dual band j pole question

[mr_fx]

http://www.k6ria.net/antenna/Emergency antennas.pdf

Having problems tuning this... should the top section effect the 440 tuning? I got 440 lined up... its got a pretty broad match... but 2m is now entered on like 143... should i just shorten the matching stub to bring the cent freq up a bit?

 

[W5LZ]

Just for illustration purposes take a look at an 'Arrow' dual band 'J'-pole. There are three vertical elements on one. The normal two for 2 meters then a shorter one for 70 cm. The short element for 2 meters is the center conductor and the other two are the braid connection. That short section for 2 meters is roughly equal to a 3/4 wave at 70 cm so acts as the long element on 70 cm. See how that works?
Now for an 'emergency' or easily portable dual band 'J'-pole, how could you add that shorty element for 70 cm? Space it from the short 2 meter element and glue it on? Beats me, but that's all that would be required...
- 'Doc