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On Jan 7, 11:35*am, RHF wrote:
On Jan 6, 9:17*am, RHF wrote: On Jan 5, 11:53*pm, RHF wrote: On Jan 5, 4:25*pm, Carter-k8vt wrote: RHF wrote: Undeniable Fact # 1 - The Man Made RFI-EMF Environment Has Changed Greatly : Increasing one or two Magnitudes from the 1930s to the 1990s. Undeniable Fact # 2 - Man's Ability to Accurately Measure the RFI-EMF Environment and It's Effects Has Changed Greatly : Increasing at least a Magnitude from the 1930s to the 1990s. - Undeniable Fact # 3 - According to a direct quote of Doty, - UN-shielded lead-in wires are susceptible to noise. - Coaxial cable is SHIELDED. So why does Doty say bury it? Fact is most Coax Cable does not have a perfect Shield. - Undeniable Fact # 4 - Even though the RFI environment has - changed and even though man's ability to measure it has - changed, burial in a few inches of soil provides no noise - mitigation. You provide no Empirical Data to dispute my Anecdotal Observations. - Undeniable Fact # 5 - Yes, the environment has changed and - measurement techniques have changed, but that does NOT - mean the Laws of Physics have changed. I would have to conclude that 'our' knowledge of the Laws of Physics has improve from 1930s to 1990s. - Finally, for the sake of this discussion, assume your neighbor/ - neighborhood is throwing out a lot of RF hash and trash. - Furthermore, let us assume you've buried your coax in hopes - of alleviating the problem (even though it won't). - - What, pray tell, is to keep this neighborhood RF hash and - trash from impinging directly on the antenna itself and being - piped right in to your receiver? Nothing -but- that's the Antenna itself -and- at least it ain't the Coax Cable feed-in-line; acting as a Noise Pick-Up Antenna. - -If you need to avoid the lawn mower, bury by all means. Good Point. - -If you need to avoid the wrath of your wife, bury by all means. She Who Must Be Obeyed - Must Be Happy Too ! - -If you want to bury to mitigate noise, save your time, trouble and energy. Alas it is 'my' Time and Money and to 'me' it is Worth-the-Trouble : To Do It Right ! Oops You Forgot : # 2 - Dang - See # 1 + Safety - It's a Tripping Hazard. KEY POINT - Burying the Coax Cable is simply one of the many Synergistic Elements that goes into making a Low Noise Shortwave Radio Listening (SWL) Antenna -a-la- John Doty 1 - At the Antenna using a Matching Transformer between the Antenna Element and the Coax Cable feed-in-line. {The Far-End} 2 - Plus a Ground Rod at this Matching Transformer. 3 - Near the entry to the House using an Isolation Transformer between the Coax Cable feed-in-line and Coax Cable going into the House to the RadioShack. {The Near-End} 4 - Plus a Ground Rod at the Isolation Transformer. 5 - Bury the Coax Cable feed-in-line between the Two Ground Rods and Transformers. Number "5" is realy only important when you have first accomplished Numbers 1~4. Effectively the Outer-Shield of the Coax Cable is : 1- 2- 3- 4- 5- etc... Three Rec.Radio.Shortwave Messages to Read -by- John Dotyhttp://groups..google.com/group/rec.radio.shortwave/msg/1abc6a2bf8acc12d * SWL Longwire * Low Noise Antenna Connection * Grounding Is Key To Good Reception John Doty will tell you that he did not Invent any of these things or Uniquely Combine them to Create a New Concept. *He more or less studied what was out-there and empirically tried things until he found what seemed to Work : "The Best". *He Wrote about them; and Help to Popularize them in the 1990s in the Shortwave Radio Listening (SWL) community. *As far as I know he makes no claim that any one of these things will work by itself -but- as a group they do improve things greatly over a simple Classic Horizontal Bare Wire Antenna with an Insulated Wire feed-in-line -or- an Improved Horizontal Bare Wire Antenna with a Coax Cable feed-in-line. step-by-step - one-step-at-a-time - the endless quest for better shortwave radio listening (swl) - iane ~ RHF *. KEY POINT - Burying the Coax Cable is simply one of the many Synergistic Elements that goes into making a Low Noise Shortwave Radio Listening (SWL) Antenna -a-la- John Doty 1 - At the Antenna using a Matching Transformer between the Antenna Element and the Coax Cable feed-in-line. {The Far-End} 2 - Plus a Ground Rod at this Matching Transformer. 3 - Near the entry to the House using an Isolation Transformer between the Coax Cable feed-in-line and Coax Cable going into the House to the RadioShack. {The Near-End} 4 - Plus a Ground Rod at the Isolation Transformer. 5 - Bury the Coax Cable feed-in-line between the Two Ground Rods and Transformers. Number "5" is realy only important when you have first accomplished Numbers 1~4. Effectively the Outer-Shield of the Coax Cable is/does : # 1 - Connects both the Antenna Ground and the House's Feed-in-Line Entry Ground {RadioShack Grounding Point} : -Thus- "Bonding" these two Grounds. 2- 3- 4- 5- etc...- Hide quoted text - - Show quoted text - KEY POINT - Burying the Coax Cable is simply one of the many Synergistic Elements that goes into making a Low Noise Shortwave Radio Listening (SWL) Antenna -a-la- John Doty 1 - At the Antenna using a Matching Transformer between the Antenna Element and the Coax Cable feed-in-line. {The Far-End} 2 - Plus a Ground Rod at this Matching Transformer. 3 - Near the entry to the House using an Isolation Transformer between the Coax Cable feed-in-line and Coax Cable going into the House to the RadioShack. {The Near-End} 4 - Plus a Ground Rod at the Isolation Transformer. 5 - Bury the Coax Cable feed-in-line between the Two Ground Rods and Transformers. Number "5" is realy only important when you have first accomplished Numbers 1~4. Effectively the Buried Outer-Shield of the Coax Cable is/does : # 1 - Connects both the Antenna Ground and the House's Feed-in-Line Entry Ground {RadioShack Grounding Point} : -Thus- "Bonding" these two Grounds.http://www.hamuniverse.com/grounding...ing-Part-1-of-... # 2 - Functions as a Ground Radial for the Wire Antenna Element to 'unify' the "Ground Effect" {Ground Conductivity Efficiency} between the two Ground Rods.http://www.sgcworld.com/radialstechnote.html # 3 -IF- The Wire Antenna Element is hung in the Air 'over' this Buried Coax Cable it is in-effect a Counterpoise to the Wire Antenna Element.http://www.cebik.com/gp/cps.html READ - WHY - The Far-End-Fed Shortwave Listener's (SWLs) Inverted "L" Antennahttp://www.google.com/group/rec.radio.shortwave/msg/22cfc6b9cb2447c0http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/11698 4- 5- etc...- Hide quoted text - - Show quoted text - KEY POINT - Burying the Coax Cable is simply one of the many Synergistic Elements that goes into making a Low Noise Shortwave Radio Listening (SWL) Antenna -a-la- John Doty 1 - At the Antenna using a Matching Transformer between the Antenna Element and the Coax Cable feed-in-line. {The Far-End} 2 - Plus a Ground Rod at this Matching Transformer. 3 - Near the entry to the House using an Isolation Transformer between the Coax Cable feed-in-line and Coax Cable going into the House to the RadioShack. {The Near-End} 4 - Plus a Ground Rod at the Isolation Transformer. 5 - Bury the Coax Cable feed-in-line between the Two Ground Rods and Transformers. Number "5" is realy only important when you have first accomplished Numbers 1~4. Effectively the Buried Outer-Shield of the Coax Cable is/does : # 1 - Connects both the Antenna Ground and the House's Feed-in-Line Entry Ground {RadioShack Grounding Point} : -Thus- "Bonding" these two Grounds. http://www.hamuniverse.com/grounding.html http://www.mikeholt.com/newsletters....y&letterID=134 http://mikeholt.com/mojonewsarchive/...2~20041005.php # 2 - Functions as a Ground Radial for the Wire Antenna Element to 'unify' the "Ground Effect" {Ground Conductivity Efficiency} between the two Ground Rods. http://www.sgcworld.com/radialstechnote.html # 3 -IF- The Wire Antenna Element is hung in the Air 'over' this Buried Coax Cable it is in-effect a Counterpoise to the Wire Antenna Element. http://www.cebik.com/gp/cps.html READ - WHY - The Far-End-Fed Shortwave Listener's (SWLs) Inverted "L" Antenna http://www.google.com/group/rec.radi...cfc6b9cb2447c0 http://groups.yahoo.com/group/Shortw.../message/11698 # 4 - Digging the Trench to Bury the Coax Cable feed-in-line Opens-Up-the-Ground ! -meaning- You now have a Trench in the Ground to place 'things' in. http://en.wikipedia.org/wiki/Ground_conductivity * While the Braided Outer Shield of the Coax Cable can 'connect' the two Ground Rods at each end of the feed-in-line : It is not a Solid Copper Wire. http://en.wikipedia.org/wiki/Ground_%28electricity%29 * While the Braided Outer Shield of the Coax Cable can 'be' a Ground Radial between the two Ground Rods at each end of the feed-in-line : It is not a Solid Copper Wire. http://en.wikipedia.org/wiki/Radial_%28radio%29 TIP - While the Trench is Open : Place a Solid Copper Wire in it to : http://www.chem.hawaii.edu/uham/radials.html * Better Connect {Bond} the two Ground Rods at each end of the feed-in-line. * Be a Better Ground Radial in the Ground then the Coax Cable can be by itself. ABOUT - Ground Radial Wire Buried Radials: A Small Compendium -by- L. B. Cebik [W4RNL] http://www.cebik.com/gp/gr.html * Solid Bare Copper Wire to 'connect' along it's full lenght with the Earthen-Soil {Ground} that it is laying in. http://www.bencher.com/pdfs/00361ZZV.pdf * # 16 AWG or Larger - In the trench running parallel with the Coax Shield # 16 AWG Solid Bare Copper Wire will do OK. http://www.radiobooks.com/products/grw1k.htm -but-if- you happen to have a coupl of hundred feet of # 12 or #14 Insulated Solid Copper Wire laying around; and want to Strip the Insulation off-of-it to use as for Ground Radials - Go For It ! http://www.signalengineering.com/ult...th_ground.html The Radial "Rule-of-Thumb" for Receive Only Shortwave Antennas : The More Radials the smaller the Radial Wire that can be use; with # 16 AWG being about the smallest. http://www.davisrf.com/ham1/grndwire.htm 16~18 or more Radials : # 16 AWG Solid Bare Copper Wire 8~9 Radials : # 14 AWG Solid Bare Copper Wire 3~4 Radials : # 12 AWG Solid Bare Copper Wire Single Wire Counterpoise : # 10 AWG Solid Bare Copper Wire http://en.wikipedia.org/wiki/American_wire_gauge The Guiding Principle of Radials : The More Radials The Better. http://www.ncjweb.com/k3lcmaxgainradials.pdf 5- etc... iane ~ RHF |
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