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WROA Gulfport DA History

S

Schroedingers Cat

When you were talking about WLCY being heard in the Caribbean and Central and South America, it reminded me of the technical details of the WROA 1390 Gulfport directional antenna in the 1960 NAB Engineering Handbook. It wasn't labeled as such, just as WKMH/WKNR 1310 Dearborn wasn't labeled as such, but when you thought about it, that was what it was. For one thing, the DA resonance and impedance information was near 1390. The night pattern went in a mainly Southern direction, and other information pointed to it. It was 5000 watts daytime then with just a two tower directional array, and 500 watts with a four tower parallelogram at night. Now it is 5000 watts fulltime, but has 8 towers day and night. I wonder why they went from 2 to 8 towers daytime. The nulls aren't that deep, and it appears that the 2 tower day DA was pretty much at full efficiency. It was 100 degrees spacing with 100 degrees phase with a 0.8 field ratio. I will try to find the page on David's site.
 
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Just looked at the 1969 WRTH. WROA was 1000 watts nondirectional daytime only in 1969. Also, the resonance shown in the NAB Book was actually at 1380. Maybe this was a plan or CP for them to move to 1380, with 5000 daytime with 2 towers and 500 nighttime with 4 towers, back around 1960. I've been remembering and hearing a lot about old CPs and plans since David's site has aided in remembering obscure things that happened in the past like old upgrade plans and CPs that were never built.
 
Now that I look at it again, there are just too many details for this to have been a mock up, it had to be an actual facility. I guess you could make up monitor point values, but it just looks too complete. It was an actual station on 1380, not 1390, in the Southern regions of the country. It is in Section 2 of the 5th Edition. It has most likely been moved or rebuilt with different parameters. You'd need a really old Pattern Book to figure it out, unless you knew the patterns already. There are few geographical clues that I could find, other than that the night pattern main lobe went mainly Southwest. Could be West Coast too then.
 
As you may already know, we usually spend a week or so on the gulf once or twice per year. Our first visit was in 1971. I always stand to be corrected, but I believe WROA was on 1390 by then....although I don't recall whether or not it was fulltime at that point. FWIW, where we stay now on the beach at the Alabama-Florida state line, WROA is one of the very few AMs on the coast between Panama City and New Orleans that's effectively absent during the daytime. Even the 1kw New Orleans graveyards, 1230, and the now-defuct 1450 are/were audible from 160-odd miles away underneath the Pensacola stations on the same channels.
 
Well, my next best guess is the station that was KUDL 1380 Fairway, KS, but they have torn their DA and gone 2500 watts day, 29 watts night, nondirectional. It was directional with 5000 watts before, and away from Michigan. I heard them in Michigan but I am surpised that neither the day nor the night directional radiated much in this direction.
 
With their pattern, WROA could have been heard near South America at night. It has 8 towers and is beamed South. The maximum inverse field at 175 degrees true is 2230.71 mV/m at 1 km. This is a solid Class B minimum "ERP" in excess of 50 kW, though not quite a Class A 50 kW equivalent inverse field.
 
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Schroed, I can't recall the last time I saw a depiction of a nighttime null as severe as that southeast one of WROA. That's like holding part of your breath from sunset to sunrise.

By day, there is no null that way. The water-path contour behaves accordingly.

What station(s) does WROA protect in that direction at night ?
 
Schroedingers Cat said:
With their pattern, WROA could have been heard near South America at night. It has 8 towers and is beamed South. The maximum inverse field at 175 degrees true is 2230.71 mV/m at 1 km. This is a solid Class B minimum "ERP" in excess of 50 kW, though not quite a Class A 50 kW equivalent inverse field.
Click to expand...

The real issue is that the higher frequencies (Above 1200 or so) in Venezuela and Colombia are "local" channels, with 1 kw to 5 kw non-directional stations in multiple locations in each country. The chances for Gulfport to be heard over the local interference is minimal.

Of course, with most Mexican AMs moving to FM, the AM band will become very clear, so hearing WROA in the Yucatan Peninsula would be very likely. Central America is even more likely, as AMs are disappearing from the dial, particularly on the higher frequencies.
 
I wonder if that daytime-only operation of WROA in 1969 would have been a temporary result of the destruction of the area by Hurricane Camille? I remember watching a TV documentary about Camille that used recordings of WROA's watches and warnings before it hit.

I remember looking at the coverage of many stations on the Gulf Coast awhile back (in a thread discussing WWL's Gulf coverage) and being amazed at WROA's eight towers beaming from almost the shore right out to sea, thinking it may have one of the smallest "coverage area to land occupied by array ratios" around.

The comparison to WKNR et al 1310 still seems odd.
 
In a previous thread about WROA's somewhat illogical tower/pattern/wattage it was stated that the owner strongly believed that he needed to be 5kw 24 hours a day in order to dominate local add sales. He was willing to put up with building 8 towers for the tight night pattern in order to accomplish this.
 
In response to VHF, I was only identifying or trying to identify the stations whose information was shown in the NAB Handbook, with the call letters redacted. The information about Proofing a DA was clearly WKMH/WKNR, because I was more familiar with the area around the transmitter, and they showed roads and Map features like Van Born Rd., Kilfoil Drain, and the Detroit Industrial Expressway which were on old USGS Maps. I could even see the area as being familiar without the road names. WKMH/WKNR has/had six towers, and also a very high "ERP" major lobe in the night pattern.
 
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