Topband: Topband Digest, Vol 113, Issue 8

[gw3jxn]

----- Original Message ----- 
From: <topband-request at contesting.com>
To: <topband at contesting.com>
Sent: Saturday, May 05, 2012 7:00 PM
Subject: Topband Digest, Vol 113, Issue 8


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> Today's Topics:
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>   1. Re: Fwd: radals fer 160m vertcal (Jim WA9YSD)
>   2. Re: Fwd: radals fer 160m vertcal (ZR)
>   3. Re: Fwd: radals fer 160m vertcal (Charlie Young)
>   4. Re: Fwd: radals fer 160m vertcal (Richard Fry)
>   5. Re: Fwd: radals fer 160m vertcal (James Rodenkirch)
>   6. Radials on top band (John Harden)
>   7. Re: Fwd: radals fer 160m vertcal (Mike Waters)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 5 May 2012 07:00:08 -0700 (PDT)
> From: Jim WA9YSD <wa9ysd at yahoo.com>
> Subject: Re: Topband: Fwd: radals fer 160m vertcal
> To: Top Band <topband at contesting.com>
> Message-ID:
> <1336226408.63699.YahooMailNeo at web111714.mail.gq1.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> Keep in mind this Sole purpose of a BC station is to get coverage of about 
> 60 miles running 5KW day time and 1 KW night time with no fad and quality 
> signal not to work DX.
>
> I read in some posts or on some web site that it does not matter if the 
> ends are tied to a ground rod or not.??Note then ends not at the base of 
> the vertical.
>
> My backyard is only 35 by 36 feet.??You guys only think you have a small 
> back yard.??Compare it with this one.
>
> The City water pipe system sure works as the good ground I guess so does 
> the neighbors plumbing cause their house in only 8 feet from mine :-)
>
> Jim K9TF
> ?
> Stay on course, fight a good fight, and keep the faith.?Jim K9TF/WA9YSD
>
> ------------------------------
>
> Message: 2
> Date: Sat, 5 May 2012 10:34:06 -0400
> From: "ZR" <zr at jeremy.mv.com>
> Subject: Re: Topband: Fwd: radals fer 160m vertcal
> To: "Richard Fry" <rfry at adams.net>, <topband at contesting.com>
> Message-ID: <F637FEFE70F444C692A62D16142B015F at computer1>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=original
>
> There have been several reports of established AM stations that the FCC 
> gave
> permission to replace a decayed or destroyed inground radial system with
> elevated radials or an elevated mesh/radial arrangement.
>
> In all the cases I read the FS measurements exceed the original and power
> had to be reduced to the original level.
>
> Carl
> KM1H
>
>
> ----- Original Message ----- 
> From: "Richard Fry" <rfry at adams.net>
> To: <topband at contesting.com>
> Sent: Saturday, May 05, 2012 8:07 AM
> Subject: Re: Topband: Fwd: radals fer 160m vertcal
>
>
>> James Rodenkirch wrote:
>>>What about radials above the ground?
>>
>> This link http://www.commtechrf.com/documents/nab1995.pdf leads to a 
>> paper
>> by Clarence Beverage with some real-world results for monopoles with
>> elevated wires used as a counterpoise.   Here is a quote from it:
>>
>>
>> \ \The antenna system consisted of a lightweight, 15 inch face tower, 120
>> feet in height, with a base insulator at the 15 foot elevation and six
>> elevated radials, a quarter wave in length, spaced evenly around the 
>> tower
>> and elevated 15 feet above the ground. The radials were fully insulated
>> from
>> ground and supported at the ends by wooden tripods.
>>
>> Power was fed to the system through a 200 foot length of coaxial cable
>> with
>> the cable shield connected to the shunt element of the T network and to
>> the
>> elevated radials. A balun or RF choke on the feedline was not employed 
>> and
>> the feedline was isolated from the lower section of the tower. The system
>> operated on 1580 kHz at a power of 750 watts.
>>
>> The efficiency of the antenna was determined by radial field intensity
>> measurements along 12 radials extending out to a distance of up to 85
>> kilometers. The measured RMS efficiency was 287 mV/m for 1 kW, at one
>> kilometer, which is the same measured value as would be expected for a
>> 0.17
>> wave tower above 120 buried radials. / /
>>
>>
>> So while such "elevated" installations are rare for AM broadcast 
>> stations,
>> their performance has been measured to be about the same as when using an
>> r-f ground consisting of 120 buried wires, each 1/4-wave long (free space
>> length).
>>
>> These elevated systems are readily modeled using NEC-2.  However the
>> radiation patterns shown by a typical NEC far-field analysis do not
>> accurately show the fields actually "launched" by them, or by any 
>> vertical
>> radiator with its base near the earth, because they do not include the
>> surface wave.
>>
>> The fields radiated in and near the horizontal plane by any vertical
>> monopole of 5/8 wavelength height and less are the greatest fields it
>> radiates in the entire elevation plane, regardless of earth conductivity.
>> Those fields from very low elevation angles (say, less then 5 degrees) 
>> can
>> reach the ionosphere, and under the right conditions return to the earth
>> as
>> a useful skywave.
>>
>> The link below illustrates this concept.
>>
>> http://i62.photobucket.com/albums/h85/rfry-100/Space_Surface_Wave_Compare.gif
>>
>>
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>>
>>
>> -----
>> No virus found in this message.
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>>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sat, 5 May 2012 09:50:31 -0500
> From: Charlie Young <weeksmgr at hotmail.com>
> Subject: Re: Topband: Fwd: radals fer 160m vertcal
> To: <rfry at adams.net>, <topband at contesting.com>
> Message-ID: <SNT121-W31A9696DD0956B08138ADAD82D0 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> Dick, thanks very much for posting the link for the Beverage elevated 
> counterpoise article.   Very interesting reading.
>
> Also thanks for the surface wave vs skywave graphic.
>
>
> 73 Chas N8RR
>
>
>> From: rfry at adams.net
>> To: topband at contesting.com
>> Date: Sat, 5 May 2012 07:07:11 -0500
>> Subject: Re: Topband: Fwd: radals fer 160m vertcal
>>
>> James Rodenkirch wrote:
>> >What about radials above the ground?
>>
>> This link http://www.commtechrf.com/documents/nab1995.pdf leads to a 
>> paper
>> by Clarence Beverage with some real-world results for monopoles with
>> elevated wires used as a counterpoise. Here is a quote from it:
>>
>>
>> \ \The antenna system consisted of a lightweight, 15 inch face tower, 120
>> feet in height, with a base insulator at the 15 foot elevation and six
>> elevated radials, a quarter wave in length, spaced evenly around the 
>> tower
>> and elevated 15 feet above the ground. The radials were fully insulated 
>> from
>> ground and supported at the ends by wooden tripods.
>>
>> Power was fed to the system through a 200 foot length of coaxial cable 
>> with
>> the cable shield connected to the shunt element of the T network and to 
>> the
>> elevated radials. A balun or RF choke on the feedline was not employed 
>> and
>> the feedline was isolated from the lower section of the tower. The system
>> operated on 1580 kHz at a power of 750 watts.
>>
>> The efficiency of the antenna was determined by radial field intensity
>> measurements along 12 radials extending out to a distance of up to 85
>> kilometers. The measured RMS efficiency was 287 mV/m for 1 kW, at one
>> kilometer, which is the same measured value as would be expected for a 
>> 0.17
>> wave tower above 120 buried radials. / /
>>
>>
>> So while such "elevated" installations are rare for AM broadcast 
>> stations,
>> their performance has been measured to be about the same as when using an
>> r-f ground consisting of 120 buried wires, each 1/4-wave long (free space
>> length).
>>
>> These elevated systems are readily modeled using NEC-2. However the
>> radiation patterns shown by a typical NEC far-field analysis do not
>> accurately show the fields actually "launched" by them, or by any 
>> vertical
>> radiator with its base near the earth, because they do not include the
>> surface wave.
>>
>> The fields radiated in and near the horizontal plane by any vertical
>> monopole of 5/8 wavelength height and less are the greatest fields it
>> radiates in the entire elevation plane, regardless of earth conductivity.
>> Those fields from very low elevation angles (say, less then 5 degrees) 
>> can
>> reach the ionosphere, and under the right conditions return to the earth 
>> as
>> a useful skywave.
>>
>> The link below illustrates this concept.
>>
>> http://i62.photobucket.com/albums/h85/rfry-100/Space_Surface_Wave_Compare.gif
>>
>>
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
>
> ------------------------------
>
> Message: 4
> Date: Sat, 5 May 2012 09:57:53 -0500
> From: "Richard Fry" <rfry at adams.net>
> Subject: Re: Topband: Fwd: radals fer 160m vertcal
> To: "ZR" <zr at jeremy.mv.com>, <topband at contesting.com>
> Message-ID: <48160BBF32D34941B2939C7D44EEC6C4 at ToshLaptop>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
> reply-type=response
>
> Carl KM1H wrote:
>> There have been several reports of established AM stations that the FCC
>> gave permission to replace a decayed or destroyed inground radial system
>> with elevated radials or an elevated mesh/radial arrangement.
>>
>> In all the cases I read the FS measurements exceed the original and power
>> had to be reduced to the original level.
>
> The FCC requires minimum "efficiencies" for the radiators of various 
> classes
> of licensed AM broadcast stations, expressed as the r.m.s. field intensity
> of the ground wave produced at 1 km for 1 kW of power applied to the 
> antenna
> system.  The FCC doesn't have an upper limit for AM broadcast field
> intensities except when a directional radiation pattern is required.
>
> For an example of the non-directional case, there are stations licensed 
> for
> 1 kW on 1400 kHz that use 1/2-wave monopoles instead of 1/4-wave (or
> shorter) monopoles.  Such stations using 1/2-wave monopoles still use 1 kW
> transmitters, produce higher fields at all distances, and have larger 
> useful
> groundwave coverage areas than those using 1/4-wave and shorter monopoles.
> This is all perfectly legal.
>
>
>
> ------------------------------
>
> Message: 5
> Date: Sat, 5 May 2012 09:12:18 -0600
> From: James Rodenkirch <rodenkirch_llc at msn.com>
> Subject: Re: Topband: Fwd: radals fer 160m vertcal
> To: <rfry at adams.net>, <topband at contesting.com>
> Message-ID: <SNT137-W17B94AC6B37214734AACD0F02D0 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> Thank you, Richard, fore passing the paper on....looks like I won't 
> "suffer" by having elevated radials in the least.  Jim R. K9JWV
>
>
>
> > From: rfry at adams.net
>> To: topband at contesting.com
>> Date: Sat, 5 May 2012 07:07:11 -0500
>> Subject: Re: Topband: Fwd: radals fer 160m vertcal
>>
>> James Rodenkirch wrote:
>> >What about radials above the ground?
>>
>> This link http://www.commtechrf.com/documents/nab1995.pdf leads to a 
>> paper
>> by Clarence Beverage with some real-world results for monopoles with
>> elevated wires used as a counterpoise.   Here is a quote from it:
>>
>>
>>  \ \The antenna system consisted of a lightweight, 15 inch face tower, 
>> 120
>> feet in height, with a base insulator at the 15 foot elevation and six
>> elevated radials, a quarter wave in length, spaced evenly around the 
>> tower
>> and elevated 15 feet above the ground. The radials were fully insulated 
>> from
>> ground and supported at the ends by wooden tripods.
>>
>> Power was fed to the system through a 200 foot length of coaxial cable 
>> with
>> the cable shield connected to the shunt element of the T network and to 
>> the
>> elevated radials. A balun or RF choke on the feedline was not employed 
>> and
>> the feedline was isolated from the lower section of the tower. The system
>> operated on 1580 kHz at a power of 750 watts.
>>
>> The efficiency of the antenna was determined by radial field intensity
>> measurements along 12 radials extending out to a distance of up to 85
>> kilometers. The measured RMS efficiency was 287 mV/m for 1 kW, at one
>> kilometer, which is the same measured value as would be expected for a 
>> 0.17
>> wave tower above 120 buried radials. / /
>>
>>
>> So while such "elevated" installations are rare for AM broadcast 
>> stations,
>> their performance has been measured to be about the same as when using an
>> r-f ground consisting of 120 buried wires, each 1/4-wave long (free space
>> length).
>>
>> These elevated systems are readily modeled using NEC-2.  However the
>> radiation patterns shown by a typical NEC far-field analysis do not
>> accurately show the fields actually "launched" by them, or by any 
>> vertical
>> radiator with its base near the earth, because they do not include the
>> surface wave.
>>
>> The fields radiated in and near the horizontal plane by any vertical
>> monopole of 5/8 wavelength height and less are the greatest fields it
>> radiates in the entire elevation plane, regardless of earth conductivity.
>> Those fields from very low elevation angles (say, less then 5 degrees) 
>> can
>> reach the ionosphere, and under the right conditions return to the earth 
>> as
>> a useful skywave.
>>
>> The link below illustrates this concept.
>>
>> http://i62.photobucket.com/albums/h85/rfry-100/Space_Surface_Wave_Compare.gif
>>
>>
>> _______________________________________________
>> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
>
> ------------------------------
>
> Message: 6
> Date: Sat, 05 May 2012 13:02:26 -0400
> From: John Harden <jhdmd at bellsouth.net>
> Subject: Topband: Radials on top band
> To: topband at contesting.com
> Message-ID: <4FA55D22.6030408 at bellsouth.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I can work anything I can hear on 160. That's the whole deal... If I
> can't hear it on the Hi-Z 4-square I can't work it......
>
> I have a 45G 100 foot tower shunt fed with an Omega match of vacuum
> variables. I am always flat as the variable to ground is motor driven. I
> have 32 radials..... At this point the curve starts to become
> asymptotic. But, I still plan to add 32 more before the next top band
> season....
>
> I've really enjoyed hearing all of the theory. It is in the books...all
> of it...
>
> I have one book here entitled "Electromagnetics" by the late John Krause
> (W8JK, SK) of the EE department of Ohio State Univ. The book has all of
> the theory (if you can do calculus and differential equations) to
> substantiate the fact that 120 radials is optimal.... He goes way beyond
> opinions and assertions. All of his statements are guided by double
> blind scientific studies..
>
> I had a quiz question at GA Tech eons ago. The question was "why is the
> sky blue"? You couldn't BS those guys there. It took 5 pages of calculus
> to answer it... It had to do with electrons going from one energy level
> to another....
>
> Go get 'em on top band..
>
> 73,
>
> John, W4NU
> K4JAG (1959 to 1998)
>
>
>
>
> ------------------------------
>
> Message: 7
> Date: Sat, 5 May 2012 13:33:35 -0500
> From: Mike Waters <mikewate at gmail.com>
> Subject: Re: Topband: Fwd: radals fer 160m vertcal
> To: topband <topband at contesting.com>
> Message-ID:
> <CA+FxYXicETxooHVBnLm__5vDkcAKEFerR74v1542L5ztXkVJtg at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Thanks for the wisdom, Rich. :-)
>
> However, I've always wondered about the following statement. My question
> is, on what amateur bands is this common? And on what amateur bands is 
> this
> possible?
>
> On Sat, May 5, 2012 at 7:07 AM, Richard Fry <rfry at adams.net> wrote:
>
>> Those fields from very low elevation angles (say, less then 5 degrees) 
>> can
>> reach the ionosphere, and under the right conditions return to the earth 
>> as
>> a useful skywave.
>>
>
> 73, Mike
> www.w0btu.com
>
>
> ------------------------------
>
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> End of Topband Digest, Vol 113, Issue 8
> ***************************************