What is really interesting is that the green signal lines clear the other buildings in both major directions.
This is a 4-bay antenna:
https://www.antennasdirect.com/store...v-antenna.html
http://www.amazon.com/Antennas-Direc.../dp/B0074H3IU6
http://www.bestbuy.com/site/antennas...&skuId=4875742
http://www.solidsignal.com/pview.asp?p=db4e
The assembly instructions show how the reflector is attached:
https://www.antennasdirect.com/cmss_...L_20130723.pdf
With the reflector, the antenna is directional. For best results, the antenna must be aimed at the transmitter. See the antenna pattern on page 2:
https://www.antennasdirect.com/cmss_files/attachmentlibrary/Technical%20Data%20PDF's/DB4E-TDS.pdf
When the reflector is removed, the antenna becomes bi-directional, with the major lobes of the pattern 180 degrees apart. What you lose is some gain (~3 dB) that the antenna had when it was directional. The bi-directional pattern looks something like this:
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Also, what is a VHF element, and how is one added to an existing antenna?
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There are three TV bands:
VHF-Low, real channels 2-6
VHF-High, real channels 7-13
UHF, real channels 14-51
WTVI PBS, real channel 11 and WSPA CBS, real channel 7, are VHF-High channels. The basic UHF antenna covers 14-51, so another element can be added for VHF-High, if needed. The VHF dipole add-on has more gain on VHF-High than the UHF antenna, and is suitable for strong VHF signals.
https://www.antennasdirect.com/store...tenna-Kit.html
https://www.antennasdirect.com/cmss_..._201402062.pdf
The VHF dipole is bi-directional.
I suggest you try the antenna in the attic without removing the reflector, first aimed at 260 degrees magnetic with a pocket compass not a smart phone compass, with the VHF dipole broadside to 107 degrees magnetic to see how it does. You might need to try different locations in the attic. Then aim it for 115 degrees. You might be happy with 260 without needing to remove the reflector.
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What would the tolerance/range in each direction be?
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High gain antennas have a narrow beamwidth, so the aim is more critical; that's the tradeoff. Beamwidth is measured at the half-power points, 3 dB down.
