antenna element lengths?

[Hogie]

I have an old Channel Master TV antenna that got blown down and the elements damaged. After I canceled cable TV (expensive!!!!) I decided to put up what was left of the antenna. Basically the UHF portion of it was undamaged. It is a fringe area antenna. It seemed to be VERY directional in a narrow beam without the VHF elements. So, I decided to shorten the elements on the broken VHF portion and rebuild it. I was not sure of what the length should be so I made the reflector 16 inches on each side (the elements form a vee and are isolated from each other on each side of the boom) with each element forward shortening til I got down to about 13 inches. So now it is a 5 element VHF beam (10 if you count each side separately).

It works much better now and now seems to receive in a broader beam. I just wonder what the lengths should be for today's HDTV and digital?

 

[boba]

Channel 7 wavelength should be about 66.8 inches/Ch13 should be 55.4 inches but most antennas use 1/2 or 1/4 wavelength for elements. The wave lengths haven't changed since analog changed to digital.

You don't say where in N.Y. you are but most broadcast since the digital transition are UHF not VHF so your butcher job may be just cosmetic.

 

[Hogie]

Well, it is less directional now with the shortened elements. The formerly long back elements were mangled from the crash so my "butcher job" was worth a try. They were not usable as is. Before my modification, I had to turn the antenna to get each station. Now I can leave it in one position and get all of them. So, it did improve.

I found an ad online for a new antenna supposedly made for the "digital HD TV" of today. I looked at the elements and guestimated that they were about 16 inches or so. I was hoping to get the length refined here by someone who may have one of these newer antennas.

If it works, then no problem. I will leave it as is.

 

[boba]

Go to AntennaWeb or TV Fool and find out what you have for broadcasters. But you are right if it works don't knock it.

 

[Don_M]

I looked at the elements and guestimated that they were about 16 inches or so.

That was a fairly good guess. I have an AntennaCraft Y5-7-13, designed for channels 7 through 13. Its longest elements, the reflector at the back of the boom, are just under 36 inches wide. The folded dipole that is its driven element is about two inches narrower than that, and the three directors at the front are roughly another two inches narrower. While it is of a different design than your CM, optimum element length for a given frequency (channel), or band of frequencies, is a constant.