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Incoming radiation angles
Looking for a site or information on incoming
radiation angles specifically for 160 metres. 1 How is it measured ? 1a Can it discriminate between vertical and horizontal or what ever polarisation 2 What is the angles per percentage of contacts 3 Are they all horizontally polarised when subject to skip? for distances over say 1000 miles distance One well known DXer (Tom) stated on this newsgroup that a horizontal dipole at 1/2 wave length was inferior to his other antennas, but no specifics given! Appreciate any pointers on the above. Happy New Year Art |
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In message , Art Unwin
KB9MZ writes Looking for a site or information on incoming radiation angles specifically for 160 metres. 1 How is it measured ? The same way it was measured in the 20's for B/C reception. Two separated antennas at different heights feeding an oscilloscope to produce an ellipse. The phase difference between the antennas allows the angle to be calculated. Mike -- M.J.Powell |
Art, K9MZ wrote:
"---radiation angles specifically for 160 meters. 1. How is it measured?" In degrees above the horizon. It`s geometrical. The effective height of the reflecting layer above the earth has been observed for a long time and can be predicted with some accuracy, based upon location, time, solar radiation, etc. The angle of incidence is equal to the angle of reflection to a reference normal to the reflecting plane. So, low angles serve for long distances between stations, and high angles for short distances that are too distant to be reached by the groundwave. Capt. Paul H. Lee, USNR, K6TS has a chart of degrees above the horizon versus distance to the first reflection zone (a single hop) on page 11 of "Vertical Antenna Handbook", a "CQ" publication. As the height of the latyer is variable, this is an approximation based on probabilities. A 5/8-wave vertical gives optimum low-angle radiation between 3 and 27 degrees. The latter angle gets you out to about 500 miles. Lower angles get you out to about 2000 miles on one hop. Vertical antennas work with vertically polarized waves. Once the wave is reflected by the ionosphere, polarization of the reflection is more or less random. "2. What is the angles per percentage of contacts?" Depends on where your station is in respect to the majority of stations you want to contact. "3. Are they all horizontally polarized when subject to skip?" No. The ionosphere does not care what the wave polarization is. It will reflect whatever strikes it at various polarizations. It won`t maintain polarizations! You can receive via the ionosphere almost equally well, on average, with any polarization regardless of what was transmitted. Noise reception is likely worse using a vertical receiving antenna. "Tom stated on this newsgroup that a horizontal dipole at 1/2-wavelength was inferior to his other antennas---." Can`t argue with Tom`s observation about his antennas, but it does not correspond with most observations of horizontal antenna performance when you have a resonant dipole at 1/2-wave above the earth. Look at Fig 12-D on page 3-11 of the 19th edition of the ARRL Antenna Book. Maximum radiation is at 30-degrees above the horizon. From Capt. Lee`s diagram, that would get you stations as close as 500 miles, and beyond 1000 miles due to the range of strong elevation angles in the pattern. I don`t know what Ton`s problems are but suspect that he ignores some of the ground effects. He has expressed dissatisfaction with his verticals too. Vertivcals in particular are sensitive to good earth under and around the antenna. Horizontal polarization isn`t bad for HF. Most of the world`s HF commercial stations use horizontal antennas for skywave propagation. Best regards, Richard Harrison, KB5WZI |
Incoming radiation angles can be obtained by geometric calculation.
Pythagorus and all that, taking earth curvature, height of ionospheric layers, number of hops, etc, etc, into account. Then point your receiving beam into it, if it is adjustable in the vertical plane. Very non-critical. Antenna apperture angles in the vertical plane are extremely broad. The stuff often comes in from more than one angle. Interference between the different paths causes fading and distortion. An antenna will collect from all vertical angles regardles of elevation. ---- Reg =================== "Art Unwin KB9MZ" wrote in message m... Looking for a site or information on incoming radiation angles specifically for 160 metres. 1 How is it measured ? 1a Can it discriminate between vertical and horizontal or what ever polarisation 2 What is the angles per percentage of contacts 3 Are they all horizontally polarised when subject to skip? for distances over say 1000 miles distance One well known DXer (Tom) stated on this newsgroup that a horizontal dipole at 1/2 wave length was inferior to his other antennas, but no specifics given! Appreciate any pointers on the above. Happy New Year Art |
"Richard Harrison" wrote in message ... Art, K9MZ wrote: "---radiation angles specifically for 160 meters. 1. How is it measured?" In degrees above the horizon. It`s geometrical. The effective height of the reflecting layer above the earth has been observed for a long time and can be predicted with some accuracy, based upon location, time, solar radiation, etc. Where can I see these predictions for the present time? The angle of incidence is equal to the angle of reflection to a reference normal to the reflecting plane. So, low angles serve for long distances between stations, and high angles for short distances that are too distant to be reached by the groundwave. Understood Capt. Paul H. Lee, USNR, K6TS has a chart of degrees above the horizon versus distance to the first reflection zone (a single hop) on page 11 of "Vertical Antenna Handbook", a "CQ" publication. As the height of the latyer is variable, this is an approximation based on probabilities. I will pull that one out. A 5/8-wave vertical gives optimum low-angle radiation between 3 and 27 degrees. The latter angle gets you out to about 500 miles. Lower angles get you out to about 2000 miles on one hop. O.K. Vertical antennas work with vertically polarized waves. Once the wave is reflected by the ionosphere, polarization of the reflection is more or less random. Hmm, so a vertical tho low angle would miss out on horizontal polarisations which leaves a lot of unknown with respect to best antenna for Top band "2. What is the angles per percentage of contacts?" Depends on where your station is in respect to the majority of stations you want to contact. Over 1000 miles "3. Are they all horizontally polarized when subject to skip?" No. The ionosphere does not care what the wave polarization is. It will reflect whatever strikes it at various polarizations. It won`t maintain polarizations! You can receive via the ionosphere almost equally well, on average, with any polarization regardless of what was transmitted. Well I thought that kmost transmitions changed to horizontal after reflection! Noise reception is likely worse using a vertical receiving antenna. Well I am confused about that My present rotatable dipole at a 'low" height matches a beverage at 15 degrees but unfortunately the gain continues to a max at 90 degrees where as the beverage whereas the beverage nulls out the higher angles which ius why I presume it was chosen as a listening antenna. "Tom stated on this newsgroup that a horizontal dipole at 1/2-wavelength was inferior to his other antennas---." Can`t argue with Tom`s observation about his antennas, but it does not correspond with most observations of horizontal antenna performance when you have a resonant dipole at 1/2-wave above the earth. Look at Fig 12-D on page 3-11 of the 19th edition of the ARRL Antenna Book. Maximum radiation is at 30-degrees above the horizon. From Capt. Lee`s diagram, that would get you stations as close as 500 miles, and beyond 1000 miles due to the range of strong elevation angles in the pattern. I don`t know what Ton`s problems are but suspect that he ignores some of the ground effects. He has expressed dissatisfaction with his verticals too. Vertivcals in particular are sensitive to good earth under and around the antenna. Horizontal polarization isn`t bad for HF. Most of the world`s HF commercial stations use horizontal antennas for skywave propagation. Well I have put my dipole in the vertical position also which negates use of radials but I have not noticed any profound differences as yet after a few days ! This new band to me is raising a lot of questions for me that I haven't thought of before so I am at a new horizon and without the spirit level as the bubble has burst. Cheers Art band Best regards, Richard Harrison, KB5WZI |
"Reg Edwards" wrote in message ...
Incoming radiation angles can be obtained by geometric calculation. Pythagorus and all that, taking earth curvature, height of ionospheric layers, number of hops, etc, etc, into account. Then point your receiving beam into it, if it is adjustable in the vertical plane. Very non-critical. Antenna apperture angles in the vertical plane are extremely broad. The stuff often comes in from more than one angle. Interference between the different paths causes fading and distortion. An antenna will collect from all vertical angles regardles of elevation. ---- Reg =================== Interesting thing happened with the antenna last night. Had the antenna in the vertical position close to ground ( it is a truncated co linear dipole) And was prevented from joining the local group because of multiple QSOs on the same frequency! Art |
AArt, KB9MZ wrote:
"Where can I see these predictions for the present time?" Inquire of the National Institute of Science and Technology for propagation forecasts. (Your tax dollars at work) The National Bureau of Standards used to broadcast a limited amount of propagation forecasts on WWV. Haven`t listened in a long time, so don`t know what`s on WWV now. NBS also made available extensive propagation forecast information for the world, by mail, on a subscriotion basis. Best regards, Richard Harrison, KB5WZI |
Art, KB9MZ wrote:
"And was prevented from joining the local group because of nultiple QSOs on the same frequency." Single-element vertical antennas are deficient in directivity at any azimuth. They have a single null off their tips, that is toward the zenith. At HF, groundwave disappears with increasing frequency. Thus, short range communication is hindered. Best regards, Richard Harrison, KB5WZI |
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Richard Clark wrote in message
No doubt you were "prevented." They couldn't hear you! I would tend to believe this account. Small vertical antennas next to the ground with no radials, will be just a tad better than a dummy load on that band. MK |
Mark Keith wrote:
"For DX transmitting on the lower bands, vertical polarization is the best way to go." In some cases. If that were always the case, why do commercial shortwave stations all use horizontal polarization for both point-to-point service and broadcasting? During my years in shortwave broadcasting, I never saw a single vertically polarized antenna used for HF transmitting. My experience is not unique. E.A. Laport was Chief Engineer, RCA International Division of Radio Corporation of America (RCA). For many years RCA was the largest short-wave communications organization in the world. In his book, "Radio Antenna Engineering", Ed Laport says: "The earliest high-frequency beam antennas used vertical polarization, but subsequent evolution has caused the almost universal use of horizontal polarization. There may be a reversion to vertical polarization in the future for certain applications." It was natural to try vertical polarization first for directional arrays as low and medium frequencies were first exploited for radio and these had to use vertical antennas. It was uneconomical to elevate horizontal antennas to heights necessary for sky wave performance and there is no ground wave propagation of horizontally polarized waves. The directional vertical antenna had been developed early in broadcasting by Brown, Lewis, and Epstein who did their RCA development work at HF for economy and convenience. Work was already in place for the earliest vertical HF beam antennas. These only evolved into the universal horizontal polarization at HF due to real advantages. Huge investments are made in HF transmitting antenna farms. I worked in a station that had a farm of over 400 acres of HF antennas, all horizontally polarized. This was no flip of a coin decision. The decision was based on the preponderance of experience at the time. Our paths were so long that we had to consider 2-hops in addition to a single hop on most. There surely must be instances where vertical polarization proves better than horizontal, but these are exceptions, not the rule. An example might be an antenna closely surrounded by the sea. A vertical array should be ideal. Best regards, Richard Harrison, KB5WZI |
Yuri, K3BU wrote:
"Recent studies found efficiency of various polarizations based on geographical location, related to geomagnetic fields (gyrofrequency). Do antenna modelimg programs adjust for gyrofrequencies? I can readily see that soil conductivity at a geographical location would affect efficiency and perhaps the polarization choice. John H. Nelson, RCA Short-Wave Radio Propagation Analyst, found that those signals which pass through or close to the auroral zone suffer the greatest degradation. If the signal must take a great circle route over the North Polar region, problems increase. Nelson also found that propagation here on the earth correlated with the relative positions of the planets in the solar system. Be this astronomy or astrology, it allowed Nelson to make pretty good radio propagation forecasts. See: "The Propagation Wizard`s Handbook", a "73" publication by J.H. Nelson. Best regards, Richard Harrison, KB5WZI |
Richard Harrison wrote:
There surely must be instances where vertical polarization proves better than horizontal, but these are exceptions, not the rule. Vertically polarized noise is about 10 dB higher than horizontally polarized noise at my QTH rendering a vertical antenna virtually useless for receiving compared to a horizontal antenna. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil Moore wrote:
Richard Harrison wrote: There surely must be instances where vertical polarization proves better than horizontal, but these are exceptions, not the rule. Vertically polarized noise is about 10 dB higher than horizontally polarized noise at my QTH rendering a vertical antenna virtually useless for receiving compared to a horizontal antenna. Sorry, forgot to say this was on 40m. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Here's my experience.
On transmit: 160 meters: 90 foot vertical is 20 dB better than 60 ft high inv vee 80 meters: 60 foot vertical is 10 dB better than 60 ft high inv vee 40 meters: 30 foot vertical is equal to 90 ft high inv vee 20 meters: 30 foot vertical is beaten by 90 ft high inv vee about 25% of the time 15 meters and up: Any dipole trounces any vertical. On receive: 160 and 80 meters: A low dipole trounces any vertical 40 meters and up: best receive antenna is best transmit antenna Rick N6RK There surely must be instances where vertical polarization proves better than horizontal, but these are exceptions, not the rule. Vertically polarized noise is about 10 dB higher than horizontally polarized noise at my QTH rendering a vertical antenna virtually useless for receiving compared to a horizontal antenna. Sorry, forgot to say this was on 40m. -- 73, Cecil http://www.qsl.net/w5dxp - 19 Different Servers! =----- |
What distances are you talking about? DX, local, etc...
"Rick Karlquist N6RK" wrote in message news:bBDJb.48697$I07.144572@attbi_s53... Here's my experience. On transmit: 160 meters: 90 foot vertical is 20 dB better than 60 ft high inv vee 80 meters: 60 foot vertical is 10 dB better than 60 ft high inv vee 40 meters: 30 foot vertical is equal to 90 ft high inv vee 20 meters: 30 foot vertical is beaten by 90 ft high inv vee about 25% of the time 15 meters and up: Any dipole trounces any vertical. On receive: 160 and 80 meters: A low dipole trounces any vertical 40 meters and up: best receive antenna is best transmit antenna Rick N6RK There surely must be instances where vertical polarization proves better than horizontal, but these are exceptions, not the rule. Vertically polarized noise is about 10 dB higher than horizontally polarized noise at my QTH rendering a vertical antenna virtually useless for receiving compared to a horizontal antenna. Sorry, forgot to say this was on 40m. -- 73, Cecil http://www.qsl.net/w5dxp - 19 Different Servers! =----- |
What distances are you talking about? DX, local, etc...
"Rick Karlquist N6RK" wrote in message news:bBDJb.48697$I07.144572@attbi_s53... Here's my experience. On transmit: 160 meters: 90 foot vertical is 20 dB better than 60 ft high inv vee 80 meters: 60 foot vertical is 10 dB better than 60 ft high inv vee 40 meters: 30 foot vertical is equal to 90 ft high inv vee 20 meters: 30 foot vertical is beaten by 90 ft high inv vee about 25% of the time 15 meters and up: Any dipole trounces any vertical. On receive: 160 and 80 meters: A low dipole trounces any vertical 40 meters and up: best receive antenna is best transmit antenna Rick N6RK There surely must be instances where vertical polarization proves better than horizontal, but these are exceptions, not the rule. Vertically polarized noise is about 10 dB higher than horizontally polarized noise at my QTH rendering a vertical antenna virtually useless for receiving compared to a horizontal antenna. Sorry, forgot to say this was on 40m. -- 73, Cecil http://www.qsl.net/w5dxp - 19 Different Servers! =----- |
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This is a S+N/N problem, not propagation. It is not like the magnetic pole is sucking signals into the ground. What the pole IS attracting is the ionic flow from the sun's emissions which create a plasma of noise. 73's Richard Clark, KB7QHC On 160 and 80 during disturbed conditions (aurora, etc.) signals are skewed by as much as 90 deg from their short path directions. So it is not sucking but blowing signals away from the disturbed region. Maybe sucking too, I haven't been up there to see it. It is not just noise problem. Some outrageous propagation stuff is in my old article at http://members.aol.com/ve3bmv/bmvpropagation.htm Yuri, K3BU, VE3BMV |
Mark
I do believe that where the feed point is will make all the difference in the world. A similar feed point up in the air but feeding colinear verticals even tho they may be truncated will blow that thought away! Regards Art "Mark Keith" wrote in message om... Richard Clark wrote in message No doubt you were "prevented." They couldn't hear you! I would tend to believe this account. Small vertical antennas next to the ground with no radials, will be just a tad better than a dummy load on that band. MK |
Richard Clark wrote:
"The "earliest high frequency antennas" were in fact BCB." Yes, but not in Ed Laport`s book. Ed`s book covers LF, MF, and HF. Ed as Chief Engineer of RCA International was most interested in RCA`s maritime service, radiograms, shortwave broadcast, and radio relay services. These were conducted above 1700 KHz. Ed observes that HF propagation is a statistical business, as the ionosphere is always in flux. Ed gives guidance in using the NBS Central Radio Propagation Lab publications, hardly the advice of someone stuck in low gear. Ed gives some of the most complete information to be found on horizontal rhombics and rhombic arrays, hardly the advice of someone treating the use of low frequencies. Richard Clark wrote: "And guess what, they (earliest high frequency antennas) are still Vertical antennas. I agree that 1.7 MHz is medium wave as the break is often chosen as 3MHz. I also agree that MW broadcasting antennas are universally vertically polarized. The primary service area of a MW broadcast station is defined by the FCC as the area well served by the ground wave. Of course vertical polarized antennas are used because horizontal polarization produces no ground wave. Art Unwin started this thread it seems because he faulted a vertical antenna for not having a 100-mile range using low power. The vertical has a null overhead almost guaranteeing no short-hop sky wave. Low power obviates ground wave DX. To make an evening sky wave trip of 100 miles at 160 meters, Art needs an antenna with a lot of high-angle radiation, 60 or 70-degrees more or less to use the ionosphere for short skip, or he needs enough effective power to punch a signal through along the ground. A horizontal dipole could provide the high-angle radiation for the sky wave. A vertical antenna could provide the ground wave signal which only needs enough power to work day or night. A 1/4-wave vertical antenna can produce an unattenuated field strength at the earth`s surface of about 195 mV/m at one mile. At 100 miles, the field strength is 1%, or about 2 mV/m.. Depending on the soil conductivity, the actual signal reaching a receiver at 100 miles is likely much less than the unattenuated value. In a quiet location, not much signal is needed. Best regards, Richard Harrison, KB5WZI |
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Let me clarify this statement so that we are on the same page.
I was hearing several conversations going on the same frequency. Those conversing obviously were oblivious to other users on the frequency because of propergation or the peculiarities of my antenna. I refrained from entering into conversation with the local group because by joining one group would have caused problems for other groups on the same frequency. On reflection it would appear that the horizontal dipole gave low angle TOA all the way thru 90 degrees. Thus this is inferior to a vertical that captures the low angles and descriminates against the high angles plus inferior to a poor vertical that discriminates against low angles. This just shows how much ground effect controls the verticals but only to a much lower extent on horizontally polarised signals with respect to selectivity.With respect to noise it does not affect me to much in the comparison because of the use of a Faraday shield. Regards Art "Art Unwin KB9MZ" wrote in message m... "Reg Edwards" wrote in message ... Incoming radiation angles can be obtained by geometric calculation. Pythagorus and all that, taking earth curvature, height of ionospheric layers, number of hops, etc, etc, into account. Then point your receiving beam into it, if it is adjustable in the vertical plane. Very non-critical. Antenna apperture angles in the vertical plane are extremely broad. The stuff often comes in from more than one angle. Interference between the different paths causes fading and distortion. An antenna will collect from all vertical angles regardles of elevation. ---- Reg =================== Interesting thing happened with the antenna last night. Had the antenna in the vertical position close to ground ( it is a truncated co linear dipole) And was prevented from joining the local group because of multiple QSOs on the same frequency! Art |
" Art Unwin KB9MZ" wrote in message news:9LFJb.49578$I07.153955@attbi_s53...
Mark I do believe that where the feed point is will make all the difference in the world. A similar feed point up in the air but feeding colinear verticals even tho they may be truncated will blow that thought away! Regards Art I doubt it. I use fairly large antennas on that band and still don't come close to many of the "big strappers" on that band. I've got a full size inv L, about 45 ft vertical, and also a 42 ft top loaded vertical. The top loading consists of four 60 ft wires. Current up the vertical section is nearly constant on that antenna. I bet that simple antenna will truncate your short collinear verticals in any direction, and even it's nothing to really get excited about. MK |
" Art Unwin KB9MZ" wrote in message news:acKJb.51720$xX.290427@attbi_s02...
Let me clarify this statement so that we are on the same page. On reflection it would appear that the horizontal dipole gave low angle TOA all the way thru 90 degrees. ??? 90 degrees is straight up. NO low horizontal dipole will have very good low angle performance on that band. Trust me. I used a full size Z dipole for two years,"01-02" and ended up yanking it down. Good for close in local stuff. Pitiful for lower angle far off stuff. Thus this is inferior to a vertical that captures the low angles and descriminates against the high angles plus inferior to a poor vertical that discriminates against low angles. How is it inferior? It's just different. You choose the antenna to match the path you want to work. If you are going to talk 100-150 miles away, yes a low dipole will work pretty well, maybe the best. But so will an inv L, or even my top loaded vertical will usually do fine also. The L will usually be the better of the verticals close if it's up and down sky wave, as it has more horizontal componant. My loaded vertical has an overhead null. Even still, many times, even just 200 miles away, my loaded vertical is better than the L. Actually, the loaded vertical beats the L probably 90% of the time. Even fairly close. Farther off paths? The dipoles I had were poor at best. The vertical is the only way to go in that case for a simple antenna. Remember, my dipole was at maybe 35-40 ft. Thats like a 80m dipole at 15-20 ft off the ground. Will be poor for long distance use. Of course, using ground wave, the loaded vertical is king of the hill here... This just shows how much ground effect controls the verticals but only to a much lower extent on horizontally polarised signals with respect to selectivity. ?? With respect to noise it does not affect me to much in the comparison because of the use of a Faraday shield. ?? Shield for what? You? MK |
"Rick Karlquist N6RK" wrote in message news:bBDJb.48697$I07.144572@attbi_s53...
Here's my experience. On transmit: 160 meters: 90 foot vertical is 20 dB better than 60 ft high inv vee 80 meters: 60 foot vertical is 10 dB better than 60 ft high inv vee 40 meters: 30 foot vertical is equal to 90 ft high inv vee Sounds about right, but try the 90 ft dipole against a 1/4 wave ground plane mounted say at 55-60 ft. :) "That makes the overall height about the same.. I bet the vertical trounces the dipole. 20 meters: 30 foot vertical is beaten by 90 ft high inv vee about 25% of the time I usually prefer the dipole on this band... 15 meters and up: Any dipole trounces any vertical. Have to disagree here though. I've had numerous 10m verticals that beat any dipole I tried on most low angles...Same for 17m, when I used an elevated 5/8 ground plane at 36 ft. Dogged all my other antennas. On receive: 160 and 80 meters: A low dipole trounces any vertical Not sure on this one...I assume you see this due to a better s/n ratio with the dipole...Overall, I don't totally agree with this one though...I think it's reciprical. Which ever transmits best, usually receives best in what I see here. I often receive using the vertical. But I don't have any fancy receive antennas like beverages, or small phased verticals, etc.. 40 meters and up: best receive antenna is best transmit antenna I agree..Actually, I think this is really the case on any band, not counting any s/n problems with a certain antenna on receive. I'm a firm believer in reciprical operation. Only in a very few cases will that not pan out. No matter what band I'm on, I usually transmit on the antenna that receives the best. Very, very rarely is it not also the best transmit antenna. MK |
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When both antennas have about the same height at their centres -
A half-wave vertical is better at low elevation angles. A half-wave horizontal dipole is better at high elevation angles. There's nothing at all to choose between them at 45 degrees. For each of the following factors allow a predicting uncertainty of +/- 1/2 S-unit - MF, HF, sun-spot cycle numbers, day, night, summer, winter, aurora, N/S, E/W, giro-magnetic disturbances, high-rise city centers, arid deserts, the oceans, mountain ranges, prairies, pampas, steppes, tropics, arctic regions, G5RV's and unsociable noisy neighbours. Use RMS summation of predicting uncertainties. If you are using Roy's S-meter calibration multiply by 2. ;o) And that just about sums it up. ---- Reg, G4FGQ -- .................................................. .......... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp .................................................. .......... "Richard Clark" wrote in message ... On Sat, 3 Jan 2004 10:35:51 -0600 (CST), (Richard Harrison) wrote: If the signal must take a great circle route over the North Polar region, problems increase. Hi Richard, This is a S+N/N problem, not propagation. It is not like the magnetic pole is sucking signals into the ground. What the pole IS attracting is the ionic flow from the sun's emissions which create a plasma of noise. 73's Richard Clark, KB7QHC |
Art, KB9MZ wrote:
"Thus this is inferior to a vertical that captures the low angles and discriminates against the high angles plus inferior to a poor vertical that discriminates against low angles." Yes, a vertical discriminates against high angles as it has a null in its pattern overhead. What "poor vertical" discriminates against low angles if ground conductivity is OK? A too-short vertical still has maximum radiation toward the horizon though it has less than a 1/4-wave or 5/8-wave vertical antenna has. Best regards, Richard Harrison, KB5WZI |
Mark Keith wrote:
"My dipole on 40m was only 35-40 ft. Not 1/2-wave up. But not once did it ever beat my vertical long haul." I believe Mark. The scales may be tilted in the favor of Mark`s vertical by the high-conductivity soil at Mark`s QTH. Commercial stations spend what it takes to put those horizontal antennas up at elevations which bring the take-off angle down low enough to reach out the distance to the target area. At high elevation, a dipole becomes bidirectional in azimuth. This gain is often enhanced by a reflector, directors, extended element lengths, or additional in-phase elements. Curtain arrays are popular transmitting antennas. So are rhombics, especially for point-to-point, for both transmission and reception. Receiving antenna farms rely on rhombics, Beverages, fishbones, etc, where the object is directivity and gain to give S/N, if not efficiency. Best regards, Richard Harrison, KB5WZI |
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