WRPT

[mwaters@wesleyan.edu (Martin J. Waters)]

At 03:31 PM 4/17/97 +0000, I wrote:
>        Perhaps someone in the right location can listen to hear if WRPT
>turns down the power at sunset. The few times I've heard them post-sunset,
>it sounded suspiciously strong. But, then again, it is (was) a clear
>channel, and that makes a lot of difference.

Dan Strassberg wrote:
>No. WRPT cuts its power one hour after local sunset here, which sometimes is
>and sometimes isn't the FCC-defined time of local sunset in Nashville.
>Depending on the month, Nashville sunset occurs between 45 minutes and 1
>hour and 15 minutes after Boston sunset. Now. maybe the rule for PSSAs for
>daytime stations _within_ the 0.5 mV/m 50% skywave contour of a dominant
>Class A station located west of the daytimer is different from that for
>stations outside that contour. (My guess the rules _are_ different.) WILD
>cuts power at Boston sunset and signs off at a time that _roughly_, but
>doesn't always exactly, coincide with Baltimore sunset. The timing of WILD's
>signoff and WRPT's power cut relative to sunset at the dominant station are
>similar.

        The time when it reduces power and the time when it is supposed to
reduce power may be different times. I think that the power reduction
should be made at WRPT's local sunset. WILD is in the circumstance of being
well within the 0.5 mV/50% skywave contour of WBAL. So it can only stay on
at the reduced PSSA power until local sunset at Baltimore--which is
calculated as a monthly average, so it could be an extra 15 minutes in some
months or 30 minutes in some other months. But the starting time of the
PSSA would be the same in both cases--the average monthly local sunset at
WRPT or WILD, as stated on the license.

In another post, Dan Strassberg wrote:
> As I see it, there are four cases for "daytime-only" stations on US Class A
>channels:

>1. The daytime station is east of the Class A and is outside the Class A's
>0.5 mV/m 50% skywave contour.

>2. Same as case 1 except the daytime station is west of the Class A.

>3. Same as case 1 except the daytime station is within the Class A's 0.5
>mV/m 50% skywave contour.

>4. Same as case 3 except the daytime station is west of the Class A.

>I would think that the rule for case 1 would be that the daytime station
>could remain on the air two hours past local sunset and could use its day
>facilities for one hour after local sunset or until sunset at the location
>of the Class A--whichever is earlier. This is the case that applies to WRPT.

        In your case 1, the "daytime" station should power down at its
local sunset. The old provisions for "limited time" and "specified hours"
licenses (which, like daytime-only licenses, are no longer issued for new
stations), provided for some stations to continue to use daytime facilities
until sunset at the class A station to the west or, for daytimers, to
remain on the air with full power until sunset at the station to the west.
(WLIB in NYC on 1190 is such a limited time / daytime only station, for a
little while longer. It gets to stay on at full power for about 45 minutes
past NYC sunset, until sunset at Fort Wayne). Existing stations are
grandfathered. But I can't think of any way that WRPT would have such a
license.

>I would think that daytime stations covered by cases 2 and 4 might be
>entitled to pre-sunrise authority, although I am confused about how much
>power these stations could use and what pre-sunrise hours they could
>operate. Do you, by any chance, have this information? Clearly, cases 2 and
>4 don't apply to any New England stations. The only North American Class A
>station to the east of New England is CBA. It's in Canada, and the rules for
>US daytimers on Canadian clear channels are different.

        The presunrise authorizations start at 6 a.m. local time (when
sunrise is later than 6 a.m.) except for stations inside the 0.5 mV skywave
contours of class A stations. For them, it's 6 a.m. or sunrise at the
nearest class A station east of them, whichever is later. As you noted,
that doesn't apply in New England because we're as east as it gets. The
PSRA reduced power continues until local sunrise at the "daytime" station.
Because of engineering factors I don't even remotely understand, the PSRA
powers apparently are almost always lower than the PSSA powers for the same
stations.

>Interestingly, WJLT would seem to be eligible for a PSSA under case 3,
>although such a PSSA would only extend the broadcast day by 15 minutes in
>some months and 30 minutes in others. I think, though, that WJLT would be
>eligible for more post-sunset power than the old WGTR was allowed
>pre-sunrise. WGTR's original PSRA was for 1.6W. I think WJLT is entitled to
>a 3.3W PSRA because of the reduced high-angle radiation from the taller
>tower. During post-sunset hours, WJLT would have to protect KYW's groundwave
>service--not its skywave service. I suspect that KYW's 0.5 mV/m 50% skywave
>contour is closer to WJLT than is the groundwave contour that WJLT would
>have to protect, but that may not be so. Since KYW is a Class A station,
>WJLT might have to protect KYW's 0.1 mV/m groundwave contour. That would
>mean limiting WJLT's 50% post-sunset skywave to 5 microvolts/meter at KYW's
>0.1 mV/m groundwave contour.

        During the PSRA and PSSA operations, the "daytime" station is
supposed to protect the 0.5 mV skywave contour or, if that is not present,
the 0.1 mV groundwave contour. KYW's protected groundwave contour must be
somewhere in New Jersey or the NYC area, so that's no problem. But in this
case the PSSA is going to be both very low power and very brief, because
Philadelphia is so close.

>Anyhow, it seems that the wording of the FCC regulations poses an
>interesting dilemma for certain daytime-station owners. I gather that if a
>station is authorized nighttime service, it is ineligible for a PSSA and may
>also be ineligible for a PSRA, regardless of how low the authorized
>nighttime power is. Thus, WRPT can operate until two hours past sunset,
>using full power for roughly one hour and 25W the rest of the time. If WRPT
>were granted nighttime service, it would probably be with lower power (maybe
>8W), but WRPT could not then use full power for the first hour after sunset
>and 25W for the next hour.

        Yes. It's one or the other. And, with the non-DA antenna, a regular
nighttime authorization would be less than 25 watts. With its own antenna
site, with a bunch of towers, this station probably could have a pretty
decent fulltime facility. But, as you note, whether that's economically
attractive for someone to build is another question.

------------------------------