Help with attic antenna

Stumped2 · 4-Jul-2011, 2:16 AM

I’m in a two story townhouse & it may be difficult to put up an outside antenna, especially since each unit has its own attic antenna. It has always worked quite well when I had to rely on it, which was not often when I had Comcast cable. But I’m now using it more with a Dish DVR which includes dual OTA tuners. It works great 99.9% of the time, but once in a while I get a brief temporary signal loss.

The Dish installer used existing coax to connect both the OTA & satellite signal & it goes through a coupler splitters & diplexers.

According to the DVR, I get 100% signal strength on a couple OTA channels, but low 80s on a couple others. And sometimes those dip into the 70s. Problem is I don’t know how low they dip when I get the signal loss. It could be caused by multipath, trees blowing in the wind, snow on the roof, etc. I would think the signal at the antenna should be OK and I thought using a medium gain preamp or an adjustable unit in order to give the signal a slight boost.

I could use a different antenna but do need VHF hi-band for channel 12 CBS/WBBM. The antenna that’s stuffed in the attic is quite large. In fact the longest elements are not properly locked into place due to interference with structural members. I don’t know if a replacement antenna would be any better since I really can’t go much larger. But since I don’t need VHF low-band then a replacement would not have the long elements.

Here is my TV Fool report:
http://www.tvfool.com/?option=com_wr...03d91aacd57121

I thought about getting something like the Winegard HD7697P or HD7698P. However my current antenna looks like a slightly smaller version of the Winegard HD7084P. I’d have to climb back into the attic in order to count the elements, but I did not see any make or model number on it.

I don’t see a lot of difference in specs between these 3 Winegard models. If mine is similar to the 7084P, would there be any advantage to getting a 7697P or 7698P?

I realize I’m not providing a whole lot to go on regarding my current antenna specs, but typically would my scenario benefit more from a preamp or from a new antenna?

Any suggestions or comments would be greatly appreciated.

John Candle · 4-Jul-2011, 9:32 PM

What direction is the antenna pointed?

Stumped2 · 5-Jul-2011, 12:15 AM

I used a compass & protractor and tried to aim it at the 66 degrees as shown in the report. I also had my wife watching the DVR's signal strength display & letting me know if the readings were getting higher or lower.

I tried to peak the SS for CBS because originally it was only in the upper 70% range. I did get it into the lower 90s, but could not get it to stay there. It seemed to fluctuate as I moved around in the attic. With me out of the attic it's usually in mid 80s, however sometimes does dip into the upper 70s and I still get a good picture. I just don't know what happens to the SS when I do get a dropout. Dropouts do not happen very often but they are irritating.

John Candle · 5-Jul-2011, 2:01 AM

Attics are not friendly environments for Tv reception , multipath is the reason (reflected signals). Are there any large trees close that can be blockig reception?? Any big buildings close the can be blocking or creating bad multipath. Do not connect a amplifier , it will make the reception worse because the amplifier will amplify the reflected signals. Are there any airports around ?? Reflected signals off of planes are multipath. You can try this multipath/ghost reducing antenna in the attic , http://www.solidsignal.com/prod_disp...p?prod=ANWGHST . I am thinking that a Tv antenna will need to go to the outside of the roof.

John Candle · 5-Jul-2011, 6:37 AM

Also strong FM radio transmissions can cause trouble with Tv reception. I suggest install a FM filter close to the antenna in the attic , Radio Shack model # 9FT293C-1 , catalog number 15-024 . Also I suggest grounding the coax with a coax grounding block. A cold water metal pipe can be ground.

Stumped2 · 5-Jul-2011, 6:50 AM

There is a tree partially in the way. There are no big buildings, at least tall ones, that I am aware of. There is O'Hare to the north of my LOS and Midway to the south.

Is there any way to tell if I really am experiencing multipath, versus just losing signal strength because of the attic?

I searched Winegard's website in order to find out more.
http://winegard.com/kbase/kb_tip_res...hp?tip_num=258
"The average gain for the HD7210P antenna is -3dB on channels 2-6, +5.5dB on channels 7-13 and +8dB on channels 14-69."

The gain is less than some of their other antennas such as the 7697 or 7698. Is this an area of concern? IOW would the benefit of ghost reducing outweigh any potential loss in gain?