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SFO soil conductivity
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Jim W
Oct 16, 2011, 1:59:36 PM10/16/11
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When I look at the SFO area soil conductivity charts I am envious, 8, 15,
30.
In the New York area about the best we have is 4 upstate New York and New
Jersey.
Western Connecticut comes in at 1, and Long Island as well as northern New
Hampshire show a rousing .05.
At what level does that become non-conductivity vs. conductivity?
30.
In the New York area about the best we have is 4 upstate New York and New
Jersey.
Western Connecticut comes in at 1, and Long Island as well as northern New
Hampshire show a rousing .05.
At what level does that become non-conductivity vs. conductivity?
Phil Kane
Oct 16, 2011, 6:08:16 PM10/16/11
to
On Sun, 16 Oct 2011 13:59:36 -0400, "Jim W" <4j...@att.net> wrote:
>In the New York area about the best we have is 4 upstate New York and New
>Jersey.
I'm sure that the Jersey Swamps, now called the Meadowlands, where
>In the New York area about the best we have is 4 upstate New York and New
>Jersey.
many of the NYC AM directional antennas are, have a much higher
conductivity. That's what happens when one relies on the chart.
--
Phil Kane
Beaverton, OR
David Kaye
Oct 17, 2011, 12:32:08 AM10/17/11
to
"Jim W" <4j...@att.net> wrote
> When I look at the SFO area soil conductivity charts I am envious, 8, 15,
> 30.
Depends depends depends. The Bay Area has microclimates where it could be
90 in Walnut Creek and 55 in SF at exactly the same time. Well, soil in
this region has sort of microclimates, too. SF is sandy and is fraught with
lots of covered creeks and rivers. A few years ago after a rainstorm, part
of 16th Street at Valencia fell into Mission Creek, which runs beneath the
street.
And yet, 30 miles away in Concord, the soil conductivity under KWUN's AM
antennas was so bad (a 1 or 2 痠ho as I remember, even though the FCC map
shows it as a 15) that they had to install a second set of ground radials
above the ground to improve the station's groundwave! I'd never seen such
an installation before.
> When I look at the SFO area soil conductivity charts I am envious, 8, 15,
> 30.
90 in Walnut Creek and 55 in SF at exactly the same time. Well, soil in
this region has sort of microclimates, too. SF is sandy and is fraught with
lots of covered creeks and rivers. A few years ago after a rainstorm, part
of 16th Street at Valencia fell into Mission Creek, which runs beneath the
street.
And yet, 30 miles away in Concord, the soil conductivity under KWUN's AM
antennas was so bad (a 1 or 2 痠ho as I remember, even though the FCC map
shows it as a 15) that they had to install a second set of ground radials
above the ground to improve the station's groundwave! I'd never seen such
an installation before.
Dave Barnett
Oct 17, 2011, 10:39:22 AM10/17/11
to
On 10/16/2011 10:59 AM, Jim W wrote:
> When I look at the SFO area soil conductivity charts I am envious, 8, 15,
> 30.
>
I guess it's still "grass is greener" (literally) syndrome. I remember
> When I look at the SFO area soil conductivity charts I am envious, 8, 15,
> 30.
>
growing up in South Dakota, where the 5 KW from WNAX would stop the
"scan" function on car radios 200 miles away. I then moved to Quincy,
Illinois and wondered why the Chicago stations were so weak. Seems like
50 KW should be stronger here... California is even worse.
So it's all a matter of perspective, I guess.
Dave B.
Steve O
Oct 18, 2011, 4:46:50 PM10/18/11
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On Oct 17, 7:39 am, Dave Barnett <dave.dbarnet...@SPAMgmail.com>
wrote:
What is the highest conductivity rating 100?
wrote:
Mark Roberts
Oct 19, 2011, 10:53:28 PM10/19/11
to
Steve O <st...@chooseone.net> had written:
| On Oct 17, 7:39?am, Dave Barnett <dave.dbarnet...@SPAMgmail.com>
| > Illinois and wondered why the Chicago stations were so weak. ?Seems like
| > 50 KW should be stronger here... ?California is even worse.
Having lived in Iowa and Missouri, I'm a little surprised at what
Dave reported about Quincy. There's a nice pocket of highly conductive
soil in central Illinois that, in my experience, channels the
Chicago AMs downstate nicely. WNAX benefits from a low dial
position (570 kHz). I've heard it at high noon in downtown Columbia, Mo.
(electrical noise capital of the universe) in the winter; cold
temperatures and snow cover enhance conductivity. Comparable
stations in that general region are KWMT Fort Dodge, IA (540),
KTRS St. Louis (550), WIBW Topeka, KS (580), and KCSP (ex-WDAF, 610),
Kansas City -- all with 5 kW signals in the daytime that cover
as well as 50 kW signals on higher frequencies.
This part of California, to me, seems about comparable to parts of
Missouri, ranging from 8 to 15 millimhos. The challenge in the
Bay Area is that there are no daytimers and, perhaps, the rocky
ridges such as the Berkeley and Oakland hills aren't are
conductive as the FCC map shows.
| What is the highest conductivity rating 100?
Sea water. The FCC map in 47 CFR 73 assumes a value of 5000
millimhos (a mho, ohm spelled backwards, is a reciprocal of
resistance/impedance). No doubt that's one reason there are
so many AM transmitter sites near the bay.
--
Mark Roberts - E-Mail address is valid but I don't use Google Groups
If you quote, please quote only relevant passages and not the whole article.
| On Oct 17, 7:39?am, Dave Barnett <dave.dbarnet...@SPAMgmail.com>
| wrote:
| > On 10/16/2011 10:59 AM, Jim W wrote:> When I look at the SFO area soil conductivity charts I am envious, 8, 15,
| > > 30.
| >
| > I guess it's still "grass is greener" (literally) syndrome. ?I remember
| > On 10/16/2011 10:59 AM, Jim W wrote:> When I look at the SFO area soil conductivity charts I am envious, 8, 15,
| > > 30.
| >
| > growing up in South Dakota, where the 5 KW from WNAX would stop the
| > "scan" function on car radios 200 miles away. ?I then moved to Quincy,
| > Illinois and wondered why the Chicago stations were so weak. ?Seems like
| > 50 KW should be stronger here... ?California is even worse.
Having lived in Iowa and Missouri, I'm a little surprised at what
Dave reported about Quincy. There's a nice pocket of highly conductive
soil in central Illinois that, in my experience, channels the
Chicago AMs downstate nicely. WNAX benefits from a low dial
position (570 kHz). I've heard it at high noon in downtown Columbia, Mo.
(electrical noise capital of the universe) in the winter; cold
temperatures and snow cover enhance conductivity. Comparable
stations in that general region are KWMT Fort Dodge, IA (540),
KTRS St. Louis (550), WIBW Topeka, KS (580), and KCSP (ex-WDAF, 610),
Kansas City -- all with 5 kW signals in the daytime that cover
as well as 50 kW signals on higher frequencies.
This part of California, to me, seems about comparable to parts of
Missouri, ranging from 8 to 15 millimhos. The challenge in the
Bay Area is that there are no daytimers and, perhaps, the rocky
ridges such as the Berkeley and Oakland hills aren't are
conductive as the FCC map shows.
| What is the highest conductivity rating 100?
millimhos (a mho, ohm spelled backwards, is a reciprocal of
resistance/impedance). No doubt that's one reason there are
so many AM transmitter sites near the bay.
--
Mark Roberts - E-Mail address is valid but I don't use Google Groups
If you quote, please quote only relevant passages and not the whole article.
joewo
Oct 21, 2011, 2:04:30 AM10/21/11
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