3 Band EFHW Trapped antenna

Hi Ignacio

Absolutely right.

I want to use the EFHW with the MTR-3b to avoid carry the ATU, i e, be lighter.
I’ve made a trapped dipole but in some summits the space is not that much…

73 de Pedro

PS - TNX fer QSO on CT/BA-002!

Hi Pedro,
hope you will enjoy with your small setup soon, it is a nice compact system!
Thanks fer BA-002, glad to have a CT CW activator close to us :clap:
73 de Ignacio

1 Like

I too use and like the broadband matching network approach to EFHW antennas. I have a 5 band trapped EFHW which I find works very well on the whole. Details and dimensions are on my blog:

Anyone interested in broadband matching networks of this type may also be interested in Owen Duffy’s analysis - they’re not simple transformers!

http://owenduffy.net/blog/?p=7073

73

David
VK3IL

Hi David,

thanks for sharing the interesting link with detailed information.
Did you know I found your design some months ago and I am building a replica nowadays here? Funny coincidence.

But I’m trying to combine it with coils to avoid making it so long for 40 meter… Difficult task!

73 de Ignacio

Hi Ignacio,

Pleased to hear you found the information useful. To shorten it on 40m, perhaps add a 20-30uH coil after but fairly close to the last trap (i.e in the 40m only section of wire, but as close as possible to the current maxima). Then trim that last section to resonance. I’d try and model it in NEC2 first though. You’ll lose some efficiency of course, but would be interesting to see how it performs.

73

David
VK3IL