Re: Topband: [Bulk] Best wire antenna for roof top location
Thankyou verymuch to Grant KZ1W, Greg ZL3IX, Mike W0BTU, Garry NI6T and Jim K9YC for all the suggestion. As suggest by Grant KZ1W and Jim K9YC, I will install a half-lambda dipole on 160M with both ends were 90 degrees bent due to the size of the building ,and find out what will be the Tx / Rx performance... To Mike W0BTU, it is slightly difficult to install the radial for the vertical antenna or inverted L as the roof top is not empty flat, hi hi Regards, Nuradi, YB0UNC / KU2B -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Saturday, August 08, 2015 11:23 AM To: topband@contesting.com Subject: Re: Topband: [Bulk] Best wire antenna for roof top location And remember -- the roof of this building is 110m, so a horizontal antenna is high enough to have pretty good low angle radiation! See http://k9yc.com/VertOrHorizontal-Slides.pdf and double the heights for the graphs of 80M performance. When you're thinking height, consider the building a tower -- it's mostly the far field reflection that determines the vertical pattern. As to ground for a vertical antenna -- let's not confuse the word ground with counterpoise or radial system. An end-fed current-fed vertical needs a counterpoise or radials, NOT a connection to earth. I strongly concur with the advice to spend some serious time LISTENING on that roof before doing anything else. It's pretty common for the stuff described on that roof to be MONDO NOISY, and it's unlikely that you can do much about most of it unless the guys who maintain it are HF hams. 73, Jim K9YC On Fri,8/7/2015 8:02 PM, Garry Shapiro wrote: And Bob Brown used a monograph by J.A. Ratcliffe--The Magneto-Ionic Theory and its Application to the Ionosphere which says the same thing. It has to do with the angle between the E vector and the Earth's Geomagnetic Field, which is horizontal at the geomagnetic equator. Bob borrowed my copy of the book when he was writing the Big Gun's Guide. Garry, NI6T On 8/7/2015 6:24 PM, Greg - ZL3IX wrote: Careful Mike! Jakarta is close to the equator, and power coupling is likely to be better from a horizontally polarised antenna, especially in an E-W direction. Ref The Big Gun's Guide to Low-Band Propagation by Bob Brown, NM7M (SK) _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
If the noise level is too high, perhaps you could use a separate receive antenna. A pennant, flag, or coaxial loop, might help null noise from certain directions. Art NK8X ᐧ On Sat, Aug 8, 2015 at 6:18 AM, Nuradi yb0...@gmail.com wrote: Thankyou verymuch to Grant KZ1W, Greg ZL3IX, Mike W0BTU, Garry NI6T and Jim K9YC for all the suggestion. As suggest by Grant KZ1W and Jim K9YC, I will install a half-lambda dipole on 160M with both ends were 90 degrees bent due to the size of the building ,and find out what will be the Tx / Rx performance... To Mike W0BTU, it is slightly difficult to install the radial for the vertical antenna or inverted L as the roof top is not empty flat, hi hi Regards, Nuradi, YB0UNC / KU2B -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Saturday, August 08, 2015 11:23 AM To: topband@contesting.com Subject: Re: Topband: [Bulk] Best wire antenna for roof top location And remember -- the roof of this building is 110m, so a horizontal antenna is high enough to have pretty good low angle radiation! See http://k9yc.com/VertOrHorizontal-Slides.pdf and double the heights for the graphs of 80M performance. When you're thinking height, consider the building a tower -- it's mostly the far field reflection that determines the vertical pattern. As to ground for a vertical antenna -- let's not confuse the word ground with counterpoise or radial system. An end-fed current-fed vertical needs a counterpoise or radials, NOT a connection to earth. I strongly concur with the advice to spend some serious time LISTENING on that roof before doing anything else. It's pretty common for the stuff described on that roof to be MONDO NOISY, and it's unlikely that you can do much about most of it unless the guys who maintain it are HF hams. 73, Jim K9YC On Fri,8/7/2015 8:02 PM, Garry Shapiro wrote: And Bob Brown used a monograph by J.A. Ratcliffe--The Magneto-Ionic Theory and its Application to the Ionosphere which says the same thing. It has to do with the angle between the E vector and the Earth's Geomagnetic Field, which is horizontal at the geomagnetic equator. Bob borrowed my copy of the book when he was writing the Big Gun's Guide. Garry, NI6T On 8/7/2015 6:24 PM, Greg - ZL3IX wrote: Careful Mike! Jakarta is close to the equator, and power coupling is likely to be better from a horizontally polarised antenna, especially in an E-W direction. Ref The Big Gun's Guide to Low-Band Propagation by Bob Brown, NM7M (SK) _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
And remember -- the roof of this building is 110m, so a horizontal antenna is high enough to have pretty good low angle radiation! See Large buildings are not towers or poles. Buildings have a significant amount of large conductive metallic things and noise generating junk inside. A simple vertical antenna has elevation pattern mostly determined by ground several wavelengths from the antenna. A simple horizontal antenna generally has elevation pattern mostly determined by ground immediately below the antenna up to a few wavelengths out. If the building has wiring and large connected metallic things under the horizontal antenna, it will act like a reflector. If the antenna is somewhat low to the roof (less than 1/4 wave or more above the roof), the elevation pattern won't be much different than a low dipole over flat earth. Most of the radiation will be beamed straight up. A vertical also will have a null below the antenna, nulling building coupling for RF. A horizontal has maximum possible signal into and out of the building. Even with a 400 ft high building, a horizontal antenna a fraction of wave over the roof can be very disappointing. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
Some years ago, on 80 meters, an LZ station had a horizontal between two tall buildings and had a very strong signal. 73 Bruce-k1fz www.qsl.net/k1fz/beverage_antenna.html On Sat, 8 Aug 2015 10:58:22 -0400, Tom W8JI wrote: And remember -- the roof of this building is 110m, so a horizontal antenna is high enough to have pretty good low angle radiation! See Large buildings are not towers or poles. Buildings have a significant amount of large conductive metallic things and noise generating junk inside. A vertical also will have a null below the antenna, nulling building coupling for RF. A horizontal has maximum possible signal into and out of the building. Even with a 400 ft high building, a horizontal antenna a fraction of wave over the roof can be very disappointing. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
I have been in Jakarta and also a number of places in China trying to operate from a city environment, you cannot believe the noise, S9 if your lucky, and its 360 degs, impossible to null, Operating from BY1QH building top, the best was a dipole stretched between two buildings roofs. At times the noise would go below S9, was there two weeks trying to pull 160 signals out. If you have never been there and heard that, its hard to grasp. Putting out a signal was never a problem, hearing any one was. We complain about plasma TV noise and other noise from Chinese made appliances just think of trying to operate in the center of 5 or 10 million of these devices all around you, and an the same care taken for the infrastructure of electric lines etc, coated with coal and smog dust and pollution, arcing at every juncture. I bet the space station can hear the buzz on their electronics as they pass over these areas. 73 Merv K9FD/KH6 If the noise level is too high, perhaps you could use a separate receive antenna. A pennant, flag, or coaxial loop, might help null noise from certain directions. Art NK8X ᐧ On Sat, Aug 8, 2015 at 6:18 AM, Nuradi yb0...@gmail.com wrote: Thankyou verymuch to Grant KZ1W, Greg ZL3IX, Mike W0BTU, Garry NI6T and Jim K9YC for all the suggestion. As suggest by Grant KZ1W and Jim K9YC, I will install a half-lambda dipole on 160M with both ends were 90 degrees bent due to the size of the building ,and find out what will be the Tx / Rx performance... To Mike W0BTU, it is slightly difficult to install the radial for the vertical antenna or inverted L as the roof top is not empty flat, hi hi Regards, Nuradi, YB0UNC / KU2B -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Saturday, August 08, 2015 11:23 AM To: topband@contesting.com Subject: Re: Topband: [Bulk] Best wire antenna for roof top location And remember -- the roof of this building is 110m, so a horizontal antenna is high enough to have pretty good low angle radiation! See http://k9yc.com/VertOrHorizontal-Slides.pdf and double the heights for the graphs of 80M performance. When you're thinking height, consider the building a tower -- it's mostly the far field reflection that determines the vertical pattern. As to ground for a vertical antenna -- let's not confuse the word ground with counterpoise or radial system. An end-fed current-fed vertical needs a counterpoise or radials, NOT a connection to earth. I strongly concur with the advice to spend some serious time LISTENING on that roof before doing anything else. It's pretty common for the stuff described on that roof to be MONDO NOISY, and it's unlikely that you can do much about most of it unless the guys who maintain it are HF hams. 73, Jim K9YC On Fri,8/7/2015 8:02 PM, Garry Shapiro wrote: And Bob Brown used a monograph by J.A. Ratcliffe--The Magneto-Ionic Theory and its Application to the Ionosphere which says the same thing. It has to do with the angle between the E vector and the Earth's Geomagnetic Field, which is horizontal at the geomagnetic equator. Bob borrowed my copy of the book when he was writing the Big Gun's Guide. Garry, NI6T On 8/7/2015 6:24 PM, Greg - ZL3IX wrote: Careful Mike! Jakarta is close to the equator, and power coupling is likely to be better from a horizontally polarised antenna, especially in an E-W direction. Ref The Big Gun's Guide to Low-Band Propagation by Bob Brown, NM7M (SK) _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
Some years ago, on 80 meters, an LZ station had a horizontal between two tall buildings and had a very strong signal. 73 Bruce-k1fz Between buildings is entirely different than on a building roof. Full context is important. As I said: A simple vertical antenna has elevation pattern mostly determined by ground several wavelengths from the antenna. A simple horizontal antenna generally has elevation pattern mostly determined by ground * immediately below the antenna up to a few wavelengths out. If the building has wiring and large connected metallic things under the horizontal antenna*, it will act like a reflector. If the antenna is somewhat low to the roof (less than 1/4 wave or more above the roof), the elevation pattern won't be much different than a low dipole over flat earth. Most of the radiation will be beamed straight up. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
Even with a 400 ft high building, a horizontal antenna a fraction of wave over the roof can be very disappointing. Tom is 100% right, one of the best rood top signal on top band is from 9M2AX. Ross tested several antennas and the only one that worked well was the inverted L. He has a tall fiberglass mast on top a water mast to keep the vertical part of the L high above the roof top. Ross also used a sloper for some time. Ross can provide more details of his excellent top band antenna. Best combination is a horizontal loaded loop like a flag for RX or a Waller Flag and the vertical inverted L for TX. Regards JC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
Have you surveyed the site for HF RFI? One mountain top property I was considering had awesome 360d unlimited visibility but had so much power supply hash, PIM, intermod, etc. from comm installations that any amateur operation would be near impossible. My spectrum analyzer showed huge amounts of general hash RF that could not be high pass band filtered out. Grant KZ1W On 8/7/2015 16:52 PM, Nuradi wrote: Dear all, In preparation of this coming WW big contest, I plan to install wire antenna on a roof top of a 33rd storey building (about 110metres above the ground) for operating on the 160M, 80M and 40M band. The building roof top rectangular size about 45 metres long (from NWtoN-326.8 degress to SEtoS-146.8degrees) and 33 metres wide (fromNEtoE-56.8 degrees to SWtoW-236.8 degrees) located in centre of Jakarta city. The roof top have plenty of cellulair microwave operator antennas (operating in 5GHz and above ALSO one TV operator with around 400MHz working freq.) and there are also two SelfSupportingTower-15metres high, on each end of the long side of the building. There is also one-SST belong to theTV operator which is about 50 metres high, located on the SE end of the roof top. Good grounding terminal is available as it's used for grounding all the communication antennas/equipments. I have my own room in the centre of the roof top where we put all our indoor microwave devices and routers/switch. Prefereable wire antenna is lazy 'laying'H or quad, dipole, slope.. I appreciate verymuch any suggestion, input from all, regarding the best wire antenna for this site to be used in the 160M, 80M and 40M band. Thankyou very much indeed in advance. Regards, Nuradi, YB0UNC / KU2B Cellulair +62811138378 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
For 160 DX, a vertically-polarized antenna (fed against a proper ground) is best. http://www.w0btu.com/160_meters.html 73, Mike www.w0btu.com On 8/7/2015 16:52 PM, Nuradi wrote: I plan to install wire antenna on a roof top of a 33rd story building (about 110 metres above the ground) for operating on the 160M, 80M and 40M band. ... Preferable wire antenna is lazy 'laying'H or quad, dipole, slope.. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
Careful Mike! Jakarta is close to the equator, and power coupling is likely to be better from a horizontally polarised antenna, especially in an E-W direction. Ref The Big Gun's Guide to Low-Band Propagation by Bob Brown, NM7M (SK) On 2015-08-08 12:40 p.m., Mike Waters wrote: For 160 DX, a vertically-polarized antenna (fed against a proper ground) is best. http://www.w0btu.com/160_meters.html 73, Mike www.w0btu.com On 8/7/2015 16:52 PM, Nuradi wrote: I plan to install wire antenna on a roof top of a 33rd story building (about 110 metres above the ground) for operating on the 160M, 80M and 40M band. ... Preferable wire antenna is lazy 'laying'H or quad, dipole, slope.. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
Really?! I think I just learned something important. Thanks, Greg! 73, Mike www.w0btu.com On Fri, Aug 7, 2015 at 8:24 PM, Greg - ZL3IX zl...@inet.net.nz wrote: Careful Mike! Jakarta is close to the equator, and power coupling is likely to be better from a horizontally polarised antenna, especially in an E-W direction. Ref The Big Gun's Guide to Low-Band Propagation by Bob Brown, NM7M (SK) On 2015-08-08 12:40 p.m., Mike Waters wrote: For 160 DX, a vertically-polarized antenna (fed against a proper ground) is best. http://www.w0btu.com/160_meters.html 73, Mike www.w0btu.com On 8/7/2015 16:52 PM, Nuradi wrote: I plan to install wire antenna on a roof top of a 33rd story building (about 110 metres above the ground) for operating on the 160M, 80M and 40M band. ... Preferable wire antenna is lazy 'laying'H or quad, dipole, slope.. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
And Bob Brown used a monograph by J.A. Ratcliffe--The Magneto-Ionic Theory and its Application to the Ionosphere which says the same thing. It has to do with the angle between the E vector and the Earth's Geomagnetic Field, which is horizontal at the geomagnetic equator. Bob borrowed my copy of the book when he was writing the Big Gun's Guide. Garry, NI6T On 8/7/2015 6:24 PM, Greg - ZL3IX wrote: Careful Mike! Jakarta is close to the equator, and power coupling is likely to be better from a horizontally polarised antenna, especially in an E-W direction. Ref The Big Gun's Guide to Low-Band Propagation by Bob Brown, NM7M (SK) On 2015-08-08 12:40 p.m., Mike Waters wrote: For 160 DX, a vertically-polarized antenna (fed against a proper ground) is best. http://www.w0btu.com/160_meters.html 73, Mike www.w0btu.com On 8/7/2015 16:52 PM, Nuradi wrote: I plan to install wire antenna on a roof top of a 33rd story building (about 110 metres above the ground) for operating on the 160M, 80M and 40M band. ... Preferable wire antenna is lazy 'laying'H or quad, dipole, slope.. _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Best wire antenna for roof top location
And remember -- the roof of this building is 110m, so a horizontal antenna is high enough to have pretty good low angle radiation! See http://k9yc.com/VertOrHorizontal-Slides.pdf and double the heights for the graphs of 80M performance. When you're thinking height, consider the building a tower -- it's mostly the far field reflection that determines the vertical pattern. As to ground for a vertical antenna -- let's not confuse the word ground with counterpoise or radial system. An end-fed current-fed vertical needs a counterpoise or radials, NOT a connection to earth. I strongly concur with the advice to spend some serious time LISTENING on that roof before doing anything else. It's pretty common for the stuff described on that roof to be MONDO NOISY, and it's unlikely that you can do much about most of it unless the guys who maintain it are HF hams. 73, Jim K9YC On Fri,8/7/2015 8:02 PM, Garry Shapiro wrote: And Bob Brown used a monograph by J.A. Ratcliffe--The Magneto-Ionic Theory and its Application to the Ionosphere which says the same thing. It has to do with the angle between the E vector and the Earth's Geomagnetic Field, which is horizontal at the geomagnetic equator. Bob borrowed my copy of the book when he was writing the Big Gun's Guide. Garry, NI6T On 8/7/2015 6:24 PM, Greg - ZL3IX wrote: Careful Mike! Jakarta is close to the equator, and power coupling is likely to be better from a horizontally polarised antenna, especially in an E-W direction. Ref The Big Gun's Guide to Low-Band Propagation by Bob Brown, NM7M (SK) _ Topband Reflector Archives - http://www.contesting.com/_topband
