Difference in signal strength from 540 to 1700

[kudzooter]

Sitting in my car on one of the boat launching areas here on Bull Shoals Lake, just south of the Ark/Mo border, I regularly hear 1620 WTAW College Station TX, 1640 WTMI Gulfport MS, 1650 KCNZ Cedar Falls IA, 1670 WTDY Madison WI, 1690 WVON Chicago, and 1700 KKLF Dallas -- all during late afternoon but not yet "nighttime" dark...and I've heard each of these with good signals as early as 3PM CST, even on days with no low-hanging clouds. Also occasionally hear 1620 WNRP Pensacola FL, 1630 KCJJ Iowa City IA, and 1700 KBGG Des Moines IA. Have also heard identifiable stations but not particularly strong signals on 1660 and 1680. But I have never managed to decipher anything on either 1610 or 1710, and around here, 530 and 540 are nothing but "hash" -- can't even tell if what I'm hearing is English or some other language. I've just wandered across all of this since early November. Want to see if seasonal changes make any big difference. Any clues on what differences I might see?

 

[gr8oldies]

In the winter here in southwest Ohio, often i can get WTDY in Madison and the Radio Disney in Michigan all day.

 

[crainbebo]

For the X-Band, here's what I get day AND night.

Daytime (Summer)
1610: extremely weak WPKL360 Woodinville (TIS)
1620: weak KYIZ Renton
1630: nothing
1640: nothing, KDZR logged around 5PM
1650: nothing, Redmond Community Radio (Redmond, WA TIS) logged with the best antenna
1660: nothing
1670: slop
1680: KNTS Seattle
1690: slop
1700: nothing

Daytime (Winter)\
1610: WPKL360 TIS, sometimes WPUJ642 (Kingston Ferry Terminal TIS) logged under, very faint
1620: KYIZ Renton, fair
1630: nothing, sometimes bleed from 1000 kHz
1640: KDZR Lake Oswego, OR, very faint to fair at times, depending on conditions and the time you're listening
1650: nothing, Redmond Community Radio logged with the best antenna
1660: sometimes KTIQ Merced, CA makes it here, faint however
1670: slop
1680: KNTS Seattle (local)
1690: slop, sometimes very faint KFSG Roseville, CA
1700: nothing, a TIS from Issaquah, WA logged once, with a very faint het

Night
1610: WPKL360 Woodinville, WA, sometimes WQBV569 Union Gap, WA poorly
1620: KYIZ Renton, WA, sometimes KSMH Sacramento, CA
1630: usually very faint KRND Fox Farm, WY
1640: KDZR Lake Oswego, OR and KDIA Vallejo, CA under KDZR. Logged KBJA Sandy, UT once.
1650: usually hash or very faint KFOX Los Angeles. KBJD Denver logged once.
1660: interference mix with KTIQ Merced and sometimes KXOL Brigham City. Used to get them more frequently when they were oldies.
1670: weak KNRO Redding, CA. Once logged KQMS accidently on 1670.
1680: KNTS Seattle
1690: KFSG Roseville, CA
1700: XEPE Tecate, BCN, Mexico, poor

-crainbebo

 

[vchimpanzee]

Plus, it is flat as a pancake. 8)

Not so. I drive the entire length of Kansas at least once a year and find it has many significantly hilly areas along I-70 through much of the Central part of the state. Also, Flatness is not extremely critical for AM propagation but is a big factor for FM propagation.

And there are mountains near Smallville.

 

[Icangelp]

I don't know about 540 to 1700, but...

A while back I took some notes either from a web site or wrote down the bullet points from an old article. If it is copyrighted material or proprietary, I will gladly delete it.

Night propagation depends on:
Frequency
During sunrise and sunset skip, a high frequency location will deliver significantly higher signal strenth. A 50KW signal at 1530KHZ will be on average 15db stronger than one on 700KHZ. In a couple of hours the difference becomes 3 -5db and around midnight they are about equal.
Latitude
Skywave field strength decreases with increasing latitudes. So the higher the latitude of your receiving setup, the lower your chances of receiving that distant signal.
Solar and Magnetic
Increased solar activity and magnetic storms have a significant affect on MW reception. The higher the latitude and station frequency, the more it is affected by magnetic storms.
Time of Year
Lower latitude areas are less affected by seasonal variation. Medium and high latitudes can have a seasonal variation of 6-10db, with summer being the weakest and winter bringing the strongest skywave signals.

The exceptions to these "rules" are many and that's why MW DXing is a year round activity.

As I said, I don't recall where I picked this information up, but it makes good sense to me.

 

[KR4BD]

I don't know about 540 to 1700, but...

A while back I took some notes either from a web site or wrote down the bullet points from an old article. If it is copyrighted material or proprietary, I will gladly delete it.

Night propagation depends on:
Frequency
During sunrise and sunset skip, a high frequency location will deliver significantly higher signal strenth. A 50KW signal at 1530KHZ will be on average 15db stronger than one on 700KHZ. In a couple of hours the difference becomes 3 -5db and around midnight they are about equal.
Latitude
Skywave field strength decreases with increasing latitudes. So the higher the latitude of your receiving setup, the lower your chances of receiving that distant signal.
Solar and Magnetic
Increased solar activity and magnetic storms have a significant affect on MW reception. The higher the latitude and station frequency, the more it is affected by magnetic storms.
Time of Year
Lower latitude areas are less affected by seasonal variation. Medium and high latitudes can have a seasonal variation of 6-10db, with summer being the weakest and winter bringing the strongest skywave signals.

The exceptions to these "rules" are many and that's why MW DXing is a year round activity.

As I said, I don't recall where I picked this information up, but it makes good sense to me.

I think most will agree on this information you cite regarding skywave/night propagation, but the original discussion here revolved around daytime (mid-day) groundwave where the lower frequencies outperformed, by far, the higher frequency stations even with their much higher power than lower powered stations in the lower end of the band.

 

[Icangelp]

My apologies.

I've seen a couple coverage maps (omnidirectional and directional) from WLW's 500KW days, and it is amazing how much of the country they covered like a local during the daylight and evening hours.

 

[schmave]

Any links? I'd love to see those.
I think parts of the U.S., such as the desert Southwest from west Texas out toward Phoenix, could use a 150-200K AM full-service station for news and weather. XEROK or a station from Phoenix, Albuquerque, etc. would be ideal, but I can't see that ever happening.