[powerfactor]

Hi -


First post here. Thanks for the great forum and thread.


I need some help solving an OTA riddle.


I'm located on a hill in suburbia, 15 miles S.E. of the Sutro Tower broadcasting site in San Francisco. The top of that tower is >1800'; I am at 630'. There are some trees around, and there is a 1000' hill halfway between the tower and here, but nothing that should greatly attenuate the signals. I reckon it as pretty much line-of-sight conditions.


TVFOOL predicts -27 dBm signals at my house. I should be able to get a signal with a wet noodle, no?


But I get pretty rocky reception on most channels.


So I dragged a spectrum analyzer off the lab bench and hooked it up to my antenna (a Wineguard 7080p 10 feet above the roofline).


UHF signals measure in the range of -60 to -70 dBm. That is maybe 40 dB below expectation (net of antenna gain, cable loss, etc.)


I tried another antenna/feedline in the same location and got consistent results.


I have yet to try moving the antenna site. But is it likely that slightly perturbing the location will change such a deep null in the signals?


If you have any thoughts or suggestions, I'd love to hear them.

 

[GeekGirl]

Welcome to AVS forum! My thinking is that you are experiencing multipath. I'm on the East coast and not familiar with the area, but a 1000' "hill" may have some say in the matter.


Before you move the location: In addition to pointing in azimuth (horizontal), you might try pointing in elevation (up/down). It would be interesting to see if you can find a peak that's not line-of-sight.


I'd also take a guess at some diffraction from the hill if it's in the path to the tower.

 

[coyoteaz]



Quote:
Originally Posted by coyoteaz /forum/post/17705338


Looks like there's some confusion between WHBF's full-power channel 4 broadcast and the low-power channel 47. The listing for 4 is missing from the locator and online map. 47 has the right text in the box when selected on the online map, but the overlay looks to be for 4.

FYI, the online map for WHBF's channel 4 transmitter is currently wrong. Selecting the channel 4 transmitter brings up the channel 47 overlay.

 

[Tower Guy]



Quote:
Originally Posted by powerfactor /forum/post/18146660


UHF signals measure in the range of -60 to -70 dBm. That is maybe 40 dB below expectation (net of antenna gain, cable loss, etc.)


I tried another antenna/feedline in the same location and got consistent results.


I have yet to try moving the antenna site. But is it likely that slightly perturbing the location will change such a deep null in the signals?

The nulls in the vertical pattern of your receive antenna are probably less than 20 db. Changing the height a few feet may gain somewhat, but not 40 db worth.


Do the VHF stations have the same weak signal?


Is there a building in the way?


One poster found a bad balun caused a problem of your magnitude.

 

[powerfactor]



Quote:
Originally Posted by Tower Guy /forum/post/18149497


The nulls in the vertical pattern of your receive antenna are probably less than 20 db. Changing the height a few feet may gain somewhat, but not 40 db worth.


Do the VHF stations have the same weak signal?


Is there a building in the way?


One poster found a bad balun caused a problem of your magnitude.

Thanks for the balun tip I'll take down the yagi and check it out.


VHF stations are about 20 dB stronger; that's still less than predicted but enough for solid reception.


There are no buildings in the way, just a few trees.


I'll try playing with the elevation angle, as GeekGirl suggested.


Thanks for the suggestions.

 

[gmd1]

Why is WNMN sticking to channel 40? They're limiting their reach up North because of CHOT in Hull (QC).


People in Ottawa can get WCFE-DT, and would be able to get WNMN as well if it was using another channel. Come on, pick a number!


-gmd

 

[BCF68]

I still like to know why TvFool doesn't provide Google Earth maps of the Paducah, KY area

 

[TV Fringe Viewer]



Quote:
Originally Posted by BCF68 /forum/post/18280610


I still like to know why TvFool doesn't provide Google Earth maps of the Paducah, KY area

Yes that is a very good question?



Market: Paducah, KY-Cape Girardeau, MO-Harrisburg-MT Vernon, IL


When will these Google Earth Maps be Available?

____________________________________________________________ _____
Local TV Reception and Dxing from Thayer, MO and The OZARKS

Everybody can view my blog that wants to!!! Check out my polls and please VOTE if you like!

 

[tvlurker]



Quote:
Originally Posted by gmd1 /forum/post/18279486


Why is WNMN sticking to channel 40? They're limiting their reach up North because of CHOT in Hull (QC).


People in Ottawa can get WCFE-DT, and would be able to get WNMN as well if it was using another channel. Come on, pick a number!


-gmd

WMNM can barely cover Saranac lake. They're only using 12 kW or so right now.

If you follow their FCC submissions, you can see that they've been plagued by Murphy's Law from the start.


In their current incarnation, I think WMNM only exists as a nominal full-power station to feed their network of translators around Vermont and to get cable carriage.


Even if they moved to channel 44, and they didn't have to protect channel 40 here in Ottawa, I doubt we would get it. WCFE is much more favourably located than WMNM, onw on a short tower in Saranac Lake rather than in Tupper Lake.

 

[andy.s.lee]



Quote:
Originally Posted by BCF68 /forum/post/18280610


I still like to know why TvFool doesn't provide Google Earth maps of the Paducah, KY area

Quote:
Originally Posted by TV Fringe Viewer /forum/post/18315071


Yes that is a very good question?



Market: Paducah, KY-Cape Girardeau, MO-Harrisburg-MT Vernon, IL


When will these Google Earth Maps be Available?

OK. Consider it done for the next batch of updates.


Best regards,

Andy

 

[raj2001]

Anyone know if the NYC coverage includes the applications when the freedom tower is (eventually) built? My TVFool seems way off:

http://www.tvfool.com/?option=com_wr...b7c86cef718c65


For example, my strongest NYC station on UHF (I'm talking about those that are in Manhattan proper) appears to be WNBC and WCBS. Fox WNYW and WWOR are the weakest. That's not what the signal analysis says.


Great tool otherwise though. I've recommended it to many of my friends!

 

[BCF68]



Quote:
Originally Posted by andy.s.lee /forum/post/18435571


OK. Consider it done for the next batch of updates.


Best regards,

Andy

When are the next updates? You guys haven't updated in 6 months.

 

[andy.s.lee]

The latest Google Earth coverage maps were just posted. For the complete list, look here .


Best regards,

Andy

 

[JimboG]



Quote:
Originally Posted by andy.s.lee /forum/post/18732344


The latest Google Earth coverage maps were just posted. For the complete list, look here .


Best regards,

Andy

Sweet! Once again, thank you Andy for all your hard work! TV Fool and FM Fool are indispensible tools.