While a stub can be made to act just like a resonant circuit at one
frequency, and almost like one over a range of frequencies, it behaves
quite differently at frequencies which are quite different from the
resonant frequency -- such as on other bands. That is, the stub will act
like a trap at one band, but not at all like a conventional trap at
other bands. There's no inherent disadvantage in this, but it means you
can't simply replace traps with stubs and have the antenna behave the
same as before on all bands. Considerable redesign or adjustment might
be required.

Another caution is that a stub is likely to have lower Q than a good
trap. This can, but doesn't necessarily, result in significant loss on
some bands. Careful modeling can give a pretty realistic idea of the
loss you can expect.

Finally, if you model a stub in an application like this, you can't use
NEC or EZNEC transmission line models, because the currents on the wires
aren't equal and opposite -- you have to make the stub models out of
wires. And be sure to include wire loss if you want the model to give a
realistic assessment of loss.

Roy Lewallen, W7EL

pegge wrote:
I´m planning to build a new multi-band antenna, and found something
entirely new to me , an antenna like a w3dzz but with ´stubs´instead of
traps. Take a look at www.g3ycc.koroo.net/lattin.htm
Should be possible to build with wires and spacers?
Anyone know (and uses!) this antenna?
I also have been thinking of a T2FD-ant, tips on
inductance-free resistors tnx, someone built a smart T2FD?
(smart meaning simple solutions for R and feeding (coax) )
Comments please!

Happy Newyear etc / per / sm7aha