I do believe that the antenna is too low and that it is being affected by the nearby roof and gutter. Second disconnect that fence from the mast.
Did you set the length of antenna by freqency? What frequency did you use? Attached is the chart shown on page 3 of the ar10's instruction booklet for that info if you don't have the booklet. I found it on line.
Looking at that info for center frequency and ranges and the specifications of antenna given on the last page and also attached, the antenna will not achieve a bandwidth into the 11 meter frequencies.
What would I do well, I would spend time and effort into getting it up as high as possible and see if that would help. I would also disconnect the fence that you have attached to the antenna at the bottom of the mast. The design of this antenna appears to me, after looking at the diagrams on the instruction booklet, to use both the coax and the mast as "counterpoise" and should be sufficient. If more counterpoise is needed it should be added in the form of a longer coax cable and taller mast and not the loose lattice type fence for the reasons shockwave mentioned.
If you want an antenna that is trouble free and will cover both 10 and 11 meters I would spend money on the Sirio Gain Master and on a tower or a push pole to get it up to at least 6 meters away from nearby objects or ground.
In so far as decoupling the antenna from mast by using 3 1/4 wave wires, whips or even aluminum tubing to provide the necessary counterpoise,,,What shockwave means is to add those to antenna at the feed point location up on top and not on the bottom. This would allow replacing the mast and coax as the counterpoise with out affecting the radiation pattern but your are getting into redesigning antenna.
I would try elevation first, it is money well spent for this antenna or any other omni or beam antenna you may wish to install any way in the future.
The instruction booklet mentions securing the feed line and ff tuning stub to the mast by the use of tape. This may be nothing but can't hurt if you have not done it.
As far as the meter I don't know how well it could be trusted outside the 4-5 watts that it was prolly designed for on cb.
Well let us know how you are getting along with this. Best of luck.
