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Please bear with me, I'm a total newb to all this, and I know absolutely nothing about building an antenna but we really needed one so I came here a few days ago and started reading. Great forum with tons of useful information! This is actually kinda fun and i'm enjoying tinkering with it.

Heres my tv fool report: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d8d17b2ef68a9b1

The main channel we'd like to get is KDKA-DT (2.1)....but needless to say as many channels as possible on the list would be nice. Channel tower info if needed http://www.fcc.gov/fcc-bin/tvq?call=KDKA

So I did a quick rough attempt to see if one of the diy ones posted here would work for us and I built this: http://www.digitalhome.ca/forum/album.php?albumid=722&pictureid=3706

I plan on building a better version, more durable, better quality etc once I get the bugs worked out. Anyhow, we do get the KDKA station we had hoped for but it drops out alot and my antenna signal strength is around 50% as measured by my converter box. The above crude work has 10" whiskers with the end gaps at 9 1/4".

Any changes or suggestions from you guys would be greatly appreciated. Did I run the phase lines correctly???( is that the right way to run it with that many whiskers or should it be an upper and lower?) Should I add more whiskers? Should I outright try another design that is posted here? Maybe a reflector? (but will that limit the number of channels?) Sorry for so many questions, but I'm still kinda winging it so please bear with me.
 

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Welcome to the forum.

The photo of your DIY antenna doesn't show up in your post. I had to look at your album to find it. I suspect that you didn't use the BBCode. Please read these instructions:
http://www.digitalhome.ca/forum/showthread.php?t=92167

Your antenna is a good first attempt, but the phasing lines are not correct for your 8-bay antenna. Some of the bays will cancel the signal received by other ones, reducing its performance. Actually, a well-designed 4-bay should be enough for KDKA.
Should I add more whiskers?
No
Should I outright try another design that is posted here?
You should optimize this design before trying another. Try a 4-bay (called M4 on this forum). If you need 8-bays, it might be better to connect two separate 4-bays together. But, you will only get a little more gain (less than 3dB) for a lot more trouble.
Maybe a reflector? (but will that limit the number of channels?)
A reflector would give more gain, but limit the pickup direction as you suspect.
Sorry for so many questions, but I'm still kinda winging it so please bear with me.
You're doing fine; we all start as beginners.

Suggested DIY designs are here:
Best Do-It-Yourself OTA Antennas - see these links
http://www.digitalhome.ca/forum/showthread.php?t=119489

This thread is about your type of antenna (where stampeder might move your question):
Bow Tie TV Antenna Designs (mclapp's M4 featured)
http://www.digitalhome.ca/forum/showthread.php?t=100137

You should find everything you need there; mclapp has diagrams at post #816.
 

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If you want to correct the phasing of your present antenna, there should be an X crossover between all bays except the center two. The downside of phasing all eight together is that errors are additive as you move away from the design frequency, so the outer bays aren't doing as much work as they could.

You will need a separate VHF antenna for WPCW on CH11 if it's important to you.
 

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Wow! Your target stations are very scattered like mine are and you would require a wide beamwidth bi-directional or an omni directional antenna,.. or you would have to gang two wider beamwidth antennas. Otherwise you would need to use an antenna rotor.

Being that most of your station are within 50 miles and have good NM figures, I would try a simple Stealth Hawk antenna outdoors with a CM7777 preamp mounted as high a possible.

Stealth Hawk link:
http://www.digitalhome.ca/forum/showthread.php?t=123803
 

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Discussion Starter #5
Thank you guys for the replies and information. I'll try and correct my mistakes and post how it goes.

rabbit73 "If you want to correct the phasing of your present antenna, there should be an X crossover between all bays except the center two. The downside of phasing all eight together is that errors are additive as you move away from the design frequency, so the outer bays aren't doing as much work as they could." If you need 8-bays, it might be better to connect two separate 4-bays together.


I figured I had done something wrong with the phase lines but wasn't sure how to correct it. So if I may, which way is correct in the picture below? And equally important, how do I connect the balund in the correct way to either of those? I think your recommending that I use the diagram on the right, connecting two 4 bays for best performance? Can you please explain how to connect the two together and where to attach the balund?

 

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Discussion Starter #6
ota_canuck
Wow! Your target stations are very scattered like mine are and you would require a wide beamwidth bi-directional or an omni directional antenna,.. or you would have to gang two wider beamwidth antennas. Otherwise you would need to use an antenna rotor.

Being that most of your station are within 50 miles and have good NM figures, I would try a simple Stealth Hawk antenna outdoors with a CM7777 preamp mounted as high a possible.

Stealth Hawk link:
http://www.digitalhome.ca/forum/showthread.php?t=123803

Thank you for the recommendations and link. I can see me building several antenna, just because its enjoyable to tinker with them. I will probably add a rotor to whatever set up I finally settle on as well. My current one posted above is mounted at about 25 feet, maybe slightly more at the top bay.
 

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First time Ive seen a TVFool report with 4 relatively strong NBC stations in one area. A lot of people barely get 1, heh.

I think youre much better off making that 8 bay into a 4 bay for a wider beamwidth and less phasing problems.
 

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300ohm
First time Ive seen a TVFool report with 4 relatively strong NBC stations in one area. A lot of people barely get 1, heh.

I think youre much better off making that 8 bay into a 4 bay for a wider beamwidth and less phasing problems.

Looks like I may do just that. I had the stuff laying around and I figured while I was putting it together that I might as well just do 8 or 10 bays...( bigger has to be better! right!?..lol). Anyhow, right now with the 8 bay, I'm getting 31 channels, with several of them dropping in and out for several seconds from time to time. I thought maybe it was my phase lines or my directional pointing.


I have two other replies and questions pending approval to the above very helpful posts as well.
 

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Agreed that the vertical 8-bay is too much trouble for what is required. An M4 variant or a GH are more in order, or of course the Stealth Hawk if it would be able to pull in what you require.
 

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stampeder: Agreed that the vertical 8-bay is too much trouble for what is required. An M4 variant or a GH are more in order, or of course the Stealth Hawk if it would be able to pull in what you require.

Thanks... I'm exploring the threads on these now and trying to decide which one.
 

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Xauto "ride the world : You could cross at the ? mark and feed off the bottom of the antenna on the right"
Thanks. I didn't know it could be done that way. Easy.

I now have no idea which antenna I'll build next...I went out this afternoon and disconnected the bottom 4 bays, re-ran the the phase wires the right way for just the top 4 bays and put it back up. Signal strength jumped from 50% up into the 65% area.

Maybe this is a strong enough signal if a preamp is added, and distribution amps in the house? Or should I shoot for a higher signal strength?
 

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If you're getting solid reception at the current signal strengths, you don't need more. The picture won't get any sharper.
 

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Discussion Starter #14
Dave Loudin "If you're getting solid reception at the current signal strengths, you don't need more. The picture won't get any sharper"

I'm still getting some pixelation/freezing on several of the channels with lower signal strength, so i figured it could be better...idk?
 

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Usually, achieving the strongest possible signal strength, is best. More signal stength will help avoid drop-outs etc...

On the other hand, too much amplification could cause some tuner overload on those stronger signals that are only 10 miles away. It's all about determining that fine balance using moderate amplification to get both the distant and local stations.
 

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ota_canuck Usually, achieving the strongest possible signal strength, is best. More signal stength will help avoid drop-outs etc...

On the other hand, too much amplification could cause some tuner overload on those stronger signals that are only 10 miles away. It's all about determining that fine balance using moderate amplification to get both the distant and local stations
I do have at least 2 tv's to connect to, so I'll probably lose some in the cables and splitters. Hopefully I'll put together another antenna with an at least slightly stronger signal than the % I'm getting now. Then I can determine if I will need the pre amp and/or distribution amps when splitting the signal down room to room. I read all day, and I'm still considering what antenna to build.
 

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Multi-TV households:
One antenna using a rotor, and two TV's presents an obvious problem for what each individual viewer can watch. If one viewer wants a channel from the west and the other wants a channel from the east, then the fight is on :p

Keeping above the signal strength threshold:
You will likely need a preamp for those marginal 50mile stations.

Preamp,..how big?:
Preamp selection [17db or 29db] greatly depends on how long your downlead cabling will be from the antenna, to a splitter, and the cable lengths going to the two TV's. A very powerful preamp could be a problem because of those stations that are withing 10 miles.

Line loses?:
The more cable you have in the system, the more line loses you will have to overcome. Also, having two TV's means you'll have to use a splitter at the end of the downlead to join 2 lengths of cabling for the two TV's. A splitter can create significant line loss. So, depending on your cabling lengths, you may need some sort of a mast mount preamp / downlead cable / connected to a splitter / and then 2 cable runs to the two TV's. [if the signal is too weak after the splitter, then a dist amp may be needed between the downlead end and the spitter to compensate for the splitter loses]
 

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One antenna using a rotor, and two TV's presents an obvious problem for what each individual viewer can watch. If one viewer wants a channel from the west and the other wants a channel from the east, then the fight is on
Look like you gave me a good reason to build a second antenna before I even managed to finish one! I'll tinker with a Stealth Hawk.


You will likely need a preamp for those marginal 50mile stations.

Preamp,..how big?:
Preamp selection [17db or 29db] greatly depends on how long your downlead cabling will be from the antenna, to a splitter, and the cable lengths going to the two TV's. A very powerful preamp could be a problem because of those stations that are withing 10 miles.

Sounds like a catch 22...and looks like I'll have to compromise somewhere.

Thanks alot for taking the time to help and to explain. I greatly appreciate it.
 

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Sorry, I wasn't specific. The center two bays of your 8-bay stay the same as in your original photo; the balun (short for BALanced-to-UNbalanced) connects the same way. If you want to connect two 4-bays together, you first connect the two feedpoints together, and then attach your balun to the midpoint of that line. Not to be insulting, but I assume that you know that where the phasing lines cross, they must not touch each other.



I suggest that before you correct the phasing lines, you take some signal strength readings of selected channels. Then, after you correct the phasing lines you take another set of readings for comparison to see if you have made any improvement. Since you have already built this antenna you might just as well use it for tests before going on to the next antenna.

Keep in mind, however, that OTA signals are constantly changing in strength, and your second set of readings might be at a time when the signals have changed strength. The only way around that (as I did here) is to set up two antennas with an A/B switch to make an instant comparison between a reference antenna and the antenna under test. Even if the signals have changed strength, the difference between the two antennas will remain constant.
 

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Thanks for the correct phase line connections....and not insulting at all, in fact I appreciate it. I definitely will do as you suggested, and take some general readings with my converter box before I make changes and hope they can be compared.

Thanks again
 
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