can modern tvs be recieve too much signal from broadcast antennas?

by having two giant antennas

Are these folks related to Kalvin?

Never mind

oh, I hear stuff when we get together for breakfasts and lunchs , most of it is how its presented too me.

the specifics are Bennett iowa in the center, Rock Island il , 55 miles to the east and cedar rapids Iowa, 56 miles to the west.

trying to get 8 stations from each big city

If the antenna in Bennet is on high ground with no obstructions between it and the towers it might be possible with a high gain antenna and a booster. 55-60 miles is a long way with the digital signals being broadcast today. I am pretty certain the transmitters have reduced their power considerably from the old analog signal days. If he gets it the picture will be very good but the digital signals are pretty much all or nothing, they do not fade in and out like the old system, they either come in clearly or not at all.

I'd say it is almost certainly impossible to have too much.

There are topo maps available from FCC showing signal levels, taking into account, frequency, power, antenna, terrain, etc. for each station.

One such is https://nocable.org/hd-antenna-coverage-map

Yes, it is possible to have too much signal. Will saturate the receiver's front end and cause distortion (analog) or disruption (digital).

quote:

Originally posted by ensigmatic:
Yes, it is possible to have too much signal. Will saturate the receiver's front end and cause distortion (analog) or disruption (digital).

What would the signal level be say, 1 mile from the transmitter antenna?

Typical TV dynamic range runs from -83 dbm to -5 dbm. -5 dbm is .316 mw signal at the antenna terminal. That is an awfully strong signal.

You need the signal level of each station at your location, the height of the antenna, the gain of the antenna, loss in the system from antenna to terminals, and a bunch of math to calculate the expected levels.

Here is the website I was thinking about: https://www.fcc.gov/media/engineering/dtvmaps

quote:

I'd say it is almost certainly impossible to have too much.

It's absolutely possible. Too high a signal level can damage digital tuners in modern televisions.
When building distribution systems for coax networks in store displays, we had to carefully balance the system so that the signal received at the set was between 0 and -5dB. Too low or too high and you'd get pixelation and eventually complete loss of signal. For locations closer to the broadcast towers we usually had to build in quite a bit of signal attenuation.

TV Station Network Channel Location Miles Away Direction Frequency (MHz)
KIIN PBS 12 IOWA CITY, IA 19.0 W 210
KWKB CW 20 IOWA CITY, IA 19.6 W 542
WHBF CBS 4 ROCK ISLAND, IL 28.9 ESE 72
KGCW 26 BURLINGTON, IA 42.6 S 0
KWQC NBC 6 DAVENPORT, IA 42.6 SE 608
KQIN PBS 36 DAVENPORT, IA 42.6 SE 596
WQAD ABC 8 MOLINE, IL 42.6 SE 620
KLJB 18 DAVENPORT, IA 42.6 SE 0
WQPT ETV 24 MOLINE, IL 42.6 SE 530
Stations below should be considered likely but not guaranteed.
KFXB 40 DUBUQUE, IA 56.8 NNE 650
KPXR ION 48 CEDAR RAPIDS, IA 60.0 NW 674
KGAN CBS 2 CEDAR RAPIDS, IA 60.3 NW 566
KCRG ABC 9 CEDAR RAPIDS, IA 60.4 NW 192
KRIN PBS 32 WATERLOO, IA 60.4 NW 602
KFXA FOX 28 CEDAR RAPIDS, IA 62.1 WNW 554
KYOU FOX 15 OTTUMWA, IA 63.2 SW 482
KWWL NBC 7 WATERLOO, IA 63.9 NW 180
KWWF 22 WATERLOO, IA 70.6 NW 0
Bennett, IA

If you can make sense of this cut & paste, the Cedar Rapids NW stations are 60 miles away. The SE stations are 42 miles away. I don't see how you could get too much signal strength in Bennett.

Broadcast towers may be at a different location than the city the station is associated with. Towers can broadcast a pattern to focus their signal to specific markets. Around here, the towers are located between Mobile, AL and Pensacola, FL and broadcast in an East and West "peanut" pattern to cover both cities. But if a tower is "off the reservation", like FOX above, you may need a specific antenna just for that.

thanks I found that cne, but could not figure out how to work it.

the guy in the news room at Kcrg said that I should only need one really good antenna , ant should be able to pick up both the eastern and western cities.

I was thinking two really good antennas pointed in oposite directions, with switchs to shut one off/ block the signal, when not in use

One of my ham friends has fun when we have a good band opening down here. He lives just north of Baton Rouge and gets TV stations all over the south. Even got a Cuban analog station a month or so ago.

Dd you check the second link I posted?

quote:

Originally posted by bettysnephew:
55-60 miles is a long way with the digital signals being broadcast today.

That distance is a long way, but a lot depends on your line of sight. I receive all of the major digital network broadcasts from South Mountain (in south Phoenix) out here (68 miles away), with no amplifier or booster. In fact, I use an antenna considerably smaller than what antennaweb.org recommends for my location. The key is direct line of sight and proper orientation of the antenna. If you don't have those two things, then forget it.
 

Try this site. I think it is the one I used when I cut the cord. My house sits in a hole with hills in every direction so I had to up the quality of my antenna to get signals.
http://www.homeantenna.org/dig...a-reception-map.html

quote:

I was thinking two really good antennas pointed in oposite directions, with switchs to shut one off/ block the signal, when not in use

If the broadcast antennas in each direction are physically located such that you can "see" each station in either of the two directions, then you may want to consider just stacking two antennas on one mast pole - one antenna facing each of your directions of interest - and dump them into a "splitter" and then run just one coax downfeed. I don't see any dupe frequencies in your list above so there shouldn't be any problem there. If you do stack a couple or three antennas, be sure you know the minimum vertical separation guidelines for such an arrangement.

If one stationary antenna cannot "see" everything you desire in the general direction toward which it's pointed, then you may be better off just going with one good antenna and a rotator on the mast.

Good luck with your project.

What about repeaters? might not be a current term. But I get stations from more than a couple hundred miles with no antenna. Not flat country either. Just lucky I guess?

Fact: a cable signal is normally about 1 mW of signal from the 75 ohm cable. Give or take some.

This is the strongest signal your TV will ever see, and you will find that it is fine with this strong cable TV signal.

Antenna signals from your antenna are MUCH WEAKER.

Look up Multipath, which is an affect of signals bouncing off objects before reaching you. In the analog days, this would result in ghosting. In DTV, if the receiver can't calibrate (equalize) it out, it results in drop outs even with a strong signal.

quote:

I was thinking two really good antennas pointed in oposite directions, with switchs to shut one off/ block the signal, when not in use

no switch needed. Use a splitter baclwards tp combine the feed. If signal strengths are really different you'd want to attenuate the hottest ones so they're all in about the same range. If for some reason you need to amplify the signal, you want to do it as close to the antenna as possible. I built systems like this for fifteen years.