You Say "Skizzum", I Say "Sizz-um"...
Sat Dec 4 17:27:52 EST 2010
WQOM's day pattern is a three-tower modified cardioid with the
radiation maximum at 90 degrees true. IIRC, the maximum
inverse-distance field--and it's pretty broad--is ~5700 mV/m @1km,
which is equivalent to ~200 kW from the better-than half-wave towers.
If you compare 5700 mV/m with the Class B minimum of 281 mV/m/kW @
1km, the equivalent power is about 400 kW ND.
Forget about not feeding the fishes! All that power really is
necessary to deliver a competitive signal to downtown Boston because,
according to measurements taken for WAMG and (then) WBIX, the soil
conductivity east of the site is a very dramtically low 0.1 mS/m, a
value that I thought never ocurred in nature except in granite
quarries and between the skyscrapers of places like midtown Manhattan.
Apparently, the low conductivity is real east-northeast of Ashland,
The pattern has two closely spaced radiation minima at 240 and 300
degrees true. The ID field at 1 km is 281 mV/m, the equivalent of what
you'd get from those tall towers if you fed one of them with a skosh
less than 500W ND. The 240-degree minimum is the one that protects KYW
and the value was set to provide daytime-skywave protection so that no
separate critical-hours pattern is required. Between those two minima
is a tiny lobe with an ID maximum at 270 degrees of a little more than
300 mV/m @ 1km or roughly the equivalent of 1 kW ND from 1/4-wave
The five-tower night pattern runs at 2.5 kW and produces a fairly
narrow teardrop pattern centered at 90-degrees true with about 240
degrees of deeply suppressed radiation and an ID value of ~1600 mV/m
@1km at 90 degrees. I don't know WQOM's NIF. I do know that it was 8.6
mV/m back in the early '80s when the station was WGTR and the FCC had
not yet redefined NIF to include contributions from
first-adjacent-channel skywaves. The 8.6 mV/m came almost entirely
from KYW. Today it's bound to be more than a little higher (probably
more than 10 mV/m) because of the contributions from WEPN and CBA.
CBA, though dark, almost surely does not drop out of the calculation
because, by US-Canada treaty it requires protection over Canadian soil
notwithstanding that it is not operating. Anyhow, WQOM's NIF probably
does not cross Route 128.
Dan Strassberg (email@example.com)
----- Original Message -----
From: "Steve Snow" <firstname.lastname@example.org>
Sent: Monday, November 29, 2010 12:12 PM
Subject: Re: You Say "Skizzum", I Say "Sizz-um"...
> You're looking in the wrong direction to justify their claims. If
> directional pattern is anything like WRKO's
> (or others in the market) the people cited may be in Maine, New
> Rhode Island and Canada's maritimes
> depending on the co-channel and adjacent channel protections they
> need. The
> main object is to put just
> enough signal over Boston without "feeding the fishes" with extra
> signal and to put the rest somewhere
> it will do some good. Did I understand that the daytime pattern
> would be
> generated with two towers only?
> That would result in some kind of modified "figure eight" plus or
> minus some
> parasitic re-radiation from the
> other towers and the local high tension power lines. Not as neat as
> you can get with three live towers,
> I suppose. But if the FCC signed off on it... Oh, wait, I retract
>>Their website claims that the signal will reach 5.5 million people,
> the whole population of
>>Massachusetts. Considering that it will generate about 300 mv
> about the same as
>>non-directional WILD-AM at full power, this seems unlikely. Maybe
> letters could stand
>>for We Quote Outsize Metrics.
More information about the Boston-Radio-Interest