KGA night app

[Dan.Strassberg]

The reason is quite simple. KGA and KPIG (AM), licensed to Piedmont CA
near Oakland, are co-owned (by a company named Mapleton
Communications, which purchased KPIG only recently, with the idea of
upgrading it). KPIG currently runs 230W-N into a five-element DA atop
a warehouse near the water's edge in Oakland. (AFAIK, this is the only
rooftop DA in the US.) Despite the salt-water path to downtown San
Francisco, there is no way that, at 230W, KPIG delivers an NIF signal
to San Francisco. Mapleton wants to cover SF around the clock (KPIG
runs 8 kW days but still cannot cover much of the Bay area south of SF
because there is a 1500 station (I think it's 10 kW-D/5 kW-N) in San
Jose at the south end of the Bay.) By downgrading KGA from a Class A
to a Class B, KPIG is relieved of severe protection requirements to
the north and will be able to increase its night power 10-fold and
remove the fifth element from its night array. (Note my use of the
word element, rather than tower. The fifth element is a drop wire
suspended from a horizontal wire that joins the tops of two of the
four real towers.) Powering down KGA and changing its directional
pattern will reduce the skywave signal it delivers to the Bay area,
thus reducing KPIG's NIF value and ensuring that much of the
population of San Francisco officially becomes part of the population
KPIG serves at night.

Meanwhile, the downgrade of KGA is a bit less Draconian that that of
WOWO a decade or so ago. WOWO's transmitter site is mostly west of
Fort Wayne and quite a few miles from the east edge of that city. WLIB
is due east of Fort Wayne. This situation required a compromise. WOWO
had to reduce its signal to the east to allow WLIB's night operation
to deliver an NIF signal to 80% of New York's five boroughs. Yet,
using its existing three towers (but with a new night pattern), WOWO
had to deliver 5 mV/m at night to at least 80% of Fort Wayne. WLIB
also had to protect CHTN to its northeast. Because WLIB was able to go
to 30 kW at night (using four towers, two of which were used in the
existing 10-kW day array, which was not changed),WOWO's 9.8 kW night
operation just managed to meet both criteria. Notwithstanding that
WOWO's night signal to the east is now equivalent to only about 2 kW
ND (vs more than 100 kW before the downgrade), WLIB's NIF is in the
neighborhood of 15 mV/m and AFAIK, WOWO is the sole contributor. In
contrast, KGA will have to protect to its south and, fortuitously, its
transmitter site (a diplex with KJRB) is south of Spokane. A side
benefit of the KGA downgrade is that several 1510 stations south of
KPIG will enjoy significant improvements in their night coverage.

-----
Dan Strassberg (dan.strassberg@att.net)
eFax 1-707-215-6367

----- Original Message ----- 
From: "Robert F. Sutherland" <madprof@ix.netcom.com>
To: "BRI" <boston-radio-interest@rolinin.bostonradio.org>
Sent: Sunday, April 06, 2008 9:15 PM
Subject: KGA night app


>I loaded the FCC application data, night 15kw, 4 towers, parameters,
>etc,
> and ran a plot / calculation.
> They are proposing severely cutting their coverage!
> Yes, Spokane would still be well covered,  but I doubt western WA
> or previously covered parts of BC would still recieve a usable
> signal at
> night.
> And virtually all signal to the east will be gone.
>
> Does anyone have hunches, clue, or inside info
> on why they would do this?
>
> Is it a sign of the times, re IBOS & skywave becoming considered
> useless?
>
> Or is it a case similar to when WLIB bought WOWO, and
> grossly cut WOWO's night pattern so that WLIB could increase
> its own pattern?
>
> Whatever, it's sad when a legacy AM station proposes
>
> Bo
>