Indoor Antenna Reception Performance

Aaron62

Contributor
Staff member
#1
I'd like to get some feedback on indoor antenna's and their peformance with DTV and HDTV. How many miles away from broadcast towers can a good line of sight indoor antenna receive digital signals? Will it's performance results differ for UHF and VHF broadcasts? What about a powered UHF/VHF antenna?

The reason why I ask is because I've always been under the impression that indoor antennas can receive signals from less than 15-20 miles. Anything over requires an attic mounted or outdoor antenna but looking at TVFool reults lately, it suggests an indoor antenna in some cases when broadcast towers are approximately 25-30 miles away.
 
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Piggie

Super Moderator
#2
Location location location.

Never judge a TV antenna by miles. This was something made up long ago to try and make a scale for people to buy antenna. Then it got grossly exaggerated on outdoor antennas.

TVFool still is the best answer. If the person's signals at 3ft are in the 60's, they don't even need a powered antenna. Over flat terrain from a tower 300 meters up with maximized power, this is about 10 miles. A 500 meter tower about 15. I tower on a mountain and the house in the valley and it can 20 miles.

If the signals on TV Fool are mostly in the 50's, sometimes un-powered will work. But powered or amplified might be better.

What is the best unpowered antenna? Rabbit ears with a loop. If there is a lot of mulitpath (like fading in wind) then rabbit ears combined with a Silver Sensor into a UVSJ Pico Macom UVSJ UHF VHF Band Separator/Combiner for Antenna (UVSJ) | UVSJ [Pico Macom] not a splitter. A splitter will loose about 3.5 db and a UVSJ only about 0.5 db.

The same advantage of a Silver Sensor stopping mulitpath also means you may have to move it if all the UHF stations in town are not the same direction.

Same is true powered. For a person with no mulitpath problems, some of the amplified rabbit ears are good. Or if you need directionality on UHF the Terk HDTVa.

The Terk gets good reviews so without data I am guessing it has a low noise amp.

But a lot of perfectionists and more of the home builders if they need an amp on their indoor antenna use an outdoor preamp inside. Because they know they are low noise. Something small like the Winegard HDP 269 SquareShooter Pre-Amplifier for SquareShooter SS-1000 (HDP-269) | HDP-269 [Winegard] can be used inside if the TVFool is in the low 50's.

Then remember remember then remember, the gain in the amp doesn't help much if at all in receiving a signal and is just as likely to overload the TV as help. Why a small 12 db amp is such a good idea.

What helps the TV with a GOOD amp is a noise figure around 3 db. This is typically lower then even a good TV and most CECBs. The system (antenna, amp, coax and TV) then assume a noise figure of the amp, or 3db. The lower the noise figure the better.

In particular in the analog days, a cheap TV might be made to work perfect for cable (strong signal) and adequate for OTA, after all who used OTA? so indoor antenna began having amps. These cable ready TVs with a soso OTA tuner really benefited from any reduction in noise figure even those of cheap amps and distribution amps.

Today's digtal TVs and CECB's have a pretty good noise figure themselves. So a cheap amp raises the noise. Makes things worse.
 

Don_M

DTVUSA Member
#3
+1 for Piggie's fine discussion. Just like to add: All distances mentioned get chopped way, way down on antennas inside homes with aluminum, brick, stone or stucco siding, or those with foil-lined insulation/vapor retarder in the walls. All of these materials act as shielding, blocking signals. (The mastic used to attach stucco and brick/stone facades "sticks" because a steel mesh is attached to the wall first.)

Even moving the antenna(s) over to a window may not help much in newer homes or those with replacement windows. Most of those "low-E" windows that are so good at saving energy contain a thin film of metal oxide, which is another pretty effective signal attenuator. (Here's proof: Ever wonder why your cell phone has five bars right outside your office, but only three or four just inside a window? It's mostly the glass.) The film gives the glass a dull greenish or bluish hue when viewed from the outside during daylight.
 

Aaron62

Contributor
Staff member
#4
I've read at a few different sources that the CECBs have horrible signal noise too. I appreciate the info and the time you've taken to explain this.

I went to my school library last week and searched for a book on digital or analog reception and found absolutely nothing. Closest book was one on radio broadcasting, but no digital signal info.

Also found a couple of reviews on different antennas.

Again, thanks again.
 

divxhacker

DTVUSA Member
#5
I went to my school library last week and searched for a book on digital or analog reception and found absolutely nothing. Closest book was one on radio broadcasting, but no digital signal info.

Again, thanks again.
Way way way too new for any low cost (under $200) book to be out on it yet. Better wait a few years or so. The best bet would be some broadcasting college classbooks, which will damage your wallet quite fairly, even in used condition.
 

Piggie

Super Moderator
#6
I've read at a few different sources that the CECBs have horrible signal noise too. I appreciate the info and the time you've taken to explain this.

I went to my school library last week and searched for a book on digital or analog reception and found absolutely nothing. Closest book was one on radio broadcasting, but no digital signal info.

Again, thanks again.
I don't know much about the S/N off the CECBs. I do know some work better than others. But some of that might be decoder not the RF parts. I just don't know them at that level.

The second comment about a book. This is what I meant on a super long post I did about are all the low power high band VHF stations causing the post transition blues, the fault of the FCC or engineers?

The lack of information maybe the biggest cause of all of the VHF stations not running enough power and many of the other pitfalls the transition caused. Much of this book you seek is still being written.

========

Edit: Aaron, I said above I don't know the noise figure of the CECBs. But what I meant in the post above that they were good, was compared to an older analog TV. If they are not really any better (since I am not totally sure now you mention it) than an older analog TV I would be surprised. If they are not I guess I would not be surprised either. I am getting very hard to surprise lately.... :mad:)
 
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EscapeVelocity

Moderator, , Webmaster of EV's Antenna Blog
#8
Im getting good reception 45 miles from the towers in flatland (across some water) but along the coast with unstable air, with quite a few indoor antennas. Amps are helping at this distance.
 
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