I often have wondered whether you could just have separate linked transmitters locked to a single oscillator frequency with computer generated power level/amplitudes and phase shifts driving each tower independently, rather than a phasor. No doubt, some tweaking would be necessary just like Barry Mishkind and Ron Rackley have described with WFLA WSUN with the mutual impedances, but I'd like to see this tried if it hasn't been done already.
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Nighttime Protection of the Original 'Regionals' ?
- Thread starter Steve Green NEPA
- Start date
I often have wondered whether you could just have separate linked transmitters locked to a single oscillator frequency with computer generated power level/amplitudes and phase shifts driving each tower independently, rather than a phasor. No doubt, some tweaking would be necessary just like Barry Mishkind and Ron Rackley have described with WFLA WSUN with the mutual impedances, but I'd like to see this tried if it hasn't been done already.
You are describing having a single driver feeding one amplifier for each tower
and then adjusting the power of each amplifier and the length of each transmission line to each tower.
I have fantasized about linking several part fifteen AM transmitters, each located at its own three-meter radiator.
Each unit would be set to the full 100mw and at least one model has a phase delay circuit for linking them.
The phase adjustment is intended to put nulls in areas of parking lots where there are few cars
because getting directional gain this way has been determined to be cheating and illegal.
Also, the full project would require several thousand dollars and a few acres.
Spending all that time, effort, and money, and then getting shut down would be funless.
I can just see doing monitor points with a laptop where the engineer could tweak the relationships online and measure the change at the actual monitor point. No more cranking or tapping coils, no more swapping out vacuum caps to make it work! And switching day and night patterns would be a snap.
Imagine the old 1500 Detroit with racks filled with individual transmitters!
About the current AM620 (formerly WSUN) two-tower array. The towers are located on pilings over the saltwater of Tampa Bay.
While the saltwater is great for the AM620 signal, the night pattern shifts as the tide changes. The tides affect the depth of the station's NNW null.
While the saltwater is great for the AM620 signal, the night pattern shifts as the tide changes. The tides affect the depth of the station's NNW null.
Quote (David Eduardo): Imagine the old 1500 Detroit with racks filled with individual transmitters!
50000 watts into 9 towers. Speaking of phasors on stun, there was a lady in Lincoln Park who lived just North of the WJBK array when it was turned on for the first time, and she couldn't turn her house lights off! They finally got her house detuned, along with about 200 high tension towers, to control reradiation. To this day, you can see the detuning circuit loops on the sides of the high tension towers as you drive down I-75 near the array.
50000 watts into 9 towers. Speaking of phasors on stun, there was a lady in Lincoln Park who lived just North of the WJBK array when it was turned on for the first time, and she couldn't turn her house lights off! They finally got her house detuned, along with about 200 high tension towers, to control reradiation. To this day, you can see the detuning circuit loops on the sides of the high tension towers as you drive down I-75 near the array.
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Does the tide actually affect the measured IDF, or is it just the conductivity change that changes the field strength at the monitor point in the null?
When WRIZ/WRHC had four towers in Biscayne bay, Miami,
they had two ground radial systems:
one was below the water at the lowest tide,
the other was above the water at the highest tide.
The phase and current readings changed a little bit,
but not a whole lot. Nothing remains.
Nothing Remains.
I have wanted to start a thread about old Antenna Site Archaeology. I recently discovered a wetland lot that was used circa 1960 for a three tower in line AM DA-D array. It was apparently too swampy and didn't put a good signal over the COL, especially if full time was planned. It was in the wrong direction. There is a row of scrubby trees in the same orientation as the towers apparently were arranged It looks like they tried to drain the swamp by tiling along the line of the towers, and that apparently allows a strange ecology of ideal irrigation for the scrubby trees to this day 50+ years later. I suspect that the roots go into the drain tiles. The site was soon rebuilt elsewhere. I haven't had a chance to see what other remnants might be there. Anyone else have similar stories?
Decades later, they went Fulltime at the new site with two more towers for a dogleg three tower Night pattern. The station was deleted about 10 years after that. Towers are gone.
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Second the motion for Antenna Site Archaeology thread. There are many tales of how weather and economics combined to permanently cut down a number of UHF stations...even a VHF station, such as channel 3 in Pueblo CO in the early 50s. Or what's left of a number of former multi-tower AMs, like a 500 watt 4 tower DA daytimer in a town of 4500 people.
Back to protections on the Regionals: when did the more aggressive shoe-horning of night time facilities begin? Such as those facilities that needed an 8 or 10 mV/m NIF contour over their COL....
Back to protections on the Regionals: when did the more aggressive shoe-horning of night time facilities begin? Such as those facilities that needed an 8 or 10 mV/m NIF contour over their COL....
I loved that WQAM tower. I even envied it!
In essence then, going by what Schroedinger says, all of the position jockeying began when nighttime 'regionals' increased their power. Is it safe to say that all of the regionals (and of course the graveyarders) at one time had been omni at night?
If so, then the various mutual protections (like those between WDRC and WSAI) would have been achieved by individual, musical-chairs arrangements ... at different times ... different years .... though they'd have to follow the resolute FCC interference guidelines.
And if such was the case, there needn't've been any handshakes between the engineering departments at either WSAI or WDRC, right? There'd only be field measurements from one station (say WSAI) that passed FCC muster. WDRC had no say in the matter?
(Am just using those two stations as examples. I don't know if either ever had been omni 1000 watts or 500 watts at night. Lol -- I guess the reason I cite the two is because of our local WPPA Pottsville on 1360. During the day they're 5000 watts, casually sent in an east-west way. WPPA has a total of 5 sticks in an array like the '5' on a die. At night they drop to 500 watts ... pull it in away from Hartford and Cincinnati .... and send most of the 500 watts SOUTH. Two guesses as to what stations I've heard here at night instead of WPPA:
WSAI and WDRC, of course).
If so, then the various mutual protections (like those between WDRC and WSAI) would have been achieved by individual, musical-chairs arrangements ... at different times ... different years .... though they'd have to follow the resolute FCC interference guidelines.
And if such was the case, there needn't've been any handshakes between the engineering departments at either WSAI or WDRC, right? There'd only be field measurements from one station (say WSAI) that passed FCC muster. WDRC had no say in the matter?
(Am just using those two stations as examples. I don't know if either ever had been omni 1000 watts or 500 watts at night. Lol -- I guess the reason I cite the two is because of our local WPPA Pottsville on 1360. During the day they're 5000 watts, casually sent in an east-west way. WPPA has a total of 5 sticks in an array like the '5' on a die. At night they drop to 500 watts ... pull it in away from Hartford and Cincinnati .... and send most of the 500 watts SOUTH. Two guesses as to what stations I've heard here at night instead of WPPA:
WSAI and WDRC, of course).
You can find many of the answers on americanradiohistory.com by looking at old Broadcasting Yearbooks. There were also mutual agreements, but those are hard to find online. 5 on a die sounds like CKLW and WGAR, and many of those were designed by Carl Smith. Look at CKLW and WGAR arrangements on fccdata.org. Not sure if CKLW will come up though. Maybe David will post the NARBA Plan link again.
CKLW is a parallelogram with a tower in the center of the parallelogram. I suspect that the 5 on a die arrays are mostly parallelograms of some description with a tower in the middle. Also, Consider also WOKY which is a 4 tower parallelogram Days, and a 3 tower in line along one side of the parallelogram Nights. The middle tower of that is along the side and not used Days.
CKLW is a parallelogram with a tower in the center of the parallelogram. I suspect that the 5 on a die arrays are mostly parallelograms of some description with a tower in the middle. Also, Consider also WOKY which is a 4 tower parallelogram Days, and a 3 tower in line along one side of the parallelogram Nights. The middle tower of that is along the side and not used Days.
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All the early predecessors of Regional channel stations were nondiectional until the 1930s, usually mid to late 1930s to 1941-2. Not sure what year the 40 AM BC DA total was from.
What five kilowatt, omni-directional, regional channel stations
exist in the lower forty-eight (48) states tonight?
I only recall this one, way over in the top left corner.
I can add the former WDAF (now KCSP) 610 Kansas City and the former WOW (now KXSP) 590 Omaha.
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There are quite a few more 1000 watt and 500 watt nondirectional stations from the early days of radio still around. We had a thread about this a few years ago. As for 5000 watt ND-N, what about KFRC...KEAR San Francisco, CA? I think KJR was that way before they went to 50000 watts. I'll look in my 1969 WRTH later.
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Here's a question that takes us back to 1939, when WMT 600 Cedar Rapids and WREC 600 Memphis operated with 1000 watts at night, per Broadcasting Yearbook. Did both stations operate ND at night with 1 kW in '39?
If so, why were both stations' DAs designed with such severe nulls towards each other? In the case of WMT, that left Iowa City, just 30 miles south, with a sub-par signal. It may have been an acceptable strength sixty and seventy years ago, but not in today's RF environment. It seems like the nulls between Cedar Rapids and Memphis could have been let out so they could have sent 500 watts toward each other.
If so, why were both stations' DAs designed with such severe nulls towards each other? In the case of WMT, that left Iowa City, just 30 miles south, with a sub-par signal. It may have been an acceptable strength sixty and seventy years ago, but not in today's RF environment. It seems like the nulls between Cedar Rapids and Memphis could have been let out so they could have sent 500 watts toward each other.
KMJ 580 was 5 U1 before going to 50 kW. KSFO 560 was 5/1 U1 in the 1969 WRTH. KJR 950 was 5 U2 in the 1969 WRTH. Incidentally, what was the first station to be allowed to increase power at Night, at least in recent History (last 50 years or so)? Answer: WRTH 0.5/1 590 Wood River, IL.
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