Yes, I feel Nists modeling on.... the channel 13 deficiency noted on the YA-1713 is unfounded.
I agree completely. I have a pair of YA-1713's stacked vertically by 40 inches for what I found by experimentation for the middle of the band.
I have them aimed at Jacksonville, FL, at 61 miles. There is a 7, 10 and 13, nearly perfect to see the antenna across the band. My stacked array clearly works very very well on Channel 13.
I never bought into Nist's arguement and would have to re-read his comments where I think he eludes he is not sure it's true (guess I or someone could look again).
But the point is traditional TV antenna design and used on both the YA1713 and the Y10-7-13 is to make the directors tuned to the highest channel and the reflector tuned to the lowest channel. Then use either a log type feed (Winegard) or a folded dipole (AntennaCraft) to match across the band.
Hence from my experience playing with yagis on 10, 2 and 1.25 meter ham bands the reflector bigger than needed has only a small effect, but the directors length are more critical. So with that, then either antenna should preform very well on Channel 13, Winegard or AntennaCraft.
If you have not followed my trials and tribulations with stacking my YA-1713s a quick thumbnail of my trials. First, no test equipment except a receiver.
Tried 60 inches, not any difference from a single yagi. Then 50 inches, very slightly better, but not worth the trouble. 40 inches, WOW! Signals that I only saw during strong band openings from Jacksonville (61 miles and 2 edge) suddenly where there 90% of the time (actually most of the time but killed by co-channel off the back from Tampa).
I asked Hans at Winegard what he thought and he said 42 inches was the center of the band for his antennas. So I was very close by experimenting.
As an aside, I also have a channel 9 (WNBW) that is LOS. I only see a slight increase in gain toward it. But the 2 edge signals from Jacksonville I see a tremendous increase in signal. I can't measure it, but it goes from 15 to 25 on my quality meter to 50 between one antenna and the two.
I guessed at this because years ago I played a lot on 2 meter SSB which uses horizontally polarized antennas. The stations with vertically stacked yagis out performed other stations even when they were 100 miles away and only 20 ft in the air. I believe it's akin to pointing a UHF at a close by knife edge hill by maximizing reception where it's needed for VHF, right at the horizon.
I knew those hams that stacked them were on to something. As their signals from 20 to 30 ft off the ground were as strong or stronger than those with a single long boom yagi up twice as high.