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Reception question
- Thread starter radiojay1
- Start date
C
cd637299
Guest
I am not a chief engineer, but there are factors involved:
(1) Frequency (in the daytime, the lower the frequency, the more bang-for-the-buck, as far as wattage of the station).
(2) Directionality (WCBS & WFAN are nondirectional, but WBZ is directional, at least at night, sending their signal up-and-down the Atlantic seaboard, less over water than the other two).
(3) Saltwater vs. fresh water, if I recall.
(4) Time of year, of course, as daylight varies each day.
I was in Bermuda in June 2005, trying to take advantage of as much daylight as possible to find out what AM stations from the US mainland can be heard there. On a 1-10 "signal scale", I think I gave WFAN & WCBS a 4, and maybe WBZ a 2. I rated WTAR 850 Norfolk the highest, at a 5---I believe VERY directional 50 kW out over the Atlantic to protect the other 850's.
I am sure that one of our senior members here can give you *much* more info than I could.
PM me if you like. (I will say that AM DX is not my strong suit anymore, as much as FM & TV.)
cd
(1) Frequency (in the daytime, the lower the frequency, the more bang-for-the-buck, as far as wattage of the station).
(2) Directionality (WCBS & WFAN are nondirectional, but WBZ is directional, at least at night, sending their signal up-and-down the Atlantic seaboard, less over water than the other two).
(3) Saltwater vs. fresh water, if I recall.
(4) Time of year, of course, as daylight varies each day.
I was in Bermuda in June 2005, trying to take advantage of as much daylight as possible to find out what AM stations from the US mainland can be heard there. On a 1-10 "signal scale", I think I gave WFAN & WCBS a 4, and maybe WBZ a 2. I rated WTAR 850 Norfolk the highest, at a 5---I believe VERY directional 50 kW out over the Atlantic to protect the other 850's.
I am sure that one of our senior members here can give you *much* more info than I could.
PM me if you like. (I will say that AM DX is not my strong suit anymore, as much as FM & TV.)
cd
I was in Bermuda a little over a year ago. The radio I used was one of the "whiz-bang" mini-portables...a Tecsun PL-606 using the internal loop. At miday, WOR-710 was, by far, the strongest, but weak, stateside signal. 850 from Norfolk was also very listenable. New York's 660, 770 and 880 were "there" but sketchy. 1540 from the Bahamas was also heard, but quite weak.
radiojay1 said:
WFAN and WCBS use the same tower on High Island in Long Island Sound near The Bronx, NYC. A great circle path from that site to Southampton, England has a bearing of about N52oE.
That path travels down Long Island Sound from WFAN for about 20 miles, crossing the coastline into Connecticut between Stamford and Darien. From there the path travels over land, crossing Boston, and then the Atlantic coastline about 207 miles downrange, near Gloucester, MA.
Accounting for the conductivity of that path to Gloucester, the field intensity of WFAN is less than 0.1 mV/m as it reaches the Atlantic Ocean. From that point on the groundwave will only reduce as it travels across the ocean.
A field intensity of 0.1 mV/m is getting close the lowest useful field for a consumer-level AM receiver, in a low noise area.
For reference, if that path to Southampton was completely over the ocean, below are a few field intensities WFAN would produce, according to FCC groundwave propagation charts for their frequency and radiated power:
mVm miles
1 389
0.5 480
0.1 705
These are the fields existing just above the surface of the open ocean, and won't be the same as those in/near an ocean-going vessel.
I forget the name of the poster who said it but someone here once said they were in the Bahamas and WCBS and WFAN could be heard during the day all day. I think the time of year was March.
My best saltwater midday catch with an official ID was 740 KTRH Houston at the Gulf in Dunedin, Florida - 775 miles.
That's the same distance from New York to Bermuda.
For anyone who can figure it out, I know they are directional and I'm wondering how much signal in kw they send in that direction during the day.
Although I couldn't get any ID because it was non stop preaching behind the stronger Spanish station, I'm certain I heard 1030 KCTA from that location too.
At Daytona Beach midday, I couldn't hear any listenable signal on 880 but WZAB was there along with another weaker station fluttering behind it. Couldn't have been the Cuban because that's barely audible here on the west coast daytime and it would have to pass over the spine of the state to reach Daytona Beach which would obliterate the signal.
That's why I think it was a trace of WCBS I was getting.
The Sangean PR-D5 is a great radio. My car radio was not picking up anything at all on 880 when I was there.
My best saltwater midday catch with an official ID was 740 KTRH Houston at the Gulf in Dunedin, Florida - 775 miles.
That's the same distance from New York to Bermuda.
For anyone who can figure it out, I know they are directional and I'm wondering how much signal in kw they send in that direction during the day.
Although I couldn't get any ID because it was non stop preaching behind the stronger Spanish station, I'm certain I heard 1030 KCTA from that location too.
At Daytona Beach midday, I couldn't hear any listenable signal on 880 but WZAB was there along with another weaker station fluttering behind it. Couldn't have been the Cuban because that's barely audible here on the west coast daytime and it would have to pass over the spine of the state to reach Daytona Beach which would obliterate the signal.
That's why I think it was a trace of WCBS I was getting.
The Sangean PR-D5 is a great radio. My car radio was not picking up anything at all on 880 when I was there.
gar fla said:
The great-circle path from KTRH to the beach in Dunedin, FL is 746 miles long at a bearing of N97oE. It crosses land into the Gulf for the last time just SE of Houma, LA.
For the radiated power in that direction with their daytime directional pattern, frequency, and the earth/sea conductivities, the groundwave field intensity from KTRH should be about 0.3 mV/m where their signal reaches the Gulf near Houma.
For the rest of that path to Dunedin (about 492 miles across the Gulf), that signal will be attenuated to approximately 28% of the value it had near Houma, which would be ~ 0.084 mV/m.
These numbers are derived from the FCC groundwave propagation charts for the frequency, the conductivities along the path, and radiated power.
A little O/T , but rather than start a new thread ......
Were there as much of a percentage of the European AM stations which had directional setups as we Yanks have ?
Radio Luxembourg 1439? The BBC on 881 ? West Deustche Rundfunk on 1586 ? Were they directional? I know they had a lot of wattage.
From this side of the pond, stations such as WKBW and WAPE 690 sent it ALL east. And various regionals such as on 1380, 1480 etc also did. The regional channels in this country had FAR more directional signals than omni signals.
* * * * * * *
Never been on a cruise, but stations such as WBZ and WWL should not go as far into the Gulf and the Atlantic as the omnis because they send it all away from Davey Jones' Locker.
Were there as much of a percentage of the European AM stations which had directional setups as we Yanks have ?
Radio Luxembourg 1439? The BBC on 881 ? West Deustche Rundfunk on 1586 ? Were they directional? I know they had a lot of wattage.
From this side of the pond, stations such as WKBW and WAPE 690 sent it ALL east. And various regionals such as on 1380, 1480 etc also did. The regional channels in this country had FAR more directional signals than omni signals.
* * * * * * *
Never been on a cruise, but stations such as WBZ and WWL should not go as far into the Gulf and the Atlantic as the omnis because they send it all away from Davey Jones' Locker.
Steve Green NEPA said:
I sailed across the Atlantic from England to Ft. Lauderdale in late 2011. WBZ was heard midway between Bermuda and the Azores at night. It was weaker than the Non Directional 50 KW Eastern Stations, but it was "there". In a few weeks, I will be checking out WWL when I am in Belize and Honduras at night. I'll report my findings on this....
KR4BD said:
Just to note that earlier posts in this thread pertained to daytime, groundwave fields.
The h-plane pattern of WBZ directs less radiated power toward the Atlantic than the omni patterns of WFAN and WCBS. But that radiation from WBZ has a lot shorter path across land before reaching the Atlantic coast.
While I haven't done the math (so far), probably the groundwave field of WBZ over the ocean is quite a bit better in many/most locations than that of both WFAN and WCBS.
I talked to the CE at WBZ back in the 1970s. I asked why it always seemed that WBZ was the daytime skywave king in Michigan. He thought it had to do with mineral deposits. Not sure about that.
I also asked him about the DA and its effect on DX. He said the reports followed the pattern close in, but that the signal had been known to go all the way around the earth and fill that null in. I think WKBW also claimed that when David used to hear them in Cleveland.
But I think high angle skywave accounts for some of the DXing in nulls from these stations. Particularly within 250 miles or so from the transmitter.
I also asked him about the DA and its effect on DX. He said the reports followed the pattern close in, but that the signal had been known to go all the way around the earth and fill that null in. I think WKBW also claimed that when David used to hear them in Cleveland.
But I think high angle skywave accounts for some of the DXing in nulls from these stations. Particularly within 250 miles or so from the transmitter.
WBZ can be heard at night across the Atlantic. I hear it regularly on the Global Tuners node in Northern Ireland.
R. Fry said:
Thanks for the info. That's interesting!
If it weren't for WORL, KTRH would have an easily listenable signal where I heard it.
I knew it had to be KTRH in the background every time I was over there at the beach but I finally was lucky enough to get an ID during a lull in talking on WORL.
I'm wondering too. Can you figure out the signal strength of WCBS in Daytona Beach daytime? I know it passes over land on and off until it's final complete ocean path.
And why do the stations from inland Florida come in so much stronger out on Honeymoon Island in Dunedin as compared to Tampa?
WORL is barely audible daytime in Tampa but very good out on Honeymoon island.
I can't get even a trace of 640 WVLG the Villages daytime in Tampa but out there, it's easily heard.
In Tampa, WQAM Miami is barely audible daytime but out there, it's a lot stronger and very listenable.
Why the big difference when most all the path is on land and only a mile or two on saltwater as compared to an all land path in Tampa?
R. Fry said:
WBZ is usually weaker than those. What really surprises me is that I've never heard WRKO on that receiver. It looks like they send more signal towards Europe, but all I ever hear on 680 from North America is CFTR and I've tried many times.
The strongest US station across the Atlantic is WBBR which sometimes comes in almost like a local.
Many midwest stations come in such as WJR, KMOX, WTAM, and four Chicago 50KWs especially WBBM which is the most regular.
Picked up KOMO from the west coast instead of WMVP the other night.
What is the time limit for edits? 15 minutes? I think they should increase it to 30 minutes.
K
kenglish
Guest
I'd think that there would still be a "Ground Wave" component (even if it's really seawater), and a Sky Wave component.
The salt water probably just does a heckuva lot to extend the ground wave (conductivity), and then you get a dead zone after that, until the skywave fills in from above.
BTW, the comment about WBZ "filling it's null by going around the world"......I once heard WMAZ-AM, on night pattern, in Southern Maryland, when I was in the Navy in the mid-70's. According to Billy Sowelll, their CE, their pattern was fine, and I just got multiple hops "around the back way".
Gotta love that troposphere ;D.
The salt water probably just does a heckuva lot to extend the ground wave (conductivity), and then you get a dead zone after that, until the skywave fills in from above.
BTW, the comment about WBZ "filling it's null by going around the world"......I once heard WMAZ-AM, on night pattern, in Southern Maryland, when I was in the Navy in the mid-70's. According to Billy Sowelll, their CE, their pattern was fine, and I just got multiple hops "around the back way".
Gotta love that troposphere ;D.
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