Re: Topband: earth tester
Hi Rick et al, Just reminds me of 3Y0X from Peter 1 Island in 2006. They used a 3 el yagi laying on the ice and had a VFB sig on 160 ...but calculations were made before they went to this distant QTH. Nice memory! 73 SM7BIC Len -Ursprungligt meddelande- Från: Topband [mailto:topband-boun...@contesting.com] För Richard (Rick) Karlquist Skickat: den 26 april 2015 19:50 Till: Henk PA5KT; topband@contesting.com Ämne: Re: Topband: earth tester Is there some way you could lay a half wave dipole on the ground and measure the resonant frequency and radiation resistance vs the known free space values, and convert this to ground conductance and permittivity? Perhaps model it in some version of NEC and play with the ground constants until the modeling program agreed with the measured impedance and frequency? Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
Is there some way you could lay a half wave dipole on the ground and measure the resonant frequency and radiation resistance vs the known free space values, and convert this to ground conductance and permittivity? Perhaps model it in some version of NEC and play with the ground constants until the modeling program agreed with the measured impedance and frequency? Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
Another website with a measurement tool: http://www.technik.dhbw-ravensburg.de/~lau/gc.html I did not yet try this or N6LF's system. 73 Henk PA5KT Jorge Diez - CX6VM schreef op 4/22/2015 om 7:34 PM: Thanks Jim I will look at N6LF website, I want to measure my soil conditions 73, Jorge -Mensaje original- De: Topband [mailto:topband-boun...@contesting.com] En nombre de Jim Brown Enviado el: miércoles, 22 de abril de 2015 01:48 p.m. Para: topband@contesting.com Asunto: Re: Topband: earth tester What do you want to measure? These testers, as well as the fall of potential method, measure the impedance to earth at dc and low audio frequencies. It's important to remember that a connection to earth is for lightning protection, and does not make a TX antenna work better. If you want to measure your soil conditions, N6LF shows a method on his website. It uses a driven rod that passes through an opening in a wire screen. Z between the rod and the screen is measured using a vector impedance analyzer, first before the rod is driven, and again after being driven to its full length, and soil parameters are computed from the two measurements. I've thought about doing this, but never got around to it. This measurement yields the data on the soil conditions that affect the performance of vertical antennas. 73, Jim K9YC On Wed,4/22/2015 6:00 AM, Paul Christensen wrote: Do you use a earth tester? Which brand do you know is very good and accurate to consider? Jorge, If you can, try and find a clamp-on earth tester rather than the type that relies on the fall-of-potential method with electrodes. There are several good clamp-on units by Megger, Fluke and AEMC. I recently acquired an AEMC model 3711. It wasn't supplied with a calibration loop, but I found one from Fluke that quickly checks calibration at 100, 50, 12.5, and 0.5 ohms. You'll want that calibration loop to validate the accuracy of the clamp tester, especially if you use an off-brand model from Asia. N4CC and I recently installed a large grounding field, with some ground rods driven down to a depth of 24 ft. The clamp-on device was useful for quick validation. Had we used a unit with electrodes, it would have taken us much longer to perform our tests. By the way, in sandy/clay type soil here in north FL, we found that connecting 8 ft. rods end-to-end to form a 24 ft rod substantially lowered earth resistance by a factor of 10x. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
What do you want to measure? These testers, as well as the fall of potential method, measure the impedance to earth at dc and low audio frequencies. It's important to remember that a connection to earth is for lightning protection, and does not make a TX antenna work better. If you want to measure your soil conditions, N6LF shows a method on his website. It uses a driven rod that passes through an opening in a wire screen. Z between the rod and the screen is measured using a vector impedance analyzer, first before the rod is driven, and again after being driven to its full length, and soil parameters are computed from the two measurements. I've thought about doing this, but never got around to it. This measurement yields the data on the soil conditions that affect the performance of vertical antennas. 73, Jim K9YC On Wed,4/22/2015 6:00 AM, Paul Christensen wrote: Do you use a earth tester? Which brand do you know is very good and accurate to consider? Jorge, If you can, try and find a clamp-on earth tester rather than the type that relies on the fall-of-potential method with electrodes. There are several good clamp-on units by Megger, Fluke and AEMC. I recently acquired an AEMC model 3711. It wasn't supplied with a calibration loop, but I found one from Fluke that quickly checks calibration at 100, 50, 12.5, and 0.5 ohms. You'll want that calibration loop to validate the accuracy of the clamp tester, especially if you use an off-brand model from Asia. N4CC and I recently installed a large grounding field, with some ground rods driven down to a depth of 24 ft. The clamp-on device was useful for quick validation. Had we used a unit with electrodes, it would have taken us much longer to perform our tests. By the way, in sandy/clay type soil here in north FL, we found that connecting 8 ft. rods end-to-end to form a 24 ft rod substantially lowered earth resistance by a factor of 10x. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
Perhaps a few words on how you joined the rods would be useful here. Regards,Jeff W6JK On Wednesday, April 22, 2015 1:00 PM, Paul Christensen w...@arrl.net wrote: Do you use a earth tester? Which brand do you know is very good and accurate to consider? Jorge, If you can, try and find a clamp-on earth tester rather than the type that relies on the fall-of-potential method with electrodes. There are several good clamp-on units by Megger, Fluke and AEMC. I recently acquired an AEMC model 3711. It wasn't supplied with a calibration loop, but I found one from Fluke that quickly checks calibration at 100, 50, 12.5, and 0.5 ohms. You'll want that calibration loop to validate the accuracy of the clamp tester, especially if you use an off-brand model from Asia. N4CC and I recently installed a large grounding field, with some ground rods driven down to a depth of 24 ft. The clamp-on device was useful for quick validation. Had we used a unit with electrodes, it would have taken us much longer to perform our tests. By the way, in sandy/clay type soil here in north FL, we found that connecting 8 ft. rods end-to-end to form a 24 ft rod substantially lowered earth resistance by a factor of 10x. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
Do you use a earth tester? Which brand do you know is very good and accurate to consider? Jorge, If you can, try and find a clamp-on earth tester rather than the type that relies on the fall-of-potential method with electrodes. There are several good clamp-on units by Megger, Fluke and AEMC. I recently acquired an AEMC model 3711. It wasn't supplied with a calibration loop, but I found one from Fluke that quickly checks calibration at 100, 50, 12.5, and 0.5 ohms. You'll want that calibration loop to validate the accuracy of the clamp tester, especially if you use an off-brand model from Asia. N4CC and I recently installed a large grounding field, with some ground rods driven down to a depth of 24 ft. The clamp-on device was useful for quick validation. Had we used a unit with electrodes, it would have taken us much longer to perform our tests. By the way, in sandy/clay type soil here in north FL, we found that connecting 8 ft. rods end-to-end to form a 24 ft rod substantially lowered earth resistance by a factor of 10x. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
Thanks Paul Will search about this 73, Jorge -Mensaje original- De: Topband [mailto:topband-boun...@contesting.com] En nombre de Paul Christensen Enviado el: miércoles, 22 de abril de 2015 10:00 a.m. Para: topband Asunto: Re: Topband: earth tester Do you use a earth tester? Which brand do you know is very good and accurate to consider? Jorge, If you can, try and find a clamp-on earth tester rather than the type that relies on the fall-of-potential method with electrodes. There are several good clamp-on units by Megger, Fluke and AEMC. I recently acquired an AEMC model 3711. It wasn't supplied with a calibration loop, but I found one from Fluke that quickly checks calibration at 100, 50, 12.5, and 0.5 ohms. You'll want that calibration loop to validate the accuracy of the clamp tester, especially if you use an off-brand model from Asia. N4CC and I recently installed a large grounding field, with some ground rods driven down to a depth of 24 ft. The clamp-on device was useful for quick validation. Had we used a unit with electrodes, it would have taken us much longer to perform our tests. By the way, in sandy/clay type soil here in north FL, we found that connecting 8 ft. rods end-to-end to form a 24 ft rod substantially lowered earth resistance by a factor of 10x. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband --- El software de antivirus Avast ha analizado este correo electrónico en busca de virus. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
“Perhaps a few words on how you joined the rods would be useful here.” We used TB/Blackburn 60CNT2 non-threaded couplers to join the ground rods. A compression fit is used to join the rods. The rods and couplers were obtained from our rural electric company.The utility also supplied a head driver that fits inside a ground rod bit for use with a rotary impact drill. http://www.tnb.com/ps/fulltilt/index.cgi?part=60CNT2 Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
Thanks Jim I will look at N6LF website, I want to measure my soil conditions 73, Jorge -Mensaje original- De: Topband [mailto:topband-boun...@contesting.com] En nombre de Jim Brown Enviado el: miércoles, 22 de abril de 2015 01:48 p.m. Para: topband@contesting.com Asunto: Re: Topband: earth tester What do you want to measure? These testers, as well as the fall of potential method, measure the impedance to earth at dc and low audio frequencies. It's important to remember that a connection to earth is for lightning protection, and does not make a TX antenna work better. If you want to measure your soil conditions, N6LF shows a method on his website. It uses a driven rod that passes through an opening in a wire screen. Z between the rod and the screen is measured using a vector impedance analyzer, first before the rod is driven, and again after being driven to its full length, and soil parameters are computed from the two measurements. I've thought about doing this, but never got around to it. This measurement yields the data on the soil conditions that affect the performance of vertical antennas. 73, Jim K9YC On Wed,4/22/2015 6:00 AM, Paul Christensen wrote: Do you use a earth tester? Which brand do you know is very good and accurate to consider? Jorge, If you can, try and find a clamp-on earth tester rather than the type that relies on the fall-of-potential method with electrodes. There are several good clamp-on units by Megger, Fluke and AEMC. I recently acquired an AEMC model 3711. It wasn't supplied with a calibration loop, but I found one from Fluke that quickly checks calibration at 100, 50, 12.5, and 0.5 ohms. You'll want that calibration loop to validate the accuracy of the clamp tester, especially if you use an off-brand model from Asia. N4CC and I recently installed a large grounding field, with some ground rods driven down to a depth of 24 ft. The clamp-on device was useful for quick validation. Had we used a unit with electrodes, it would have taken us much longer to perform our tests. By the way, in sandy/clay type soil here in north FL, we found that connecting 8 ft. rods end-to-end to form a 24 ft rod substantially lowered earth resistance by a factor of 10x. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband --- El software de antivirus Avast ha analizado este correo electrónico en busca de virus. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: earth tester
Jim, And after measuring it, I don't believe anyone will do anything about it. The PolyPhaser manual has some good info on lightning protection. 73 de Price W0RI On Wednesday, April 22, 2015 11:47 AM, Jim Brown j...@audiosystemsgroup.com wrote: What do you want to measure? These testers, as well as the fall of potential method, measure the impedance to earth at dc and low audio frequencies. It's important to remember that a connection to earth is for lightning protection, and does not make a TX antenna work better. If you want to measure your soil conditions, N6LF shows a method on his website. It uses a driven rod that passes through an opening in a wire screen. Z between the rod and the screen is measured using a vector impedance analyzer, first before the rod is driven, and again after being driven to its full length, and soil parameters are computed from the two measurements. I've thought about doing this, but never got around to it. This measurement yields the data on the soil conditions that affect the performance of vertical antennas. 73, Jim K9YC On Wed,4/22/2015 6:00 AM, Paul Christensen wrote: Do you use a earth tester? Which brand do you know is very good and accurate to consider? Jorge, If you can, try and find a clamp-on earth tester rather than the type that relies on the fall-of-potential method with electrodes. There are several good clamp-on units by Megger, Fluke and AEMC. I recently acquired an AEMC model 3711. It wasn't supplied with a calibration loop, but I found one from Fluke that quickly checks calibration at 100, 50, 12.5, and 0.5 ohms. You'll want that calibration loop to validate the accuracy of the clamp tester, especially if you use an off-brand model from Asia. N4CC and I recently installed a large grounding field, with some ground rods driven down to a depth of 24 ft. The clamp-on device was useful for quick validation. Had we used a unit with electrodes, it would have taken us much longer to perform our tests. By the way, in sandy/clay type soil here in north FL, we found that connecting 8 ft. rods end-to-end to form a 24 ft rod substantially lowered earth resistance by a factor of 10x. Paul, W9AC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
