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Andy,


Notice these stations in my area are missing Virtual channel info ( "virt" column is just blank for them) for the post-transition plot :


WXIX-DT - "virt" should be 19.1 instead of blank

WRTV-DT - "virt" should be 6.1 instead of blank


They are both correct(19.1 and 6.1 respectively) for current plot ...


I didn't check elsewhere/other stations, but would imagine there may be some other "holes" like this ....



Note: Someone noticed this and brought it up in local thread(and incorrectly assumed since it was "blank" it meant the VC's would = the physical channel # post transition, LOL), Sorry, I'd missed this in my last "round" of updates/corrections for my area ...
 

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Discussion Starter #302

Quote:
Originally Posted by Nitewatchman /forum/post/14903408


WXIX-DT - "virt" should be 19.1 instead of blank

WRTV-DT - "virt" should be 6.1 instead of blank

Thanks Jeff,


These two have been fixed. Let me know if you find any others...


Best regards,

Andy
 

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Errata for San Diego, CA:


1. Post-Feb2009, KGTV-DT will move from Ch25 to Ch10, taking over their current analog

assignment. Ch10 has always been elected DTV channel and is consistent with "RabbitEars" report.


So how did the error re long settled KGTV-DT election creep into TVFool????

It was correct in earlier versions. Could there be errors in other locations????


========================================

2. In Mar2008 KFMB-DT vacated DTV Ch55 (taken over by Qualcomm for MediaFlo) and

temporarily initiated operations on DTV Ch7 (they'll replace analog Ch8 in Feb2009):
http://www.sbe36.org/index.php?optio...d=211&Itemid=1

"The KFMB VHF 16-panel Delta Wing array antenna made by Dielectric beams in a

cardioid pattern with a sharp null in the direction of KABC's line-of-sight Mt. Wilson

transmission antenna." Hopefully this helps you pick an antenna type....


Due to interference with KABC in L.A. and local cable system (huh???), they

reportedly were forced to drop from initial 14 kW to 3.16 kW and never

made it to the 140 kW they were shooting for...


FCC database reveals that an Experimental Ch7 license exists, but no data is provided:
http://fjallfoss.fcc.gov/cgi-bin/ws....ion_id=1224057


BTW: RabbitEars spread sheet correctly shows Ch7:
http://www.rabbitears.info/ss/
 

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Hi Andy,


I have probably one of the worst locations for OTA ATSC reception in the world.


Attached is the plot of what I have.


Currently, my setup is as follows:

My elevation is at 530'+-. The hill at 300 degrees is at 1200' and the hill on the east is at 1100'. The valley is about 1/2 - 3/4 mile wide. I'm right on a river.


2x AD 91XG's with a 4th boom section (total is 110" long) spaced 48" apart (couldn't find a longer rigid fiberglass pole)

1x Winegard YA1713 VHF-hi

TinLee notch filter for UHF ch 18 between antenna combiner and uvsj.

PicoMacom UVSJ splitter and a VHF Hi-Low splitter.

PicoMacom VHF-low is terminated on the splitter, I may install one at a later point in time for FM. VHF side of the UVSJ is terminated as well w/ 75 ohm cap.


Antenna mast is at 31'.


CM7777 pre-amp. All wiring is RG11. Cable run to the house is 90'+- with RG11. I have 650 series P3 Commscope hardline I need connectors for that will replace the RG11 to the house. Inside the house it's 30' of RG11 to my tv with my Zenith DTT901.


My question is about my antenna aiming. For me to receive the signals coming in from 300 degrees, I have to point my antennas to approx 100 degrees, towards a hill. I get no useful signal with it pointed in the general direction of 300 degrees.


UHF 18 (digital)and UHF 20 (analog gone after Feb) are really a LOS for me. I can see Burke Mt. from my roof. I needed the notch filter because UHF 18 and 20 are overloading my preamp. I had it tuned for 18 because after Feb 20 won't be an issue.


With just my YA1713 plugged into the CM7777 I was able to pick up Digital UHF 18 and analog UHF 20!!! that's why I got the notch filter and UVSJ and Hi-Low VHF splitter.


I am not able to receive WVNY-DT at all. It is borderline decodeable, but it has never decoded, not even once after leaving it there all night long.


I am able to receive WFFF-DT at -29.4 db with minimal dropouts at night. During the day, it is watchable, but every 30 seconds it drops out.


I'm also able to pick up a station not listed on my plot. WENH-DT on UHF 57 virt 11. It's approx 92 miles away at 589 KW.


WFFF-TV, analog 44 is not broadcast from Mt. Mansfield. It is broadcast from Northpole, NY. Much further away.



On the analog sides I can pick up WMUR-LP and CIVST.


But again, my biggest problem is only related to channels coming from 300 degrees. All other channels I get correctly when pointed at the transmitters.


I also am not sure if FM is going to be a problem for me. I can pick up in my truck with a 1/2 broken antenna 107.9 at Rx dbm of -76.5.


Thanks,


~ryan

 

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TVfool gives magnetic azimuth of 42 for W36DO 36.1 from here in Swarthmore PA 19081, same as for all the other stations at the Roxborough antenna farm. Yet when I point my rooftop UHF only antenna in that direction the picture drops out.


The FCC contour map here http://www.fcc.gov/fcc-bin/FMTV-serv...LD1247543.html seems to show the broadcasting location well to the south of what TVfool is indicating and more to my east which agrees with the antenna direction that successfully pulls in the station. So looks to me like there is a little glitch in TVfool database for this station.


TVfool is wonderful. Other than the small glitch just mentioned gives spot on information for what I receive here.
 

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Quote:
Originally Posted by otaguy /forum/post/14939457


TVfool gives magnetic azimuth of 42 for W36DO 36.1 from here in Swarthmore PA 19081, same as for all the other stations at the Roxborough antenna farm. Yet when I point my rooftop UHF only antenna in that direction the picture drops out.

Sounds to me like this may be a result of signal overload. I get the same thing from 2 Baltimore stations here. I have to rotate the antenna 25 degeees away from the actual signal source of 2 Balt. stations because of the overload caused by the closeby DC stations.
 

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Quote:
Originally Posted by Digital Rules /forum/post/14939629


Sounds to me like this may be a result of signal overload. I get the same thing from 2 Baltimore stations here. I have to rotate the antenna 25 degeees away from the actual signal source of 2 Balt. stations because of the overload caused by the closeby DC stations.

No, W36DO-D has a license to transmit from a location that is not the Roxborough tower site most of the other stations use, and he's saying that TV Fool is listing it as coming from there.


Now W36DO-D has a construction permit to move to Roxborough in the future, but at the moment it transmits from a different site as far as I can tell.


- Trip
 

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Quote:
Originally Posted by Digital Rules /forum/post/14939629


Sounds to me like this may be a result of signal overload. I get the same thing from 2 Baltimore stations here. I have to rotate the antenna 25 degeees away from the actual signal source of 2 Balt. stations because of the overload caused by the closeby DC stations.

I don't think so. When I put the coordinates for W36DO from the FCC website (39 56 7.99N 75 12 17.35W) into Mapquest I get a spot just south of the Grays Ferry Ave bridge. When I put in the coordinates for WCAU 10.1 (40 02 30N 75 14 11W) I get a spot in Roxborough with the rest of the antenna farm. These two broadcasting locations are 7.5 miles apart.
 

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Question for andy...


In the db figures that TVFool gives in the chart, are these reflecting co-channel and adjacent channel interference? Or are they just reflecting the terrain analysis?


I'm trying to peg my real world results against post-transition reality on a few channels that will no longer have Cs and As next to them.
 

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Discussion Starter #310

Quote:
Originally Posted by otaguy /forum/post/14939457


TVfool gives magnetic azimuth of 42 for W36DO 36.1 from here in Swarthmore PA 19081, same as for all the other stations at the Roxborough antenna farm. Yet when I point my rooftop UHF only antenna in that direction the picture drops out.


The FCC contour map here http://www.fcc.gov/fcc-bin/FMTV-serv...LD1247543.html seems to show the broadcasting location well to the south of what TVfool is indicating and more to my east which agrees with the antenna direction that successfully pulls in the station. So looks to me like there is a little glitch in TVfool database for this station.


TVfool is wonderful. Other than the small glitch just mentioned gives spot on information for what I receive here.
Quote:
Originally Posted by Trip in VA /forum/post/14940073


No, W36DO-D has a license to transmit from a location that is not the Roxborough tower site most of the other stations use, and he's saying that TV Fool is listing it as coming from there.


Now W36DO-D has a construction permit to move to Roxborough in the future, but at the moment it transmits from a different site as far as I can tell.


- Trip
Quote:
Originally Posted by otaguy /forum/post/14940256


I don't think so. When I put the coordinates for W36DO from the FCC website (39 56 7.99N 75 12 17.35W) into Mapquest I get a spot just south of the Grays Ferry Ave bridge. When I put in the coordinates for WCAU 10.1 (40 02 30N 75 14 11W) I get a spot in Roxborough with the rest of the antenna farm. These two broadcasting locations are 7.5 miles apart.

On August 11, W36DO was granted a construction permit for a transmitter at 40.041668 x -75.236152. The application details can be found here .


They are apparently still operating out of their licenced facility further to the south at 39.93567 x -75.20441.


There's no telling when they will actually switch over to their new facility, but since the CP record is the newer entry in the FCC database, that is the one that is currently being used by TV Fool. I'm guessing that they will switch some time soon, but if we get word from their chief engineer that they are NOT moving any time soon, I can put in a database correction to point to the older record.


Best regards,

Andy
 

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Quote:
Originally Posted by andy.s.lee /forum/post/14949932


On August 11, W36DO was granted a construction permit for a transmitter at 40.041668 x -75.236152. They are apparently still operating out of their licensed facility further to the south at 39.93567 x -75.20441.

I miss the data in the table that shows the ERP. I used it to verify which FCC application was used for the calculation.


Yet, having that data for the average user is overwhelming.


How about another, more advanced, display option that includes the ERP?
 

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Quote:
Originally Posted by Tower Guy /forum/post/14951088


I miss the data in the table that shows the ERP. I used it to verify which FCC application was used for the calculation.


Yet, having that data for the average user is overwhelming.


How about another, more advanced, display option that includes the ERP?

I agree. It's also useful for Canadian stations, where the FCC database does not include Canadian antenna pattern data. That way, we could adjust the received dBm value to match something other than the maximum ERP. (IC tables include the average and maximum ERP, so we can ball park the difference if we know where the null(s) are.)


Even more, it's useful to figure out which data you're using for American stations whose maximization apps have yet to be approved. (Or, in the case of WCFE, whether an old CP or the licensed value is being used, to say nothing of the maximization APP.)


TVl

Ottawa, ON
 

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In reference to my post above. Andy Lee has contacted me directly and he has provided me with some great information and hopefully we can get my antennas figured out.


I just wanted to say I appreciate his time and the free information he provides for us via TVFool and FMFool.


Thanks,


~ryan
 

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Reinstating TX power (in direction of the receiver) greatly simplifies use of my

DTV Signal Calculator spread sheet:
http://www.avsforum.com/avs-vb/showp...postcount=2890

Antenna Gain, cable/splitter loss, Preamp improvement, et. al. can then be incorporated.


Otherwise the user has to find the polar plot for each station and determine correct value.

[An annoying and error prone endeavor.]


A column for authorized ERP is valuable to cross check with changing local conditions,

although (with effort) it can be found by clicking on Google Earth (*.kmz) tower location.

Due to changing conditions, I've found that this happens a lot....


==========================

What are assumptions you used to determine the NM=0 point for DTV & NTSC?

Is it simply the difference wrt a sensitivity value (seems about -91 dBm for DTV

and about -79 dBm for NTSC)?

Although -91 dBm would apply for ideal Preamps, how do we adjust for typical

DTV tuner sensitivity of about -84 dBm?


I took a quick stab at it here:
http://www.avsforum.com/avs-vb/showt...php?p=14938532

Your comments would be appreciated by everyone concerned....


Ditto assumptions re RX Pwr(dBm)....is it simply the output of a 0 dBi antenna?

Hence user can adjust for antenna gain, Preamp & downlead losses?


=========================

Are you now using F(50,90) RX signal statistics for Pwr(dBm)?
 

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Discussion Starter #317

Quote:
Originally Posted by holl_ands /forum/post/14923717


1. Post-Feb2009, KGTV-DT will move from Ch25 to Ch10, taking over their current analog

assignment. Ch10 has always been elected DTV channel and is consistent with "RabbitEars" report.

OK. I think this has been fixed.



Quote:
2. In Mar2008 KFMB-DT vacated DTV Ch55 (taken over by Qualcomm for MediaFlo) and

temporarily initiated operations on DTV Ch7 (they'll replace analog Ch8 in Feb2009):
http://www.sbe36.org/index.php?optio...d=211&Itemid=1

"The KFMB VHF 16-panel Delta Wing array antenna made by Dielectric beams in a

cardioid pattern with a sharp null in the direction of KABC's line-of-sight Mt. Wilson

transmission antenna." Hopefully this helps you pick an antenna type....


Due to interference with KABC in L.A. and local cable system (huh???), they

reportedly were forced to drop from initial 14 kW to 3.16 kW and never

made it to the 140 kW they were shooting for...


FCC database reveals that an Experimental Ch7 license exists, but no data is provided:
http://fjallfoss.fcc.gov/cgi-bin/ws....ion_id=1224057


BTW: RabbitEars spread sheet correctly shows Ch7:
http://www.rabbitears.info/ss/

OK. I picked a Dielectric antenna with a cardiod pattern and a null directed toward KABC at 3.16 kW. I hope this gives a reasonable representation of KFMB's current coverage on channel 7. The online coverage map will still be incorrect until I get around to re-processing it, but the Signal Analysis results should reflect the updated KFMB data.


Best regards,

Andy
 

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Discussion Starter #318

Quote:
Originally Posted by Tower Guy /forum/post/14951088


I miss the data in the table that shows the ERP. I used it to verify which FCC application was used for the calculation.


Yet, having that data for the average user is overwhelming.


How about another, more advanced, display option that includes the ERP?
Quote:
Originally Posted by tvlurker /forum/post/14951153


I agree. It's also useful for Canadian stations, where the FCC database does not include Canadian antenna pattern data. That way, we could adjust the received dBm value to match something other than the maximum ERP. (IC tables include the average and maximum ERP, so we can ball park the difference if we know where the null(s) are.)


Even more, it's useful to figure out which data you're using for American stations whose maximization apps have yet to be approved. (Or, in the case of WCFE, whether an old CP or the licensed value is being used, to say nothing of the maximization APP.)


TVl

Ottawa, ON
Quote:
Originally Posted by Falcon_77 /forum/post/14951513


That has my vote. I miss that the most. Much more than the -100dBm and LOS columns. It's a lot harder to figure out what record is being used now.

All right, TV Fool fans. We just launched another new feature on the Signal Analysis reports. You should now have the ability to click on a channel in the table and that will take you to a detailed view for that transmitter. From there you can see the coordinates, channel, max ERP, and effective ERP (for your location). It will also show a cross-section of the terrain profile between you and the transmitter so that you can get a feel for what's obstructing some of your signals.


We're pretty excited about this new feature and I hope you will be too.


Best regards,

Andy
 
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