Is Nighttime Skywave Better on Higher Frequencies?

[Gregg.]

In another thread, ai4i said that skywave propagation is better at 1540 than 640. I think we all know that in the daytime, AM stations carry farther, the lower on the dial they are. I mentioned 540 on Long Island. Even when it only ran at 250 watts in the daytime, it still could be heard in Hartford CT and Princeton NJ. Meanwhile a 250 watt station at 1600 might not get heard more than 20 miles from its transmitter.

But has it been your experience that stations higher on the dial travel better at night? In LA, KFI and KNX are both non-directional 50,000 watt stations. Can you hear 1070 KNX better at night in Boise or Santa Fe than you can hear 640 KFI? If you're in Michigan or Tennessee, can you hear 1210 WPHT Philadelphia better than the NYC non-directional 50 kw stations (660, 770, 880)?

I don't doubt what ai4i says, but I really have never noticed the difference, whether I'm listening for a distant station low or high on the AM dial at night.

 

[Schroedingers Cat]

After 2 hours past Sunset until 2 hours before Sunrise, there is little difference. During Critical Hours, higher frequencies have better skywave than lower frequencies. You'll notice that the expanded band has skywave many days for most of the day. But it is a gradual change with frequency. And a gradual change before and after Sunset and Sunrise.

 

[davideduardo]

More depends on the congestion on the channel. KNX is on a congested channel and KFI is not. In general, the higher the frequency you get the closer to short wave it is. That is why the X Band stations get transcontinental reception at night.

A good example of the effectiveness of a top of the dial station was KOMA 1520 in the 60's when it was TlHE top 4O station for the rural Dakotas, Kansas, Nebraska, Oklahoma, much of Texas and Colorado, New Mexico and Wyoming at night. The ads announce movie openings and show from Raton to Lamar to Sheridan and Sidney.

Foreign DXers generally report vastly better catches on high frequencies too...even though in most of the world there are fewer high power stations high on the band.

 

[radioman148]

KFI used to be on a clear channel and was easy to hear almost everynight in the Chicago area where I live. Now however, 640 is loaded with stations at night and even though I don't hear either one often, in recent years I do get KNX more than KFI.

 

[Ai4i]

I would add these two additional thoughts in comparing low-end skywave with high-end skywave.
Fading at the bottom of the band is slower than at the high end, something like ¼ as rapid at ½ the frequency. In fact, longwave stations received via skywave fade in when the path becomes dark at the west end, and out when the sun comes up at the east end of the path, but never between those two times.

Also, especially during noticeable during critical hours, the first hop is shorter, closer in at the low end. Of course this is somewhat offset by the weaker signal level, but it can create more phase distortion for those low-down stations.

 

[boombox4]

Great MW propagation sometimes starts at the higher frequencies and works its way down the band. Numerous times I've turned on the radio (whether SR, PR-D5, whatever radio) and the high band is hopping and the low band is half dead, only to 'wake up' later.

And there have been many evenings the good DX conditions never reach the bottom of the band.

 

[rbrucecarter5]

Great MW propagation sometimes starts at the higher frequencies and works its way down the band. Numerous times I've turned on the radio (whether SR, PR-D5, whatever radio) and the high band is hopping and the low band is half dead, only to 'wake up' later.

And there have been many evenings the good DX conditions never reach the bottom of the band.

I remember listening to an X-band station in Lubbock during the daytime for HOURS with no ID (illegal). There was nothing listed on that frequency for hundreds of miles, occasionally it would fade but it would come back quickly. The daytime conditions were great, too, with lower band stations from Chicago and Minneapolis there all day long. That wasn't dead of winter, either. It was summer. The fading on lower band stations was deep and they would be gone for minutes, but come back as strong as before.

 

[Ai4i]

This is all very true.

I know that 49m, known to be a strong night-time band, has a weak short hop skywave all day. When I lived in DC, I could hear Toronto's CFRX (6070) all day. Also, WRMI (formerly WYFR) has a high angle 49m log periodic for daytime service to Mexico and the nearby Gulf thereof, very short skip.

Many years ago, I (in Miami) could hear a 60m Haitian evangelical missionary station preaching the gospel to the nearby Caribbean area fading in and out all day.

Daytime skywave does not generally dip down to the 80m ham band,
but I suppose the ground (LOL) is really the limit.

 

[billmich]

If you're in Michigan or Tennessee, can you hear 1210 WPHT Philadelphia better than the NYC non-directional 50 kw stations (660, 770, 880)?

In the Metro Detroit area we have a local at 1200 now that arrived circa 1990; from what I remember from the 80's, 1210 came in every bit as good as 660 and 880, maybe a tad better

770 does not come in well in Detroit- area because of WJR on 760
710 comes in decently now, a Niagara Falls station on 710 used to mess with it pretty bad back in the day; 1010 used to be Toronto, now it is more New York.

One of the most solid upper band clear channel station to be received in SE Michigan is 1530 Cincinnati, a very regular, solid (stops the seek button) station

 

[Steve Green NEPA]

Twas back in the 60's when my buddy (four blocks west of me) and I each got some walloping good DX from near JFK International, Queens NY.

With 'KB off, and apparently with KOMA OK off, I got a readable ID out of KYMN from Oregon -- 'Kim Radio'.
On the next channel down, at the same time, my pal was getting 2NA from Australia.
Ironically, he never logged Oregon. And for some reason, I never got around to logging any of those pests that might be there from Australia, either.

And he both of us were listening to 1580 one sunset in front of his Atwater Kent .... and past sunset .... and past-past sunset, and we followed sign-offs on 1580 all the way 'cross country to log KDAY from Santa Monica.

Neither of us ever gave too much technical thought to skywave/frequency back then. But since those short-wave stations (like Radio Australia on ? 9620) used to come in at twilight sunrise in a Philadelphia basement apartment, maybe there is some sort of enhanced nighttime skip involved on those higher AM frequencies .....

 

[cyberdad]

I always thought nighttime skywave was slightly better on the upper end of the band. And certainly the stations on the high end were the first in before sunset and last out after sunrise. Not to mention all day skywave sometimes on the higher frequencies...usually in winter. But all that said, probably my farthest catch of the last couple of years was on 530.