# OTA Transition - Xmit Power



## SE_Sooner (Aug 12, 2008)

According to www.tvfool.com after the transition on Feb., 2009, most tv stations transmit power will be far less than they currently transmit. Will the coverage map still be the same?

Most my locals are 80+ miles away but are stable and watchable. Will I have a problem receiving these signals next year?

Does the digital signal take less power to cover the same area?

Thanks


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## Stewart Vernon (Jan 7, 2005)

Some general things...

All things being equal, VHF tends to travel farther than UHF. This means with equal terrain/weather conditions the same signal strength via VHF will travel farther than UHF... so a VHF conversely doesn't need to be transmitting as strong to go as far. Some stations that will switch down to a VHF frequency in Feb 2009 would not need as much power.

Analog signals have a range, but there is a point of diminishing quality beyond which the viewer gets increasingly poorer but still watchable TV. Eventually you get nothing.

Digital signals have a range, but there is a point of increasing signal errors/breakups beyond which you get increasingly more breakups but perhaps still watchable TV. Eventually you get nothing.

To some, an analog signal with a little snow is preferrable to a digital signal that breaks up, skips, etc.

In theory, the FCC is attempting to match the digital coverage to the analog coverage today... so I assume (perhaps incorrectly) that someone said channel ZZ is receivable at acceptable quality some distance from the tower in analog... then determined that an appropriately lower digital signal would reach that level and no farther.

Lots of assumptions on my part, but in theory I think that is what they are trying to do... which means some stations may go lower power if their current power is going past that determined range.

At least part of that reasoning is to prevent adjacent markets from overlapping and/or interfering with each other. There could also be a side-agenda hoping to see more OTA digital stations popup in the future too, but that's a guess on my part.


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## SE_Sooner (Aug 12, 2008)

Thanks for moving the post to the appropriate forum. My bad...

HDME, I hope the TV broadcasters and FCC get it right after the transition, for those of us that live on the fringe of the signal, it means the difference in continuing to receive their broadcast signal and nothing at all.

I guess it's selfish on my part, but I hope they're not to conservative on the transmit power.


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## Nick (Apr 23, 2002)

SE_Sooner said:


> ...for those of us that live on the fringe of the signal, it means the difference in continuing to receive their broadcast signal and nothing at all.
> 
> I guess it's selfish on my part, but I hope they're not to conservative on the transmit power.


Don't count on broadcasters to pump up the volume -- the FCC broadcast license limits maximum xmit power.

For OTA fringe-dwellers, this post may be of interest...or, of _concern_.
http://www.dbstalk.com/showpost.php?p=1791416&postcount=153


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## krock918316 (Mar 5, 2007)

Where you at SE SOONER? I'm in Poteau. I use a CM4228, and am able to get KHBS-DT, KFSM-DT, KFTA-DT with no problems from Fort Smith. I'm at about 55 miles from KFSM and KFTA.

Oh and BOOMER SOONER!


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## krock918316 (Mar 5, 2007)

Nick said:


> Don't count on broadcasters to pump up the volume -- the FCC broadcast license limits maximum xmit power.
> 
> For OTA fringe-dwellers, this post may be of interest...or, of _concern_.
> 
> http://www.dbstalk.com/showpost.php?...&postcount=153


Nick -

Your link doesn't work.


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## n3ntj (Dec 18, 2006)

Yeah, I can 2nd that the link is no good.

As said, the FCC is trying to get digital radiation patterns to closely match those of the current analog patterns. With many stations changing digital freqs after Feb 2009, I think some modifications may be made, but probably on a station-by-station basis. 

The stations moving from their current UHF digital freq to their current analog VHF freq (for digital), they may very well be able to lower their ERP to get comparable radiation patterns. 

One thing I can say about Feb 2009, it should be an interesting time for TV... especially those into DX TV..

See the Digital/Analog TV Plug-in available for Google Earth. Way Way Cool!


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## SE_Sooner (Aug 12, 2008)

krock918316 said:


> Where you at SE SOONER? I'm in Poteau. I use a CM4228, and am able to get KHBS-DT, KFSM-DT, KFTA-DT with no problems from Fort Smith. I'm at about 55 miles from KFSM and KFTA.
> 
> Oh and BOOMER SOONER!


I'm about 40 miles west of you in Wilburton. I can get 40/29 but none of the other Fort Smith stations. I do however get channels 2, 6, 11 and 41 out of Tulsa. Also, PBS out of Eufaula and channel 10 from Sherman/Denison TX. Some of the other Tulsa stations are come and go.

I was reading on other posts that some have good luck with a Channel Master Amp. Will this help on the marginal stations? OBTW, I'm using a old UHF Yagi antenna about 6 feet above the roofline.

We'll see what the Sooners can do with Washington this evening!


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## Richard King (Mar 25, 2002)

krock918316 said:


> Nick -
> 
> Your link doesn't work.


Fixed link. Try again.


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## krock918316 (Mar 5, 2007)

SE_Sooner said:


> I'm about 40 miles west of you in Wilburton. I can get 40/29 but none of the other Fort Smith stations. I do however get channels 2, 6, 11 and 41 out of Tulsa. Also, PBS out of Eufaula and channel 10 from Sherman/Denison TX. Some of the other Tulsa stations are come and go.
> 
> I was reading on other posts that some have good luck with a Channel Master Amp. Will this help on the marginal stations? OBTW, I'm using a old UHF Yagi antenna about 6 feet above the roofline.
> 
> We'll see what the Sooners can do with Washington this evening!


Wife used to work in Wilburton. Thank goodness she got to transfer back to Poteau. That was a lot of gas money with her driving from Poteau to Wilburton every day, and me driving from Poteau to Fort Smith every day.

80 miles is definitely fringe. There are so many mountains in between you and KFSM and KFTA that I think it will be tough, especially since both are currently on UHF (and UHF doesn't travel as well as VHF).

With me at 55 miles, and my antenna pointed at KFSM and KFTA, I am only getting about 55-60 on my HR20's signal meters. I am using the CM4228 antenna and a Channel Master 7777 pre-amp.

I wish I could get KTUL. 40/29 drives me crazy preempting ABC games (usually the Sooners) for a Raycom game.

Now that 40/29 is broadcasting The CW on 40-2, they are using their HD tape delay unit to do commercials on CW, so all preemptions are are in SD (and their SD tape delay unit looks like it is a 20 year old VCR).


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## SE_Sooner (Aug 12, 2008)

krock918316 said:


> With me at 55 miles, and my antenna pointed at KFSM and KFTA, I am only getting about 55-60 on my HR20's signal meters. I am using the CM4228 antenna and a Channel Master 7777 pre-amp.
> 
> I wish I could get KTUL. 40/29 drives me crazy preempting ABC games (usually the Sooners) for a Raycom game.
> 
> Now that 40/29 is broadcasting The CW on 40-2, they are using their HD tape delay unit to do commercials on CW, so all preemptions are are in SD (and their SD tape delay unit looks like it is a 20 year old VCR).


I read somewhere, maybe on KTUL website that their xmit antenna is shaped to not cover anything south of I-40. I can't get it but I don't have a VHF antenna and I think there're still in the high VHF range.

So does your 7777 pre-amp help with drop outs? When my signal get below 60 things get iffy.

Hey, isn't 40/29 transmitting from Cavanal Hill? The TALLEST HILL IN THE WORLD!


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## krock918316 (Mar 5, 2007)

SE_Sooner said:


> I read somewhere, maybe on KTUL website that their xmit antenna is shaped to not cover anything south of I-40. I can't get it but I don't have a VHF antenna and I think there're still in the high VHF range.
> 
> So does your 7777 pre-amp help with drop outs? When my signal get below 60 things get iffy.
> 
> Hey, isn't 40/29 transmitting from Cavanal Hill? The TALLEST HILL IN THE WORLD!


Yes, KTUL limits their signal south of I40 to stop interference with another station. I believe that KTUL will be moving their DT transmission back to 8 when the DTV transition happens, so that might eliminate the problem south of I40.

The CM7777 just helps with the signal overall. Without the preamp, my KFSM and KFTA signal drops to about 40, and is very pixelated.

Because I'm so close to Cavanal, I actually have a lot of problems with 40/29 because of multipath. I really need a second antenna with a filter, so that I can point that antenna at Cavanal, just for 40.

You might try coming over to the AVS Fourm for Fort Smith OTA. We have a real antenna expert "ARXAW" and the engineers from 4029 post a lot, and can offer a lot more help. Here's the link: http://www.avsforum.com/avs-vb/showthread.php?t=463765

BOOMER SOONER!


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## SE_Sooner (Aug 12, 2008)

Thanks for the invite... I've got some questions about combining antennas in different directions, and the best way to do that. Because splitter/combiners suck.

*7 to ZIP*


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## krock918316 (Mar 5, 2007)

I know it can be done. You'll need a product called a "Jointenna". It helps isolate the signal from different antennas.

http://www.warrenelectronics.com/Antennas/Jointennas.htm


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## SE_Sooner (Aug 12, 2008)

krock918316 said:


> I know it can be done. You'll need a product called a "Jointenna". It helps isolate the signal from different antennas.
> 
> http://www.warrenelectronics.com/Antennas/Jointennas.htm


The Jointenna sounds like the gear I need. I didn't see any specs on their website, like db loss etc. I think I would be ok with a CM 7777 pre-amp and the Jointenna. Logically, any loss caused by the Jointenna would be offset by the pre-amp. But I could be wrong. The only reason I worry about loss is the fact that I'm already marginal on sig. strength.

Thanks for the link.

*20 zip*


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## krock918316 (Mar 5, 2007)

SE_Sooner said:


> The Jointenna sounds like the gear I need. I didn't see any specs on their website, like db loss etc. I think I would be ok with a CM 7777 pre-amp and the Jointenna. Logically, any loss caused by the Jointenna would be offset by the pre-amp. But I could be wrong. The only reason I worry about loss is the fact that I'm already marginal on sig. strength.
> 
> Thanks for the link.
> 
> *20 zip*


No problem!

*27 zip*


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## n3ntj (Dec 18, 2006)

krock918316 said:


> I know it can be done. You'll need a product called a "Jointenna". It helps isolate the signal from different antennas.
> 
> http://www.warrenelectronics.com/Antennas/Jointennas.htm


This isn't viable if you are trying to receive multiple channels from 2 or more antennas!


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## krock918316 (Mar 5, 2007)

n3ntj said:


> This isn't viable if you are trying to receive multiple channels from 2 or more antennas!


Actually, you can.....


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## krock918316 (Mar 5, 2007)

SE Sooner-

If you want to get an idea of what you can get, check out this site that has coverage maps....

http://www.tvfool.com/index.php?option=com_wrapper&Itemid=80


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## n3ntj (Dec 18, 2006)

krock918316 said:


> Actually, you can.....


Since you'd have to purchase one of these for each channel you want on the 2nd antenna, I don't see that as a 'realistic' option.. maybe 1 or 2 stations, but not all the stations from another city. For example, I use one of my antennas for my local stations (Harrisburg/Lancaster, PA) with a pre-amp and then another antenna for the Phily stations (5 or 6 stations in all).


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## krock918316 (Mar 5, 2007)

n3ntj said:


> Since you'd have to purchase one of these for each channel you want on the 2nd antenna, I don't see that as a 'realistic' option.. maybe 1 or 2 stations, but not all the stations from another city. For example, I use one of my antennas for my local stations (Harrisburg/Lancaster, PA) with a pre-amp and then another antenna for the Phily stations (5 or 6 stations in all).


How are you doing this now? If it works, then you don't need one. The join-tennas are particularly useful when trying to avoid multipath. In my setup, my CBS and FOX stations are to the NE at about 55 miles. However, the ABC station is on a mountain about 5 miles to my west.

Since my antenna is pointed NE, I tend to get some multipath from the other mountains in the area. Getting 2 antennas and using the join-tenna eliminates the multipath problem from the ABC station.


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## SE_Sooner (Aug 12, 2008)

Krock918316, In my case this would work for me, maybe. All my locals except for one come from the North. The exception is one channel almost due East. The only issue is that it says on their website:

There is significant attenuation on either side of the channel the JoinTenna is tuned for. We do not recommend using a JoinTenna if you have a channel immediately adjacent.

So what does mean? I want a jointenna for broadcast channel 40 - real channel 21
Are the adjacent channels 20 and 22 or 39 and 41?

If it's 20 and 22, then it won't work because 22 is my fox channel.

Anyone have an idea? This new real channel fake channel, broadcast channel business has be confused!


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## Kansas Zephyr (Jun 30, 2007)

SE_Sooner said:


> Krock918316, In my case this would work for me, maybe. All my locals except for one come from the North. The exception is one channel almost due East. The only issue is that it says on their website:
> 
> There is significant attenuation on either side of the channel the JoinTenna is tuned for. We do not recommend using a JoinTenna if you have a channel immediately adjacent.
> 
> ...


RF channels may be susceptible to adjacent channel interference, not virtual ones.

But, in the digital world, there's only been limited real world experience to see how much of a problem it is.


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## krock918316 (Mar 5, 2007)

SE_Sooner said:


> Krock918316, In my case this would work for me, maybe. All my locals except for one come from the North. The exception is one channel almost due East. The only issue is that it says on their website:
> 
> There is significant attenuation on either side of the channel the JoinTenna is tuned for. We do not recommend using a JoinTenna if you have a channel immediately adjacent.
> 
> ...


The adjacent channels would be the "real" channels. So in your case it would be 20 and 22.

I agree, the virtual channels are a nightmare. Especially for the stations that are not going back to their original frequencies after the analog cut off.


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## From The Fray To The Grav (Sep 19, 2008)

There is a good chance you will actually lose some channels from 80 miles away. The only thing I know to suggest is that you try out a converter box with an enhanced digital tuner. I'm not really sure what the range it on them though. I know I have heard a lot of complaint about people losing channels that were further away once they hooked up their converter box.


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## Jim5506 (Jun 7, 2004)

Virtual channels are probably the stupidest thing the FCC has done in this whole mess (well, maybe their choice of encoding schemes is up there also).


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## Scott in FL (Mar 18, 2008)

Jim5506 said:


> Virtual channels are probably the stupidest thing the FCC has done in this whole mess (well, maybe their choice of encoding schemes is up there also).


It wasn't the FCC that came up with the virtual channel idea, it was the tv stations and the NAB. They wanted the stations to keep their identity. As an engineer, I agree with you. When I first heard about the proposal my immediate reaction was: why? Move on, use your new channel allocation. But I guess normal Joe and Jane viewer need to see they're still watching Channel 6 in Philly, even though it's now way up on channel 64. And my daughter in the mountains of Central PA, where she can only receive a very few OTA digital signals, is sure glad that she can receive both ABC and FOX on one RF channel. Plus a lot of people like the weather sub-channels. So we as informed technical types have to deal with it. It is confusing, I admit.

The encoding isn't a bad choice. It's the modulation the FCC chose, despite last minute efforts by Sinclair to convince them it was a mistake. Nothing new there... the FCC has a history of choosing the wrong standard (for example, NTSC).


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## Scott in FL (Mar 18, 2008)

Kansas Zephyr said:


> RF channels may be susceptible to adjacent channel interference, not virtual ones.


Adjacent channels are not a problem in the digital world, as long as their signal strengths are equal (or very nearly so). There are several markets where adjacent channels are assigned, broadcasting from the same tower at the same eirp. Philadelphia has two pair of adjacent channels operating (26/27 and 66/67). The key is they must be received at the same power level (or very nearly so). Two adjacent channels, transmitting from the same tower at the same eirp will meet this requirement. Two separate adjacent channels from different markets/directions may or may not.

If you want to know what real channels are in your area, go to tvfool.com.


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