Re: Topband: The Quest to save AM radio
Unlikely to ever get past the starting gate as AM Broadcast is a worldwide allocation and I'd think that many other nations have an opinion on this. 73 Bob k2euh Mike Armstrong armst...@aol.com wrote: Brad, *I* say GOOD, let them kill AM broadcast and give the band to US. we will put it to good use he he he he. Plus, since so many people have AM broadcast receivers _ Topband Reflector _ Topband Reflector
Re: Topband: More anecdotal stories to cause one to stop and....
Paul Christensen, W9AC wrote: The surface wave tool most be used in conjunction with the normal modeling application to get a complete and accurate vertical profile from 0 through 90 degrees. Agreed. That a vertical monopole 5/8 wavelength and less in height, using a less than perfect ground plane has a certain takeoff angle above the horizon where radiated field is maximum is a very common (almost universal) belief of ham radio operators This is based on the use of MoM software such as NEC to model only its far-field elevation pattern. The graphic below shows a different conclusion when considering the surface wave in NEC evaluations, for the parameters shown. The NEC far-field pattern for 0.1 km shows a maximum field intensity of 590 mV/m at an elevation angle of 23 degrees (the assumed takeoff angle). It also shows that the field at an elevation angle of 5 degrees is 348 mV/m. The NEC surface-wave pattern for 0.1 km shows that the maximum field lies in the horizontal plane rather than at 23 degrees, and is about 890 mV/m rather than 590 mV/m. The surface wave analysis also shows that the field radiated toward 5-degree elevation is about 850 mV/m, rather than the 348 mV/m shown by the far-field analysis. Of course, the ratios of these fields are even greater for elevation angles below 5 degrees, and infinite in the horizontal plane. It is true that at great distances from a vertical monopole, the radiation present at low vertical angles is much less than at higher angles. But that does not mean that the greater radiation directed at low elevations __as launched by the monopole__ no longer exists. The radiation toward an elevation angle of 5 degrees shown in the surface wave plot continues in essentially a straight line, to reach the ionosphere. It is the radiation launched at these low elevation angles that can provide the greatest single-hop range and fields for skywaves reaching that range, even though its existence might be unrecognized, or disregarded. http://s24.postimg.org/6nchfpt1h/NEC_FF_vs_NF_Calcs.jpg R. Fry _ Topband Reflector
Topband: Measuring Vertical input parameters while installing radials
Eddie, LU2DKT, I read your post with great interest!...Great work there. I am very much interested in your findings report. I wish to request if you can send to me, when you find a method. Additionally I wish to request for your permission to post your data on my Blog-Website at: http://radialstaple.wordpress.com/ Currently working on a upgrade/revision at: http://www.rossradio.net/ Your valued information may then be shared with all who share our same interest in RF ground radials! Of course your data will be given acknowledgment as submitted produced by Eddie-LU2DKT. Running a ground mounted Butternut HF9V here with the addition of 130 ground radials, was a monumental improvement in both transmit receive. They say there is a point of diminished returns-however that point for me was very subtle. Looking forward to your valuable data, and hope to publish it on RossRadio RF Ground Radial site! -73- Ross, KB8NTY ++ - Original Message - From: topband-requ...@contesting.com To: topband@contesting.com Sent: Thursday, September 12, 2013 12:00 PM Subject: Topband Digest, Vol 129, Issue 20 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: Stacked verticals - followup (David Raymond) 2. The Quest to save AM radio (Ken Claerbout) 3. Re: Stacked verticals - followup (HAROLD SMITH JR) 4. Re: The Quest to save AM radio (rfoxw...@tampabay.rr.com) 5. Measuring Vertical input parameters while installing radials (Eduardo Araujo) 6. Re: More anecdotal stories to cause one to stop and (Richard Fry) -- Message: 1 Date: Tue, 10 Sep 2013 15:01:27 -0500 From: David Raymond daraym...@iowatelecom.net To: Bill Cromwell wrcromw...@gmail.com, topband@contesting.com Subject: Re: Topband: Stacked verticals - followup Message-ID: 832F1E4536934B84BE0D014FAA4516F4@radiocomputer Content-Type: text/plain; format=flowed; charset=iso-8859-1; reply-type=response We have a Franklin antenna at WHO, 1040 KHZ, here in Des Moines. I've been told it is one of the few remaining in the country. 73. . . Dave W0FLS - Original Message - From: Bill Cromwell wrcromw...@gmail.com To: topband@contesting.com Sent: Tuesday, September 10, 2013 12:34 PM Subject: Re: Topband: Stacked verticals - followup Hi Ed, The engineer at WTIC responded. That station does not have a Franklin antenna but has series fed halfwave during the day and switches in a second one at night, phased to change the radiation pattern. He also told me that their 'sister station', KDKA in Pittsburgh, does use a Franklin antenna. Some members near Pittsburgh may want to roll by for a peek at it. 73, Bill KU8H On 09/06/2013 04:13 PM, Edwin Karl wrote: There are several interesting articles if you Google Franklin Antenna they are mechanically BIG and require feeding ingenuity (hams are known for this feature ...) but are stacked verticals, note- phase the top element to avoid cancellation. If memory serves me right WTIC in Hartford phased two of these puppies, but it's been a long time ... 73! ed k0kl _ Topband Reflector _ Topband Reflector -- Message: 2 Date: Wed, 11 Sep 2013 19:29:00 -0500 (CDT) From: Ken Claerbout k...@verizon.net To: Topband@contesting.com Subject: Topband: The Quest to save AM radio Message-ID: 14507091.1201183.1378945740542.JavaMail.root@vms170033 Content-Type: text/plain; charset=UTF-8 Exactly right. Isn't small government wonderful? That's really not the problem. Many federal agencies, including the one I work at, have plenty of money and personnel. It's more a function of priorities and who sets them. Years ago when I was in a Master's program, one of the courses I took was Telecommunications Law taught at the George Mason University School of Law. It was taught by an adjunct professor who was an attorney at the FCC. I was the only engineer in the class. It was a fantastic class, the best one of the program! One of the things we looked at was expanding broadband access in the US. BPL was prominent at the time. I remember trying to make the case about its interference potential to existing services and I was basically told I hear you, your right, but you are barking up the wrong tree. It was clear many of the decisions were being made by policy types and not by people that understood its implications, especially the technical part. If BPL was going to be
Re: Topband: and KDKA
Hello Herb and all, In the early 70 I was on one of my many trips to DL land. My friend DL2VP, now SK, was an engineer at DW-TV and German Radio on 1584kHz. The final was 12kV at 80 Amps. 960kW input. The vacuum variables were bigger than trash cans. The power-supply took up a room about 12 X 15ft. They had yellow lines to stay within. I guess we could have put it on 160... 73 Price W0RI Thanks, Herb Schoenbohm, KV4FZ amps On 9/12/2013 5:05 PM, Donna Halper wrote: I have heard a number of similar stories, some of which seem to be legends or perhaps based on some kernel of truth that got exaggerated. I don't know for sure about the one Herb mentioned, because I find no reporting on it in any of the sources I've checked. We do know that in 1938, KDKA was one of 12 stations that applied to be a super-power station, like WLW, which had temporarily been allowed to use 500 kw. But KDKA withdrew its request in mid-1938, and settled for operating at 50,000 watts. In fact, as of 1940, the Pittsburgh AM station was one of the handful of stations broadcasting with 50,000 w. In mid-1942, Westinghouse advertisements still stressed the 50,000 watt transmitters in use by KDKA and other stations in the group. The only record I can find of high-powered broadcasting is on the _short-waves_-- requests for super-power were received in 1941, and the FCC permitted about 12 stations to utilize this high power. And in 1943, it was widely reported that high-powered shortwave stations were beaming pro-American news over to Europe, and Westinghouse stations were among the high-powered broadcasters doing this-- but there was no mention of KDKA in the list of shortwave stations involved; WBOS in Boston was one that did receive some press for this activity. That doesn't mean the story is false-- it just means that all of the sources to which I have access don't mention it: I even looked for reports by well-known radio columnists who generally wrote about such things. Perhaps someone with access to legal databases (which I do not have) can check to see if a lawsuit was actually filed, or if this is the stuff of legend. And just as an FYI, we also know there was a high-powered station with 250,000 watts as far back as 1925-- the Tropical Radio Telegraph Company put it on the air in Hialeah, Florida. _ Topband Reflector _ Topband Reflector
Re: Topband: More anecdotal stories to cause one to stop and....
I will preface my question by saying that I haven't worked through a problem like this in 20 years, so it's quite possible that I'm forgetting some obvious details. I'm puzzled by how this surface wave can reach the ionosphere. I believe you are saying that the standard MoM solution ignores the surface wave because, by construction, it includes only real outgoing (up) fields. Then it would seem that what you call the surface wave must be the remaining part of the complete solution, and so it must decay exponentially in the vertical direction. While this part of the total field undoubtedly makes a large contribution near the surface and relatively close to the source, a decaying solution can't be projected in a straight line and assumed to reach the ionosphere. Perhaps I am misunderstanding your terminology. Jack WS3N On Sep 12, 2013, at 9:35 AM, Richard Fry r...@adams.net wrote: Paul Christensen, W9AC wrote: The surface wave tool most be used in conjunction with the normal modeling application to get a complete and accurate vertical profile from 0 through 90 degrees. Agreed. That a vertical monopole 5/8 wavelength and less in height, using a less than perfect ground plane has a certain takeoff angle above the horizon where radiated field is maximum is a very common (almost universal) belief of ham radio operators This is based on the use of MoM software such as NEC to model only its far-field elevation pattern. The graphic below shows a different conclusion when considering the surface wave in NEC evaluations, for the parameters shown. The NEC far-field pattern for 0.1 km shows a maximum field intensity of 590 mV/m at an elevation angle of 23 degrees (the assumed takeoff angle). It also shows that the field at an elevation angle of 5 degrees is 348 mV/m. The NEC surface-wave pattern for 0.1 km shows that the maximum field lies in the horizontal plane rather than at 23 degrees, and is about 890 mV/m rather than 590 mV/m. The surface wave analysis also shows that the field radiated toward 5-degree elevation is about 850 mV/m, rather than the 348 mV/m shown by the far-field analysis. Of course, the ratios of these fields are even greater for elevation angles below 5 degrees, and infinite in the horizontal plane. It is true that at great distances from a vertical monopole, the radiation present at low vertical angles is much less than at higher angles. But that does not mean that the greater radiation directed at low elevations __as launched by the monopole__ no longer exists. The radiation toward an elevation angle of 5 degrees shown in the surface wave plot continues in essentially a straight line, to reach the ionosphere. It is the radiation launched at these low elevation angles that can provide the greatest single-hop range and fields for skywaves reaching that range, even though its existence might be unrecognized, or disregarded. http://s24.postimg.org/6nchfpt1h/NEC_FF_vs_NF_Calcs.jpg R. Fry _ Topband Reflector _ Topband Reflector
Re: Topband: and KDKA
On 9/12/2013 4:06 PM, Herb Schoenbohm wrote: It might well have been WLW instead of KDKA and according the the story I recall it had something to do with the nation's station which was WLW for sure. I think that for national defense in 1932 it was granted a 500,000 watt power level. I worked at WLWT while an EE student, and our senior class got a great tour of both WLW AM and the Crosley-run VOA site a few miles away. The 500 kW TX was still there (late 1963 or early 1964) and they fired it up into a dummy load for us (cooled by circulating water to a big pool outside). I think I remember that it was an experimental license, rarely if ever on the air. Some research might prove my memory wrong. :) 73, Jim K9YC _ Topband Reflector
Re: Topband: and KDKA
On 9/12/2013 4:06 PM, Herb Schoenbohm wrote: the nation's station which was WLW for sure Another interesting point -- WLW was a 50kW clear channel station, and one of a handful that had their frequency to themselves at night for all of North America, which is why the Commission might have considered licensing them for 500kW. As I recall, the other might have been WOAI, on 1200 kHz. 73, Jim K9YC _ Topband Reflector
