Re: Dual Frequency Day & Night

[Norm Rosen <inorm99@earthlink.net>]

1150 AM WMET  COL Gaithersburg Maryland, now with 1000 watts daytime, and 500
watts nightime has a CP to
significantly increase their power, and to broadcast on 1160 post sunset, and
continue at 1150 during the day.

1190 WBIS Annapolis has a similar plan.

dan.strassberg@att.net wrote:

> There is one station in the US at present, ethnic-
> formatted WNZK, licensed to the Detroit suburb of
> Dearborn Heights, MI. WNZK operates with 1 kW-DA day and
> night. It's on 690 days and 680 nights and uses separate
> six-tower day and night arrays at the same site.
>
> One report I've heard says that the station uses the
> Kahn Powerside modulation system--a modified single-
> sideband, full-carrier modulation technique, to put most
> sideband energy below the 690-kHz daytime carrier and
> above the 680-kHz nighttime carrier. Thus--at least on
> analog-tuned radios--the claim is that listeners do not
> notice the change in frequency and do not have to retune
> their radios.
>
> In years past, Canada had at least two such stations,
> but under Canadian rules, each "station" was licensed as
> two stations--one operating days, the other operating
> nights. One was CHIR/CHYR Leamington ON, east of
> Detroit. I forget which calls were used by day and which
> by night, but the daytime operation was on 710 with 10
> kW and the night operation was on 730 with, I believe, 1
> kW.
>
> The other was CFGR/CFRG in the Francophone enclave of
> Gravelbourg, SK. Again, I'm unclear about which calls
> were used when, but the station was originally full-time
> on 1290. This was when Canadian Class IIIs were limited
> to 5 kW. The station applied for, was granted, and built
> a 10-kW daytime facility on the much better frequency of
> 710, a US Class IB channel not then available for
> nighttime use in Canada, but continued its nighttime
> operation on 1290. For sure, that one required retuning
> of radios at sunrise and sunset.
> --
> dan.strassberg@att.net
> 617-558-4205
> eFax 707-215-6367
> > Do any AM stations use dual frequencies? A different one for day and night?
> >
> > Is this a real thing or just something I've misheard?
> >
> > --Mike
> >
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