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Its all gone quiet. Let's stir it up again.
A TALE OF TWO OLD WIVES
There are two cantankerous old wives: One old wife asserts it is obvious radiation occurs mainly from the middle portion of a dipole because that's where the current is strongest and the magnetic field is most concentrated. The other old wife asserts it is obvious radiation occurs mainly from the ends of a dipole because that's where the highest voltages occur and the electric field is most intense. Since the pair of arguments are logically identical in form they are of equal validity. But because it is impossible to reconcile the two women .... they cannot BOTH be right .... only one conclusion can be drawn ... .... both arguments are false! The old wives are telling tales. Citizens - drag 'em off to that old English custom - the ducking stool. |
On Sat, 6 Mar 2004 18:45:48 +0000 (UTC), "Reg Edwards"
wrote: A TALE OF TWO OLD WIVES There are two cantankerous old wives: One old wife asserts it is obvious radiation occurs mainly from the middle portion of a dipole because that's where the current is strongest and the magnetic field is most concentrated. The other old wife asserts it is obvious radiation occurs mainly from the ends of a dipole because that's where the highest voltages occur and the electric field is most intense. Then there is our THIRD OLD WIFE who sitting at her kitchen table looking out the window at the first two, takes notes of their argument, sets them aside and returns to measuring mud's recuperative powers and bottling it as a nostrum at the next fair. What is the Q of her mud? When the early English author, Samuel Richardson, wrote his ground breaking novel "Pamela, or Virtue Rewarded" it was met immediately by Henry Fielding's sardonic "Shamela." Fielding was responding to the arrogance of the subtitles in that first work: "Aggressive Chastity" and "Provocative Prudence"; dare I point out the parallels (non resonant) that attract me to these current ironies? 73's, Richard Clark, KB7QHC p.s. for those who take umbrage at favourable quotation of eminent British authors (oddly enough, Brits), please note this missive has been sprinkled with on-topic references of: ground[breaking], Field[ing], parallel[s], resonant, current and one technical enquiry for Q that will no doubt be ignored in favor of off-topic condemnations of these sources. ;-) |
Richard Clark wrote:
"What is the Q of her mud?" First, the Q of mud is likely less useful than antenna Q. That is, not worth much. Second, Q depends on mud consistency, temperature, location, and frequency of interest. The earth behaves like a lossy capacitor. Above 10 MHz, the capacitnce in ordinary soil bypasses the resistance of the soil. Below 10 MHz, conductance of the soil shunts the capacitance making soil capacitance (permittivity) less important. Soil as a lossy dielectric has a dielectric constant which is defined as the capacitance with dielectric material filling the void versus the capacitance without the dielectric material. Thickness of a mud layer is relevant. At medium wave and lower frequencies, where the earth is mainly resistive, r-f renetration of the earth, not sea water, is so deep that rain wetting has little effect on propagation or refleection. But, at h-f, penetration of the earth is shallow. Water and salt content are significant to penetration and loss. An ideal capacitor is lossless. There`s no dielectric leakage nor conductor loss resistance. Earth is not ideal. Capacitor quality is judged by how much its current`s phase angle deviates from 90-degrees lead of the applied voltage. This deviation angle is called the capacitor`s "phase angle". The tangent of this angle is called the "dissipation factor". The reciprocal of this dissipation factor is the Q of the capacitor. As mud is wet soil, it has Q, but not just one Q value. Best regards, Richard Harrison, KB5WZI |
and the Fourth Old wife said "its really the force exerted on a far point,
as you sum up effect of each current in each part of the antenna" as she pulled down the laundry off of the longwire. "It is a summation of all the little ones (she means currents), and then you get a field" says she, walking back the the radio shack with he head just a buzzing with electrons.(yea ... she bonkers) She was my Fields Proff too. "Richard Harrison" wrote in message ... Richard Clark wrote: "What is the Q of her mud?" First, the Q of mud is likely less useful than antenna Q. That is, not worth much. Second, Q depends on mud consistency, temperature, location, and frequency of interest. The earth behaves like a lossy capacitor. Above 10 MHz, the capacitnce in ordinary soil bypasses the resistance of the soil. Below 10 MHz, conductance of the soil shunts the capacitance making soil capacitance (permittivity) less important. Soil as a lossy dielectric has a dielectric constant which is defined as the capacitance with dielectric material filling the void versus the capacitance without the dielectric material. Thickness of a mud layer is relevant. At medium wave and lower frequencies, where the earth is mainly resistive, r-f renetration of the earth, not sea water, is so deep that rain wetting has little effect on propagation or refleection. But, at h-f, penetration of the earth is shallow. Water and salt content are significant to penetration and loss. An ideal capacitor is lossless. There`s no dielectric leakage nor conductor loss resistance. Earth is not ideal. Capacitor quality is judged by how much its current`s phase angle deviates from 90-degrees lead of the applied voltage. This deviation angle is called the capacitor`s "phase angle". The tangent of this angle is called the "dissipation factor". The reciprocal of this dissipation factor is the Q of the capacitor. As mud is wet soil, it has Q, but not just one Q value. Best regards, Richard Harrison, KB5WZI |
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In view of the nil replies to the following posting it's safe to say that's
another old wives' tale which bites the dust. The next ingrained tale on the list is the so-called SWR meter nonsense versus the TLI. ========================= A TALE OF TWO OLD WIVES There are two cantankerous old wives: One old wife asserts it is obvious radiation occurs mainly from the middle portion of a dipole because that's where the current is strongest and the magnetic field is most concentrated. The other old wife asserts it is obvious radiation occurs mainly from the ends of a dipole because that's where the highest voltages occur and the electric field is most intense. Since the pair of arguments are logically identical in form they are of equal validity. But because it is impossible to reconcile the two women ..... they cannot BOTH be right .... only one conclusion can be drawn ... ... both arguments are false! The old wives are telling tales. Citizens - drag 'em off to that old English custom - the ducking stool. |
"Reg Edwards" wrote in message ... In view of the nil replies to the following posting it's safe to say that's another old wives' tale which bites the dust. The next ingrained tale on the list is the so-called SWR meter nonsense versus the TLI. ========================= A TALE OF TWO OLD WIVES There are two cantankerous old wives: One old wife asserts it is obvious radiation occurs mainly from the middle portion of a dipole because that's where the current is strongest and the magnetic field is most concentrated. The other old wife asserts it is obvious radiation occurs mainly from the ends of a dipole because that's where the highest voltages occur and the electric field is most intense. Since the pair of arguments are logically identical in form they are of equal validity. But because it is impossible to reconcile the two women .... they cannot BOTH be right .... only one conclusion can be drawn ... ... both arguments are false! The old wives are telling tales. Citizens - drag 'em off to that old English custom - the ducking stool. |
Reg:
Compared to current, voltage is just so ephemeral.... Voltage is a line integral, it depends upon the path over which one evaluates the integral. While current is something more substantial... one does not have to plan the path of integration to know the current. What? -- Peter K1PO "Reg Edwards" wrote in message ... In view of the nil replies to the following posting it's safe to say that's another old wives' tale which bites the dust. The next ingrained tale on the list is the so-called SWR meter nonsense versus the TLI. ========================= A TALE OF TWO OLD WIVES There are two cantankerous old wives: One old wife asserts it is obvious radiation occurs mainly from the middle portion of a dipole because that's where the current is strongest and the magnetic field is most concentrated. The other old wife asserts it is obvious radiation occurs mainly from the ends of a dipole because that's where the highest voltages occur and the electric field is most intense. Since the pair of arguments are logically identical in form they are of equal validity. But because it is impossible to reconcile the two women .... they cannot BOTH be right .... only one conclusion can be drawn ... ... both arguments are false! The old wives are telling tales. Citizens - drag 'em off to that old English custom - the ducking stool. |
Reg Edwards wrote:
In view of the nil replies to the following posting it's safe to say that's another old wives' tale which bites the dust. Reg, we have a clear example of where the high voltage part of the antenna is not allowed to radiate (much). That would be a balanced top hat. Not allowing the high voltage part of the antenna to radiate leaves the high current part to do most of the radiating. We know from field strength measurements that a mobile antenna with a balanced top hat can radiate as well (or better than) an antenna equipped with a radiating high voltage top section. If you keep the high voltage portion of the antenna and replace the high current portion with an antenna tuner, the field strength falls by some 12 dB. Lengthening the high current section under the loading coil has a much greater effect than lengthening the high-voltage section on top of the loading coil. -- 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! =----- |
Cec, I don't doubt your experimental results. It's your extrapolated
imagination and logic which worries me. ;o) ---- Yours, Reg. |
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