz equates to a near good perfect match of 50ohms. With the values shown in the above results list, the max SWR values is around 1 ♶5, equating to 82ohms antenna load for a 50ohm coax line feed after the 300ohm to 50 ohm balam. Depending upon the values of "Cshunt" and "Lcoil", component values for the trap circuit design, so the complete antenna behaves differently. The physical width of the trap dipole is 4 metres, each arm of the trap has constructed from two 1 metre wire section, laballed as each part "1st sec" and "2nd sec", with a parallel tuned trap circuit between each 2 metre wire section on each arm of the overall trap dipole.
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