[CQ-Contest] Adding 80m Shunt feed w/160

[Scott Bauer]

Has anyone out there combined an 80m shunt feed on a tower that already has a shunt feed for 160m ?

I have an 76 foot tower, with a 160m shunt feed, with the shunt wire connected at about 60 feet.  It works very well for me on 160m, or at least it seems to.  I only run 100W on 160m, since my amplifier does not have 160.

I tried adding an 80m shunt feed, first with the shunt wire connected at about 50 feet, which didn't work then moved it to 60 feet, which also didn't work.  I am using an L network, with a shunt roller inductor and a series variable capacitor to the shunt wire.  I have more than enough inductance and capacitance to work with, both value and tuning range.

The 160m shunt feed took all of 30 seconds to tune.  On 80m I can't even get it close.

The tower has a PRO-67 on top at 77 ft (40m thru 10m), with three other yagis at 64, 50 and 37 feet, and an 80m dipole.

Since the dipole I have on 80m doesn't seem to do well, I want to shunt feed the tower on 80m and take advantage of the radials already installed for 160.

The only other option is to buy tubing and make an 80m vertical and put down another set of radials.  Anyone have experience with the tubing that Texas Towers sells ?  I don't really want to use irrigation tubing, looks like it is harder to support.

Thanks in advance for the help.

73 Scott W2LC