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Old 4-Apr-2016, 6:20 AM   #1
traker1001
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Is there a way to get 25 KCKS 2edge channel

Hello, I am trying to help my grandfather get setup with an antenna after moving. Currently he has a Rooftop antenna probably 5ft off the roof on a single story house. The antenna is a double bowtie type, and a cable is run straight into the TV. We get most the channels at 100% signal and excellent quality. One channel he had before he moved and really wants back is about 25 miles away. That is KCKS 25.X channels. But if possible wants to maintain his other channels.

This is the TVFool report, http://www.tvfool.com/?option=com_wr...5134db34d0fbf5

So with this do you think there would be an antenna that would make it possible to get this channel.

Any help would be greatly appreciated.
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Old 4-Apr-2016, 11:09 AM   #2
Jake V
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KCKS-LD is a low power station with towers only 200 feet above the ground. That's part of why the signal strength is so low even through the broadcast tower is only 22 miles away.

What direction does your antenna currently point? My expectation is that it is currently pointed to about 170 degrees on a compass (just east of south). I'd try pointing it directly at KCKS-LD (255 degrees) and see what happens. The rest of your stations are pretty strong and you might receive them off the side.
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Old 4-Apr-2016, 11:32 AM   #3
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Did you try aiming the current antenna back to the west to see if it could be received, disregarding any ill effect to the rest of the stations?
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Old 4-Apr-2016, 7:01 PM   #4
traker1001
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Hello, Thanks for the replies, We really appreciate them.
Yes I connected my hd homerun to the antenna and climbed up there with my laptop and adjust the antenna as I watch the signal strength. best signal strength we could get was 56% and nothing would go green (Lock on and show call letters.).

Thanks for the explanation Jake, I didn't fully understand what I was reading, That's kind what I though the case might have been. You are exactly correct about where the antenna we lose about 2 channels and 2 more go really weak when it is pointed directly at the station. I also tried raising the antenna by about 10ft and that didn't really help at all either.
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Old 4-Apr-2016, 7:31 PM   #5
rabbit73
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If KCKS is important, you will need a separate antenna with more gain aimed directly at it. If you try to use a preamp for that antenna only, it might be overloaded by your strong local signals, unless it is resistant to overload. Also, the strong signals will be weaker when the separate antenna is aimed away from them.

You can use an A/B switch to select which antenna is needed. You will need to rescan after each antenna change unless the TV can add a channel after a scan like my Sony.

An alternate plan would be to connect the main antenna to the TV antenna input and the KCKS antenna to a separate tuner with its output connected to the TV aux input.

It is possible to buy a custom combiner to integrate the KCKS antenna into one system, but that would be expensive. Each antenna should get what you want before combining. Using a splitter in reverse as a combiner probably would not work.
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Last edited by rabbit73; 4-Apr-2016 at 7:43 PM.
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Old 4-Apr-2016, 9:37 PM   #6
traker1001
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Well I think the first thing I would want to do is just try to get those KCKS stations and not worry about the current closer stations at the moment. Could you recommend a setup if for example that was the only station I desired to get and didn't care about the other stations at all? Is there a specific amp or roof top antenna that would do me good?
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Old 5-Apr-2016, 1:28 AM   #7
rabbit73
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Fascinating question. I can see why he might like it; look at all those sub channels.
https://en.wikipedia.org/wiki/KCKS-LD
http://www.rabbitears.info/market.ph...&callsign=KCKS

Since your HDHR test showed that you almost go it, maybe it's possible.

The antenna would need more gain and have a pattern that would reject the stronger signals from the south when it is aimed at KCKS at 255 degrees magnetic.

Antennas to consider are:
Antennas Direct DB4e for a little more gain and a little more narrow beamwidth
https://www.antennasdirect.com/cmss_files/attachmentlibrary/Technical%20Data%20PDF's/DB4E-TDS.pdf

Antennas Direct 91XG; even more gain and more narrow beamwidth to reject signals from the south
https://www.antennasdirect.com/cmss_files/attachmentlibrary/Technical%20Data%20PDF's/91XG-TDS.pdf

How long is the feedline from the antenna to the TV?

Try it without a preamp first. If you must have a preamp, consider the CM3410 or the Antennas Direct Juice.

Aim the antenna for best signal quality and best symbol quality on the HDHR,

The last resort would be a high gain UHF antenna, custom single channel bandpass filter for channel 25 from Tin Lee Electronics, and an overload resistant preamp.
http://www.tinlee.com/index.php

Tin Lee also makes the AC7 signal injector that could combine the KCKS antenna signal with the main antenna.
http://www.tinlee.com/PDF/AC7-custom...kup%20Info.pdf
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Last edited by rabbit73; 5-Apr-2016 at 1:58 AM.
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Old 5-Apr-2016, 2:40 AM   #8
traker1001
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Ok so I jumped right in and ordered the 91XG Antenna. Ill give that a try first and see where we will go from there. The feed line is about 40ft~50ft of rg6. When I aim the current antenna I show about 56% signal quality, But I get 0% symbol quality, Should I show symbol quality or does that only happen when the tuner is able to lock on to signal?

@Edit I think I am confusing quality and strength. I get 56% strength, but quality and symbol both stick at 0.

@Edit, Sorry for the edits. I got back up on the roof this evening and raised the antenna and aim little more. I was able to get a steady 64% Strength, still no lock, symbol or signal quality.

Last edited by traker1001; 5-Apr-2016 at 3:06 AM.
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Old 5-Apr-2016, 3:23 PM   #9
rabbit73
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Thank you for making another test.

Signal strength is just about enough, but signal quality and symbol quality aren't what they should be. Signal quality is similar to SNR and symbol quality is the inverse of uncorrected errors. You want 100% symbol quality for no uncorrected errors.

I think I know what is going on. If you look at your tvfool report you will see a red "a" next to the KCKS callsign. This is a warning of adjacent channel interference, in this case from KCTV with a NM of 72.4 dB, making it 70.7 dB stronger than KCKS with a NM of 1.7 dB.

The signal strength reading you are getting might not be only from KCKS, it might also include some signal from KCTV spilling over into the KCKS channel.

TV tuners are expected to be able to decode a weak signal that is 33 dB weaker than a stronger adjacent channel. It is not known if your HDHR or the TV tuners meet or exceed that spec, but 70.7 dB is a lot more than 33 dB.

ATSC Recommended Practice:
Receiver Performance Guidelines

Document A/74:2010, 7 April 2010

RECEIVER PERFORMANCE GUIDELINES

5.4.2 Adjacent Channel Rejection

Quote:
The receiver should meet or exceed the thresholds given in Table 5.2 for rejection of first adjacent-channel interference at the desired signal levels shown above the columns therein.


The antenna pattern for the 91XG will make KCTV 20 dB weaker when it is aimed at KCKS, so it is now only 17.7 dB over spec.



So, try the 91XG when it comes, with the HDHR and the TV tuners and let us know the results.

If you are not quite there yet, a custom filter, the two-antenna trick, or a shielded antenna enclosure are next on the scale of extreme measures for your grandfather.
Attached Images
File Type: jpg 91XGtraker1001TVF.jpg (135.8 KB, 1254 views)
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Last edited by rabbit73; 5-Apr-2016 at 7:02 PM.
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Old 5-Apr-2016, 11:03 PM   #10
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I have been making calculations based on your tvfool report which was done at 10 feet. I was curious to know how KCKS would look at higher antenna heights, but I don't have your exact location.

I derived two estimated locations based on your report. Both of my estimates are close together and have the same short coordinates as your report, but give different results for KCKS, while giving similar results for the strong signals, azimuths, and distances.

I think the big changes in KCKS with a small change in location are because of the uneven terrain in your area and the low height of the KCKS transmitting antenna as noted by Jake V.

KCKS Antenna
Antenna Height Above Ground Level: 220' 67m
Antenna Height Above Mean Sea Level: 1220' 371.8m
http://www.rabbitears.info/tvq.php?r...s&facid=187964

I assume that you used the coordinates for the location of your antenna for your report and checked them with the interactive map browser. The coordinates below the map change as you move the cursor to the antenna location.
http://www.tvfool.com/index.php?opti...pper&Itemid=90

I used my estimated locations for you and saw that there are a lot of trees in your area. I hope you can get the antenna above the trees.

I then used those two sets of coordinates, called Location A and Location B, to generate reports at 10, 25, 50 feet using the regular tvfool report:
http://www.tvfool.com/index.php?opti...pper&Itemid=29

Location A:
10 feet, KCKS NM -3.3 dB
http://www.tvfool.com/?option=com_wr...513470c8fd6329

25 feet, KCKS NM +10.5 dB
http://www.tvfool.com/?option=com_wr...5134b1a3b38c9e

50 feet, KCKS NM +22.2 dB
http://www.tvfool.com/?option=com_wr...5134fe89ad9246

Location B:
10 feet, KCKS NM +5.7 dB
http://www.tvfool.com/?option=com_wr...513412a9f8fd26

25 feet, KCKS NM +16.4 dB
http://forum.tvfool.com/showthread.php?t=15967

50 feet, KCKS NM +24.2 dB
http://www.tvfool.com/?option=com_wr...51345fc62009fe

Maybe your chances are a little better than I thought if you can get above the trees.

I'll send the coordinates I used to you by PM, so you can see how close I came.
Attached Images
File Type: jpg traker1001TVFtowerKCKS.JPG (79.8 KB, 237 views)
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Last edited by rabbit73; 6-Apr-2016 at 12:39 AM.
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Old 6-Apr-2016, 1:00 AM   #11
rabbit73
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Here is the terrain profile between the KCKS transmitter at the left and your location at the right. You can see why the terrain causes a problem for the signal because of the low height of the transmitting antenna, and why raising the receiving antenna helps.
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File Type: jpg traker1001TVFp2KCKS.JPG (88.3 KB, 1131 views)
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Last edited by rabbit73; 6-Apr-2016 at 1:07 AM.
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Old 6-Apr-2016, 2:43 AM   #12
traker1001
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All I can say is Wow! You really know your stuff. I PM'd you with my exact cords, But you were really close on. This is the antenna that is currently mounted to the roof.

http://www.amazon.com/Eagle-Aspen-EA.../dp/B000GIT002

It is mounted roughly 10ft off the ridge of the roof of a single story home. I am unsure how high off ground level that is.
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Old 8-Apr-2016, 1:33 AM   #13
traker1001
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So the antenna should arrive tomorrow hopefully, So Ill get up there and get it setup, Fingers crossed, Ill let you know what happens. I am really super grateful for all the assistance.
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Old 8-Apr-2016, 5:50 PM   #14
traker1001
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Hello, I haven't gotten the new antenna yet, But I have a question. can you combine two antennas pointed in the same direction and increase sensitivity even further or is there basically a limit.

I.e. If I were to take the yagi type antenna, and the bowtie I have and point them both towards this station and join the connection via splitter? Or does that kinda setup just mess things up?

I only ask, Because I look at many of these grid type antennas and they look like they are just multiple antennas joined. Also this stuff kinda fascinates me.
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Old 8-Apr-2016, 7:03 PM   #15
rabbit73
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Yes, you can combine two antennas aimed in the same direction for more gain, but they must be identical antennas, and the two feed lines must be the same length. This is what Calaveras has done with his two 91XGs:
http://www.aa6g.org/DTV/index.html

The theory predicts a gain of 3 dB, but the most you can expect when using a splitter in reverse as a combiner is 2.5 dB because of the internal loss of the combiner.

The reason why you must have identical antennas, aimed in the same direction, with identical length feed lines is because you want the two signals to arrive in phase at the combiner.

Under any other conditions, it might or might not work; trial and error, good luck, you are on your own.

First, each antenna alone must get what it should. If you then combine them and some channels are missing, then it isn't working.

If you are combining two antennas that have printed circuit baluns, they will be in phase. If you are combining two antennas that have the older style 300 0hm to 75 ohm pigtail baluns, you must reverse the 300 ohm wire leads on ONE of the baluns to see which way gives the most gain. When they are not correctly phased together, the main lobe splits in two with a null between them at the aiming point.



Sometimes you want the two antennas out of phase, to split the main lobe in two. This is done when you want strong local signals placed in the null to make them weaker, so that one of the two lobes can pick up weaker signals from another direction. This is called the two-antenna-trick (outdoor version), and could be used in your case to make KCTV weaker. See Example 3:
http://www.hdtvprimer.com/antennas/ganging.html

I assume you are talking about two UHF or two VHF antennas. If you are combining a VHF antenna with a UHF antenna, they should be combined with a UVSJ UHF/VHF combiner, not a splitter in reverse.
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Last edited by rabbit73; 8-Apr-2016 at 7:55 PM.
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Old 9-Apr-2016, 8:36 PM   #16
traker1001
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So With the new antenna (Which is huge BTW) the best I can seem to see is 40% signal strength, However, I suddenly get a 40% symbol quality as as well. I show a 0% - 5% signal quality. If I mess with it enough, I get burst to about 90% an all goes green for about 5 seconds then it drops back to where it was.

as soon as I can, I am going to get a longer poll and see if I can raise the antenna up about 20 ft off the roof see if that makes a difference.
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Old 10-Apr-2016, 6:29 PM   #17
traker1001
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Do you think a preamp might help when I get the antenna up higher?
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Old 11-Apr-2016, 12:29 AM   #18
Billiam
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If you try a preamp go to Menards and get the RCA pre amp they sell. I use one at my home in Cincinnati in the shadow of many, very strong signals. The RCA is not overloading like other pre amps do when strong signals are present. As a result I am able to get some weak signals from Dayton.

More height on your antenna may help. Try that first. Or try moving it around to one or more different spots on the roof or property to see if that helps. Digital signals are finicky. Right now I live east of KC and use a 4 bay antenna inside my apartment. Moving it from one window (facing west) to another about three feet further south, I am suddenly getting a lot of multipath from Ch. 41 and on Ch. 5. But moving the antenna back to the window further north by 3 feet, suddenly the pictures are fine and very rarely break up.

Also, consider buying some RG11 cable if your cable run is really long. That will reduce some signal loss. I've done that in the past with runs of cable over 50 feet and it added perhaps a half db of signal strength to some of the UHF signals.
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Old 12-Apr-2016, 1:30 AM   #19
rabbit73
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I did a tvfool report using your exact coordinates at 25 feet:
http://www.tvfool.com/?option=com_wr...513446ab1b8443

The NM difference is now only
KCTV 72.4 dB - KCKS 17.4 dB = 55 dB

55 dB - 33 dB adjacent channel allowed = 22 dB

22 dB - 20 dB from antenna pattern = only 2 dB away from spec

Raising the antenna makes the KCKS NM much better, with little change in the KCTV NM, because the KCKS signal is coming in at a very low angle and skimming the trees and terrain. You must get the antenna as high as possible to clear the path from the west.






Using a preamp is a last resort. The AD Juice and the CM3410 are more resistant to overload than the RCA TVPRAMP1R; see attachment 3.

RCA TVPRAMP1R max input UHF = -35.5 dBm
Antennas Direct Juice max input UHF = -21.3 dBm

RCA TVPRAMP1R SFDR UHF = 67.3 dB
Antennas Direct Juice SFDR UHF = 81.7 dB

SFDR is the difference between the weakest and strongest signal that the preamp can handle.

Even if the preamp can avoid overload, the tuner might be overloaded by your strongest signals. KCPT has a NM of 73.7 dB even before adding antenna and preamp gain. The preamp would improve the system noise figure, but you would need to add an attenuator after the power inserter to prevent tuner overload.



Interpreting Noise Margin in the TV Fool Report
http://www.aa6g.org/DTV/Reception/tvfool_nm.html
Attached Images
File Type: jpg traker1001TVFtrees2.JPG (100.0 KB, 1024 views)
File Type: jpg traker1001TVFtrees_1.jpg (161.0 KB, 1081 views)
File Type: gif Peamp.gif (82.7 KB, 250 views)
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Last edited by rabbit73; 12-Apr-2016 at 11:39 AM.
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Old 14-Apr-2016, 7:00 PM   #20
rabbit73
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I did an FM signal report for your location. You have some very strong local FM signals that might interfere with TV reception. Ordinarily, they would only interfere with VHF signals, but since they are even stronger than your strongest TV signals they might interfere wit the reception of KCKS.
http://www.fmfool.com/modeling/tmp/6...6/Radar-FM.png

http://www.solidsignal.com/pview.asp?p=zhlsj
http://www.nsccom.com/hlsj.aspx

If the antenna is outside, the coax shield should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety and to reject interference. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge, but the system will not survive a direct strike.



Grounding the coax with a grounding block makes the FM filter more effective.
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Last edited by rabbit73; 14-Apr-2016 at 7:32 PM.
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