Northern VA reception issue

[rodstv]

Anybody in the area approximately 50 miles west of Washington, D.C., near Purcellville, VA, been experiencing random, but daily drop-out of the NBC channel 4-1 programming?

This was especially noticable during the afternoon Olympics. It was, we discovered, not just our problem, but several other neighbors complained of the same situation with their OTA. All of them, including us, have antenna systems that have been trouble free, since their installation. Program reception returns during the early evening and is working the following morning. I am very aware of the effects weather can have on our reception, but it is happening at multiple locations at the same time!

An angry neighbor suggested that NBC, now owned by Comcast, was reducing transmitter power during the Olympics, in an attempt to get non-cable users to subscribe to Comcast, which is the only cable provider in our area. An extreme suggestion, but is it really?

Specs on our antenna installation are:
Channel Master 4228HD VHF-HI/UHF TV Antenna - 12dB UHF gain
Winegard AP-8275 Preamplifier - VHF 29dB gain, UHF 28dB gain
Belden 9066 RG-6 Coaxial Cable - 6dB loss/100ft (RG-59 has a 10dB loss/100ft)
No splitter loss, antenna only feeds the Samsung LED/LCD TV, nothing else.
Samsung UN60F8000 LED HDTV
TV Signal Analysis Results at this link.
-Rod

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Possible inerference from RF 48 in Winchester. I suggest playing with aim/height to maximize RF 48 from DC. How well do you get CW 50?

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Oh RF 48 is the channel WRC uses.

[StephanieS]

Yes, play with location. Sometimes moving just a few inches can be the difference between reliable and unreliable reception.

Co-channel interference can be unpleasant because with enough signal from another station on the same channel, your tuner will lose a lock. At worst, you'll get nothing because with the two signals your tuner can sort one from the other out.

If I were you I'd perhaps as a test orientate the antenna to magnetic heading 218 to test NBC WVIR. It is extremely weak and may not be received at all, however if your conditions are slightly more favorable, you may have a chance at it. It also has no co-channel problems.

Do you have any strong FM stations near by?

[rodstv]

Originally Posted by StephanieS

Snip... Yes, play with location. Sometimes moving just a few inches can be the difference between reliable and unreliable reception. Do you have any strong FM stations near by?

Well, up until mid last month and our very cold weather, reception has never been a problem, just as it isn't now this morning (6.5F and clear), or up until about 2PM, when it starts dropping out and continues to do so until about 7PM. No other stations around the NBC antenna location exibit this problem, even though they may be transmitting at less power. And the problem exists with several neighbors, within about a mile of us. All very odd and given the fact that we've lived here for 31 years and have never had this reception problem, even in the analog days and a lower gain antenna.

Thanks for your response, but given the weather and our slippery tin roof, it'll be spring before we'll venture up there.
-Rod

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Can call the Tv station and have a informational conversation with the engineering department.

Do not send text.

Do not e-mail.

Do not go to social jibber jabber web sites.

Have a real voice conversation with the engineering department.

http://en.wikipedia.org/wiki/WRC-TV.

[ADTech]

Give the station's engineering department a call and see if they might be having any technical issues that require them to run at reduced power. Sometimes things break...

Other than that, there is no reason for them to jeopardize their license to broadcast by doing as your paranoid neighbor suggested.

If the station engineering department indicates that they are and have been running normally, then that opens up the probability of interference as the probable cause. It might be something local to you and your neighbors, perhaps a new cellular or 4G wireless tower was recently lit up and it's causing interference into your receiving gear.

[rodstv]

teleview and ADTech,
A quick follow-up...
Checked with WRC Engineering who indicated everything was optimal and there were no known issues. This past Sunday, the WRC-TV signal remained solid all day and evening, including at the two other nearby OTA folks having the same problem we saw earlier. Monday the signal was solid at any hour and has been so this morning. What ever the problem was, it appears to have gone away, at our location and the two other OTA installations. Ain't electronics great?
-Rod
(retired SMPTE member)

[rodstv]

Another Update -
The random reception problem is back, not happening as frequently or for the extended periods as before, but enough to make you want to change channels.

I dug out our old (Nov. 2008) DIGITALSTREAM DTX9900 D/A DTV converter box, primarily to see if there was a problem with my Samsung receiving CH.4 versus the DTX9900 and also to be able to see what the signal strength was doing, viewing the DTX9900 signal strength indicator. I found that the 4-1 and 4-2 signal strength varies considerably, compared to all the other channels received. From WRC-TV's 813KW transmitter? The DTX9900 shows that the channel 4 signal is varying from a low of 30 to a high of 62, a 32 point signal level swing with anything below 30 resulting in a bits and pieces picture. The Samsung with its multiple inputs allows me to switch immediately between the Samsung tuner and the DTX9900 A/V output, both showing they have trouble below '30' as indicated on the DTX9900.

Weather and time permitting, I am going to the neighbors house who is having the same OTA reception problems with Channel 4, to see if his antenna is also seeing large signal level swings. Of the 35 channels we receive, channel 4 is the only one that shows these large random signal level swings, versus a 4 to 5 point average random change in signal level as reported by the DTX9900 on all the other channels, which I monitored last night and again this morning.

-Rod

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Trees and tree leaves that are moving because of wind will cause signal strength changes that can effect one channel more then other channels.

Moving trees also create moving multi path signals bouncing all around.

Wet trees and wet tree leaves make the situation worse.

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Moving the antenna up or down can put the antenna in a better spot for reception.

A different location can improve reception.

Changing the antenna aim can help reception.

As a Test of reception , run a New continues length of coax from the antenna direct to 1Tv , no amplifier , no splitters.

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Also Digital Tuners can develop -Digital Glitches- that are not cleared out with simple channel scans.

To clear tuner do Double Rescan.

http://www.wchstv.com/DoubleReScanAlert.pdf

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Varying signal strength is a sympton of multipath. (Reflected signals arriving at the antenna at different times/different angles) It can usually be overcome enough to allow reliable reception by moving the antenna to a different location. Many times moving the antenna up or down can resolve the issue (sometimes as little as 6-12 inches is all it takes)

Also, you could be getting interference from WAZW in Winchester which broadcasts on the same frequency as WRC. It has been a known issue in areas close to you in the past & may crop up intermittently under certain weather conditions.

Maximizing the signal from DC using the same procedure as described above is your best bet to avoid this scenario as well.

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Just in case you still haven't solved your issue . . . .

Quoted from AVS Forum

POST:"Hi to everyone. I've been reading a lot of helpful posts on this forum for a long time, and now it's time for me to make my first post. I've been having a terrible time with reception of WRC in Washington DC. . . . . . .WRC bounces back and forth between 60-83 with occasional dips into the 50's or momentary total signal loss."


REPLY:"You should post this in the Baltimore-Washington thread. Your problem is not unique out where you are with getting the digital signal for WRC-DT NBC 4 which is broadcast on UHF 48. The reason is that there is a low power analog station WAZW-CA 48 located in Winchester, VA which interferes with the digital reception of WRC-DT. The FCC data for WAZW-CA is at http://www.fcc.gov/fcc-bin/tvq?list=0&facid=57911. You need to try to block out the interfering signal from WAZW and/or get a better ATSC tuner. Again, take this to Baltimore-Washington thread."