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Old 19-Oct-2010, 4:09 AM   #1
staylor
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3rd Antenna Still a Problem

Hi,
I live close to the broadcast towers, 9.4-9.6 miles. Antenna is chimney mount on 2nd story. Channel 9-1 pixels in/out. Sometimes signal drops. Other channels are good. Current unit is a Winegard HD7697. It is pointed at the two towers 42 & 40 degrees. Directly in the path are large trees, 100 ft away, 60+ ft high.

Other issues, the cable runs from the antenna to a grounding splitter, then to the set top tuner. Also used previously a ChannelMaster 4221HD. Same issues on 9-1.

Should I run one cable directly to the tuner bypassing the outside grounding splitter? Try another antennna?

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Old 19-Oct-2010, 6:11 AM   #2
GroundUrMast
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Logical next step

You should bond your mast and coax shield to ground for safety reasons as well as reducing undesired signals present on the coax shield. The exact method required in your jurisdiction is governed by the local electrical code.

Having said that... As a test (And for safety reasons, a short, temporary test) Running a known good coax directly from the antenna to a known good receiver is a good place to start.

The goal would be to determine if the splitter or coax disconnected during the test is causing part or all of the problem.

Pay close attention to signs of moisture, corrosion or looseness at connections. Also look for kinks or sharp bends in the coax.

The CM 4221 is not designed to receive VHF channels. The HD7697 on the other hand should be PLENTY of antenna for your situation.

A second thing to consider; If possible, try experimenting with elevation and small aim point changes.

Best regards
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Old 19-Oct-2010, 6:26 AM   #3
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Two more thoughts...

1.) Are any splitter ports unused (either nothing connected or cabled to an unused jack)? If so you should terminate the unused port(s) with a 75 ohm termination plug. http://search.solidsignal.com/?q=ter...earch=1&cart=4

2.) Is there an amplifier installed in your system? If so, remove it as your first test. You have more than enough raw signal strength at you location - An amplifier would likely overload and cause mixing and distortion of the desired signals... not a good thing.
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Old 19-Oct-2010, 1:31 PM   #4
staylor
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Smile Thank U

GroundUrMast,

Thank you for your response. I will get a new cable & run it through a window as a test. Will check the ground splitter also.


Staylor
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Old 19-Oct-2010, 3:04 PM   #5
Tower Guy
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Quote:
Originally Posted by staylor View Post
Channel 9-1 pixels in/out.
Perhaps the strong FM signals bother your TV. Consider trying an attenuator or a HLSJ to filter out the FM.
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Old 21-Oct-2010, 7:52 PM   #6
John Candle
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Tv Reception

The television transmissions at your location are Very Strong. 100 even 200 feet is not that far , try putting the Tv antenna on the other side of the trees , or have the antenna down low to the ground at the trees , tip the antenna up in the front and shoot under the tree branches for a clearer shot at the transmitters.
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Old 21-Oct-2010, 9:45 PM   #7
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Tv Reception

This ghost/multipath reducer antenna might clear up the situation. Winegard HD7210P
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Old 22-Oct-2010, 4:03 AM   #8
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I think that Tower Guy hit it right on the head when he suggested some FM interference: channel 9.1 actually broadcasts on physical channel 9 in DC, and would be susceptible to FM overload with an antenna as powerful as the HD-7697P. A smaller antenna will not solve your problem, and would cause problems with the Baltimore channels.
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Old 22-Oct-2010, 4:21 AM   #9
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Agree on the FM interference as well. An FM trap is necessary in much of Northern VA for reliable reception of WUSA-9 & WJZ-13. Connect the antenna to the IN/OUT terminal of the HLSJ & the HI terminal of the HLSJ to the TV. A terminator is generally recommended for the unused LO terminal, but I have never seen it make a difference.
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Old 22-Oct-2010, 4:29 AM   #10
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One other thought. Are you using a Channel Master 7000 converter box? I had 2 of them & they both had a pixelation issue every 30 seconds or so with WUSA. (Even before they moved back to RF9)
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Old 22-Oct-2010, 12:37 PM   #11
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In Annandale, the closest FMs are 106.7 and 105.9 (co-located with RF24), 98.7 and 100.3 from just outside Falls Church, and 105.1 and 90.9 from Arlington. As others have said, an FM trap is essential to clean things up.

As an aside, I still get audio drop outs on RF34, now WPXW, even though it's always been one of my strongest signals.
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Old 22-Oct-2010, 2:06 PM   #12
staylor
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Results with FM Trap

When I installed the 7967, I removed the HLSJ from the cable run. (Since I was having issues with both it & the previous antenna) I reinstalled it and it did improve the reception on 9-1. During a brief test, no dropouts and greatly reduced pixelation. I'll terminate the low end to see if it makes a difference in my case.

The leaves are beginning to drop here, in the past this increased the dropouts/pixel problems. Will play with the position little by little to see what works best.

I am replacing the cables & grounding block to remove an open terminal on the ground block. Is it good practice to seal the coax connectors at the block to prevent weather intrusion?

Also, not using a Channel Master 7000. Thanks for all the help.
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Old 22-Oct-2010, 8:06 PM   #13
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Yes, keeping water out of the coax is worth the effort. Drip loops will keep most of the rain away from the connections. There are several opinions about connectors and sealing methods. So far my compression connectors covered with boots filled with dielectric grease are doing fine. Some people have had trouble with dielectric grease effecting signal strength though. (I started using dielectric grease back in the 90's when I was installing microwave antennas. A few of the small systems fed IF and power from the ground mounted mux/demux using RG6.)

Last edited by GroundUrMast; 22-Oct-2010 at 8:11 PM.
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Old 3-Nov-2010, 2:11 AM   #14
staylor
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Smile It worked!!

Based on feedback from this forum:
Yesterday I replaced the cable from the antenna to the grounding block, replaced the old dual grounding block which had open unterminated connections with a single block, replaced the cable into the house and terminated the FM filter open connection and an open antenna out connection on the LG digital receiver. I didn't do all the changes incrementally, BUT the results are very positive!! No dropouts on the Wash DC 9-1 station and now getting Baltimore stations that were never available! Thank you for all the help. I am amazed at the difference. Listen to these guys, they know what they are talking about.

Thanks again!
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Old 3-Nov-2010, 3:36 AM   #15
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Congratulations Good to hear you are now able to take full advantage of the outstanding HD options available in the DC metro area.
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Old 8-Nov-2010, 3:12 PM   #16
staylor
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Can You Have Too Strong a Signal

One week and everything comes in without dropouts. But, seems a few channels might be a little noisy? I thought if a signal is too strong it would also create drop outs/loss of signal. Can the quality of the picture/signal be affected by too strong of a signal?
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Old 8-Nov-2010, 3:42 PM   #17
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It is nearly inpossible to overload without an amplifier. You would have to be a lot closer to Merrifield to even consider overloading. What kind of noise are you experiencing & on what channels? I'm thinking you are seeing compression artifacts.
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Old 8-Nov-2010, 6:59 PM   #18
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All the SD subchannels will get blocky when the picture is very dynamic. WETA-HD is also nortoriously bit-starved. You'll notice the artifacts in the scene from a promo where a bear is catching a fish in the river.
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