Will a 40 meter dipole work on 20 meters?
Even with an external it should NOT work just fine! Do what Jim said, make it a 2 band (actually 3 band 40/15 and 20) dipole and you will REALLY be fine.
What is an RF trap?
A quadrupole ion trap is a type of ion trap that uses dynamic electric fields to trap charged particles. They are also called radio frequency (RF) traps or Paul traps in honor of Wolfgang Paul, who invented the device and shared the Nobel Prize in Physics in 1989 for this work.
What is an antenna trap circuit?
A trap is a parallel circuit of L and C on the frequency you want to close an antenna segment. For n working frequencies of an antenna, you need n-1 traps in each part of the antenna. For example a 2-band-dipole needs one trap in each half of the antenna. The trap can consist of a coil and a separate HV-capacitor.
What is an antenna trap?
Where is the antenna located on a 40 meter trap?
As mentioned earlier, the antenna in this case is an 80/40 meter trap vertical. A 40 meter trap is located at the top of a quarter wave 40 meter vertical. The top of the trap supports a whip, which is sized to bring the whole antenna into resonance on 80 meters.
Why do you need a trap dipole for 40m?
The trap will work as a stopper for 40m, for this band arm 1 is only used because the LC circuit will start to resonate absorbing any energy going into arm 2. On 80m the trap is mostly a resistor, or better a lengthening (or loading) coil so that you can shorten arm 2 until the SWR of the antenna becomes acceptable for 80m.
What is the resonant frequency of a 40 meter trap?
I trimmed about 2 inches off the 20 meter legs and the frequency increased to 14.14mhz. The 40 meter resonant frequency was 7.35mhz. So I added 12 inches to the 40 meter extensions the the 20 meter resonant frequency did not change noticeably. But the 40 meter resonant frequency decreased to 7.17mhz.
Which is shorter 20 meter or 40 meter trap inverted vee?
In my case, comparing it to my linked inverted vee which has links for 20, 30 and 40 meters, the 20 meter segment of this trap inverted vee is 3-1/2 inches shorter than the same segment of the linked inverted vee. To deal with that you take a trial and error approach to find the balance between the length of the two segments.