Three Or More FM Stations In Michigan Using One Tower

[Ben Zonia]

A while ago, AM diplexes in Michigan were listed.

The "Magic" Stick In Royal Oak Township. Originally used for WMJC 94.7.

1. WCSX 94.7
2. WDVD 96.3
3. WYCD 99.5
4. WMGC 105.1

The stick near 10 Mile and Greenfield in Oak Park, originally put up by Bob Liggett for 99.5.

1. WDRQ 93.1
2. WDKL 102.7
3. WDMK 105.9

The "Whittle" Stick On Pine Tree Rd. near Lansing.

1. WJIM-FM 97.5
2. WFMK 99.1
3. WITL-FM 100.7

Hudson Lookout near Vanderbilt, originally used for Channel 45.

1. WBLW 88.1
2. WTLI 89.3
3. WGFM 105.1

Tower near Good Hart originally put up by Dr. Don Benson for WMKC.

1. WTCK 90.9
2. WMKC 102.9
3. WCMW-FM 103.9

There are quite a few others with two, but for now, let's list three or more STATIONS using the same tower.

[k8jd]

I actually had to drive past the Vanderbilt tower to get to the State of MI Comm site on the top end of the road ! Did that in deep snow a few times , OOOhhh yes.

[k8jd]

Isn't the Oak Park stick mentioned, just 1/8 Mile south of the fat WLDM...WKQI now, tower ?

[Ben Zonia]

Yes, that's the WKQI tower with the half Blaw Knox design. There are so many directions we could go from here, including nearby antenna farms, translators on the same sticks, TVs, auxiliaries, which are often on another nearby stick, etc. The fccdata.org site is great for zooming in to see on the map the exact locations, and now has a feature called "Tower Payload" which shows other facilities on the same towers and nearby towers, but it appears to be under construction. The other confusion is that so many towers are no longer owned by the company that owns the stations, which seems like a bad idea. It's good that there are some entrepreneurs who have bought a few tower sites who actually have a love of the broadcasting business. I've noticed also that some stations who use diplexed antennas have an unusual spacing that suggests that another station planned to or did use the same antenna. WDVD shows 0.93 wavelength, WYCD, 0.96 wavelength. which suggests that another station with full wave spacing used the antenna or planned to at one point have an AUX there. That would figure out to around 4% higher, which would be around 103.5, which could possibly be done with a reduced power nondirectional AUX. The slightly less than 1 wavelength spacing does produce a slight antenna gain over 1 wavelength, but I doubt that that such a small difference would have been enough to influence the design of a two station diplex.

[Ben Zonia]

The best thing to happen was that WDVD and WYCD went into an agreement with WHNN and WUGN to go to at or near maximum buildable facilities. Oddly enough, both sets of short spaced stations have been coowned at some point in their History. WABX and WQDC were originally owned by Mid States/Panax.

[Rich F.]

... I've noticed also that some stations who use diplexed antennas have an unusual spacing that suggests that another station planned to or did use the same antenna. WDVD shows 0.93 wavelength, ... The slightly less than 1 wavelength spacing does produce a slight antenna gain over 1 wavelength, but I doubt that that such a small difference would have been enough to influence the design of a two station diplex.

The antenna manufacturer normally tells each user of a multi-station transmit antenna (and the FCC) what gain that antenna has on each frequency it was designed to radiate. Each station then would be able to apply whatever input power is needed for the antenna to produce that station's licensed h-plane ERP. So in that respect, using bay spacings other than one wavelength have no affect on the users of a multi-station (Master) antenna.

However the radiation pattern in the vertical plane will be slightly different for various wavelength spacings of the bays of a vertically stacked array. The biggest effect of this can occur close to the base of whatever structure is supporting the Master antenna.

Below is an example, comparing the radiation of WDVD at 2 meters AGL out to 1 mile from the base of the tower when using 0.93-wave bay spacing vs. 1-wave spacing.

In the case of WDVD their nearby fields at 2m AGL are a little less for 0.93-wave bay spacing, but still nearly as high.

The fields produced by each station using a Master antenna can be quite high within these nearby areas, needing a very good FM receiver not to be affected by them when tuned to other FM stations.

[Ben Zonia]

Doing some rough calculations using the Pythagorean Theorem and the FCC Propagation Curve Utility at fcc.gov, WMUZ-FM could only be a nondirectional AUX at the very most, with roughly 4.9 kW. I guess if Cris wanted to do an AUX near there, he would more likely use the WOMC tower, since they already use the site for the WCHB (WEXL) 1340 tower, Day and Night, DA-D with the short tower. WMUZ already has an AUX on the main tower. Using the sites near Ferndale and Royal Oak Township would present short spacing problems and a DA to go there for a MAIN facility. My guess is you couldn't go that close to WQUS 103.1, since it hasn't been short spaced before to WMUZ-FM, according to CFR 47 Section 73.213.

[Ben Zonia]

Rich, I guess the Manufacturer specifies the gain, but theoretical maximum for gain does max out slightly less than 1 wavelength according to this paper. The higher the number of bays, the closer it is to 1 wavelength.

https://w8ji.com/stacking_broadside_collinear.htm

[audiophile]

There is one with 5 high power FM's.

[Ben Zonia]

In Michigan? Full powers? WRIF used an AUX on the Magic Stick for several years during the analog to digital conversion. They moved back to the WXYZ-TV tower on 10 Mile Rd. The AUX is still licensed.

[WOHO]

Moving South to Ohio, how many stations worth of sh** is on the tower ready to collapse near the University of Toledo on Westwood Avenue? Gotta be at least 1 TV (48, RF36), 1 FM (WQQO), and 3 FM translators, or more? Aux too?

[Ben Zonia]

Moving South to Ohio, how many stations worth of sh** is on the tower ready to collapse near the University of Toledo on Westwood Avenue? Gotta be at least 1 TV (48, RF36), 1 FM (WQQO), and 3 FM translators, or more? Aux too?

Can you figure out, WOHO, why it took so long for WXEZ...WQQO to move their TL East into Toledo?

[ftballfan]

There's some more:
The Harrietta tower built by WPBN in the early 1960s is home to 88.7 WIAA, 91.1 WOLW, and 91.9 WGCP
A tower near Benton Harbor is home to 89.9 WCXB, 94.9 WSJM, and 107.1 WIRX

[Plate Cap]

The stick near 10 Mile and Greenfield in Oak Park, originally put up by Bob Liggett for 99.5.

1. WDRQ 93.1
2. WDKL 102.7
3. WDMK 105.9

Caution on that.....back at the time of construction, when Bob put it up and Harvey Deutch bought it (with the horrible FM blanketing going on in the neighborhood) I'm fairly sure it was 93.1, 105.1, and 105.9. At that time (perhaps later....I don't know) 102.7 was still in the toxic school site near Mt. Clemens.

93.1 was always looking for someone to join them on their Allen Dick antenna there...but due to the blanketing, there were no takers at the time. The tower was the relocation spot for 105.1 after the move from the Book Building.

That all was forty years ago, and memories may be faulty. I do recall that our report to Harvey opined that the 0.8 MHz offset between 105.1 and 105.9 and insufficient circulation/ filtering was causing sum and difference products up and down the band in the area. Automakers used to use the area to test car radios. Garage doors went up and down all day long...TVs had rolling bars from rectification....cordless phones had issues. It was truly a mess, and pretty much, it just got ignored.

[Ben Zonia]

It's in the years in between the History Cards, and the detailed Applications on CDBS.

Here's the public notice comment from 1983. As I recall, it was still WQRS then, as I recall comparing the signals 40 odd miles away with WWJ-FM nearby on my Technics ST-G5 tuner with the digital signal indicator. Both were at or near 50 dB with my setup with an FM-10 over the hills to the North. Seems like WWJ-FM was a little higher. I think WQRS 105.1 was the top antenna, WCLS 99.5 the second from the top. WDRQ was at the very top of the tower part below the mast.

WQRS/WMGC

CP TO MAKE CHGS. CHG. TL TO: GREENFIELD RD. & 10 MI. OAK
PARK, MICHIGAN. CHG. ERP TO: 16 KW (H&V);
CHG. HAAT TO: 784 FT. (H&V); 42 28' 16" 83 12' 03"

WABX/WYCD

MOD. OF CP (BPH-830404AK, AS MOD.) TO MAKE CHGS. IN ANT.
SYS.; INCREASE ERP: 17.78 FT. (H&V); DECREASE HAAT: 784 FT
(H&V); NEW COORDINATES: 42 28' 16" 83 12' 03".

Something doesn't look quite right because I recall two antennas at different heights, and 99.5 was still directional as I recall and WQRS was nondirectional. It seems like all three antennas on the mast had two bays. WDRQ has a panel antenna and it is two bays as I recall.