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#11
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On Mon, 05 Sep 2005 21:32:45 -0400, Walter Maxwell
wrote: Well, Danny, ya had to go and do it din't ya? Now people who see my face in post offices will know how to trace me through my mug shot you just posted. I thought I'd gotten away with it. Somebody hire you to post it? CSI? Law & Order? At least after I'm sent away to Attica everybody, including you, will be able to find me. Ya wanna know sumptin? I don't even have any remorse! Walt The devil made me do it! G Danny |
#12
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On Mon, 05 Sep 2005 22:22:37 -0400, Walter Maxwell
wrote: On Mon, 05 Sep 2005 14:25:09 -0700, Dan Richardson wrote: On Mon, 5 Sep 2005 15:31:18 -0500, (Richard Harrison) wrote: [snip] As Walter flattered me, I`ll reciprocate. Get hold of the April 1973 issue of QST. Look on page 35. Walter is pictured there. He is a real good looking fellow! [snip] If you don't have that QST handy you can see Walter he http://users.adelphia.net/~k6mhe/BLE_de_W2DU.html 73, Danny, K6MHE Danny, I was just perusing the data in the post re the above url and found a typo. In the ground radial data in the line showing 30 radials, the data for 0.4/wl indicating 158 mv/meter should read 185 mv/meter. I think you mean the line for 60 radials? Anyway I changed that one to the 185 figure. Please double check it for me. Thanks, Danny, K6MHE email: k6mheatarrldotnet http://users.adelphia.net/~k6mhe/ |
#13
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On Mon, 05 Sep 2005 19:33:38 -0700, Dan Richardson wrote:
If you don't have that QST handy you can see Walter he http://users.adelphia.net/~k6mhe/BLE_de_W2DU.html 73, Danny, K6MHE Danny, I was just perusing the data in the post re the above url and found a typo. In the ground radial data in the line showing 30 radials, the data for 0.4/wl indicating 158 mv/meter should read 185 mv/meter. I think you mean the line for 60 radials? Anyway I changed that one to the 185 figure. Please double check it for me. Thanks, Danny, K6MHE email: k6mheatarrldotnet http://users.adelphia.net/~k6mhe/ Ya done good, Danny, thanks. Walt |
#14
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"Walter Maxwell" wrote Back on the subject of radials, unless the FCC has changed the requirements since I was involved, the requirement is for 90 radials. However, most of the AM BC stations I'm familiar with use 120, even tho not required. ======================================== Walt, Has it taken 70 years for the old wives of the FCC to return to Earth, disregarding B.L & E who forgot to measure ground conductivity, not to mention permittivity, and think again about economics? ---- Reg. |
#15
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Has it taken 70 years for the old wives of the FCC to return to Earth,
disregarding B.L & E who forgot to measure ground conductivity, not to mention permittivity, and think again about economics? The only stations that the FCC is concerned about is commercial. And the reason they stick with the standard number is for stability and getting the max bang for buck, and an easily expected performance level. Buying a load of wire will beat using more transmitter power over the long run. If they use 120 radials, they know they will be getting close to maximum performance. If they don't, it's a crap shoot. 120 radials *will* outperform 16 of them. There is no question, unless they are over sea water. I'm not saying hams have to run that many. In fact, I think 60 will do for most, except the most hard core for good results. Even less for the more casual user. But I have no problems with the FCC wanting a certain level of performance for commercial stations. I have no problems seeing why they do it either. Wire is cheap compared to todays level of monthly light bill. With some stations, the radials, or lack of , in certain directions gives them a controlable pattern with no surprises in f/s over a period of time with changing ground conditions. The main thing is stability of performance over periods of time. Or thats my take anyway. MK |
#17
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MK,
How satisfying it is to read your message, written in plain, easy to understand, well-punctuated English, without any undeciferable coded abbreviations. I agree with what you say although I am unfamiliar with exactly how the FCC fits into the scheme of things. Amateurs and commercial broadcasters have a common fundamental requirement. There is a service area to be covered with a given field strength. Depending on frequency, requirements then diverge. But the design methods used to satisfy requirements are all confined (or should be) to the principles of engineering economics. Inevitably, the Dollar, Pound, Frank, Mark, Rouble and the Yen rule the roost. Both commercial broadcasters and amateurs do a cost-befit analysis. The broadcaster takes into account the revenue acruing from selling the service. The amateur, whether he likes it or not, has to ask himself what the satisfaction of using the station is worth. Amateurs' bank accounts are not unlimited. Field strength at the limits of the service area depends on the power efficiency of the radiating system. If engineering economics dictate use of a set of buried ground radials then the peformance of the ground radials must be included. Considering the system as a whole, it may be economical NOT to achieve the maximum possible radiating efficiency. Indeed, the maximum is seldom the target. If there is an economical choice in the matter, once the location of the station is decided, everybody agrees that efficiency depends on soil resistivity at the site. To estimate efficiency it is necessary, at the very least, to make a guess at soil resistivity. Perhaps just by looking at the type of weeds growing in it. Or it can be measured. Depending on how far it enters into station economics, it is possible to numerically estimate efficiency from the number and length of radials AND FROM SOIL RESISTIVITY. B.L & E and the FCC don't enter into it. ---- Reg. ======================================== MK wrote, The only stations that the FCC is concerned about is commercial. And the reason they stick with the standard number is for stability and getting the max bang for buck, and an easily expected performance level. Buying a load of wire will beat using more transmitter power over the long run. If they use 120 radials, they know they will be getting close to maximum performance. If they don't, it's a crap shoot. 120 radials *will* outperform 16 of them. There is no question, unless they are over sea water. I'm not saying hams have to run that many. In fact, I think 60 will do for most, except the most hard core for good results. Even less for the more casual user. But I have no problems with the FCC wanting a certain level of performance for commercial stations. I have no problems seeing why they do it either. Wire is cheap compared to todays level of monthly light bill. With some stations, the radials, or lack of , in certain directions gives them a controlable pattern with no surprises in f/s over a period of time with changing ground conditions. The main thing is stability of performance over periods of time. Or thats my take anyway. MK |
#18
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On Wed, 7 Sep 2005 14:07:39 +0000 (UTC), "Reg Edwards"
wrote: MK, How satisfying it is to read your message, written in plain, easy to understand, well-punctuated English, without any undeciferable coded abbreviations. I agree with what you say although I am unfamiliar with exactly how the FCC fits into the scheme of things. Amateurs and commercial broadcasters have a common fundamental requirement. There is a service area to be covered with a given field strength. Depending on frequency, requirements then diverge. But the design methods used to satisfy requirements are all confined (or should be) to the principles of engineering economics. Inevitably, the Dollar, Pound, Frank, Mark, Rouble and the Yen rule the roost. Both commercial broadcasters and amateurs do a cost-befit analysis. The broadcaster takes into account the revenue acruing from selling the service. The amateur, whether he likes it or not, has to ask himself what the satisfaction of using the station is worth. Amateurs' bank accounts are not unlimited. Field strength at the limits of the service area depends on the power efficiency of the radiating system. If engineering economics dictate use of a set of buried ground radials then the peformance of the ground radials must be included. Considering the system as a whole, it may be economical NOT to achieve the maximum possible radiating efficiency. Indeed, the maximum is seldom the target. If there is an economical choice in the matter, once the location of the station is decided, everybody agrees that efficiency depends on soil resistivity at the site. To estimate efficiency it is necessary, at the very least, to make a guess at soil resistivity. Perhaps just by looking at the type of weeds growing in it. Or it can be measured. Depending on how far it enters into station economics, it is possible to numerically estimate efficiency from the number and length of radials AND FROM SOIL RESISTIVITY. B.L & E and the FCC don't enter into it. ---- Reg. Sorry to disagree, Reg, but it appears you're overlooking an important point--the difference between the efficiency of the radiating system itself, versus the efficiency of the ground area external to the radiating system. BL&E shows that when 90 - 120 (actually 113) radials of 0,4 w/l form the ground system for a 1/4 wl radiator, the efficiency is 98.7% efficient, REGARDLESS OF THE SOIL RESISTIVITY UNDER THE RADIALS. This is shown by obtaining the field strength of 192 mv/meter at 1 mile for 1000 watts delivered to the antenna under the conditions described above, compared to 194.5 mv/meter with a perfect ground having an efficiency of 100% It is only the soil resistivity of the ground external to the radial system that determines the field stength external to the radial system. Consequently, the soil resistivity (or conductivity, if you like) is significant only in the areas external to the radial system. Walt, W2DU |
#19
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On Wed, 07 Sep 2005 11:41:33 -0400, Walter Maxwell
wrote: Sorry to disagree, Reg, but it appears you're overlooking an important point--the difference between the efficiency of the radiating system itself, versus the efficiency of the ground area external to the radiating system. Walter, my friend, you're beating a dead horse. It would appear that Reg's mind is made up and no amount factual proof is going to change it. Had BL&E been Englishmen I sure things would be different.G 73, Danny, K6MHE |
#20
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On Wed, 07 Sep 2005 09:39:28 -0700, Dan Richardson wrote:
On Wed, 07 Sep 2005 11:41:33 -0400, Walter Maxwell wrote: Sorry to disagree, Reg, but it appears you're overlooking an important point--the difference between the efficiency of the radiating system itself, versus the efficiency of the ground area external to the radiating system. Walter, my friend, you're beating a dead horse. It would appear that Reg's mind is made up and no amount factual proof is going to change it. Had BL&E been Englishmen I sure things would be different.G 73, Danny, K6MHE Good point, Danny, how true. Walt |
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