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Old 4-Sep-2013, 3:31 AM   #1
Pete
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Fine tuning

Hi to all, I've spent many hours reading hundreds of posts, but I still need your help/advice.

Below is my radar-chart,

http://www.tvfool.com/?option=com_wr...46ae2a419d83a4

I live in a two storey house. Behind my house there is a forest about a mile wide by half a mile deep. Trees are about 20 feet taller than my house. Surrounding area is basically flat. No hill, or mountain. The other three sides of my house are surrounded by two storey houses.

I installed a RCA ANT751 in my attic and pointed it S-W. I received 14 HD Canadian channels. All perfectly clear. I tried many orientations for the antenna and found the one which gives me the most channels.

Yesterday we had some pretty bad weather over upstate NY and where I live. Lots of clouds, rain. I did a scan and received an additional 8 American channels; 7.1 WWNY, 7.2 WNYF Fox 28, 7.3 WNYP Fox 28, 18.1 WNPI-DT PBS, 18.2 WNPI-DT PBS, 18.3 WNPI-HD PBS, 28.1 WNYF Fox 28 and 28.2 WWNY HD.

My question is do you think that I would be able to receive all Canadian and American channels if I were to install an Antenna Direct XG91 in the attic? Or do you have another suggestion? I do not care about VHF.

The antenna can't be on the roof due to seagulls and pigeons who love my roof. The roof is 1" plywood + asphalt shingles.

I have a second question.

The ANT751 is connected to approx. 50' of cable and then into an Antronix 1 port 15Db amplifier. And then (1 foot of cable) into a Microline 4 ports 7db/port amplifier.

The house was built 5 years ago and is completely wired for cable, internet and phone. If I bypass the second amplifier and go straight to a tv (located some 30' away), I only get 12 channels when I do a scan, but when I connect it to the second amplifier and then to the tv, I get 14 channels when I do a scan. Would I be better off buying a 30 amp amplifier to replace the 15 amp?

Thanks to all for your help.

Pete

Last edited by Pete; 4-Sep-2013 at 3:35 AM.
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Old 4-Sep-2013, 7:12 AM   #2
GroundUrMast
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Questions...

The short answer is, you'll need to try the 91XG to know for certain.

Given that your TV Fool report is flagged: "WARNING: Address was only resolved approximately and might not be that close to your actual location. For more accurate results, try entering a specific address or coordinates.", it's uncertain if the data actually reflects the conditions at your location.

When generating a TV Fool report, my preferred method is to open the Interactive TV Maps tool. Leave the 'input method' set to the default, 'address'. Then, enter only the Postal Code, and then click the 'Map This' button.

At this point you should have a map displayed, with a movable cursor located at the center of the Postal Code that was entered. Use your mouse to drag the cursor to the exact location you're interested in. In the upper right corner of the map you can select from four view types, I find it helpful to have all four available... The Hybrid and Terrain modes seem to be what I use the most.

At the bottom of the map, enter the antenna height. You can also find the LAT/LON coordinates of the cursor (in decimal form, not deg/min/sec).

Once the cursor location and the antenna height are set correctly, click on the 'Make Radar Plot' button located at the upper right corner of the map. The TV Fool report opens in a new tab or window. You can then copy the URL from the address bar of your browser, for posting to a thread.

I hope this helps, I just want to be sure we give you advise based on the actual conditions at your location.

Is the existing antenna pointing toward the 'forest'?

Are you willing to 'test' reception with the antenna outside, clear of the obstruction caused by the attic/roof construction materials?

What call sign(s) is(are) added when you use two amplifiers?

What's the total length of cable from the antenna to the TV on the longest run? Are there any passive splitters in line? If so, how many output ports, and are there unused ports with no termination?
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Old 4-Sep-2013, 4:41 PM   #3
Pete
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Thanks for all the help. I followed your suggestion and got a new chart using your method.

http://www.tvfool.com/?option=com_wr...46ae2d5ba57b79

Yes, the antenna is pointing right thru the forest. The forest is not dense and is 95% leafy trees.

The antenna must go in the attic, so there is no point testing it outside. No matter how many channels I get 'outside', the antenna still has to go in the attic. Sorry.

I re-did the test using only one amplifier instead of two, but I didn't succeed to repeat the previous result of obtaining only 12 channels instead of 14. It could be due to the fact I replaced a 50' cable with a 10' which took me from 90' of cable from antenna to amp down to 50' of cable. I initially didn't have a 10' cable.

Btw, in addition to receiving all the channels listed in the green portion of the table, I also get two additional channels not currently listed. 9.1 RDI (CBC in French - it comes on 9.1 and 9.2). I also get 11.1 CHCH-DT1. Also, some of the channels (virtual) do not match mines. For example, City TV is listed as 17.1 on the chart, but I get it on 65.1.

The cable/internet/phone panel in the basement has a "module 1 X 8 Way Splitter, 4 X10 Phone 110 Terminal". Max distance from module/splitter to TVs is ~ 50'.

To repeat: antenna--->50' cable--->Antronix 1 port 15db--->1' cable--->Microline 4 ports 7db/port--->~50' cable---> tv OR --->1' cable--->Module/splitter--->~50' cable---> tv.

IOW, I use 3 ports of the Microline to go directly to TVs and use one port to feed the Module/Splitter. And from the Module I go to additional TVs.

So the questions are: 1) Which antennas could go to the attic and might give me all Canadian and American channels? And, is it worth it to try a 30 db amp instead of my 15?

Thanks

Last edited by Pete; 4-Sep-2013 at 4:43 PM.
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Old 4-Sep-2013, 6:36 PM   #4
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Thanks for double checking the report Pete. Now that we're confident in your TV Fool report, I think that even a 91XG in the attic would only see the WNPI, real CH-23 and WWYF, real CH-18 signals intermittently, when the atmospheric conditions are favorable. The signal from WWNY on real CH-7 should not be expected at all when using a UHF only antenna in an attic.

In general, reception can be tested by using just the antenna, a cable up to 50' long and a single TV with a good tuner - no amplifiers or splitters. Amplifiers are applied when you have cable or splitter loss to overcome, they don't 'pull' additional signal from the cable, antenna or air. The most effect location for an amplifier is at the antenna, before the signal is degraded by loss in a run of coax. I say all that to be sure future readers understand that if the antenna is not producing a reliable signal, amplification is not going to be of much help.

Back to your case specifically, removing 40' of cable is not completely insignificant, but that would only result in about 2 dB signal improvement. I have to wonder if there was a problem with the cable that was changed from a 40' to a 10'.

I have a very difficult time recommending a single 30 dB amplifier. Most will be prone to overloading which causes signal distortion. That you have to use two amplifiers now may reflect the poor reception conditions forced on you by the antenna location. But it may indicate a problem with a cable or connector. Even if you have need for that much amplification due to cable and splitter losses, you need to consider whether TVs close to the output of a 30 dB amplifier would suffer overloading on strong signals.

From you last post, I understand that the TV most distant from the antenna has 150' of coax and two splitters to contend with. One of the splitters is built into the Microline amplifier. The math says that at the highest UHF frequency, you should have no more than 9 dB loss in the coax. A 4-way splitter should have no more than 8 dB loss and an 8-way, no more than 12 dB loss. All that loss adds up to 29 dB.

To slightly improve your system performance, I'd suggest that the Microline amp be located at the antenna. It's a 15 dB amp, followed by a 4-way splitter (15 - 8 = a net gain of 7 dB per port). On paper, the +7 dB per port is enough to drive the three 'upstairs' TVs and a 100' run of RG-6 coax to the basement. At the end of the 100' run to the basement, insert the 15 dB Antronix single output amp which directly feeds the 8-way splitter. Be sure to terminate all unused splitter ports with a 75Ω resistor cap.

This arrangement will provide at lest 2 or 3 dB improvement in net system noise margin and only cost some cable rearranging.
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Old 4-Sep-2013, 8:17 PM   #5
Pete
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Thanks for all your info. It is very much appreciated.

In regards to the antenna, are you saying that if I were to use a 91XG, I should have no problem getting all 14 CAD channels and I might be able to pickup 1 or 2 US channels?

Are there other antennas you would recommend to give this a try?

My goal is to add American channels to my CAD channels. I could go VHF if necessary.

Should I try two antennas? One mounted 40" above the other on the same pole.

I would appreciate all your antenna suggestions.
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Old 4-Sep-2013, 8:38 PM   #6
GroundUrMast
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I'm recommending that you optimize your current system. Place the existing amplifiers in their optimal locations. Then as your budget allows, experiment with other antennas.

The 91XG may be too directional. It may leave you with great reception in the direction of aim point, but you could see trouble with reception from the rear. Less aggressive antennas such as the Antennacraft HBU-33 and HBU-44 may work... The bottom line is, you'll need to experiment.

Your attic is unique, I can't predict how it impacts your antenna performance precisely. Illustrating this point, using just the low gain ANT-751, signals with NM values in the +40's and higher would be expected to drive all of your cable and splitter loss without any amplification, if not for significant penetration losses in the attic. Then there's the trees... I'm guessing that you have 10 to 30 db of penetration loss at the antenna's attic location.
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Old 4-Sep-2013, 9:34 PM   #7
Pete
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I'm afraid I wasn't clear enough in my previous posts.

The maximum length of cable is ~ 100'. 50' from the antenna to the Antronix booster in the basement and then another max 50' to each tv.

I connected a tv directly to the antenna, no amplifier and no splitter. Length of cable is about 90'. All the channels are there and very good quality of picture and sound. But the amplifier(s) seem to make the picture even stronger. So I don't absolutely need the amplifier, but since I had those two I decided to use them.

Sorry for not being more clear. Does that change your recommendations in regards to which antenna to try?

Thanks.
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Old 4-Sep-2013, 9:43 PM   #8
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Oops, I missed a very important 'OR' in your cable word diagram. That changes the loss calculation in your favor by about 3 dB.

Quote:
Does that change your recommendations in regards to which antenna to try?
No.

And the most effective location for an amplifier is still, at the antenna.
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