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#16
06-20-2008, 07:00 PM
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The "bow tie" is a phased connector for the signal. This antenna is tuned for a specific UHF channel, and is normally used with the elements horizontal and the main boom pointed to the station. I think the end pointed to the station should be the lower end as you have it mounted.
The way you have it, you will get some reception from stations in the direction into or out of your wall. Edit - you did say channel 13, so that's probably what it is tuned for 
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#17
06-20-2008, 08:06 PM
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A lot of discussion of this very subject over on another forum - most of the antennas built by forum members look like the one shown. I built a similar one, and can say they work great in my area (Norfolk-Portsmouth-Suffolk VA).
Cheers,
__________________
Brian USN RET (Avionics / Cal) CET- Consumer Repair and Avionics ('88) "Capacitor Cosmetologist since '79" When fuses go to work, they quit! Last edited by Findm-Keepm; 02-05-2015 at 10:04 AM.
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#18
06-20-2008, 09:44 PM
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__________________
 Do not attempt to adjust your set.
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#19
06-20-2008, 10:41 PM
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Quote:
Thanks for that link. I just may build another one of those my own self soon... my present combo VHF/UHF/FM RatShack antenna was their smallest available when I first got it, and it's just adequate, even with an amplifier. Tom
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Tom 
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#20
06-21-2008, 11:35 AM
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Quote:
Phil Nelson
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#21
06-21-2008, 07:42 PM
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Quote:
Of course a multi-bay antenna probably won't work indoors, which the original topic stipulated. A single-bay ought to fit ok, for example the foil one given as an example that was wall-mounted. Sure looks easy to build.
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Do not attempt to adjust your set.
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#22
06-21-2008, 11:31 PM
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Phil -
Another antenna that works quite well for DTV is the Philips (used to be Zenith) Silver Sensor. It's a UHF log-periodic that comes with its own tabletop stand and doesn't take up a lot of room. I was planning on building one of the antennas with the reflector when a co-worker loaned me his Silver Sensor, and from what I've read, it compares favorably with the reflector-style antenna. I'm about 35 miles from the broadcast towers and have the antenna pointed out my front window. I get about 85-90% signal strength on all Chicago channels and can even pick up one out of Gary Indiana if I rotate the antenna 90 degrees. -Jim
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#23
06-22-2008, 10:09 AM
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__________________
Do not attempt to adjust your set.
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#24
06-22-2008, 05:18 PM
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Quote:
The lead-in connects at the middle terminals, as per the plan. It seems to be marginally better than the funky antenna that I found in the attic. With careful positioning, I can receive a couple of stations that had occasional dropouts before. Not the miracle antenna I was hoping for, but maybe I'm already receiving much or all of what someone can reasonably expect in this location. Some stations come in just fine if you disconnect the antenna and touch your finger to one terminal of the lead-in. Phil Nelson Phil's Old Radios http://antiqueradio.org/index.html
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#25
06-22-2008, 07:51 PM
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Looks like your reflector could be out of phase. The Gray-hoverman has it 3.94 inches behind the plane of the active elements. The website you modeled after uses the wide dimension of a 2X4, which I think is around 3.75 inches. I bet someone out there can show us the math, but if I'm looking at your antenna correctly, it looks lke you used a 2x2. If the reflector is too close (or far), it's out of phase, and the reflected signal, instead of augmenting the incoming signal, will interfere with it instead -- do more harm than good. Don't know if this will help your antenna or not, but might be worth looking into.
__________________
Do not attempt to adjust your set.
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#26
06-22-2008, 08:34 PM
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Looks like the driven element is indeed too close to the reflector... and that's the first I've noticed the top and bottom bays with crossed feed lines.
 I would think that perhaps that would end up cancelling out incoming signals? Tom
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Tom
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#27
06-22-2008, 10:17 PM
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Also, the main 2x2 looks kind of metallic (gold). Might just be the photo, or maybe paint. If there's anything metallic about it, the whole antenna's one big short.
The crossed feed lines are curious, but correct. This channel-master looks to be the same design: http://www.solidsignal.com/prod_disp...om=Large#xview and the bays are cross-fed similarly. I don't know the math behind it, was hoping one of the experts would chime in...?
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Do not attempt to adjust your set.
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#28
06-23-2008, 01:04 AM
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Yes, I used a 2x2 rather than a 2x4. Didn't realize that that dimension was important, but again, I know nothing about antennas.
I painted the stick with nonconductive brass-colored paint. Don't think that's an issue. It's easy enough to rebuild it tomorrow with a 2x4 in place of the 2x2 stick. If the difference between (nominal) 3.75 and 3.94 inches is critical, I can probably find something -- like a strip of cardboard -- to shim it up, at least for testing purposes. Thanks for the advice! Phil Nelson
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#29
06-23-2008, 03:00 PM
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Here's version 2.0, built with a 2x4 shimmed up so that the bowties are just shy of 4 inches from the reflector.
It does work better. I pulled in 6 additional subchannels, compared to version 1.0. Too bad it's so fugly. Not exactly what I had in mind for this small indoor TV room. Maybe I'll have throw caution to the winds, bore a hole in the wall, and weatherproof it to mount outside. Phil Nelson
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#30
06-23-2008, 05:12 PM
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Now I'm trying to figure out which is better: crossed or uncrossed. Here's another call for experts to lend their knowledge on this, please! Tom
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Tom
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