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10 kHz AM Frequency of the Week - 620 kHz

B

Buckeyes2001

What can you get on 620 AM?

Here in Vermilion, OH it is a very weak WKHB/Irwin, PA (near Pittsburgh) with some IBOC from 610 WTVN/Columbus, OH. At night it's a jumble of stations with WTMJ/Milwaukee, WI usually on top.
 
Far northwest suburbs of Chicago....

Day: WTMJ. I'm 35 miles southwest of the stick and the signal is excellent.

Night: WTMJ goes to 10kw and throws a null at me, so I effectively get only about 800 watts in my direction. The result is a much weaker signal, but still enough to keep WTMJ reliably on top. Not enough to keep out other pests, however....most notably CKRM (formerly CKCK). Usually the others are unidentifiable, but I have ID-ed WDNC and WJDX (on day power/pattern).
 
From Cedar Rapids, Iowa:

Day -- WTMJ Milwaukee.
Night -- often CKRM from Regina, Saskatchewan. Occasionally have picked up WRJZ, Knoxville, TN
 
Daytime-nothing.

Nights I get mostly KPOJ Portland with Fox Sports, as well as KWAL Wallace, ID (C&W). CKRM Regina, SK also makes appearances.

-crainbebo
 
WTMJ has one of the lowest NIFs of any Class B/Class III in the Continental US as I recall, in the low 2 range. As such, the Midwest is in the umbrella of protection. Most unusual DX will occur around sunrise and sunset from stations on day pattern. And of course WRJZ, which has a few large narrow minor lobes, is heard.
 
Schroedingers Cat said:
WTMJ has one of the lowest NIFs of any Class B/Class III in the Continental US as I recall, in the low 2 range. As such, the Midwest is in the umbrella of protection. Most unusual DX will occur around sunrise and sunset from stations on day pattern. And of course WRJZ, which has a few large narrow minor lobes, is heard.
Click to expand...

WTMJ slips into the null of KMKI in the Dallas area at night.

Daytime Houston - XEGH Rio Bravo in the Brownsville area. Nighttime KMKI from Dallas
 
rbrucecarter5 said:
Schroedingers Cat said:
WTMJ has one of the lowest NIFs of any Class B/Class III in the Continental US as I recall, in the low 2 range. As such, the Midwest is in the umbrella of protection. Most unusual DX will occur around sunrise and sunset from stations on day pattern. And of course WRJZ, which has a few large narrow minor lobes, is heard.
Click to expand...

WTMJ slips into the null of KMKI in the Dallas area at night.

Daytime Houston - XEGH Rio Bravo in the Brownsville area. Nighttime KMKI from Dallas
Click to expand...

Do you live somewhere in Houston where you can successfully null out 610 KILT? I'm in SW Houston and can't seem to do it. I get a lot of splatter from KILT.
 
Chuck Tiller said:
rbrucecarter5 said:
Schroedingers Cat said:
WTMJ has one of the lowest NIFs of any Class B/Class III in the Continental US as I recall, in the low 2 range. As such, the Midwest is in the umbrella of protection. Most unusual DX will occur around sunrise and sunset from stations on day pattern. And of course WRJZ, which has a few large narrow minor lobes, is heard.
Click to expand...

WTMJ slips into the null of KMKI in the Dallas area at night.

Daytime Houston - XEGH Rio Bravo in the Brownsville area. Nighttime KMKI from Dallas
Click to expand...

Do you live somewhere in Houston where you can successfully null out 610 KILT? I'm in SW Houston and can't seem to do it. I get a lot of splatter from KILT.
Click to expand...

Yeah - I'm in Cypress. KILT is not an issue, it nulls easily. But that means I am closer to their towers than you are, and you should be in their null for XEGH. Maybe you null KILT, you also null XEGH. KILT has an unusual pattern, I used to be able to get them easily in Lubbock, TX, about 35 years ago, mixing with what is now KMNL Albuquerque.
 
SW Ohio

I'm fairly certain that in the last several years I have heard WTMJ at least once, but I didn't write it down. Would have been at sunset.

Days
Nothing

Night
WTUV Louisville KY
WJHX Lexington AL - I suspect they were on 5 KW day power.
WRLZ Knoxville TN

Sunrise
WWNR Beckley WV
WHEN Syracuse NY
WKHN Irwin PA
 
Southeast is the only direction that WTMJ radiates less than when it was 5000 watts nondirectional days. Since it moved closer to the 620 in Louisville, it had to reduce the radiation in that direction. The conductivity is good near Union Grove, Wisconsin and over Lake Michigan, and they probably couldn't increase it by measuring conductivity. Close in, it's probably better than the old location even to the Southeast. But in SW Ohio, it's probably not as good. I will have to check to see if the oldest database I have has the omni efficiency. W9WI probably knows if they were a full 5000 input during the day into the taller tower, which I know for sure has the height data in the old database. Since it is an old station, it probably was at full efficiency. We could reconstruct the groundwave from the old site and compare the contours based on M-3. MANY stations have reduced efficiency even to this day, and the ones with short towers are at 282 mV/m minimum efficiency for 1 kW at 1 km with full input, making them less than the often quoted "ERP" based on 300 mV/m minimum efficiency. That's why I use 282 mV/m for 1 kW at 1 km like many oldtimer engineers when I quote an "ERP", which is undefined by the FCC for AM.
 
Buckeyes2001: WTVN hasn't run IBOC in several months (thankfully!). I am guessing the Pennsylvania station you mentioned is the very faint signal I hear under WTVN slop during the daytime. When I say faint, I mean I can't get any kind of read on it at all.
 
From my recall, the tall tower was 132 degrees. If that is correct, the efficiency was 333 mV/m at 1 kW at 1 km. If that is correct, then the inverse field would be 745 mV/m at 5 kW, and 463 mV/m @ 1 mile for 5 kW, if it was full input. A 132 degree tower would be about 582 feet tall at 620 kHz. Not that unusual for an old station, but usually they are 50 kW, or the antenna was put up later for a TV station or FM, and the efficiency had to be reduced.
 
Being right across the Lake from Milwaukee, it's WTMJ 24/7 here. When phase-nulling WTMJ (to my West), I can pull in WKHB from the opposite direction and oftentimes WVMT out of Vermont without much trouble. Others heard while DXing 620:

WHEN Syracuse, NY.
WRJZ Knoxville, TN.
WSNR Jersey City, NJ.
CKRM Regina, SK.
 
Just KPOJ. It takes out pretty much everything within about 15 kHz on either side.
 
Baldwin Co., AL near the coast, it's WDAE "The Sports Animal" (or whatever it is now) from Tampa.

Nothing stands out during the nights, but I think I've logged KMKI before despite kinda being on the back side of the pattern. I've heard WJDX from Jackson, MS a time or two either sunrise or sunset.
 
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