Raleigh North Carolina Antenna Analysis / Help - AVS Forum
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post #1 of 7 Old 02-18-2013, 07:10 AM - Thread Starter
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Hey All,

I cut the cable about 2 or 3 years ago and I've struggled to get decent OTA reception the entire time.

I currently have a directional antenna (RCA ANT751R Outdoor Antenna) connected to a generic radio shack pre-amp, connected to 50 feet of RG-6 (per-fabricated terminations - I didn't crimp on the ends), connected to a wall jack, connected to the power-supply for the pre-amp then split to SiliconDust TV tuners.

I have the antenna connected to the highest point on my house outside and facing where I believe all the stations are broadcasting from. Slight tweaks to the direction the antenna points results in me getting different sets of channels (i.e. point a little North, get CBS and FOX, move it a little South, get NBC and CBS, etc).

http://antennaweb.org/ indicated I needed a 'red' medium directional antenna. TV fool analysis results here:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d1ddae11b481f1b

My next plan was to buy one of those bigger antennas or an omni directional even though antennaweb didn't recommend it. After that, I was going to hook up a rotator. Any thoughts or comments?

Thanks!
~Mike
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post #2 of 7 Old 02-18-2013, 08:19 AM
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The #1 question is what you need to get. The majors except PBS are all "the same place", close, and STRONG. Even an extremely directional antenna wouldn't normally be able to discriminate among them. In your case, I think, IF THOSE SUFFICE, that you should eliminate the amplifier and splitter(s) and try with one TV. The amplifier may be causing some of your problem. With those signal strengths, if any amplifier is needed to overcome splitter and cable loss, it would be important for it to be one with excellent overload capability.

It has been 40+ years since I lived in Raleigh and I've forgotten where the FM towers are ... if one is close and/or strong, it also could be hurting your preamp.

Try one TV and get back to us.
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post #3 of 7 Old 02-18-2013, 09:35 AM - Thread Starter
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Thanks for the response gbynum!

What stations I am trying to get?
Just the majors (NBC, CBS, ABC, and FOX) is the primary goal. PBS is a nice to have and always seems to come in regardless of what I do.

Remove amplification experiment #1:
In this experiment, I removed power from the pre-amp by removing many parts of my setup. What remained was just the antenna to the un-powered pre-amp to the 50 feet of RG-6 run directly to a single tuner. I couldn't pick up anything at all when I scanned the channels with this setup.

Remove amplification experiment #2:
Added back the pre-amp power thing but did not plug it into the wall so I had: antenna to the un-powered pre-amp to the 50 feet of RG-6 to the un-connected pre-amp power thing run directly to a single tuner. Again, I get nothing at all.

I suspect that I have to remove the pre-amp completely from the circuit which means getting a ladder and pulling it off the antenna itself. I would have thought it'd act as a pass through device if unpowered but that doesn't seem to be the case.

I'll report back after I get a ladder and pull that sucker off.

~Mike
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post #4 of 7 Old 02-18-2013, 04:40 PM
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Yes - if you're not powering a preamp, then you need to remove it AND it's power supply.

Stations - except for PBS - they are all just east of Garner within a mile of each other. I think there is even a PBS translator out there, but it's beam is pretty narrow

You CAN put antennas on your owned and/or controlled property...
http://www.fcc.gov/mb/facts/otard.html

Being A Beacon of Knowledge in the darkness of FUD
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post #5 of 7 Old 02-28-2013, 03:26 PM - Thread Starter
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So I got myself a ladder and pulled the the pre-amp off (both parts of it). My digital tuners show three metrics: signal strength, signal quality and symbol quality. The signal strength has decreased without the preamp but I have the same problem of only getting a subset of the channels (I currently have it pointed a little more West so I pick up NBC and CBS; if I got a little East, I pick up NBC and FOX; I no longer get ABC).

I'm thinking my options are trying a multi-directional antenna or a rotator or a 'better' pre-amp (I had a cheapy radio shack one before). I'm not really sure what the best approach would be.
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post #6 of 7 Old 02-28-2013, 04:18 PM
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You're probably getting multi-path in your valley which means that relocation the antenna would probably help.

Your antenna should be generally appropriate and you certainly shouldn't need an amplifier.
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post #7 of 7 Old 02-28-2013, 05:15 PM
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Quote:
Originally Posted by wunderchicken View Post

So I got myself a ladder and pulled the the pre-amp off (both parts of it). My digital tuners show three metrics: signal strength, signal quality and symbol quality. The signal strength has decreased without the preamp but I have the same problem of only getting a subset of the channels (I currently have it pointed a little more West so I pick up NBC and CBS; if I got a little East, I pick up NBC and FOX; I no longer get ABC).

I'm thinking my options are trying a multi-directional antenna or a rotator or a 'better' pre-amp (I had a cheapy radio shack one before). I'm not really sure what the best approach would be.

I would think about replacing your ANT751R with a Terk HDTVa antenna. The Terk has a narrower beamwidth than the 751R which is good for multipath rejection. The Terk is not weather resistant so you will have to mount it in the attic. At my location, I am greater than 30 miles away from the transmitter farm on Mt. Wilson and there is a small hill blocking my LOS (causing one edge reception.) In spite of that, I get all the high power stations. And this is using the unamplified version of the Terk (HDTVi) with the antenna aimed through my 2 inch thick first floor front door. YMMV, but I would at least give the Terk a try. You can return it if it doesn't work.
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