Your most distant AM DX catches

[davideduardo]

How far does 1.3 kw goes at night??

On an empty channel, 1 kw can go half way around the world, as the X-Band 1 kw at night stations have shown. The issue is more interference than power... 250 watt KRDS 1190 in the Phoenix area was widely heard in places like Ohio and PA in the early 60's when everyone in North America except them was off the air on Monday mornings.

And 1190 protects a lot more than KEX in Portland. XEWK in Mexico is another major one they protect, and the new facility protects a bunch of older-than-them co-channels and adjacents.

 

[pianoplayer88key]

Ok, then, how far would various power levels go over saltwater (5,000mS/m conductivity) during the day without any skywave at all? Frequencies would be 540kHz and 153kHz. Power levels are 2 MW (highest power for which I've seen a transmitter), 50kW (max allowed in USA), 1kW (graveyard channel), 10 watts (maximum allowed for a TIS in the USA), or 100 millliwatts (max allowed into input stage for part 15 in USA, but with a much smaller antenna than is used for answering this).
I'd like to know how far the "full-quieting" signal goes (60dB SNR? 90dB?), the signal level at which a signal barely trips a scan function or lights a tune indicator (18dB? 24dB SNR?), and max distance (0dB SNR - barely readable, nearly sinking into natural noise such that there's no way a better antenna will improve the signal.
We are assuming that:
The transmit antenna is either a Franklin (two stacked 180° elements, insulated from each other (IIRC) and fed at the center, or a half-wave over a full ground radial system.
The transmit antenna's concrete base (or whatever is used) is in the water, not onshore.
No other signal is on the air anywhere on that frequency
Atmospheric and man-made noise levels are at a level they woukd have been before Noah's flood (Bible says it had not rained yet upon the earth, and I take that to imply no lightning storms and its associated static)
Receive setup is a high-end communications receiver with a 2-wavelength beverage antenna aimed at the signal. (Aso, reception on a stock pocket-sized battery-powered portable could be considered.) The listener is at least waist-deep in the surf.

Is it possible that with the higher power levels on the lower frequencies that a groundwave could make it all the way across the Pacific Ocean, for example, and still be readable?

 

[LibertyNT]

I read somewhere that it took a kW to cover 5,000 Miles in the ocean using the old ship transmitters. (CW probably in the LW band)
not sure where I read that.

Assuming no interference what so ever it probably shouldn't take much power to go from New York to England on the LW band.

 

[davideduardo]

Ok, then, how far would various power levels go over saltwater (5,000mS/m conductivity) during the day without any skywave at all? Frequencies would be 540kHz and 153kHz. Power levels are 2 MW (highest power for which I've seen a transmitter), 50kW (max allowed in USA), 1kW (graveyard channel), 10 watts (maximum allowed for a TIS in the USA), or 100 millliwatts (max allowed into input stage for part 15 in USA, but with a much smaller antenna than is used for answering this).

I used to DX at the beach at Guánica on the southwestern coast of Puerto Rico. In the daytime, even 1 kw stations above 1200 kHz from coastal locations in Venezuela were very readable. 10 kw stations in the mid-band range were nice car radio reception, and the higher power, lower dial position stations were as loud as the Puerto Rican south coast stations.

The distances involve are from 500 to about 600 miles.

Since I don't carry around a calibrated FSM, I could not give you signal strengths... but some of the signals were local quality.

 

[Icangelp]

Ok, then, how far would various power levels go over saltwater (5,000mS/m conductivity) during the day without any skywave at all? Frequencies would be 540kHz and 153kHz. Power levels are 2 MW (highest power for which I've seen a transmitter), 50kW (max allowed in USA), 1kW (graveyard channel), 10 watts (maximum allowed for a TIS in the USA), or 100 millliwatts (max allowed into input stage for part 15 in USA, but with a much smaller antenna than is used for answering this).
I'd like to know how far the "full-quieting" signal goes (60dB SNR? 90dB?), the signal level at which a signal barely trips a scan function or lights a tune indicator (18dB? 24dB SNR?), and max distance (0dB SNR - barely readable, nearly sinking into natural noise such that there's no way a better antenna will improve the signal.
We are assuming that:
The transmit antenna is either a Franklin (two stacked 180° elements, insulated from each other (IIRC) and fed at the center, or a half-wave over a full ground radial system.
The transmit antenna's concrete base (or whatever is used) is in the water, not onshore.
No other signal is on the air anywhere on that frequency
Atmospheric and man-made noise levels are at a level they woukd have been before Noah's flood (Bible says it had not rained yet upon the earth, and I take that to imply no lightning storms and its associated static)
Receive setup is a high-end communications receiver with a 2-wavelength beverage antenna aimed at the signal. (Aso, reception on a stock pocket-sized battery-powered portable could be considered.) The listener is at least waist-deep in the surf.

Is it possible that with the higher power levels on the lower frequencies that a groundwave could make it all the way across the Pacific Ocean, for example, and still be readable?

You're lack of knowledge is showing, but I'll overlook it this time. Very simple answer: yes with reservations

A more accurate answer could have been provided if you had specified the correct height (in inches) of the listener, their body frame type, and weight.

I'm going to make some assumptions based upon your previous posts, and guess you are 5'3" tall, neandertal, and that you weigh 320 lb. Inputing that information into my formula yields: absolutely not.

 

[gar hi]

I used to DX at the beach at Guánica on the southwestern coast of Puerto Rico. In the daytime, even 1 kw stations above 1200 kHz from coastal locations in Venezuela were very readable. 10 kw stations in the mid-band range were nice car radio reception, and the higher power, lower dial position stations were as loud as the Puerto Rican south coast stations.

The distances involve are from 500 to about 600 miles.

Since I don't carry around a calibrated FSM, I could not give you signal strengths... but some of the signals were local quality.

Interesting. That makes sense.

If you're on the NW coast there, I wonder if you could hear any US stations.

WQAM Miami is low on the dial and non directional.


BTW, I finally heard the results from my brother in Hawaii as to if he could hear KFI or any other California stations on the beach near Hilo in the daytime and he couldn't get anything. I guess 2000 or more miles may be over the limit for a saltwater path signal.

I still think over 1000 miles is possible though just based on how strong the New York stations are heard in Bermuda at a little under
800 miles.

 

[davideduardo]

If you're on the NW coast there, I wonder if you could hear any US stations.

There were US signals on 550, 580, 600, 610, 630, 680, 710, 740, 760, 810, 840, 850, 170, 880, 910, 930, 940, 960, 990, 1020, 1030, 1040, 1050, 1070, 1080, 1090, 1110, 1120, 1130, 1140, 1160, 1170... etc.

But I think you meant "the US mainland" right?

I've tried from the beach area at Aguadilla, but between the Venezuelan and Dominican stations, plus all the Puerto Rico locals, I never got anything daytime except what I thought was WAPE on 690.

It's not well studied, but east-west paths in the tropics seem to be more difficult than north-south ones. Still, there were occasional unusual ones... like Lybia on 1251 frequently heard in metro San Juan on the car radio around 4 PM.

WQAM Miami is low on the dial and non directional.

Even when their transmitter was footwet, I could not get it. Nights are filled with US mainland signals, mashing it up with all the Caribbean and Latin American stations.
]

 

[gar hi]

Yes, I meant the US mainland during the day.

All those above listed frequencies were at night, I take it?

If they were night signals, what about stations like WFAN, WABC, WCBS from New York?

Though I didn't try for them all, I listened to WABC at night from St. Thomas on vacation there back in 1973.

 

[davideduardo]

Yes, I meant the US mainland during the day.

All those above listed frequencies were at night, I take it?

No, they were my local US stations, starting with WPAB 550 and ending with WLUZ 1600.

 

[EastBay]

From the San Francisco bay area, I think my furthest catch- and oddly enough, from a car radio- was WHAS 840 (Louisville). I caught that about 15 years ago from the top of a hill in Pleasanton. Otherwise, WWL 870 (New Orleans) has come in a few times here (though I've had more luck with WWL from the high desert in SoCal). KRVN 880 (Lexington, Nebraska) is a pretty routine catch in the bay area.

My absolute furthest catch ever was back in the '80s when I was in the Navy; I was just a couple hundred miles east of Japan in the Pacific ocean on my ship...I caught WOAI 1200 (San Antonio) not to mention many west coast stations (KFI, KNX, KSL, KEX, KOMO, etc). Of course, I was cheating using the big fan antenna on the ship and a VERY sensitive HF receiver I modified to pick up AM freqs.

For those of you on the west coast who have picked up anything from the far east (Japan, etc)...is a beverage antenna a must, or can I get away with just an good external loop (and, of course, a decent radio)? I don't have a ton of real estate for that big of an antenna...

 

[pianoplayer88key]

For those of you on the west coast who have picked up anything from the far east (Japan, etc)...is a beverage antenna a must, or can I get away with just an good external loop (and, of course, a decent radio)? I don't have a ton of real estate for that big of an antenna...

This is what 774 JOUB sounded like on the Tecsun PL-380 aided by the Select-A-Tenna, at about 6:45am on Oct. 20 this year.  Local pest 760 KFMB, 7.3 miles away at a heading of 320°, had just switched to their daytime 5kW non-directional pattern.  I suspect it was strong enough so I maybe could have heard it without the SAT, but I didn't try that time.

A few minutes earlier, at 6:40am, they had a respectable signal as well, even though KFMB was still on their 50kW directional night pattern (with significantly more than 50kW aimed at me) at the time.

At around 6:47am right after the better quality PL-380 clip was recorded, I recorded a usable signal on my Panasonic RQ-SW20, which isn't exactly known for razor-sharp selectivity.  It could also be heard in a clip right after the 6:40am PL-380 clip was recorded, but the 760 KFMB splatter was much more severe, due to KFMB being 50kW at the time.

 

[charlestondxman]

This morning, I just got KOA from Denver here in Charleston. That's a pretty distant catch.

 

[formula72]

From the San Francisco bay area, I think my furthest catch- and oddly enough, from a car radio- was WHAS 840 (Louisville). I caught that about 15 years ago from the top of a hill in Pleasanton. Otherwise, WWL 870 (New Orleans) has come in a few times here (though I've had more luck with WWL from the high desert in SoCal). KRVN 880 (Lexington, Nebraska) is a pretty routine catch in the bay area.

My absolute furthest catch ever was back in the '80s when I was in the Navy; I was just a couple hundred miles east of Japan in the Pacific ocean on my ship...I caught WOAI 1200 (San Antonio) not to mention many west coast stations (KFI, KNX, KSL, KEX, KOMO, etc). Of course, I was cheating using the big fan antenna on the ship and a VERY sensitive HF receiver I modified to pick up AM freqs.

For those of you on the west coast who have picked up anything from the far east (Japan, etc)...is a beverage antenna a must, or can I get away with just an good external loop (and, of course, a decent radio)? I don't have a ton of real estate for that big of an antenna...

Please tell me you can still get WHAS and WWL...

The best I can do is WOAI 1200 from Dallas, WBAP 820 ( even thought the splatter from KGO is just ridiculous ) and 1040 WHO from Des Moines. Have tried and tried WLS 890 out of Chicago, but with three stations overlapping the San Jose area, it's not possible.

 

[boombox4]

I became a forum member here long after this thread was started.

My furthest catch is JOUB, which I first heard on an FRG-7 with an 80 ft. wire.

I also heard HLAZ 1566 -- Korean language over the heterodyne on my Realistic TRF, that was about 4 years ago. No loop needed to hear speech, the external looped helped with IDing the language. It's amazing what a 200mm antenna, TRF FET and good conditions can accomplish.

I logged Rebelde on 1180 several times in 2012-2014, both with and without loops, on several radios, including a Radio Shack Pocket Radio. When I wants to come in, it will show up. Rebelde is my farthest recent catch. I've heard the het on 1566 a couple times over the past year, including traces of speech (on my PR-D5), but no definite IDing o the language.

 

[Rayradio7973]

Am dx sept 2019

700 WLW Cincinnati heard in Caracas Venezuela 14 September 11:40 PM

 

[SomeRadioGuy]

My furthest catch had been CJDC 890 in Dawson Creek, BC, Canada.. but I've since heard PJB800 TWR Bonaire, 450KW and some Cuban AMs from here in Laramie, Wyoming.. Cuba and Bonaire are about 3000 miles away

 

[davideduardo]

700 WLW Cincinnati heard in Caracas Venezuela 14 September 11:40 PM

That is a pretty good accomplishment with YVKY Radio Capital in Caracas on the air on 710 with 100 kw. What sort of receiver and antenna did you use to make that one happen?

 

[Steve Green NEPA]

Here in NE PA, my recent sequel to those fevered days gone by near JFK Airport, I managed to hear a few good ones.

Off a Lafayette HA-600 a and a loop, I managed to hear both versions of KDIA Oakland -- the 1630 one and the 1640 one. I don't know which I heard first. There are no dates here.
Wow, do I miss that radio. Some component in the back cracked and I never got it working well again.

One night on the analog Topaz CAR radio I tried for CJBC 860 and instead heard that 'het noise' and some foreign language, not French. It was from 855. I have it logged simply as 'Romania'.
Now I wouldn't know a legal ID in Romanian if it were addressed specifically to me and bit me in the neck. But there were reports of it being heard, widespread, at the time. So I'm counting it.

Come to think of it, the station might've been the farthest I'd heard even from back in Queens.

Lol -- the boss of our eatery not only was from Romania but from the Transylvania part.
We called him 'De Count!' We'd hang pictures of bats and vampires all over the place,
and he'd just look at them and shake his head. And whenever it was my turn to go out for food or coffee, he and I would confound all the other workers by talking in -- what else? -- French. So De Count knew at least three languages.

Dunno about you guys, but I'm in love with the left knee on the brunette in the Amazon ad.

 

[davideduardo]

My furthest catch had been CJDC 890 in Dawson Creek, BC, Canada.. but I've since heard PJB800 TWR Bonaire, 450KW and some Cuban AMs from here in Laramie, Wyoming.. Cuba and Bonaire are about 3000 miles away

Several factors (beyond man-made noise) make a lot of distant reception more difficult than it was 50 to 60 years ago.

First, the almost total absence of "clear" frequencies on the famous Monday Morning Maintenance Periods (caps for emphasis) when nearly every station in the US was silent a few hours.

In the early 60's, that is what let me hear a 10 kw NZ station on 1000 or 250 watt KIKI on 830 in Honolulu or 50 watt AFRTS Ramey AFB, PR, on 780 or 5 kw Radio Salta on 830 from Argentina from Cleveland. Nobody else on the channel, good conditions, anything possible.

Second is the absence of "split frequency" Latin American stations. Whether it was Radio Caaguazu on 645 from Paraguay or Radio Nacional from Lima on 854 or Esmeraldas, Ecuador on 1395 or Quito on 855 or the many "drifiting" Colombians and Central Americans, there were always stations to be hand "between the station" on the US 10 kHz spacings.

Europe is still "easy" well into the Midwest on their 9 kHz channels, but having most domestics off on Monday morning when they signed on made hearing them easier.

Third, there are fewer people DXing. A simple fact is that many of us got into DXing to hear "fun" stations at night, just as an earlier generation got into it to hear a variety of stations back when much of America had little local radio. Hearing the Opry live or Dick Biondi on WLS or a baseball game from the "other team's" hometown was fun. Hearing C2C on 500 stations is not fun.

Maybe not my record DX achievement, but in 1961 I heard and verified 500 watt WITA in San Juan, PR at its 5 AM AST sign-on; 14 years later I would be the general manager of that same station which in the meantime had increased to 10,000 watts. But during the many years I managed the station, we never got a reception report from the mainland despite running 24/7... the channel was just loaded with other 24/7 stations across North America making our directional operation impossible to hear... but we got many reports from Europe.

 

[gr8oldies]

We can add, no doubt, Cuba not having the "oomph" it used to when the Soviets were bankrolling them.

Several factors (beyond man-made noise) make a lot of distant reception more difficult than it was 50 to 60 years ago.

First, the almost total absence of "clear" frequencies on the famous Monday Morning Maintenance Periods (caps for emphasis) when nearly every station in the US was silent a few hours.

In the early 60's, that is what let me hear a 10 kw NZ station on 1000 or 250 watt KIKI on 830 in Honolulu or 50 watt AFRTS Ramey AFB, PR, on 780 or 5 kw Radio Salta on 830 from Argentina from Cleveland. Nobody else on the channel, good conditions, anything possible.

Second is the absence of "split frequency" Latin American stations. Whether it was Radio Caaguazu on 645 from Paraguay or Radio Nacional from Lima on 854 or Esmeraldas, Ecuador on 1395 or Quito on 855 or the many "drifiting" Colombians and Central Americans, there were always stations to be hand "between the station" on the US 10 kHz spacings.

Europe is still "easy" well into the Midwest on their 9 kHz channels, but having most domestics off on Monday morning when they signed on made hearing them easier.

Third, there are fewer people DXing. A simple fact is that many of us got into DXing to hear "fun" stations at night, just as an earlier generation got into it to hear a variety of stations back when much of America had little local radio. Hearing the Opry live or Dick Biondi on WLS or a baseball game from the "other team's" hometown was fun. Hearing C2C on 500 stations is not fun.

Maybe not my record DX achievement, but in 1961 I heard and verified 500 watt WITA in San Juan, PR at its 5 AM AST sign-on; 14 years later I would be the general manager of that same station which in the meantime had increased to 10,000 watts. But during the many years I managed the station, we never got a reception report from the mainland despite running 24/7... the channel was just loaded with other 24/7 stations across North America making our directional operation impossible to hear... but we got many reports from Europe.