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Old 7-Jan-2011, 8:09 PM   #21
John Candle
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Tv Antennas and Reception

The HD7210P is a highly directional Ghost/Multipath killer antenna. The HD7210P receives channel 4 and this antenna is designed to reject multipath on the sides and back of the antenna. I know what he is suggesting to do with the 91XG , however I will not say because he is just throwing out information and not being clear what to do with it.

Last edited by John Candle; 7-Jan-2011 at 8:21 PM.
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Old 7-Jan-2011, 8:16 PM   #22
Tower Guy
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Quote:
Originally Posted by youngclarkh View Post
First) Are you suggesting a 91XG directed at the translators? If so, how would that get me 25 (FOX) since it doesn't transmit from there?

Second) The 91XG is not supposed to get VHF in a range low enough to pickup channel 4 (NBC).

I'm confused
My original suggestion of aiming a 91XG at 7° remains untested.
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Old 7-Jan-2011, 8:37 PM   #23
youngclarkh
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I have been unable to find the 91XG or the 7210P anywhere in Tucson. I am reluctant to buy them over the internet because I can't easily return them if the test fails.

Is there no way to pull in channel 4 using my existing antenna?
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Old 7-Jan-2011, 9:46 PM   #24
John Candle
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Tv Antennas and Reception

Yes there is , but first if you have not done so already , ground that coax with a coax grounding block , the shield of the coax is one big long antenna , grounding the shield of the coax will help by directing undesirable signals to ground. <-- This might get you channel 4. . . The first one to try is the easyest , lower and raise the antenna a little or a lot , you can even try the antenna at closer to ground level , you can try using buildings as shields but do not block the front of the antenna. . . The next one to try is , Shielding , with a big flat metal shield about 6 feet by 4 feet , you can cover a big sheet of card board with extra thick aluminum baking foil or if you can find thin metal sheating thats used for metal flashing on roofs. What you do is hold the metal up so the long part of metal is horizontal with the ground and the move the shield so that it shields the antenna from all different angles except the front , so you hold the shield up at the back of the antenna and try for channel 4 , then hold the shield at corner back angle and then at the side of the antenna and so forth and so forth. . . . Next you can try this , if the metal receiving elements of your antenna are sticking straight out from the sides of the antenna then sweep them forward , first unlatch the spacer elements that are attached directly to the boom and turn them length ways with the boom to get them out of the way and then unlatch the VHF elements and sweep/move them so they are at about a 45 degree angle toward the front of the antenna. Doing this narrows the forward reception so the antenna is more directive.

Last edited by John Candle; 7-Jan-2011 at 9:56 PM.
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Old 7-Jan-2011, 10:07 PM   #25
John Candle
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Tv Antennas and Reception

Having the antenna directly connected to one Tv or converter box with no splitters is helpful and if that one Tv or converter box has the ability to select digital channel 4 with out scanning , that will make it easyer. . Another way to eliminate or reduce undesirable multipath is horizontal stacking of 2 identical antennas side by side. One antenna is in a fixed position and the other antenna is moved closer and further away , to find the distance between the 2 antennas that creates a 'null' of the undesirable multipath reflection.

Last edited by John Candle; 8-Jan-2011 at 12:09 AM.
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Old 8-Jan-2011, 12:01 AM   #26
youngclarkh
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Something exciting just happened.

I went to Best Buy and bought a Clearstream 2. I pointed it at 7 degrees true and rescanned. Now I am getting many of the UHF channels coming off of Mt Bigelow.

09 9.1
19 18.1
25 11.1
23 4.1
32 13.1

In addition I am also picking up channels from other directions.

40 40.1
44 58.1
28 27.1
13 13.1

The signal is not very strong but I have not grounded the coax yet so perhaps once I do that the signal will be stronger.

I am so glad that I don't have to deal with a VHF/UHF combo. Yet I am still getting channel 9 and 13. In addition, this Clearstream 2 is a tiny little thing. Much easier on the eyes.
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Old 8-Jan-2011, 12:57 AM   #27
John Candle
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Tv Antennas and Reception

You are receiving reflected transmissions. Digital tuners have ability to reject some multipath. I just remembered , FM radio transmissions cause interference in the VHF low band channels 2 thru 6. Pick up a FM Trap at Radio Shack.
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Old 8-Jan-2011, 11:59 AM   #28
Tower Guy
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Quote:
Originally Posted by John Candle View Post
Pick up a FM Trap at Radio Shack.
I doubt that will help. The C2 doesn't pick up FM very well.

Most Radio Shacks no longer carry FM traps.
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Old 8-Jan-2011, 12:39 PM   #29
youngclarkh
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Isn't it true that all U.S. TV transmitters are in the frequency range of VHF channel 7 or higher, which is far above the FM broadcast band?

In addition, all the channels I am getting are in frequency range 9 and above.
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Old 8-Jan-2011, 3:05 PM   #30
baud
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Quote:
Isn't it true that all U.S. TV transmitters are in the frequency range of VHF channel 7 or higher, which is far above the FM broadcast band?
take another look at your tvfool report the answer to your question is there.
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Old 8-Jan-2011, 3:33 PM   #31
Dave Loudin
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The problem is the frequencies for channels 7-13 line up roughly with the frequencies for FM multiplied by 2 (the first harmonic). Very strong FM signals can set up interference at that first harmonic, wreaking havoc with reception of the TV station at that frequency.

BTW, to see the terrain profile used by TVFool's model, click on any station in the list. A separate window will pop up, showing the transmitter at the far left and your location at the far right. You will see how you are shadowed from stations to the north.

Last edited by Dave Loudin; 8-Jan-2011 at 3:36 PM.
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Old 8-Jan-2011, 8:12 PM   #32
Tower Guy
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Quote:
Originally Posted by youngclarkh View Post
Isn't it true that all U.S. TV transmitters are in the frequency range of VHF channel 7 or higher, which is far above the FM broadcast band?
No,there are about 35 stations on channels 2-6.
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