OTA Station Status: Seattle, Tacoma, Bellingham WA - Page 10 - Canadian TV, Computing and Home Theatre Forums

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post #136 of 797 (permalink) Old 2007-12-12, 03:00 PM
 
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sub for KCPQ

I think the reason for the sub is to accomdate the other station MYQ2 because of the temp lic they have for that station just a guess I think a DTV aloocation is like having rental units (subs) for the best bidders?
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post #137 of 797 (permalink) Old 2007-12-17, 10:48 AM
 
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Simulation of SeaTac Reception in Langley/Abbotsford/Mission

I forgot I had done this. You would need to be at least in the green area to have a chance at a consistent signal from Sea-Tac. Green starts around -90 dBm. Yellow starts at -80 dBm and the solid orange-yellow is -70 dBm and better. The difference between Abbotsford and Langley is night and day. This map is for stations from downtown Seattle at 800 feet center of radiation. This one is for channel 39 specifically but applies to all UHF. I used some very granular data to make this calculation - took close to 3 hours



This is for a 1 megawatt ERP station from Seattle downtown.
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post #138 of 797 (permalink) Old 2007-12-18, 10:23 AM
 
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Wow - thats an amazing chart, how did you create this ?

Do you or anyone else have the time and ability to create a diagram like this for downtown van, richmond, tsawwassen area ?

That would be awesome - at least then I'd know whether its worth it to try doubling up my CM4228, or trying a preamp in my setup. I am in Richmond and have my ant 30' up on a pole, using RG-6 direct to a Panasonic ATSC tuner. ....can't get any Sea-tac stations at the moment and would love to !

Dave
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post #139 of 797 (permalink) Old 2007-12-18, 04:28 PM
 
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Simulation of SeaTac Reception in Metro Vancouver (South)

Theoretical 1 megawatt Seattle station at 800 feet elevation in mid UHF range being received by a dipole antenna constructed for channel 39 on a 45' tower

OK I let the computer really chug while I was at a meeting. Using Mapinfo professional, CRC Predict tool with the CDED (canadian digital elevation data) database, etc. at 100m precision for elevation points. Using optical earth curvature and this is an F(50,50) curve (ie 50% of time in 50% of locations).



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post #140 of 797 (permalink) Old 2007-12-18, 04:28 PM
 
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Simulation of SeaTac Reception in Metro Vancouver (North)

Theoretical 1 megawatt Seattle station at 800 feet elevation in mid UHF range being received by a dipole antenna constructed for channel 39 on a 45' tower

OK I let the computer really chug while I was at a meeting. Using Mapinfo professional, CRC Predict tool with the CDED (canadian digital elevation data) database, etc. at 100m precision for elevation points. Using optical earth curvature and this is an F(50,50) curve (ie 50% of time in 50% of locations).



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post #141 of 797 (permalink) Old 2007-12-18, 11:43 PM Thread Starter
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Terrific maps, GerryB! We owe you a big round of thanks for these. I downloaded them, put location names onto them, and put them back up here.

Clearly anyone living in the top third of a south-facing hi-rise near Metrotown in Burnaby will be getting booming signals from SeaTac with probably a small bowtie or yagi antenna on their balcony or maybe even indoors.

People living in all those new south-facing condos up at SFU will get booming SeaTac signals too!

Folks, just remember that this is a theoretical projection and that there are a variety of local factors that could create problems that aren't shown on these simulations. Trees, adjacent buildings, nearby RF or EM interference, etc. etc. can ruin what might otherwise be a steady digital lock.
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post #142 of 797 (permalink) Old 2007-12-19, 04:23 PM Thread Starter
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Gerry, the Lower Mainland topology has more ups and downs than a Midol users convention.

Since the altitude range is within about 100m (sea level to Simon Fraser University not including mountainsides) the maps would tend to average out the altitudes of all depicted low-lying areas below 100m as being equal, wouldn't they?

If so, would it be too intensive a computational task to increase the granularity (to maybe even 5 meters)?
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post #143 of 797 (permalink) Old 2007-12-19, 05:14 PM
 
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The altitude/elevation accuracy is 1 meter. When I said the CDED had a point accuracy of 100m I meant in the horizontal plane. So there is an elevation sample for every 300 feet north/south and again east/west. It's about as accurate as most of the mapping tools get.

Yes I agree there are a lot of ups and downs - I know that the model doesnt take buildings into account but Im pretty sure the latest CRC Predict DOES take into account the vegetation (like fir trees) - there is a variable in there for that - it's rough but it adds to the accuracy.

I'd be interested to know if people are getting results that are close to what the tool predicts.

But I'm like you in that I see it as a tool but not the definitive map. There are probably reflections off the sides of mountains between Vancouver and Seattle that would modify the results a bit. And then there's tropospheric activity that makes a difference depending on the day. Remember the curves are F(50,50) curves which means the signal is better 50% of the time and worse the other 50% of the time.
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post #144 of 797 (permalink) Old 2007-12-19, 05:20 PM Thread Starter
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Quote:
The altitude/elevation accuracy is 1 meter.
Thanks, I was unclear about that.

In my experience your maps are very accurate regarding the Lower Mainland, and I hope 4DTV HD will take a look at them and compare them to his lengthy experience in the TV reception business.

I caution anyone from making decisions without testing first. The maps are a huge help!
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post #145 of 797 (permalink) Old 2007-12-19, 05:38 PM
 
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Someone up on Mount Seymour would seem to get the best signal of all. Would lead me to belive that people in Seattle have an easier time picking up Vancouver than the reverse. With all those amazing mountain tops I dont understand why the Sea-Tac stations would locate on some pathetic hill in the middle of the city.
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post #146 of 797 (permalink) Old 2007-12-19, 06:09 PM
 
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Smile my location to map indicator

I can say this the map shows me why I can get so many stations with just a slight skip condition and whu I get KCPQ mornings and evenings very often for a short time. As for the vhf they are even more in line with the map as I can get snowy Sea Tac stations with just the little fading in and out less determined by skip for that.

The fellow who did my site survey did mention Sea Tac signals weak but they are there none the less, As I use TS reader I can see parts of the signal even though there is no complete lock whisch is a great tool for seeing what active.

Last edited by danbcman; 2007-12-19 at 06:20 PM. Reason: typo
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post #147 of 797 (permalink) Old 2007-12-19, 06:47 PM Thread Starter
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Quote:
Originally Posted by GerryB
Would lead me to belive that people in Seattle have an easier time picking up Vancouver than the reverse.
Some of the old analogues like CBUT and CHEK carry well down there but if you check through this thread there is a fellow who posts here from Bellingham who hardly ever gets Canadian digital station locks even just that distance.
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post #148 of 797 (permalink) Old 2007-12-19, 09:01 PM
 
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Thanks for the maps Gerry. I overlayed the images into Google Earth, typed in my address and voila!
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post #149 of 797 (permalink) Old 2007-12-19, 10:02 PM
 
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I'd also like to thank you for the maps, GerryB; Much appreciated!
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post #150 of 797 (permalink) Old 2008-01-03, 12:24 PM
 
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Bellingham Digital Translators - Construction Permits

Two of the Bellingham translator stations recieved contruction permits on December 26th for their digital stations.

Both stations are owned by Venture Technologies. One on channel 24 and the other on channel 34. Powers of 15 kW and 12 kW. Both directional towards Vancouver. I think these are the companions to analogue 38 and 65 (neither of which are operational.)

http://www.fcc.gov/fcc-bin/tvq?list=0&facid=167292

http://www.fcc.gov/fcc-bin/tvq?list=0&facid=167302

Channel 24 is occupied until Feb 2009 by the shopping channel that will stay on channel 19 digital.

I'm not holding my breath for these to go live.
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