Building a trap dipole for 7 and 14 MHz

A trap dipole is a good choice if you only want operation on two or three bands and don't want to readjust an antenna coupler to change between them.
This video describes a trap dipole for 7 and 14 MHz with emphasis on the 1:1 current balun and 14 MHz trap.
Adding 80 metres: Loading coils can be added to provide 3.5 MHz capability with very little extra room required. My loading coils used 85 turns of 2mm (od) thin insulated wire closewound on a 55mm diameter pipe. There will be some interaction between the loading coil and the 7 MHz element. Add extra wire to bring it back into the 7 MHz band. The 3.5 MHz performance won't be as good as a full sized dipole, though some excellent contacts are still possible. The bandwidth will be narrow so I suggest using an antenna coupler at the transceiver end. Further ideas on the loading coil at: users.picknowl.com.au/~wavetel...
Contents
0:00 Introduction
0:23 Source information
0:48 1 to 1 balun
1:11 Making the balun
2:33 Making the traps
2:54 Testing/adjusting traps
5:32 Antenna construction
5:39 Final dimensions
5:42 Summary
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[@cockerspanielhome]

Thank you very much for your clear instructions on how to construct a 20 meter trap and test it. I have been working on a multi band vertical antenna and looking for a good video on how to do it. Please continue making your great videos, I have learned a lot from them. Best 73, Eric

[@vk2ig]

Hi Peter,
Your video has re-inspired me - I've been thinking of designing such an antenna for 30 / 40m. I don't have a dedicated 30m antenna, instead I use the 80m inverted vee with a tuner; and I have a 40m dipole which could be modified. I like the addition of the drain holes at the bottom of the balun housing - absolutely essential to allow moisture to drain, otherwise the housing will gradually fill up (like it did on one of my baluns when the drain hole got blocked).
Cheers,
Mike VK2IG

[@SpectreOZ]

An interesting antenna... thanks Peter :)

[@user-re9rg3rk5m]

Thank you, Peter. I like

[@warplanner8852]

GDOs ("dip oscillators") may not be scaled accurately, but they are convenient variable oscillators and, in fact, represent a signal generator AND the sensing device in one package. You determine the dip point and get the actual oscillator frequency using your station receiver.

[@Bass-guitarist]

Great Video, I have a concern re:- Testing the resonant frequency, at 4.09 you use voice to excite the meter, the meter is quite unstable due to your voice output, I am wondering if a more accurate result would be gained by using CW transmission?

[@user-gz5zp2ic9i]

hello VK3YE.please,i want the circuit for the tunning unit (what meter-diode -capasitor and the scheme)

[@user-re9rg3rk5m]

To get result like this, you must live near big water