UHF 3-BAY BOWTIE - NO Reflector:
I expected that the Gain Pattern would shift upwards, but i was surprised at how SMALL the shift was across the UHF Band....and how LARGE the shift was in the middle of the Hi-VHF Band:
UHF Gain for the 3-Bay Bowtie turns out to be about half-way between an Optimized Super-2-Bay (M2) and an Optimized Super-4-Bay (M4) with no more than a mere 5-degree up-angle in the Elevation Gain Pattern...which might even offer a couple tenths of a dB improvement in some situations (e.g. Mt Wilson in L.A.).
Hi-VHF Gain points directly UPWARDS at 189 MHz as the antenna becomes more of an end-fire array (like a Yagi pointing upwards) that a Flat Panel Array. This results in a huge Gain Hole of up to -5.8 dBi (that's minus) on 189 MHz, affecting all except the lowest and highest Hi-VHF Channels.
Since you said that you are using a "Coat Hanger" 2-Bay Bowtie Design, I hope that you are using one of the larger designs optimized for the NEW UHF Band, rather than one of the several TOO SMALL designs that infect the internet. Whisker Length should be at least 8.5 and preferably 9.5-in with Bowtie-to-Bowtie separation of 9.0-in as used in mclapp's M2 and M4. Also note that these larger designs provide significant Hi-VHF Gain, and when used with an appropriately sized Reflector, are directed FORWARD, unlike smaller designs:
FYI: M4 (9.5x9.0) is Optimum size for NEW UHF Band, except when used with the Double-Angle-Reflector the slightly larger M4 (10x9.5) is a bit better, esp. on lower channels.
If you go to www.tvfool.com
and "Check Address for Local TV".....then Copy/Paste the results URL (webaddress at top of browser). From the report we''' be able to determine what sort of antenna you need for VHF channels....there are several very simple & cheap DIY projects to chose from....Edited by holl_ands - 10/20/13 at 5:47pm