• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

WLS-FM and WFMT are off the air

Ken Gustafson said:
Wait, wait, now I am really confused. WFMT just thanker their friends at WBEZ for use of a standby transmitter at Hancock Building. You can't just swing an FM TX over to another freq, and what about combiners and antenna elements that are custom made for a freq, right? Or has radio changed that much in fifty years since I worked in AM and FM? HA!
Click to expand...

Yes actually you can, Kent.. quite easily and quickly... the new solid state transmitters are field tunable and can be put on any frequency in a matter of seconds really.

Sometimes antennas are broadbanded enough you can make them work at lower power on an entirely different frequency
 
Do any broadcasters at Willis Tower have backup power, such as an alternate feed from Edison or a generator? At one time Chicago codes did not allow fuel in the upper stories of buildings.
 
It looks like the towers and supporting pylon are now lit, along with a couple of windows a few stories down, which gives it a spooky look. They said that two levels below ground had been pumped out, and they are working on pumping out the third level below ground, over 40 feet below ground level.

Utilizing various sources including vfrmap.com and Willis Tower Wikipedia, the lowest level of the lowest subbasement is about 30 feet below the level of Lake Michigan.

The Willis Tower is about 12 average city blocks from Lake Michigan, and 1 block from a nearby waterway.
 
Last edited:
Don't see any updates this morning. Probably, after the water is pumped out of the lowest subbasement, they need to dry out any remaining water in the transformers, breakers, and other circuitry and repair any water damage. That could take some time.

From last night:

https://chicago.suntimes.com/2020/5/20/21265781/water-removed-electrical-substation-willis-tower

I wouldn't be surprised if lockdown related staff shortages of people who monitored and maintained the operation of the pumps was responsible. Or maybe there was so much water the pumps couldn't handle it.
 
More trouble for WFMT. The last info I had was that WBEZ programmed a standby at Hancock for WFMT. In the past hour I noticed the signal was down a lot, not coming in at all on receivers with line cord antennas, but a good signal with a twin lead dipole in a window. Now, at 10:39 AM, that signal went dead.
 
seeing what is going on with the Willis Tower has me thinking of what would happen if something bad happened in my market that could have a similar effect to this situation for TV and radio. and being from the Dallas-Fort Worth TV/radio market, makes me wonder what DFW TV & radio stations plans are in case something like a EF3 or higher tornado was to hit the tower farm in Cedar Hill, TX (where the DFW area TV & radio stations have their towers to give the region it's TV & radio) and take all of the towers down to the ground.
 
Ken Gustafson said:
Wait, wait, now I am really confused. WFMT just thanker their friends at WBEZ for use of a standby transmitter at Hancock Building. You can't just swing an FM TX over to another freq, and what about combiners and antenna elements that are custom made for a freq, right? Or has radio changed that much in fifty years since I worked in AM and FM? HA!
Click to expand...

As noted, modern transmitters and exciters are frequency agile to a large extent. The combiner at 875 had a 98.7 port that was abandon when WFMT moved to Willis. The combiner also has a broadband port for emergency use, with several limitations. The antenna the combiner feeds is of course broadband. However, there would be an RF plumbing project at very least, as the WBEZ TX room is nowhere near the old WFMT room. IIR, WBEZ is on the 93rd floor, WFMT was on the 97th floor (as is the combiner) so the temporary connection would have to be in the combiner room. There are numerous RF patch panels in the combiner intended for bypassing the various sections that could be used to insert a new feed to the 98.7 filter, but there are also interlock circuits that would have to be dealt with, including patch link interlock switches, master VSWR and station specific VSWR interlock. And it might have been easier to plumb the temporary 98.7 feed from the WBEZ TX to the broadband port rather than the 98.7 port. But I have no idea what they actually did. The patch panels and plumbing in the combiner is all 3.125" hard line with slip fittings.

I would think this would be a decent size project that there would be no way to prepare for. There would be many reasons it may not be a stable situation.
 
When I drove through the area, around 11 AM on Tuesday 5/19, 98.7 FM WFMT was on the air. What I noticed was their audio was no where near as pristine as it normally is. Believe me, I get it, when you've got an emergency on your hands, just getting any audio on the air is the priority. I don't remember if I saw a stereo pilot or not. Decent coverage, even in Waukegan, but you could tell things were distorting, and lacking headroom. I don't think I heard any digital clipping, but it sounded like an analog device was being overdriven in the chain somewhere. I haven't listened since, so I don't know if they ever attempted to clean up the audio.
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom