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
Topband: Top Band Antenna
Thanks to all who responded to my enquiry...an Inverted 'L' was the most common advice so will give that option some serious thought. Further question: should a ground rod be used as part of a radial system, or should it be treated separately.? I have seen various arguments for and against, wondering what the group thinks on this. Thanks, Rodger/GM3JOB _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Top Band Antenna
My most recent method of connecting radials at the base of a vertical is to drive in a short copper pipe ground rod and use an all-stainless hose clamp to attach the wires to it. But in some portable operations I have dispensed with any ground rod, and the antenna still seems to work fine. 73/Jon AA1K -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of rodger bryce Sent: Saturday, August 8, 2015 7:06 AM To: topband@contesting.com Subject: Topband: Top Band Antenna Thanks to all who responded to my enquiry...an Inverted 'L' was the most common advice so will give that option some serious thought. Further question: should a ground rod be used as part of a radial system, or should it be treated separately.? I have seen various arguments for and against, wondering what the group thinks on this. Thanks, Rodger/GM3JOB _ 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: Top Band Antenna
On Sat,8/8/2015 4:05 AM, rodger bryce wrote: Further question: should a ground rod be used as part of a radial system, or should it be treated separately.? I have seen various arguments for and against, wondering what the group thinks on this. A ground rod is NOT an effective part of a radial system, but it IS important for lightning protection. Here are slides for a talk I've done at Pacificon and for several ham clubs. http://k9yc.com/160MPacificon.pdf 73, Jim K9YC _ 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: Best wire antenna for roof top location
On Aug 8, 2015, at 10:58 22AM, Tom W8JI w...@w8ji.com wrote: Large buildings are not towers or poles. Buildings have a significant amount of large conductive metallic things and noise generating junk inside. 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. Even with a 400 ft high building, a horizontal antenna a fraction of wave over the roof can be very disappointing. Many years ago, at the start of my sophomore year in college, a classmate and I decided to operate CW Sweepstakes from my room in a 5-story dormitory. The dormitory footprint was a long, skinny rectangle with brick parapets rising 10 feet above the rooftop at the four corners of the building. We had easy access to the roof, which was flat with a tar and gravel surface, so we strung an 80-meter center-fed dipole diagonally across the roof between two opposing parapets — but, with the usual wire sag, the feedpoint was about 5 feet above the gravel. We weren’t worried, because the roof was at least 70 feet above the surrounding terrain. We had a single-813 transmitter that ran 500 watts input at a time when the legal limit was 1 KW input. It was far more power than I was accustomed to, since my home station transmitter at that time was a Heath DX-40, running about a tenth as much power. I was expecting “great things” in this contest, but it was one of the most disappointing outings I’ve ever participated in — we struggled for every QSO the entire weekend! A few days after the contest we learned from the head of the college maintenance department that underneath all that tar and gravel was a solid sheet of copper! Moral of the story: Believe what Tom tells you — especially his final sentence above! Bud, W2RU _ 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: Best wire antenna for roof top location
Nuradi, how about halfwave sloping dipoles hung digonally from the top of the building? Some 30 years ago at YU1EXY we had contest shack at top of 60m tall building with student's dormitory. In spite the building was in the middle of city noise, sloping dipoles played extremely well. Later we replaced sloping dipoles with sloped yagis for 80m (3 el toward NW (USA) and 2 el toward NE (Japan). With halfwave sloping dipole we managed to QSO KH6 on 160m, very though contact from this part of Europe. Maybe building acted as kind of reflector on this band... 73, Mirko, S57AD 2015-08-08 1:52 GMT+02:00 Nuradi yb0...@gmail.com: 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: Top Band Antenna
I have this with interest---lot of stuff maybe even at age 74 you can teach an old dog new tricks...bookmarked and will attempt to absorbthanks 73 john w8wej On 8/8/2015 2:55 PM, Jim Brown wrote: On Sat,8/8/2015 4:05 AM, rodger bryce wrote: Further question: should a ground rod be used as part of a radial system, or should it be treated separately.? I have seen various arguments for and against, wondering what the group thinks on this. A ground rod is NOT an effective part of a radial system, but it IS important for lightning protection. Here are slides for a talk I've done at Pacificon and for several ham clubs. http://k9yc.com/160MPacificon.pdf 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Best wire antenna for roof top location
I agree with Mirko...sloping dipoles is the best choice for Nuradi location...THE LOW BAND DXING book is very clear. If SEA WATER is close it is better. 73Douglas, CO8DM No creo que haya alguna emoción más intensa para un inventor que ver alguna de sus creaciones funcionando. Esa emoción hace que uno se olvide de comer, de dormir, de todo. - Nikola Tesla - Original Message - From: Mirko S57AD miroslav.sibi...@amis.net To: Nuradi yb0...@gmail.com Cc: topband@contesting.com Sent: Saturday, August 08, 2015 3:03 PM Subject: Re: Topband: Best wire antenna for roof top location Nuradi, how about halfwave sloping dipoles hung digonally from the top of the building? Some 30 years ago at YU1EXY we had contest shack at top of 60m tall building with student's dormitory. In spite the building was in the middle of city noise, sloping dipoles played extremely well. Later we replaced sloping dipoles with sloped yagis for 80m (3 el toward NW (USA) and 2 el toward NE (Japan). With halfwave sloping dipole we managed to QSO KH6 on 160m, very though contact from this part of Europe. Maybe building acted as kind of reflector on this band... 73, Mirko, S57AD 2015-08-08 1:52 GMT+02:00 Nuradi yb0...@gmail.com: 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 _ Topband Reflector Archives - http://www.contesting.com/_topband
