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Old 27-Aug-2011, 2:11 AM   #1
gands
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I'm getting a Pittsburgh station in Canada. How?

I live in Oakville, Ontario. I recently built an 8 bay antenna with a reflective backing from scratch, attached a preamp, cut the minimum length for the cable to my TV, attached an amp and am now able to pick up quite a few stations. I won't list them all, but every once in a while, I can get a weak but viewable signal from KDKA in Pittsburgh. It's not dependable at all (it breaks up quite a bit when I do get it), and I don't care if I have it, but I thought this would be well out of my reach. How am I able to pick it up? Is there a repeater transmitter between Pittsburgh and Buffalo?

What's even stranger is that the signal, weak as it is, comes in only when it's overcast outside. I am baffled.
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Old 27-Aug-2011, 6:45 AM   #2
GroundUrMast
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Quote:
Originally Posted by gands View Post

... What's even stranger is that the signal, weak as it is, comes in only when it's overcast outside. I am baffled.
You're describing tropospheric ducting, AKA 'skip'. Ionized layers of the atmosphere can act as reflective wave guides. If the all of the right circumstance occurs simultaneously, you can experience the phenomenon you describe. As the weather changes and as the sun rises and sets, you'll see the ducting effect change.

I don't doubt your skill as an antenna builder, but without the aid of charged molecules in the atmosphere, your antenna is not going to 'see' Pittsburgh signals.


FWIW: http://www.rabbitears.info indicates KDKA has no translators.
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If the well is dry and you don't see rain on the horizon, you'll need to dig the hole deeper. (If the antenna can't get the job done, an amp won't fix it.)

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Last edited by GroundUrMast; 27-Aug-2011 at 6:53 AM.
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Old 27-Aug-2011, 11:59 AM   #3
John Candle
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Tv Antennas and Reception

You can join in with other DXers , it's a great hobby. http://en.wikipedia.org/wiki/TV_and_FM_DX , http://www.wtfda.org , http://www.tvdxexpo.com/canadatvdx/canadatvdxon.html , and other DX sites , type in , dx , tv dx , fm dx , am dx and etc. , in the google search box. Yes you can DX both Digital and Analog.

Last edited by John Candle; 27-Aug-2011 at 12:10 PM.
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Old 27-Aug-2011, 5:53 PM   #4
gands
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I just read what you guys provided. It has to be tropospheric ducting. I did a straight line distance measure from my house to KDKA's transmitter, and it's about 200 miles. I figured it was that far, but I just wanted to be sure. My skills as an antenna maker (my dad did most of the work -- he sort of took charge being that he used to fix TVs in the '60s) had very little to do with it. However, I don't think just rabbit ears inside the window would have cut it either seeing as the signal was very weak.

What I also noticed is that the Niagara escarpment should hamper the signal. Plus, there's large hills in PA that should also hamper the signal. It's amazing how the skies act in such a way to overcome them.

I remember picking up radio stations from New York City and Boston on occasion when I was younger, but I thought DTV was a lot more fragile. I'm curious now if I point my antenna southeast if I can pick up New York or Boston when it's overcast. I'll try.

My antenna is also tilted very slightly (maybe a couple of degrees -- barely noticeable) upward. Did this make a difference in reception? My father told me it does, but I'm still sceptical.
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Old 27-Aug-2011, 10:10 PM   #5
John Candle
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Tv Antennas and Reception

Antenna tilt does help , up and down , as a matter of fact some DXers have motorized the antenna to tilt up and down. Also rotating the antenna left and right to fine tune direction can bring in the Tv station. Also tilting the antenna side to side can bring in the Tv station because over long distance the earth's magnetic field causes the signal to tilt out of the horizontal plane that most Tv transmissions are transmitted as.
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Old 27-Aug-2011, 10:25 PM   #6
John Candle
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Tv Antennas and Reception

Don't count rabbit ears out. Yes it is less likely that rabbit ears will receive these elusive signals , however sometimes the long distance signal can be concentrated and Wham'o even the rabbit ears will receive a clear strong signal for even like hours at a time. And Digital Tv Transmissions are not as fragile as you think. In some ways Digital Tv is stronger and more durable then analog Tv. Digital Tv has built in digital picture and sound correction and produces clear pictures and sound. Analog Tv has lousy pictures and plain FM sound. It also takes less power to transmit digital over the same distance then analog.
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Old 1-Sep-2011, 4:38 PM   #7
bwilson
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Tropospheric ducting and skip are two different forms of signal travel.

Last edited by bwilson; 1-Sep-2011 at 4:41 PM.
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Old 4-Oct-2011, 7:28 AM   #8
ghz24
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Quote:
my dad did most of the work
Sounds like dads got you hooked up. 8 bay whisker antennas model as some of the best DX homebrew antennas for UHF. I have specs on one that averages 18dBi net gain.
Even though the commercial 8 bays don't perform as well as they could (phase line problems and short whiskers aimed at channels no longer assigned to tv).
Tipping the antenna up helps with tropospheric scatter which is more common and dependable than tropospheric ducting but 200 miles probably won't be dependable with out very extreme measures.
Tropospheric ducting is how you are getting Pittsburgh , tv frequencies don't really reflect off the upper atmosphere and skip.
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