# Range for OTA HD reception



## AWAHOO (Oct 21, 2004)

Can anyone give a ball park range for receiving OTA HD signals? I realize that it is somewhat dependent on the power of the local station that is broadcasting, but is there a maximum range? If you can received SD OTA, would it be correct to assume that, given the proper antenna, you could also get HD?

I am 65 miles from my locals. Before I had cable and then D*, I could get the OTA channels fine. 

I had the cheapie D* OTA antenna (round) installed since it was free, but cannot pull in an channels from Richmond, VA.


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## DavidS (Sep 27, 2000)

Everything you need to know is at antennaweb.org


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## JimSpence (Sep 19, 2001)

AWAHOO said:


> Can anyone give a ball park range for receiving OTA HD signals? I realize that it is somewhat dependent on the power of the local station that is broadcasting, but is there a maximum range? If you can received SD OTA, would it be correct to assume that, given the proper antenna, you could also get HD?
> 
> I am 65 miles from my locals. Before I had cable and then D*, I could get the OTA channels fine.
> 
> I had the cheapie D* OTA antenna (round) installed since it was free, but cannot pull in an channels from Richmond, VA.


Just because you can get SD OTA doesn't mean you can get HD OTA. Why? Because your locals are using different frequencies for SD and HD and the output power is different.

Check that website for your particular situation.


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## AWAHOO (Oct 21, 2004)

I appreciate your quick response, but that site only gives, direction, distance and frequency. 

Is there a particular antenna that is best for frequencies 6-35? Will a normal VHF antenna pick up the HD? Given the distance of 65 miles, should I expect decent reception or not?


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## DavidS (Sep 27, 2000)

The site also gives you the antenna rating you will need, though it doesn't recommend specific models.

You might also check the local reception area at AVSForums (co-owned with this board). There may be a thread for your area.


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## HogarthNH (Dec 28, 2001)

AWAHOO said:


> Is there a particular antenna that is best for frequencies 6-35? Will a normal VHF antenna pick up the HD? Given the distance of 65 miles, should I expect decent reception or not?


No, Maybe and Probably not, respectively.

Antennaweb, in addition to giving you distance, should have indicated a color code for kinds of antennas that would possibly work. Follow their advice. 

Most HD broadcasters are either not yet at full power or broadcasting near frequencies used by others. Most are broadcasting in UHF. Some are broadcasting in VHF. A normal antenna is all you need -- but you'll need a good one, a large one, and one mounted outdoors as high as possible. 

I have trouble getting some stations at 13mi.

At 65mi, you may actually be far enough out to be in a "white area" and receive Distant Network Services.

H


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## AWAHOO (Oct 21, 2004)

Thanks, HorgarthNH. I did not go far enough in the antennaweb.org site. 

I already have what appear to be a channelmaster 3671 mounted on my roof from a previous VHF setup. The channelmaster site shows this as "HDTV compatable". Maybe I can get my local TV repairman to check this out for HD reception. 

Thanks for all your help. I never would have known where to go for this inf.


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## csweeny (Jun 9, 2004)

Awahoo,

It looks like your antenna is a VHF/UHF antenna, so if you could get HD OTA you have an antenna capable. If you have an ATSC tuner give it a try. 

Good Luck


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## TyroneShoes (Sep 6, 2004)

AWAHOO said:


> ...I am 65 miles from my locals. Before I had cable and then D*, I could get the OTA channels fine...


The ATSC plan is that the new DT channel coverage is designed to replicate the original analog channel coverage. In general, and in most circumstances, if you can get the SD channels OK, you should be able to get the DT channels. YMMV due to terrain and idiosyncratic issues, but you certainly have a fighting chance. There is currrently a tendency for some DT channels to operate at partial power, which could foil this, however. I have a friend who gets DT from 90 miles away using an attic antenna pointed 90 degrees the wrong way and obstructed by mountains (pointed east towards Phoenix but also gets Tuscon), so anything is possible.

Get the best antenna you can for your situation, put a CM 7775 or 7777 preamp on it, and mast-mount it as high as you can.


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## Runch Machine (Feb 7, 2002)

Like the others said, hook it up and try it. I think it is very likely that you will get reception. By the way, MOST digital channels are at full power, as required by FCC regulations. Stations affiliated with the 4 major networks were required to be at full power last year or lose their protection from other channels. 

Of course if there were extenuating circumstances, waivers could be granted. However, most of the big 4 network affiliate are at full power and should be able to be received as far out as their analog stations are.


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## JaserLet (Dec 13, 2005)

My DT reception sure surprised me. My digital stations are from the same transmitter farm as the analog stations, yet the digital stations are much easier to pick up. The analog stations required way too much fine tuning of my antenna. I had the strange 90 degree off problem with the analog stations, that bizarre position is where I got the best analog signal. But for digital I just gave the yagi a best guess aim (no line of sight due to hills) and ba-da-bing, signal strength in the upper 80s.


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## Scott D (Jun 17, 2001)

What do you think the lowest signal strength might be before a loss of signal for OTA antennas?


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## Mark Lopez (Jan 1, 2000)

Scott D said:


> What do you think the lowest signal strength might be before a loss of signal for OTA antennas?


Do you mean on the Tivo meters? If so, I start getting annoying picture breakups at around 70.


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## cheer (Nov 13, 2005)

Runch Machine said:


> Like the others said, hook it up and try it. I think it is very likely that you will get reception. By the way, MOST digital channels are at full power, as required by FCC regulations. Stations affiliated with the 4 major networks were required to be at full power last year or lose their protection from other channels.


Is that really true? Here in Chicago I know that WBBM (CBS) at least operates at lower power because the frequency assigned for their DTV transmissions (VHF 3...NICE GOING, FCC!) steps on another station in a nearby market.

Also keep in mind that many/most DTV transmissions are UHF, so even if you get the analog version fine you might have issues with the digital version depending on your antenna, etc.

FWIW, I found that the previous owners of my house had put some kind of antenna in the attic. I'm 40+ miles from the Tower, but I figured what the heck. Ran an RG6 feed down to my TV and voila, I get pretty much everything but WBBM, though I occasionally lose WMAQ (NBC) in poor weather.

If you can go outside the attic, that's much better -- you lose roughly 90% of the signal by being in the attic. (So one of my projects is to either relocate the existing antenna or just get a new one and mount it. Soon as I get over my fear of heights...)


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## SpankyInChicago (May 13, 2005)

cheer said:


> Is that really true? Here in Chicago I know that WBBM (CBS) at least operates at lower power because the frequency assigned for their DTV transmissions (VHF 3...NICE GOING, FCC!) steps on another station in a nearby market.


As far as I know since earlier this year, WBBM-DT (VHF 3) has been operating at fully licensed power of 4.4kW.

http://www.fccinfo.com/CMDProEngine.php?sCurrentService=TV&tabSearchType=Appl&sAppIDNumber=1069502

AFAIK, there will be no increase in this power until (and if) WBBM-DT moves to VHF 11 in 2009.


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## newsposter (Aug 18, 2002)

http://www.fcc.gov/fcc-bin/tvq?stat...t2=&mlat2=&slat2=&dlon2=&mlon2=&slon2=&size=9

that's where I go to find the philly tower heights and powers. I'm sure you can adjust the parameters for your area to see what you are dealing with. Typically fox or upn/wb are the lowest powers. Maybe CW will be more powerful!

here's a pdf of tenative final channel assignments in 2009

http://hraunfoss.fcc.gov/edocs_public/attachmatch/DA-05-2649A2.pdf


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## newsposter (Aug 18, 2002)

cheer said:


> If you can go outside the attic, that's much better -- you lose roughly 90% of the signal by being in the attic.


Sorry just had to refute this since it was such a blanket statement. Depends on what you are shooting thru (reflective surfaces etc). I have just wood and shingles and get virtually the same readings inside the attic as the antenna is now mounted in the same spot on the roof for most of my channels. The difference is that my low powered fox did need the "little bit" of oomph the roof was taking away to get it into the 65-70 signal range. The uhf 64 and 67 still have the same low 80s readings inside or out.

And of course all topography is different too


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## Arcady (Oct 14, 2004)

I don't mean to hijack this thread, but I just ordered an HR10-250 and I live 1.5 to 2 miles from all local broadcast points according to antennaweb. At this close distance, can I get away with an indoor antenna? All of the stations I care about are located south of me, and my TV will be in a south-facimg room. (UPN is north, but since they dropped Enterprise, I don't watch that channel anymore anyway, and they will not become the new CW channel later this year.)


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## jautor (Jul 1, 2001)

Arcady said:


> I don't mean to hijack this thread, but I just ordered an HR10-250 and I live 1.5 to 2 miles from all local broadcast points according to antennaweb. At this close distance, can I get away with an indoor antenna? All of the stations I care about are located south of me, and my TV will be in a south-facimg room. (UPN is north, but since they dropped Enterprise, I don't watch that channel anymore anyway, and they will not become the new CW channel later this year.)


Holy cow - that close and you can probable get them with a coat hanger, or maybe just a 3 ft. piece of cable lying on the ground!!! 

Absolutely should be able to get them with a set top antenna. I would buy the absolute cheapest one you can find, and definitely one without any sort of amplifcation. If fact, you're likely going to need a signal attenuator to reduce the signal strength (see RadioShack), as the TiVo tuners can be overdriven by very strong signals.

There is also a chance that being so close, you may have some bizzare reception issues, which may require more help that I have the experience to talk about...

Jeff


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## Arcady (Oct 14, 2004)

Ok thanks. I'll pick up the $9.99 special at radio shack tomorrow. The HD TiVo is supposed to arrive friday!


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## greywolf (Apr 9, 2004)

In very strong signal areas, a variable attenuator may be needed. Do not used an amplified antenna.


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## newsposter (Aug 18, 2002)

try a paperclip out the coax jack just to see if that's big enough  just kiddin


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## Arcady (Oct 14, 2004)

Well, I received the HD tivo today. I plugged in an old set of rabbit ears (which has one "ear" that is half broken off) and I get signals in the 90's. 

Thanks for the help.


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## greywolf (Apr 9, 2004)

Arcady said:


> (which has one "ear" that is half broken off)


Mechanical attenuation. Clever.


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## newsposter (Aug 18, 2002)

Sounds like a good idea for a patent.


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## TyroneShoes (Sep 6, 2004)

Scott D said:


> What do you think the lowest signal strength might be before a loss of signal for OTA antennas?


 It's totally quantifiable, and measurable. ATSC 8VSB signals will unlock when the S/N ratio dips below 15 dB. IOW, if the background noise is at -29 dBmV at a point of reception (a common level for residential reception areas), a received signal will unlock at measured carrier level of -14 dBmV, which is the ratio of that signal being 15 dB above the noise floor. That's a theoretical number of course. In reality there can be dynamically changing environmental issues that can make it less than accurate, or maybe not exactly a hard cutoff at that ratio at every point in time.

And that's a lot lower than NTSC. As long as there is signal lock, the ATSC picture will be perfect. In comparison, NTSC analog signals need to be a minimum of 43 dB above the noise floor to provide even acceptable PQ, although complete loss of sync lock won't happen until much lower (but the PQ suffers greatly).

This also takes only signal levels into account. Interference can also cause a ATSC signal to unlock, because interference, even multipath interference, can be considered "noise". And if the ratio of such interference (that also can't be rejected by the tuner) with respect to the desired signal dips low enough, that can also thwart signal lock.

S/N is not a measurement that the HR10 can make, but many TV sets can. Most Sonys have a S/N ratio measurement. As one example, my Sony reported a s/n ratio of 19 dB on the channel that was the worst for me, and which gave me occasional breakup (while all others were about 27-30 and did not break up).

In theory that should have been good enough, and usually it was, but what I think that meant was that while the reading was usually pretty steady at 19, occasionally there was some impulse noise or other interference that would crest above the noise floor and briefly bring that ratio down below 15 dB, causing the signal to unlock briefly, and causing brief pixellation. Once I added an amp the S/N ratio on that worst channel went to 26 dB, and I have seen no problems since, probably because even with impulse noise disturbances, the S/N ratio still remains constanly at some point above 15 dB.

ATSC provides for what they call "quasi-error-free" reception. In a real world hostile environment, even under perfect conditions you will see a brief breakup on the average of once every 24 hours or so. But this degrades exponentially, to once an hour for less than average conditions, then to about once a minute for poor conditions, to regular breakup in bad conditions. Most reception scenarios fall somewhere in between optimal and "less than optimal" once everything that can be done to improve reception has been done, so it is common to see a single breakup of a ATSC signal every few hours or so for many viewers.

Sorry...gotta cut down on the Red Bulls


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## newsposter (Aug 18, 2002)

Scott D said:


> What do you think the lowest signal strength might be before a loss of signal for OTA antennas?


Well if you want that in english (big grin), I've found on the HDtivo any steady digital signal of 60 and above will produce a recordable picture with minimal to no pixels. Of course when you have a signal that low, even a tad of multipath kills the pic. That's why you gotta get the signal as high as possible so when the trees blow, you are only going from 85-65 not 60 down to 40


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