A question to gjvrieze and IDRick

NonMcTubber · 03-21-2009, 12:21 PM

Rather than post my entire TV fool report, suffice it to say, with minimal effort and expense, I now get, in digital, 14 of the 18 stations
listed in the Green, yellow, and red areas in my current TV fool report. The missing 4 are low power stations well off my current TV antenna aim, and three of the four are simply repeaters for digital channels I already get. And the remaining one, given its programming, is something I have zero interest in watching.

As as I look at the various stations in the grey areas of my TV fool report, only one channel, namely channel real channel 14 out of Bloomington, IN would be a worthwhile addition to watch.

Pre the 6/12/09 transition, my exact address TV fool reports it on real channel 14, its heading at 185 degrees, its distance at 70 miles, and its signal power at my location as -17.5 as measured by NM(dB).

For whatever reason, my post 6/12/09 TV fool reports the same data including real channel allocation, but its predicted to have a signal strength of -10.5 as measured by NM(dB).

Since the antenna gain of really good directional antenna can exceed 12 dB on channel 14, it gives me some reason to hope I might be able to get that channel. But when I factor in about 100 feet of coax between my antenna and television and one splitter, my question is there any realistic hope of getting that channel or not?

Tower Guy · 03-21-2009, 12:46 PM

Quote:

Originally Posted by NonMcTubber

For whatever reason, my post 6/12/09 TV fool reports the same data including real channel allocation, but its predicted to have a signal strength of -10.5 as measured by NM(dB).

Since the antenna gain of really good directional antenna can exceed 12 dB on channel 14, it gives me some reason to hope I might be able to get that channel.

It doesn't work that way. You must also add subtract the noise of the preamplifier.

Noise margin -10.5
Preamp noise figure -3
Antenna gain +12

Overall noise margin -1.5 db

In order to get channel 14 you'll need more antenna gain or a taller mast.

IDRick · 03-21-2009, 02:22 PM

Tower Guy is certainly correct in his calculation. By science, the probability is very low that you can acquire that station. His potential solutions are also reasonable: increase antenna gain and/or antenna height. Tvfool is a very useful tool but it is a modeling effort. The real world scenario may be better, same or worse. I know someone who was able to acquire a two edge station (40+ miles away, NM -22 db) with a four bay antenna in the attic. Certainly an exceptional case but they do happen... Really depends on your risk/reward view of the station.

In my case, I would be willing to expend serious dollars to acquire a Fox affiliate out of Jackson Hole, Wyoming. They, for whatever reason, seem to have my favorite football team on nearly every Sunday. But, I don't have a prayer with the serious mountains and distance between here and there... Their Fox doesn't even show up on my tvfool results...

Best,

Rick

NonMcTubber · 03-21-2009, 06:59 PM

Thank you very much Towerguy and IDRick, but the reality is more contained by Tower guy with quote, "Noise margin -10.5
Preamp noise figure -3
Antenna gain +12

Overall noise margin -1.5 db

In order to get channel 14 you'll need more antenna gain or a taller mast."

As a bottom line type of guy, I have to say that the state of the arts antenna gain is limited to about 12 DB on real channel 14, and even inputting a totally fictional antenna height of 100 feet, some 70 feet more than I have, only gains me a real post 6/12/09 transition gain of channel 14 of -10.5 to -8 MN(db). And since what I have in terms of a amp has a noise figure of -5 rather than -3, I will be always upsidedown on the matter.

So bottom line for me, its not worth spending any more money to upgrade my OTA antenna, because channel 14 is just going to be a bridge too far for me as IDRick points out.

But this does not end my quest, my other dogs in the fight are my mother and her near neighbors, who live in distinctly different locations.

IDRick · 03-21-2009, 07:23 PM

Take a look at this thread: http://www.digitalhome.ca/forum/showthread.php?t=100058

Note, these antenna gains are in dBi rather than dBd (conventional gain measure). You can convert to dBd by subtracting 2.15

If you use a low noise margin pre-amp, you can make the NM a positive number (assuming a slighting higher gain antenna as well). Just a thought. Course, the real situation may be better than predicted by tvfool. Possibly worse as well...

Good luck!

NonMcTubber · 03-21-2009, 08:28 PM

Quote:

Originally Posted by IDRick

Take a look at this thread: http://www.digitalhome.ca/forum/showthread.php?t=100058

Note, these antenna gains are in dBi rather than dBd (conventional gain measure). You can convert to dBd by subtracting 2.15

If you use a low noise margin pre-amp, you can make the NM a positive number (assuming a slighting higher gain antenna as well). Just a thought. Course, the real situation may be better than predicted by tvfool. Possibly worse as well...

Good luck!

-----------------------------------------------------------------------------

Thanks IDRick for telling me I am another 2.15 dB upsidedown hopeless. Somewhat of a good luck Smuck for me.

But I still have to appreciate your honesty, as it is I have spent a grand total of $46.00 to upgrade my OTA antenna system for the digital TV transition, and I have to conclude that has been money well spent. More luck than science for me, but bottom line this forum, antennaweb.org, and TVfool.com can transition anyone from a dummy to knowledgeable for anyone who is willing to learn.

Bottom line , knowledge is power, and its tells what we can realistically do and what is a waste of money.

gjvrieze · 03-23-2009, 08:31 PM

Been away from town and (good) internet for the weekend. Got a got a great gin pole made up over the weekend though:-)
Looks like your questions got answered, if you have any others, reply and we will continue to help out!

03-21-2009, 12:21 PM	#1
NonMcTubber High Definition is the definition of life. Join Date: Mar 2009 Posts: 1,292	A question to gjvrieze and IDRick Rather than post my entire TV fool report, suffice it to say, with minimal effort and expense, I now get, in digital, 14 of the 18 stations listed in the Green, yellow, and red areas in my current TV fool report. The missing 4 are low power stations well off my current TV antenna aim, and three of the four are simply repeaters for digital channels I already get. And the remaining one, given its programming, is something I have zero interest in watching. As as I look at the various stations in the grey areas of my TV fool report, only one channel, namely channel real channel 14 out of Bloomington, IN would be a worthwhile addition to watch. Pre the 6/12/09 transition, my exact address TV fool reports it on real channel 14, its heading at 185 degrees, its distance at 70 miles, and its signal power at my location as -17.5 as measured by NM(dB). For whatever reason, my post 6/12/09 TV fool reports the same data including real channel allocation, but its predicted to have a signal strength of -10.5 as measured by NM(dB). Since the antenna gain of really good directional antenna can exceed 12 dB on channel 14, it gives me some reason to hope I might be able to get that channel. But when I factor in about 100 feet of coax between my antenna and television and one splitter, my question is there any realistic hope of getting that channel or not?

03-23-2009, 08:31 PM	#7
gjvrieze High Definition is the definition of life. Join Date: Dec 2008 Location: Rochester, MN Posts: 289	Been away from town and (good) internet for the weekend. Got a got a great gin pole made up over the weekend though:-) Looks like your questions got answered, if you have any others, reply and we will continue to help out! __________________ KD0GTI http://rochestermnhd.blogspot.com/

Similar Threads to A question to gjvrieze and IDRick
Thread	Thread Starter	Forum	Replies	Last Post
The usual question - recommendations please	Bohiti	Local HDTV Info and Reception	7	03-03-2009 09:40 AM

03-21-2009, 02:22 PM	#3
IDRick High Definition is the definition of life. Join Date: Oct 2008 Location: Eastern Idaho Posts: 2,233	Tower Guy is certainly correct in his calculation. By science, the probability is very low that you can acquire that station. His potential solutions are also reasonable: increase antenna gain and/or antenna height. Tvfool is a very useful tool but it is a modeling effort. The real world scenario may be better, same or worse. I know someone who was able to acquire a two edge station (40+ miles away, NM -22 db) with a four bay antenna in the attic. Certainly an exceptional case but they do happen... Really depends on your risk/reward view of the station. In my case, I would be willing to expend serious dollars to acquire a Fox affiliate out of Jackson Hole, Wyoming. They, for whatever reason, seem to have my favorite football team on nearly every Sunday. But, I don't have a prayer with the serious mountains and distance between here and there... Their Fox doesn't even show up on my tvfool results... Best, Rick

03-21-2009, 06:59 PM	#4
NonMcTubber High Definition is the definition of life. Join Date: Mar 2009 Posts: 1,292	Thank you very much Towerguy and IDRick, but the reality is more contained by Tower guy with quote, "Noise margin -10.5 Preamp noise figure -3 Antenna gain +12 Overall noise margin -1.5 db In order to get channel 14 you'll need more antenna gain or a taller mast." As a bottom line type of guy, I have to say that the state of the arts antenna gain is limited to about 12 DB on real channel 14, and even inputting a totally fictional antenna height of 100 feet, some 70 feet more than I have, only gains me a real post 6/12/09 transition gain of channel 14 of -10.5 to -8 MN(db). And since what I have in terms of a amp has a noise figure of -5 rather than -3, I will be always upsidedown on the matter. So bottom line for me, its not worth spending any more money to upgrade my OTA antenna, because channel 14 is just going to be a bridge too far for me as IDRick points out. But this does not end my quest, my other dogs in the fight are my mother and her near neighbors, who live in distinctly different locations.

03-21-2009, 07:23 PM	#5
IDRick High Definition is the definition of life. Join Date: Oct 2008 Location: Eastern Idaho Posts: 2,233	Take a look at this thread: http://www.digitalhome.ca/forum/showthread.php?t=100058 Note, these antenna gains are in dBi rather than dBd (conventional gain measure). You can convert to dBd by subtracting 2.15 If you use a low noise margin pre-amp, you can make the NM a positive number (assuming a slighting higher gain antenna as well). Just a thought. Course, the real situation may be better than predicted by tvfool. Possibly worse as well... Good luck!