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"Richard Clark" wrote
It's satisfying enough to see you're stunned. ;-) That was the point of the sieve. __________________ Your perception of that is as inaccurate as the one you espouse about loaded verticals. Are you incapable of dealing with technical topics in a technical manner? I suppose now you'll claim that your post above was another sieve, and congratulate yourself all over again. RF |
On Wed, 30 Mar 2005 10:52:24 -0600, "Richard Fry"
wrote: Are you incapable of dealing with technical topics in a technical manner? Hi OM, I respond to all correspondence of interest. I see you enjoy talk about talking about technical topics, but I have seen no technical discussion from you for quite some time. That is your sole responsibility as no one can do your typing for you. I suppose now Yes, but too often. This is what I mean about choice and responsibility. You chose to ramble on instead of offering technical discussion. I am equally pleased to travel either path, and I suspect your protestation above given the inclination obviously revealed below it. So to match your diverging interests, can you answer "What does Do Wa Diddy mean?" If your heart of heart's desire for technical topics must be sated first What effect would surface phonon polaritons present to an antenna's efficiency? Either constitute another sieve. ;-) 73's Richard Clark, KB7QHC |
"Richard Harrison" wrote
ON4UN says on page 9-29 of his 1994 edition of the Low-Band DXing book: "Over sea-water the 5/8 wave has lost 0.8 dB of its gain already, the 1/4-wave only 0.4 dB." (It`s less than one dB). I think you should question that conclusion. Sea water (or any path of fixed parameters) attenuates every groundwave by the same decibel amount for the same path, conditions, and frequency. For example, using the FCC curves for groundwave propagation from a radiator with 1 kW of power and 120 1/4-wave radials, over a seawater (only) path at 1MHz... - a 1/4-wave vertical produces a field of 190 mV/m at 1 mile, and 85 mV/m at 2 miles. - a 5/8-wave vertical produces a field of 274 mV/m at 1 mile, and 137 mV/m at 2 miles. This is as expected. Doubling the distance reduces field strength by 6 dB in each case. The absolute value of the groundwave signal has no bearing on the percentage of it that is lost as it propagates. Even a disappearingly small radiator produces radiation less than 1/2 dB weaker than a 1/2-wave dipole, or a 1/4-wave vertical. In lossless antennas, the only difference in radiated signal between the full length antenna and a too-short antenna comes from the slight difference in their patterns. The difference in peak gain between an isotropic radiator and a reference dipole in free space is 2.15 dB. Practical antennas in real-world applications can show greater than 0.5 dB losses for shortened radiators. In my example above, the 1/4-wave radiator would need about 2 kW of input power to produce the same field as the 5/8-wave radiator with 1 kW, over the same path -- which is a 3 dB ratio. In 1949, I worked in a transmitting plant where two stations, KPRC, 950 KHz, and KXYZ, 1320 KHz, shared the same transmittinng tower. Both stations had identical RCA 5-C, 5 KW transmitters. Regional coverage was almost identical despite many more degrees in the tower at 1320 KHz than at 950 KHz. If the tower was 90 degrees at 950 kHz it would have been 125 degrees at 1320 kHz. The FCC efficiency for 90 degree towers is 190 mV/m at 1 mile for 1 kW, and about 210 mV/m for 125 degree radiators. So the 1320 kHz signal was launched with a greater groundwave, but that advantage would be lost as the signal propagated over whatever the ground conditions are for the path (higher freqs have greater losses). Using the FCC curves and a conductivity of 8 mS/m, the 5 mV/m contour should be about 35.5 miles away for the 5kW 950 kHz station, and about 27.5 miles away for the 5kW 1320 kHz station. But close in probably few would know the difference. Bill Orr writes on page 78 of "Vertical Antennas": "A helix length of about .05 wavelength or more provides good results as a substitute for a full size quarter wavelength vertical antenna." Was 0.05 lambda the pitch of the helix? If so, how many turns? How were the two installed? How were the antennas oriented, and In which direction from the antennas was he comparing them? + + + And thanks for some serious comments on this subject. RF |
"Richard Clark" wrote:
One's word is insufficient -- even if it comes from you and/or Richard Clark. And I presume you being the arbiter of what is right, then render authority to make this citation sufficient to be proof of your statement? :-) __________________ Yes, you do presume. Your primary education should have provided you with the concept of proving and supporting your work; I merely referred to it. Experience here shows that you will claim whatever you want, and supply no technical justification for it. That's up to you, but as you see by responses here, it isn't earning you very much respect from others. RF |
"Richard Clark" wrote:
Drivel not worth serious consideration. |
On 30/03/2005 10:34 AM, Tom Ring wrote:
Richard Clark wrote: On Wed, 30 Mar 2005 07:09:17 -0600, Tom Ring wrote: [...] Combat? I suppose you are fishing for the point award answers. In Order: Mr. Natural, Flakey Foont. Yes, combat - advice given to troops going to fight on the islands of the Pacific. And I must have forgotten the re-use by Crumb; I used to have all of them, way back when. I liked the Fabulous Furry Freak Brothers better. I simply cannot resist: "Antennas will get you through times of no propagation better than propagation will get you through times of no antennas." I'll admit that I've lost the plot to this thread. Although, I've picked up some interesting pointers on antenna design with respect to electrical length. I really need to pick up a copy of the Terman book, if only to read up on some of the references I've seen here. At least it will give me a reason to use my erstwhile maths skills for good, instead of for evil. |
clvrmnky wrote:
Yes, combat - advice given to troops going to fight on the islands of the Pacific. And I must have forgotten the re-use by Crumb; I used to have all of them, way back when. I liked the Fabulous Furry Freak Brothers better. I simply cannot resist: "Antennas will get you through times of no propagation better than propagation will get you through times of no antennas." I was going to use the original of that one, but decided I shouldn't. I like your version a lot. tom K0TAR |
On Wed, 30 Mar 2005 13:55:09 -0600, "Richard Fry"
wrote: That's up to you, but as you see by responses here, it isn't earning you very much respect from others. Hi OM, I will concede the post of Beauty Queen to your overwhelming lead. Tears will stain my pillow tonight. :-( However much you may pine away for technical discussion, you balance that with the relish to gust on with personalities. Clearly your contest but no points for content nor style. Careful, there are others eyeing that crown you seek. I posed a question about pop music and antennas, both, given you have abandoned the topic long ago. This in itself merely underlines how inconsequential its outcome was. The vacuum of discussion along any of those lines portends more banal gossip. I shouldn't await any surprising development in your writing skills; but I'm an optimist and look forward to that slight glimmer of talent that goes beyond the swim suit competition. 73's Richard Clark, KB7QHC |
"Richard Clark" wrote
I will concede... ____ Let us all hope so. RF |
On Wed, 30 Mar 2005 14:08:33 -0600, "Richard Fry"
wrote: "Richard Clark" wrote: Drivel not worth serious consideration. Hi OM, The sieve succeeded. We can eliminate popular music as serious consideration from your vast repertoire of experience. It appears you are somewhat constrained on the topic of Polaritons (Plasmons to some) too. In the future I will try to dumb down the technical and elevate the popular. By some accounts we would end up discussing Shakespeare again! 73's Richard Clark, KB7QHC |
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