working inside but not on roof

hi vhf or bust · 22-Dec-2013, 5:42 AM

Hi, I live at

http://www.tvfool.com/?option=com_wr...46ae092152fff8

and am interested in channel 12 (11.1) which is behind a hill from much of the city (deliberate by Comcast I think). a simple indoor v-aerial worked fine for low vhf but not channel 12. I got a Antennacraft Yagi HD Antenna Y5-7-13 which supposedly specializes in the higher range. And guess what, when mounted on a broomstick in the middle of my living room with no pre-amp and direct connect to the TV, it pulled this channel well.

Then I put it on the roof (12 feet above! outside!) with a Winegard HDP269 hi-input pre-amp, 150 feet of dual-shield RG6 (all the way down to the basement outside the house, power injector, 1:2 splitter, then back up to the bedroom inside the walls). lo-VHF still working well, but channel 12 dark again.

one detail - the antenna is mounted sort of close (18"?) above the peak of the roof to stay out of the LOS of a microwave (wireless internet) antenna on a separate mount a few feet behind it. And, it's slightly closer to the house to the south (which is uphill of mine). Not sure these types of proximities make a big difference, if I need a stronger pre-amp, more direct cable run, etc -- and how to test those theories without a lot of extra trips to the roof.

thanks for sharing your experience.

GroundUrMast · 22-Dec-2013, 7:34 AM

No consumer grade preamplifier can tolerate the extremely powerful signal levels indicated by your report. Remove all the parts of the preamplifier, completely. Then, be prepared to add attenuation to get the powerful signal levels down to reasonable levels. 100' of coax should have no more than 6 dB of loss at the top of the UHF band, the loss is half that when dealing with real VHF channels. If you have 200' of coax and 4 dB of splitter loss, you still have no more than 15 dB loss between the antenna and bedroom TV. At VHF frequencies, I'd expect the cable & splitter loss to be about 8 dB.

Also, the only L-VHF signal indicated on your report is that of K02QO, real channel 2. All the others are either UHF or H-VHF. Real channel numbers are the only thing that counts when selecting an antenna, don't get confused by the virtual channel number.

You may need to add an FM trap also, the Sutro Complex has plenty of FM signals showering your location. Some folks have had to resort to using more than one trap to get the FM levels knocked down far enough.

23-Dec-2013, 7:52 PM

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The first 10 Tv stations signal strengths are so strong signal they are Highlighted With Red.

And are Over The Top Strong Signal Strength.

And are less then 1 mile away.

DO NOT use any type or kind of amplified antenna , DO NOT use any type or kind of add on antenna system amplifier.

DO NOT use a amplifier.

The amplifier Will Over Load from the Over The Top Strong Signal Strengths of Tv stations , and the over loaded amplifier Will Be The Cause of bad reception of some channels.

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For a indoor type antenna use a , Terk HDTVi , Non amplified antenna.

Aim the HDTVi antenna at about 159 degree magnetic compass direction.

Here is how to aim indoor and outdoor antennas , http://www.kyes.com/antenna/pointing/pointing.html.

For a above the roof type antenna use a http://www.antennacraft.net , HBU11 antenna.

Aim the HBU11 antenna at about 159 degree magnetic compass direction.

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

To clear tuner , do Double Rescan.

http://www.wchstv.com/Double ReScanAlert.pdf.

For your reception situation , Tv stations might be received even with no antenna connected , Because The Tv Transmissions Are So Strong.

If that is the case , then take the Tv several miles away so that the signals are weaker.

Do the Double Rescan up to and including the no antenna connected part of the Double Rescan , and then take the Tv back to the location where the reception is to take place and happen , and connect the antenna to the Tv and scan for channels.

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Here are some places to buy antennas and etc. .

http://www.solidsignal.com.

http://www.amazon.com.

http://www.antennacraft.net.