> Noticed on the FCC CDBS this past week that WAMG 890 has
> applied for a
> Nightime Power Increase to 6kw from 3.4kw. If granted, will
> this help it's nightime coverage of Boston?
I've looked at the application, which is available for viewing and downloading from the FCC's CDBS system. As Artie Johnson used to say on "Laugh-In," "verrry interresting!"
First off, J-Sports has engaged as its design consultant Glen Clark, arguably the premiere AM DA designer. (The two top guys in this arcane field are Ron Rackley of DuTreil, Lunden, and Rackley in Florida and Glen. Glen has a true supercomputer in his office--I think it consists of 32 networked Dell PCs. He once sent me a photo of the setup. He uses the supercomputer to simulate the effects of varying DA parameters on groundwave and skywave patterns. Such calculations were impractical before the advent of low-cost PCs and appropriate software, but are still painfully time consuming without the computational power that Glen--and perhaps only Glen--has at his disposal.)
The biggest change in WAMG's night pattern is that the 6-kW version has sprouted two lobes centered at almost due north and due south. Nothing similar is present in the existing 3.4-kW pattern. Framingham is one town that should get a much better night signal--maybe three times the strength of the present signal. Percentagewise, the improvement in other areas is not terribly significant. The signal improves over two arcs from about 15 degrees to 75 degrees and from about 105 degrees to 165 degrees. The maximum improvements--approximately 15%--occur at about 45 degrees and 135 degrees. The improvement in Framingham is the equivalent of almost a 10X power increase. The maximum improvement to the northeast and southeast is equivalent to a power increase of only 30% or so--maybe enough to be noticeable to radio geeks. There is no change in the signal to the west--toward WLS. WAMG's 0.025 mV/m 10% skywave just kisses WLS's 0.5 mV/m 50% skywave somewhere near the New York Pennsylvania border at a point that appears to be more-or-less south of Batavia.
WAMG's NIF contour is 12.5 mV/m. Depending on how fussy you are about interference, that means that on most nights, you should be able to get a listenable signal out to maybe the 5 mV/m contour, whose distance from the transmitter is less than twice that of the 12.5 mV/m contour. Unless you are in Boston proper, where WAMG and WLS come from the same direction--pretty much due west--you'll be better off using a good portable radio than a car radio because portables' ferrite-loop antennas are more directional than car radios' whip antennas, which are more-or-less nondirectional. If you are, say, northeast or southeast of the WAMG Tx in Ashland, you should be able to turn the radio to maximize WAMG or minimize WLS.
But according to WAMG's application, the 6 kW signal will be ever so slightly WEAKER to the east (toward Boston) than the 3.4 kW signal. This curiosity is the result of making a comparison between the proposed standard pattern, which cannot be augmented because it has not yet been built, and the 3.4-kW augmented pattern, which has a HUGE augmentation to the east. I can't prove it and I could be wrong, but I believe this augmentation is the result of a lie by whomever designed the original incarnation of the 890 array back in the early 1990s.
At one point, 890 (might have been WBMA back then) had applied to change its COL from Dedham to Wellesley. This application was filed because the proofs of performance must have shown that the station did not deliver an NIF signal to Dedham. Then the station applied to augment its night pattern--but NOT its day pattern--and withdrew its application for a COL change. How fortuitous that, thanks to the augmentation, the NIF contour encompassed about 99.8% of Dedham! I think the claim must have been that reradiation from a tower of some sort on the railroad property just east of the 890/1060(N) site (from the site, the railroad tower is clearly visible through the trees) caused this most fortuitous augmentation. Not only is there no corresponding augmentation of the 890 day pattern, there is also no corresponding augmentation of the 1060 night pattern. Now, that part is not necessarily a falsehood; the existing 890 night system's signal amplitudes and phases could have produced the augmentation whereas the 890 day parameters and the the 1060 night parameters might not have. WAMG's proposed 6-kW night pattern appears not to need the augmentation to place an NIF signal over more than 80% of Dedham, so no waiver of the COL-coverage requirement should be necessary.
WAMG HAS, however, filed with its application an application for a waiver of prohibited nighttime-goundwave overlap with WCBS. WAMG's 0.25 mV/m nighttime groundwave will overlap WCBS's normally protected 0.5 mV/m contour east of Naragansett Bay. Such overlap already exists both day and night, but the proposed power increase will increase the area of nighttime overlap. However, the FCC has already granted waivers of similar overlaps with New York City AMs in the same general area and the application cites such an overlap between WBIX and WEPN. However, the application incorrectly describes WEPN as a Class A AM, which it is not; it's a Class B, so the nighttime overlap between WEPN and WBIX occurs outside of WEPN's normally protected service area. Elsewhere, the application refers to the WAMG towers having stood in their present location for more than 30 years. That statement won't be true for a little more than five years--but maybe WAMG's application will still be pending five years from now. That would not be a very unsual occurrence at the FCC.
