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Old 2-Sep-2014, 3:29 AM   #1
antennaCT
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Wfsb

Hello,

I've been happily using a home made 8 bay bowtie antenna all summer. Mounted outside on roof about 20'- 25' above ground level.

No reflector, about 100' of cable, one TV, TVPRAMP1R preamplifier.

I now find that I would like to pick up WFSB Real channel 33 (3.1) for occasional viewing, a few hrs, one day/night a week. I have adjusted the antenna to the correct direction but not able to pull in the signal. I have noticed it has a Co channel warning and I'm guessing this is my problem. Real channel 33 WCBS (2.1)

What kind of options are there to pick up WFSB?

http://www.tvfool.com/?option=com_wr...5b9403fa207f4a

Thanks for any and all help.
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Old 2-Sep-2014, 7:04 AM   #2
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To see what happens to signal strengths , if improve , and the over all reception situation.

Please make and post 2 more tvfool reports with antenna heights 40 and 60 feet above ground.
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Old 2-Sep-2014, 7:17 AM   #3
GroundUrMast
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I'm curious, can you provide a link to the design of the antenna you built?

You need an antenna or array with a very good front to back ratio. WCBS is about 6 dB stronger than WFSB. In theory, the signal to noise ratio of the desired signal needs to be better than 15 dB... In the air you're at roughly -6 dB SNR assuming only the signal from WCBS is contributing noise. Given the extremely weak signal levels in the air, I'm sure you have additional sources of noise to factor in... TV Fool has no way to predict those. The bottom line is that your antenna system needs to have 21 dB more gain (as a minimum) in the direction of WFSB than toward WCBS.

Be prepared to patiently and persistently experiment. I'd start with an off the shelf solution. I might try an Antennas Direct DB8E and moderate gain preamp such as the RCA TVPRAMP1R. The forward gain and F/B ratio of the DB8E are at least approaching what may be required.

I would also strongly consider stagger stacking a pair of identical UHF Yagis such as the Antennas Direct 91XG, Winegard HD9095P or Antennacraft MXU-59. If staggered and aimed correctly, the needed F/B ratio may be achieved.

Here is a bit of info re. stacking and ganging, http://forum.tvfool.com/showthread.php?t=1024. In particular, I'm thinking of the link, http://www.anarc.org/wtfda/stagger.pdf, page 5

(If you want to try to improve your existing antenna, a reflector would be vital to improving it's F/B ratio and forward gain.)
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Last edited by GroundUrMast; 2-Sep-2014 at 8:34 AM. Reason: sp. & grammar... asking for antenna details
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Old 2-Sep-2014, 12:20 PM   #4
antennaCT
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tvfool reports with antenna heights 40


tvfool reports with antenna heights 60
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Old 2-Sep-2014, 1:43 PM   #5
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GUM has correctly identified the problem. You need an antenna with a reflector. Your bi-directional antenna is probably picking up both stations and cannot resolve either,
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Old 2-Sep-2014, 4:04 PM   #6
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The two reports you've posted strongly suggest that mounting height may play a key role in your success or failure. It appears that the signal strength difference shifts toward favoring WFSB as you increase mounting height. Regardless, you'll still need as much forward gain as you can muster, while also supressing gain toward the rear. (A high F/B ratio.)
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Last edited by GroundUrMast; 2-Sep-2014 at 4:06 PM.
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Old 3-Sep-2014, 1:30 AM   #7
antennaCT
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Quote:
Originally Posted by GroundUrMast View Post
I'm curious, can you provide a link to the design of the antenna you built?
Its an 8 bay 9-5in element layout

Attached is a pic of my 4 bay prototype. I put two together and made my own co-phase line. They are side stacked.

Hoping that I don't have to purchase a new antenna.

------------------
Quote:
Originally Posted by ADTech View Post
GUM has correctly identified the problem. You need an antenna with a reflector. Your bi-directional antenna is probably picking up both stations and cannot resolve either,
I would have to agree with you. I tried a reflector on the antenna but lost quite a few channels, decided to remove it. I'll test it by covering the back side to see if WFSB comes in.

Thank you.
Attached Images
File Type: jpg 4 bay prototype.jpg (97.0 KB, 566 views)

Last edited by antennaCT; 3-Sep-2014 at 1:47 AM.
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Old 3-Sep-2014, 5:03 AM   #8
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The mclapp design is one of the better DIY options. I would consider it a good general purpose antenna. For your specific application (gooing after WFSB), I would lean toward a channel cut design, optimized for peak F/B ratio.

If you are trying to avoid a store bought solution, consier building a pair of identical Yagi antenans cut for real CH-33. I just uploaded a design for one... http://forum.tvfool.com/showthread.php?t=1106

A stagger stacked pair may achive the needed forward gain together with sufficient F/B ratio.
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Old 3-Sep-2014, 11:53 AM   #9
antennaCT
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Quote:
Originally Posted by GroundUrMast View Post
The mclapp design is one of the better DIY options. I would consider it a good general purpose antenna. For your specific application (gooing after WFSB), I would lean toward a channel cut design, optimized for peak F/B ratio.

If you are trying to avoid a store bought solution, consier building a pair of identical Yagi antenans cut for real CH-33. I just uploaded a design for one... http://forum.tvfool.com/showthread.php?t=1106

A stagger stacked pair may achive the needed forward gain together with sufficient F/B ratio.
GroundUrMaster

I just viewed your Yagi design. I know very little about them, not quite sure what to make of the info or how to build yet. I'll read up on these.

BTW Last night I covered the back of my existing antenna did a re-scan and was not able to pull in WFSB I did loose WCBS so the co channel issue should not have been a problem.

Thanks again for your assistance.
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Old 3-Sep-2014, 3:46 PM   #10
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In order to pick up WFSB reliably you'd need more than 25 db rejection of WCBS. The reflector on a McClapp is not enough to do that. GUM's stagger stacking will work, but gets complicated, and requires two identical yagis. http://www.anarc.org/wtfda/stagger.pdf

A simpler scheme is to build a second McClapp antenna with reflector and stack it 29" horizontally from the first. When aimed at WFSB at 53 degrees the signal from WCBS at 213 will be 20 degrees off the back, and will be in the first null off the back of the antenna. Read about it here. http://www.hdtvprimer.com/antennas/ganging.html
Precise aiming at WFSB will be necessary. That should get you the Patroits while WCBS carries the Jets.

Another choice for a second CBS is WRGB. A Y5-2-6 aimed at Albany and a HLSJ to join the yagi to your McClapp antenna should get two CBSs without reaiming. Unfortunately, WRGB usually carries the Jets over the Pats or Bills.
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Old 3-Sep-2014, 3:49 PM   #11
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Quote:
Originally Posted by antennaCT View Post
BTW Last night I covered the back of my existing antenna did a re-scan and was not able to pull in WFSB I did loose WCBS so the co channel issue should not have been a problem.
Actually, that indicates that interference between WFSB and WCBS is likely the cause of no reception of either CBS.
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Old 4-Sep-2014, 4:30 AM   #12
antennaCT
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Quote:
Originally Posted by Tower Guy View Post
In order to pick up WFSB reliably you'd need more than 25 db rejection of WCBS. The reflector on a McClapp is not enough to do that. GUM's stagger stacking will work, but gets complicated, and requires two identical yagis. http://www.anarc.org/wtfda/stagger.pdf

A simpler scheme is to build a second McClapp antenna with reflector and stack it 29" horizontally from the first. When aimed at WFSB at 53 degrees the signal from WCBS at 213 will be 20 degrees off the back, and will be in the first null off the back of the antenna. Read about it here. http://www.hdtvprimer.com/antennas/ganging.html
Precise aiming at WFSB will be necessary. That should get you the Patroits while WCBS carries the Jets.

Another choice for a second CBS is WRGB. A Y5-2-6 aimed at Albany and a HLSJ to join the yagi to your McClapp antenna should get two CBSs without reaiming. Unfortunately, WRGB usually carries the Jets over the Pats or Bills.
Thank you Tower Guy,

I want to be sure I understand your thoughts.
It Is the Patriots game my son is interested in (WFSB). So WRGB in this case wouldn't help great suggestion though.
  1. Build a second McClapp antenna with a reflector, set it 29" horizontally (on one side of the existing) pointing at 53 degrees towards WFSB.
  2. The reflector on new antenna would not allow signal from WCBS to conflict.
    I intending to make a second antenna. Same design but different whiskers, copper rather than Galvanized.
  3. A combiner or splitter would be needed to connect the two antennas.
  4. "the first null off the back of the antenna" Not sure I understand the meaning 100%
  5. I didn't use a deflector per say to block the back side of the antenna. I used a large piece of metallic Styrofoam about 6-8" away.

Thank you.
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