WLS transmitter question.

[radiorob2.0]

...has the infamously lax maintainence of either WLS' or WMVP's transmitter sites improved at all in the last few years?

Neither station is Lax in their transmitter maintenance, though the reception issue may leave you with that impression. The reception problem has to do with the increase in background noise from all the new microprocessor based appliances. The WLS and WMVP signal is the same strength, the background noise is just stronger these days.

The Part 15 monster is a giant reason as well. But, let's not forget about all of those cell towers that have popped up over the last twenty years. There's a factor that has done its share of damage to the AM band.

 

[StevenGastreich]

So here we have a 50kw non-directional clear channel primary station toward the bottom of the dial that has signal problems which didn't used to exist! What does that say about the over 4000 lesser signals out there? Will the noise continue to get worse? This sounds like an excellent argument for full digital HD on AM and the sooner the better!

How do you figure? Isn't HD part of the problem with the hiss? Or, are you thinking the total end of analog radio all together? Can you pick up say Chicago's HD from tations that reach the Milwaukee area?

 

[semoochie]

Without an analog signal in the way, HD should be able to greatly expand its coverage area! Apparently, it doesn't have to be done all at the same time. Stations that are still successful could wait until it's feasible for them. There's some question as to whether anyone will be in another 5 years or so.

 

[PhilJSmith67]

Full-power, exclusive HD Radio (the only signal true to the IBOC moniker) would have a coverage area more comparable to today's analog signals, because of the greater amount of power devoted to the digital-only signal. The overall bandwidth for digital-only IBOC is narrower than the hybrid flavor, too, which would theoretically reduce adjacent-channel interference.

Don't bet on seeing HD-only AM stations anytime soon, if ever. Even with so few overall listeners tuning into analog AM everyday, many cities still have AMs in their top 10. I can't see any way, even in 5 years, for there to be enough HD Radio receivers on the market to make digital-only AM stations viable. Every AM would vanish from the books, taking the entire band with it.

 

[PhilJSmith67]

In a follow-up to my post containing complete misinformation a few pages ago... I apologize. :-[ I don't know why I jotted down 860 WNOV as the "IBOC" station. It was indeed WOKY 920. I scribbled down that channels +/- 10 kHz were completely covered with noise, and "WAUR covered at IL/WI." Obviously with WAUR being on 930, it makes sense that WOKY would be the noisy culprit, and the +/- frequencies where I heard hash would have been 910 and 930.

Again, my apologies...

As for its effect on WLS, it remains very possible that a receiver with wide IF stages could make listening to WLS far more difficult in the Milwaukee area than it once was.

 

[semoochie]

Most AMs have already vanished from the books! It's the successful ones that only have 5 years or so left.

 

[w9wi]

The Part 15 monster is a giant reason as well. But, let's not forget about all of those cell towers that have popped up over the last twenty years. There's a factor that has done its share of damage to the AM band.

I don't see where cell towers have damaged AM reception...

with the possible exception of where a tower is very close to an AM transmitter and has distorted the AM station's pattern. The FCC requires the cell company to fix such problems if the AM station was there first, but I wouldn't be surprised if there were cases where it didn't happen.

Cellular frequencies are MUCH higher than AM frequencies. (heck, they're MUCH higher than *FM* frequencies) In my experience with mobile ham gear (which should be even more susceptible to interference than AM broadcast receivers) the only time a cell tower is noisy is if the electric utility line feeding the site has a bad insulator...

(not to say there aren't plenty of electric utility lines that do just that)

 

[radiorob2.0]

Re Cell towers:

I'm talking about the structures in and of themselves. This is one factor that wasn't as prominent twenty years ago. It has to have some kind of effect when most of these structures are two to three hundred feet tall, a good quarter wave height for a chunk of the AM dial. You did bring up another demon of the AM dial, bad insulators. Some engineers rode the rear end of the local utility to replace insulators; in those cities the AM dial is quiet. However, many did not. The situation where I live is beyond repair since it's cost prohibited to replace every insulator. In other words, the utility said if you hold us to part 15 rules to replace every insulator we'll have to raise our rate and we will tell our customers why.

 

[davideduardo]

Re Cell towers:

I'm talking about the structures in and of themselves. This is one factor that wasn't as prominent twenty years ago. It has to have some kind of effect when most of these structures are two to three hundred feet tall, a good quarter wave height for a chunk of the AM dial.

Most cellular towers are in the 60 or 70 foot range in urbanized areas to avoid interfereing with adjacent cells. Many, such as ones on commercial buildings and apartment houses are in the 40 foot range. And the increasingly popular "disguised like a tree" towers are about 50 feet. While a few are higher, due to irregular terrain, most are not.

At 890, a quarter wave vertical is about 276 feet high, and the optimum 5/8 wave tower used by most 1-A clears is just under 700 feet.

 

[w9wi]

Re Cell towers:

I'm talking about the structures in and of themselves. This is one factor that wasn't as prominent twenty years ago. It has to have some kind of effect when most of these structures are two to three hundred feet tall, a good quarter wave height for a chunk of the AM dial.

I think David Eduardo is suggesting (and in my experience he's right) that those in cities are too short to have that effect.

Also, if the AM station was there first, the cellular company is required to detune their tower to ensure it doesn't affect the pattern of the AM station. I know fybush.com has pictures of detuned cellular towers. I'm sure there are towers out there that were *not* properly detuned, where the station didn't know to complain.

 

[boiseengineer]

There's several caveats about the FCC's authority to regulate towers near AM stations. The FCC has no say if the tower is used by non-licensed users, such as some WIFI providers, wind power, ect... There's a loophole for some types of licensed users (I can't remember who). AM stations have had to file civil suits against those towers.

The LBA site has a good writeup about it.
http://www.lbagroup.com/associates/lbatn119.php

 

[PhilJSmith67]

As for WLS, their plot of land is a pretty decent size, and I don't recall seeing any cell towers close to it. If anything, there is a greater effect from the multi-story hotels immediately to the west of the WLS/Citadel property than any towers in the area.

 

[sebenste]

I'm 60 miles west of Chicago in DeKalb, and the signal at night can be pretty bad during this time of year. WMVP's coverage, despite a massive null to the west to protect the 890 in Omaha, has improved here since their tower rebuild--they are actually somewhat listenable now (to the somewhat delight of Sox fans when WLBK doesn't carry them in town).
Also, 94.7 FM's backup antenna is also on one of the WMVP towers,
look and you'll see it. It's significantly nulled to the west to protect 94.9 here in DeKalb.

I know I've been yelled at the former news director on here suggesting that the 890 site has not been maintained well (please note: I'm not suggesting that was a local problem, either). WSCR's tower is BIG...WGN's
is big and decently tall, but WSCR's is taller than any of the other blowtorch AM's here, significantly so. That helps them. But WLS is still as tall as the others. And further west than the others, I should get them furthest west. But WGN and WSCR usually hang out the longest. Of course, that also is due to, as others have pointed out, their dial position.

 

[skippertthomas]

:Take a look at an ol' analog AM in an older car.. You see the spacing is not uniform and the space per kilohert is wider the lower you go and starts to get wider, again at the top of the dial... The difference in wavelength between 600 to about 1000 khz is of little differnce.. The major things that might be hurting "The Big 89" could be many things.. (Conductivity at the site might not be as good as it was, when Tinley Park was a rural community outside of the burb line)...(The grounding system might be limited in effective use by any metal based buildings near the site and could be holding the angle and degree of the signal hostage, especially in the post sunset hours.... At 50kw, the more recent technology from the last few decades give a pretty equal performance if the station has a 1/4 or 1/2 wavelength tower... In the early days, they always wanted that taller configuration, when the newer systems make 1/4 wavelengths very effecient... Could be a 'skunk', 'raccoon', 'squirrel' or somebody's 'cat'..???? You never do know???? Thank God, it was WLS in the longrun and not the former time share partner they had on 870 (before going to 890)...WENR... Could you hear it now..."The BIG 89!....Is The BIG WEENER!" "The Big Dog of Butchertown, USA"...."The Big Weener gets out a LONG WAY, from the drawers middle American, The Big WEENER broadcasts near and far...".. Oh, what double meanings that would have been.. We had enough problems in the late 60's with a station I worked at.. An ol' Class IV AM on 1340am in Poplar Bluff, Missouri... Named after the owner Mr. Liddington, it was KLID.. The FCC thought it was too close to K-Lid.. Light up and smoke some Ozark Gold on 1340.... ;D

 

[Boulder Engineer]

Even though there's a lot more clutter and noise on the dial today, there's no question that the WLS signal has deteriorated over the years. They are by far the weakest of the Chicago area 1-A stations here in Colorado.

A few weeks ago when I tried to listen to the WLS music retrospective, they were completely inaudible here; a weak Mexican station was all that was on 890. At the same time, WBBM 780 was solid.

Maybe there's been construction around the WLS tower site, but there has sure has been a lot of growth around the WBBM and WGN sticks on the NW side of town, too!

Something is definitely wrong with the once smokin' signal that got a 25+ nighttime share across the entire midwest and you could consistently hear from the Arctic Circle to Los Angeles.

 

[EDwalker]

WMVP's coverage, despite a massive null to the west to protect the 890 in Omaha, has improved here since their tower rebuild--they are actually somewhat listenable now

You have your facts wrong. WMVP is on 1000, not 890.

WLS - on 890 protects nobody....its non-directional 50kw day and night.

And there is no 890 within 100 kilometers of Omaha. Likewise there's no station on 1000 within 100 kilometers of Omaha.

WMVP - on 1000 - has a directional null to the west primarily to protect KOMO/Seattle

Also, 94.7 FM's backup antenna is also on one of the WMVP towers, look and you'll see it. It's significantly nulled to the west to protect 94.9 here in DeKalb.

Well no, not really. It is directional only to extent that it prevents the 60dbu coverage of the backup site from exceeding the 60dbu contour of the main site. It would be directional at that site whether the signal in DeKalb existed or not. It cannot exceed the 60dbu coverage of the main transmitter site located downtown.

See the auxilary applicaton:

http://svartifoss2.fcc.gov/cgi-bin/ws.exe/prod/cdbs/forms/prod/cdbsmenu.hts?context=25&appn=101181054&formid=301&fac_num=73228

 

[hammondo]

Ed. You are 100% CORRECT.

 

[w9wi]

Also, 94.7 FM's backup antenna is also on one of the WMVP towers, look and you'll see it. It's significantly nulled to the west to protect 94.9 here in DeKalb.

Well no, not really. It is directional only to extent that it prevents the 60dbu coverage of the backup site from exceeding the 60dbu contour of the main site. It would be directional at that site whether the signal in DeKalb existed or not. It cannot exceed the 60dbu coverage of the main transmitter site located downtown.

Yes, and in any case any directivity of any FM antenna attached to any of the WMVP towers would have absolutely nothing to do with the directivity of the AM antenna.

 

[semoochie]

Particularly, WLS!

 

[Boogie Skank]

All of this discussion reminds me of the time that LS Assistant Chief Ed Glab accidentally found himself in the studio during the former Roe & Garry Show back around 1998 and was prompted into a special call in which they called "Ask the Engineer". First question out of the box was from a caller wondering why he couldn't pick up the signal very well in his Lakeview neighborhood. Ed went on to explain as featured above that the signal just wasn't very good to the north east due to various factors.

The listener asked, "is there anything I can do to improve my reception?"

Ed responded: "Move."

That was the end of Ask The Engineer on the Roe & Garry show.