Unfortunately, a 2:1 ratio seems difficult to
achieve.
--
73, Cecil http://www.w5dxp.com

In real life, at least in my case the stub will be made of twin-lead type
material which shortens it abt 30%.
If the shortening effect at lower frequency due to the inductive loading of
stub is less, then it would be possible.
Going one step further you could easily add another band to the design as
parallell dipole for 17m using unused parts of
douple-line. That should have litle interaction to the original double band
antenna.
http://farm4.static.flickr.com/3016/...fd3b1e6c_o.jpg


As Jim K7JEB verified, the total half length is not 20m but 15,5m due to the
loading effect of the stub.
The real stub length is 1/4 WL at higher frequency respecting the velocity
factor of material used.


73 Jouko OH5RM