AVS Forum banner

Not open for further replies.
1 - 3 of 3 Posts

4 Posts
Discussion Starter · #1 ·
I received an email that I was mentioned on this site. So I figured I better show up or get burned in secret!

1. I was told there were comments about changing antennas and reception enhancements from the stations. ERRP not true. In Chicago the reception conditions vary a huge amount because of normal propagation variances caused by weather, ionosphere changes, solar storms and similar. Watching from 35 miles south of LOOP, I can get Milwaukee usually as good as Chicago because the signals come right down the lake. At times the upper UHF (50 and up) are severly noisy because the lower atmosphere temperature layers bend the signal into the ground before it gets here. At other times, all the UHF's are bone crushing coax melting. I cannot get DTV 3 because A their signal is too weak withonly 2.8 KW ERP, and B terrestrial noise from power lines generates so much noise the ATSC decoder will not decode. All the UHF DTV signals are fine, providing the stations don't turn them off or go to low power to save on the electric as some dTV stations are doing. I can get DTV on both my winDTV card and my new Zenith ATSC big screen TV. I use a Wineguard antenna of about 10 db UHF gain (far surburban size) on a rotor at 30 feet above ground. Except for a grove of trees on a hill 30' higher than me, it is LOS to Chicago.

Southbend analog stations get here just fine, I usually don't have to move the antenna unless I want to de-snow them. I have not yet received any SB DTV stations, but have both analog and DTV from Milwaukee and Indianapolis. Champaign-Bloomington Danville signals are here all the time also. Ch 18 Lafayette sucks and I can see 100 watt ham TV signals from Cincinatti and still not get 18 from Lafayette.

Ft. Wayne is here as is St Louis, and a dozen more cities every band opening.

the solar storms over the past few days have provided crushing signals from mexico city, Texas, Florida, Boston, Denver and a few other places.

new topic: receive antennas.

For the most part, a MODEST uhf antenna is best in the Chicago area out to about 35+ miles. One reason for NOT using a high gain antenna is the side lobes on a higher gain antenna increase the ghost reception, where a simple antenna has few or no side lobes to pick up ghosts. Beyond 35 miles or in the holes of Naperville, a bigger antenna works OK. After 45 miles then a really big antenna and preamp help.

RF STUDY. I took over 8,000 field strength readings (individual locations) of all the UHF commercial stations and all the DTV stations. using a former ENG truck with a 40' mast and a Blonder Tongue broadband log periodic UHF antenna, antenna range tested at 9.4 to 10.4 db gain (channels 20-66) and 70' of coax. the mast was set at 30' at each site.


1. DTV signals were receives as far or farther than analog signals using the Zenith test rack.

2. moving multipath caused the most disruption. Even cars passing well below and a half mile away were enough to get MPEG blocks to appear.

3. power does make a difference. DTV range was much greater for the 44/45 system I built at 480KW DTV, vs the 200 KW or less of the other stations. On Analog, there was a 12 db average difference between channel 66's 5 million watts at Hancock that sucks big time, and the other 5 MW stations at Sears. The differences between the Sears stations is mostly antenna pattern, and you can easily see on the plots who paid attention in school and who didn't when it comes to RF and antennas.

How far does it go?

East: no problem receiving most UHF analog and the three strong DTV signals in NILES, MI and SOUTH BEND.

South: Analog dies (below threshold of what you would want to watch) about Rennesealear, IN but DTV was solid to 15 miles north of Lafayette, IN.

SW. Got to Dwight, IL and got tired of watching.

W. Waterman, IL

NW Darian, WI

N. 22 miles north of Milwaukee "downtown". Hand held Casio TV set analog reception of 44 and 50 in most of Milwaukee.

NE. the fish wouldnt tell. Basically if you live in Michigan, you have to be on the lake side of the hills and dunes to get Chicago TV.

Antenna pointing: It really depends on the antenna. low gain antennas were muchless critical at any distance than a higher gain antenna. The pointing issue is of course 0 if you live SW in line with Sears/hancock and worst case SE and NW where there is max angular spread between them. This diminishes with distance since the angular displacement decreases with distance.

Close in: biggest problem is ghosts, especially along the high rise lake shore areas. overload is also a problem out to about 25 miles because of the high RF levels. There are about 20 square miles with more than 1 volt of signal from each station. that's 15 volts of RF at the front end of your tuner.

Indoors: you can get it if you're lucky, have a view of downtown or clear of local (1 mile) shadows that block signals.

Yes there is a "fade out" of signal levels. I took pictures that were published in ATVQ Magazine ([email protected]) that I graded into the 5 levels similar to what we use for analog. There was a 1.2 db spread between nothing and perfect on the winDTV board and 1.8 db on the Zenith big screeen set. The Zenith set was the better, by .6 db, likely the reason is a newer set of chips to decode the signal.

D5 perfect pix/sound

D4 occasional MPEG blocks, or momentary drop outs in audio

D3 more than 50% of the time MPEG blocks, picture elements regularly over write each other with some blocks unchanged for seconds ata time, intermittant audio

D2 no audio or blips, MPEG blocks in large sectors most of the time

D1 You get a lock signal but the error rate displays only fractions of a picture and no audio

D0 no reception at all.

I used channel 8 from Milwaukee as received down here in the Indiana boonies as the nicely slowly fading in/out signal to measure the "fade out" range.

As for poor WYIN, all they need is MONEY to get the DTV on air. lets face it WTTW is wollowing in cash from endowments (WYIN has none) plus their hige donations from WW Grainger (Millions at a time) plus their constant begging for dollars, and mega bucks from productions done in their multi-million dollar 9each) studios with a milllion watts of lights. If they ever could manage their money they wouldn't have a problem but they have been fat cats all their lives and never learned. Feder's column said they had a budget shortfall of 3.5 Million. That's about double the entire WYIN annual budget. So stop wasting your money on WTTW!


729 Posts

Wow, what a post. It is an absolute joy to have technical know-how as a part of this forum. All too many of the posts are basic "Is this sporting event in a few days going to be HD?" and general whining about the lack of HD programming. (To which I will readily admit my own participation.)

WTTW in particular has infuriated myself and many others here. Personally, I would love for WYIN-DT to start broadcasting from the Sears Tower and show the Chicago area what PBS HD really looks like. But I understand that it will be quite some time before WYIN-DT is operational.

In the meantime, I will send a check to WYIN this weekend and earmark it for digital transmission. I might send a copy of the letter (and maybe a photocopy of the check) to WTTW, informing them that I will not be sending them one more nickel until they carry the national PBS HD programming and the demo loop on WTTW-DT.

Thanks again for your signal strength report -- it's somewhat startling that you are able to receive signals from all over the place there at your location, and I'm quite jealous. The only DTV I get here in Downers Grove are the Chicago stations, no South Bend, Champaign, or Milwaukee. But I am hopeful about Rockford once they get up and running.

Take care and good luck outfitting WYIN-DT.


By the way, I'm the one who called you the other day and then made a posting here about WYIN-DT and mentioned your name.

36 Posts
Thanks Henry for the info ,I wish I had you as a neighbor ! You could solve And answer a lot of my questions.Thanks again and I and others hope to here from you again. DENNY M.
1 - 3 of 3 Posts
Not open for further replies.