RE: Night Time BCB Skywave/Ground Wave Cancellation/Interaction

["Adam Rivers" <adamrivers@prodigy.net>]

I am having problems getting WBZ. As for Boston stations, I get WRKO during
the day well.. but lately I have had trouble getting WBZ at all. Last week
in Washington, DC, I got WBZ better there than I do here. As for New York
stations, I get WEVD, WFAN, WCBS, and WBBR well during the day and night. I
get WBAL well in the night (and sometimes during the day), KYW.. from Albany
I get "legends 1540" all day and night.. and I get WTIC well during the day
and night

Adam
Chicopee Mass.
-----Original Message-----
From: owner-boston-radio-interest@bostonradio.org
[mailto:owner-boston-radio-interest@bostonradio.org]On Behalf Of Mark
Casey
Sent: Tuesday, July 10, 2001 3:39 PM
To: BRI Submit; David Moisan
Subject: Night Time BCB Skywave/Ground Wave Cancellation/Interaction


The "Skip zone" , at night, (and daytime) becomes more of a factor as
frequencies increase up into the "Short Waves"

Ground wave & skywave commonly occur together at a range of  ??? or more
miles and interact,"fight themselves", or "cancel", at night on the
Broadcast Band.
At least 1 night a week, skywave from WTIC AM gives the ground wave serious
trouble, only 25 miles away, and I can actually see the WTIC towers!!
Here, just east of Springfield, the Ground Wave/Skywave interaction on WBZ
is SO BAD that nearly half of the nights, BZ is mostly unlistenable.
(Translation=You have to be a Radio Nut to put up with the fading &
cancellation) By the time you get east to Sturbridge, it's mostly all ground
wave, and the signal clears up. It's also much better in the Berkshires &
west.
The New York 50kw stations exhibit some interaction here in varying degrees,
but most are not as bad as BZ.
WFAN(660) and WCBS(880) have good signals here both day and night, and
neither are bothered by nightime cancellation more than 1 evening a week on
the average.
New York 1560 (old WQXR) seems to get a LOT better and has a good skywave
signal as you get towards Worcester & east & north.
Skywave signals are almost always stronger at the high end of the dial. Back
when AM was popular, the so-called "clear channel" stations at the High end
of the dial got to "even the score" for more listeners with their superior
skywave at night versus their inferior ground wave during the daytime.

The antenna design at the transmit site affects skywave and the skywave
angle as well.

Perhaps someone on the list with a good deal more engineering knowledge can
explain why one or another station may exhibit more or less of a degree of
skywave, and, why the skywave of a certain station may be evident closer in
or farther out from the TX site then another stations' , even though both
have similar power and patterns.

Here's a couple more good questions:
How close in to the TX site can skywave occur on the BCB?
Does skywave even occur at or near the TX site itself?
How close to the TX site is skywave commonly evident?
What's the closest in, anyone has noticed skywave cancellation on WBZ?
What effect does the splitting up of a former TX site into back yards for 5
different homes have on skywave from the current site?  (just kidding)

Perhaps skywave occurs much closer than we commonly experience, but is
masked by the intensity of the ground wave.
And, I'd make a bet that there's a significant difference in the answer
depending on which end of the BCB band you're at.

> >ok but not overwhelming...I theorize that between groundwave and skywave,
> >there's a reverse 'halo" in their nighttine coverage...it was
>
> That's a skip zone.
>
> Other evidence of skip zones:  My sometimes lack of reception of Radio
> Canada International;  on some frequencies, Sackville is too close, the
> signal bounces right over me.


Yes, and Radio Havana, Cuba, on 6000 and 9830, comes in good nearly every
evening in Southern New England, but it's almost undetectable evenings in
Ft. Lauderdale, Florida

Arnie Coro, CO2KK, has a Radio Program, "DXer's Unlimited" on RHC. It's
15-20 minutes in length and is on Tuesdays and Saturdays at about 8:40 and
10:40PM. The program time sometimes changes to 9:40 & 11:40PM. If you tune
in just before the half hour, they usually announce what's coming up at
around :30. The show features Ham subjects, BCB/SW/VHF DX reports, antenna
construction & radio design topics, among others.


Mark

Mark Casey, K1MAP  Hampden, Mass.
map@map.com