----- Original Message ----- From: <topband-requ...@contesting.com> To: <topband@contesting.com> Sent: Saturday, May 05, 2012 7:00 PM Subject: Topband Digest, Vol 113, Issue 8
> Send Topband mailing list submissions to > topband@contesting.com > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.contesting.com/mailman/listinfo/topband > or, via email, send a message with subject or body 'help' to > topband-requ...@contesting.com > > You can reach the person managing the list at > topband-ow...@contesting.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Topband digest..." > > > Today's Topics: > > 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 <wa9...@yahoo.com> > Subject: Re: Topband: Fwd: radals fer 160m vertcal > To: Top Band <topband@contesting.com> > Message-ID: > <1336226408.63699.yahoomail...@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" <z...@jeremy.mv.com> > Subject: Re: Topband: Fwd: radals fer 160m vertcal > To: "Richard Fry" <r...@adams.net>, <topband@contesting.com> > Message-ID: <F637FEFE70F444C692A62D16142B015F@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" <r...@adams.net> > To: <topband@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. >> Checked by AVG - www.avg.com >> Version: 10.0.1424 / Virus Database: 2411/4978 - Release Date: 05/04/12 >> > > > > ------------------------------ > > Message: 3 > Date: Sat, 5 May 2012 09:50:31 -0500 > From: Charlie Young <weeks...@hotmail.com> > Subject: Re: Topband: Fwd: radals fer 160m vertcal > To: <r...@adams.net>, <topband@contesting.com> > Message-ID: <snt121-w31a9696dd0956b08138adad8...@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: r...@adams.net >> To: topband@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" <r...@adams.net> > Subject: Re: Topband: Fwd: radals fer 160m vertcal > To: "ZR" <z...@jeremy.mv.com>, <topband@contesting.com> > Message-ID: <48160BBF32D34941B2939C7D44EEC6C4@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_...@msn.com> > Subject: Re: Topband: Fwd: radals fer 160m vertcal > To: <r...@adams.net>, <topband@contesting.com> > Message-ID: <snt137-w17b94ac6b37214734aacd0f0...@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: r...@adams.net >> To: topband@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 <jh...@bellsouth.net> > Subject: Topband: Radials on top band > To: topband@contesting.com > Message-ID: <4fa55d22.6030...@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 <mikew...@gmail.com> > Subject: Re: Topband: Fwd: radals fer 160m vertcal > To: topband <topband@contesting.com> > Message-ID: > <ca+fxyxicetxoohvbnlm__5vdkcakeferr74v1542l5ztxkv...@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 <r...@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 > > > ------------------------------ > > _______________________________________________ > Topband mailing list > Topband@contesting.com > http://lists.contesting.com/mailman/listinfo/topband > > > End of Topband Digest, Vol 113, Issue 8 > *************************************** _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK