Re: Topband: 40m array as RX antenna
Hello JC, There is nothing to disagree about JC, My 20 to 24 foot elements when fed into a Hi-Z amp produce a signal that is around 20 dB less than a good TX vertical. Your Waller flags produce a signal that is 40 to 50 dB below a TX vertical. What I said was that because of this difference in absolute signal level, Hi-Z systems could survive just fine in plastic boxes. Any other lower gain element certainly needs more protection like metal shielding, you are quite correct. I have a system I have been working on for years that falls in this same category of small signals that require more shielding. I do understand. Digging a weak signal is not a huge problem when you have 20 dB more signal to work with. I do not dispute what you say in regard to your Waller flag antennas. Do the plastic boxes let extraneous signal in? Yes but not enough to disturb the Hi-Z systems. And yes, circuit design is very important in both these cases. And yes, Hi-Z systems have internal common mode protection on various in and out connectors. They also have protection From signal injection from VCC. Plus a great deal more. I have no issue with what you say. I do not disparage your systems. I just don’t need the hundreds of Hi-Z customers calling about changing to metal boxes on my systems that won't be improved by this type of change... 73 Lee K7TJR Hi-Z Antennas Hi Jim and Lee Before we agree that we disagree, let me elaborate on few basic concepts for a good design. Point by point and let me know which one you disagree. 1- RF runs outside the cable surface, it does not matter what is inside, a coax cable shield, a solid # 4 wire external surface is similar to a RG58 in respect of RF current. 2- Every cable on your station is an antenna. If the cable is 1/8 to 1/2 wave long on low bands, the energy on the outside surface is very high. 100ft rotor cable , or 100ft 9913 from your 2m antenna, or 100ft of controls cable, and or 100ft of RG6 on your RX antenna have almost the same energy of your 160m inverted L ~ 120ft. 3- All these cables somehow are connected to your station ground at your station. All of them are part of your antenna system and interact with each other. 4- Any of these cables connecting into a well-designed board brings a lot of energy on low bands, normally called common mode noise, signal that we don’t want to mix with our RX signal coming from our RX antenna. 5- Prevent the external RF current to enter into our board is a big problem on low bands. On Audio, you have an excellent description of pin 1 problem on your papers, 60 and 120 Hz is the issue. On low bands 1.8 MHz, all RF signals from 50 KHz to 10 MHz are responsible for the common mode noise current on low band antennas. 6- To filter or decouple 1.8 MHz signal a 1000 pf or 1nF has a very high impedance, 10nF is not enough, it is necessary 100 nF or more. DC filter is an issue too, it is easy to inject the common mode noise into the Vcc. 7- May point is that is very difficult to protect any board or parts, like a BALUN or transformer, or any amplifier from common mode noise, PIN 1 PROBLEM. A plastic box make almost impossible to avoid that. A Metal case protects the board and avoid the external current to get into the board. 8- I can agree that the intensity of the signal and the common mode signal leak could be 20 db, 30 db or more. However when you dig a weak signal it is huge problem. 73' JC N4IS -Original Message- From: Jim Brown [mailto:j...@audiosystemsgroup.com] Sent: Wednesday, November 14, 2018 8:10 PM To: n...@n4is.com Cc: l...@k7tjr.com Subject: Re: Topband: 40m array as RX antenna On 11/14/2018 4:41 PM, n...@n4is.com wrote: > I would suggest a metal box to protect any RX system, it does help. Only if the circuit layout is poor. Lee is right - shielding of circuity is only a band-aid for poor design. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 40m array as RX antenna
I have one of JC's Waller Flags on a 40 foot boom at 95 feet.. It is fed with LMR-600 at the tower base XFMR where the 100 ohm twin-ax terminates. It is use with a K-3 in diversity receive with a Hi-Z 8 which is down the hill es across the creek. The system hears remarkably well.. Beverages, Ewes, and other RX antennas are out the door... In the shack the 40 dB N4IS pre-amp is in a steel box for shielding purposes. All components of the station are connected via 1/2 " braid to a 6 ' x 6" x 1\4' aluminum grounding bus. There are multiple chokes in the leads per N4IS es NX4D... It has been a long process. The IC-7610 is also in use from time to time since this SDR radio is Ultra-Quiet... 73, John, W4NU On 11/15/2018 7:19 AM, JC wrote: Hi Jim and Lee Before we agree that we disagree, let me elaborate on few basic concepts for a good design. Point by point and let me know which one you disagree. 1- RF runs outside the cable surface, it does not matter what is inside, a coax cable shield, a solid # 4 wire external surface is similar to a RG58 in respect of RF current. 2- Every cable on your station is an antenna. If the cable is 1/8 to 1/2 wave long on low bands, the energy on the outside surface is very high. 100ft rotor cable , or 100ft 9913 from your 2m antenna, or 100ft of controls cable, and or 100ft of RG6 on your RX antenna have almost the same energy of your 160m inverted L ~ 120ft. 3- All these cables somehow are connected to your station ground at your station. All of them are part of your antenna system and interact with each other. 4- Any of these cables connecting into a well-designed board brings a lot of energy on low bands, normally called common mode noise, signal that we don’t want to mix with our RX signal coming from our RX antenna. 5- Prevent the external RF current to enter into our board is a big problem on low bands. On Audio, you have an excellent description of pin 1 problem on your papers, 60 and 120 Hz is the issue. On low bands 1.8 MHz, all RF signals from 50 KHz to 10 MHz are responsible for the common mode noise current on low band antennas. 6- To filter or decouple 1.8 MHz signal a 1000 pf or 1nF has a very high impedance, 10nF is not enough, it is necessary 100 nF or more. DC filter is an issue too, it is easy to inject the common mode noise into the Vcc. 7- May point is that is very difficult to protect any board or parts, like a BALUN or transformer, or any amplifier from common mode noise, PIN 1 PROBLEM. A plastic box make almost impossible to avoid that. A Metal case protects the board and avoid the external current to get into the board. 8- I can agree that the intensity of the signal and the common mode signal leak could be 20 db, 30 db or more. However when you dig a weak signal it is huge problem. 73' JC N4IS -Original Message- From: Jim Brown [mailto:j...@audiosystemsgroup.com] Sent: Wednesday, November 14, 2018 8:10 PM To: n...@n4is.com Cc: l...@k7tjr.com Subject: Re: Topband: 40m array as RX antenna On 11/14/2018 4:41 PM, n...@n4is.com wrote: I would suggest a metal box to protect any RX system, it does help. Only if the circuit layout is poor. Lee is right - shielding of circuity is only a band-aid for poor design. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 40m array as RX antenna
Hi Jim and Lee Before we agree that we disagree, let me elaborate on few basic concepts for a good design. Point by point and let me know which one you disagree. 1- RF runs outside the cable surface, it does not matter what is inside, a coax cable shield, a solid # 4 wire external surface is similar to a RG58 in respect of RF current. 2- Every cable on your station is an antenna. If the cable is 1/8 to 1/2 wave long on low bands, the energy on the outside surface is very high. 100ft rotor cable , or 100ft 9913 from your 2m antenna, or 100ft of controls cable, and or 100ft of RG6 on your RX antenna have almost the same energy of your 160m inverted L ~ 120ft. 3- All these cables somehow are connected to your station ground at your station. All of them are part of your antenna system and interact with each other. 4- Any of these cables connecting into a well-designed board brings a lot of energy on low bands, normally called common mode noise, signal that we don’t want to mix with our RX signal coming from our RX antenna. 5- Prevent the external RF current to enter into our board is a big problem on low bands. On Audio, you have an excellent description of pin 1 problem on your papers, 60 and 120 Hz is the issue. On low bands 1.8 MHz, all RF signals from 50 KHz to 10 MHz are responsible for the common mode noise current on low band antennas. 6- To filter or decouple 1.8 MHz signal a 1000 pf or 1nF has a very high impedance, 10nF is not enough, it is necessary 100 nF or more. DC filter is an issue too, it is easy to inject the common mode noise into the Vcc. 7- May point is that is very difficult to protect any board or parts, like a BALUN or transformer, or any amplifier from common mode noise, PIN 1 PROBLEM. A plastic box make almost impossible to avoid that. A Metal case protects the board and avoid the external current to get into the board. 8- I can agree that the intensity of the signal and the common mode signal leak could be 20 db, 30 db or more. However when you dig a weak signal it is huge problem. 73' JC N4IS -Original Message- From: Jim Brown [mailto:j...@audiosystemsgroup.com] Sent: Wednesday, November 14, 2018 8:10 PM To: n...@n4is.com Cc: l...@k7tjr.com Subject: Re: Topband: 40m array as RX antenna On 11/14/2018 4:41 PM, n...@n4is.com wrote: > I would suggest a metal box to protect any RX system, it does help. Only if the circuit layout is poor. Lee is right - shielding of circuity is only a band-aid for poor design. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 40m array as RX antenna
Lee I agree with you, a vertical array in a quiet place works very well, I remember our friend Dale. The 8 circle array has almost 13 db RDF and can hear better than the WF with 11.5db RDF. The issue is city lot with tons of noise from everywhere. Small back yard with all cables tower and other wires nothing vertical works there. Several contest stations have problems with beverages due to much towers. Unfortunately situation is getting wroth every year, I am not using my vertical WF anymore, the noise level with LED and Variable speed motor drives, is becoming unbearable on the city. Friday and Saturday people here charge the battery of their boats to enjoy the weekends at the sea, what a mess, noise from everywhere. The noise on my vertical antenna is s9 during the week and s9+10 during weekends. EWE, loops and flags need low NF and good shield. I am just reporting what I see helping people to install WF's. Most station have serious problem with common mode noise. I would suggest a metal box to protect any RX system, it does help. You never know what you are missing if you have nothing to compare with. I understand price point is always an issue. Regards JC N4IS -Original Message- From: Topband On Behalf Of l...@k7tjr.com Sent: Wednesday, November 14, 2018 6:28 PM To: 'topband' Subject: Re: Topband: 40m array as RX antenna JC thanks for helping Jamie, I agree with most things you have pointed out however I must take issue with you on never use plastic boxes. I have used plastic boxes on my arrays for many years now and it has been very successful. The decision to use a plastic box or not depends mostly on the signal levels expected in the circuitry. My take on this is that the Waller flags have a very low signal output which requires extreme low noise and high gain amplification. The phased vertical arrays such as I make have a much greater signal output level and have never shown any ill affects using plastic. There is no need for my customers to go on a mission to change all their arrays to metal boxes. As far as DX is concerned I wish my very good friend Dale N4NN from Florida was still around because he and I would compare what you were hearing and what he was hearing. He always reported to me he would hear everything you did with his Hi-Z 8 array. I suspect the difference as you say was he was in the country without a lot of vertically polarized noise where your recording clearly indicate considerable power line noise on your VWF compared to your HWF. Eliminating local noise is quite a process of peeling back the layers one at a time. Without any other tools your best noise finding friend is a small transistorized BC band radio. It is amazing what you hear when you place one near different powered objects in your area. Put one next to your TX antenna and you will find noises and signals that are reradiated. Put one next to your computer monitor and you are likely to faint. The biggest problem we see is RG-6 coaxial cable that has been contaminated and the shield connection is damaged. To a great degree that causes all directivity to be compromised as the array then electrically looks just like a bunch of wire laying on the ground. Interesting that you indicate some say front to back does not affect RDF but this I will assure you, if you have an array that does not show significant front to back you can be rest assured the array will not have much RDF. The writings of Jim K9YC are very valuable for knocking down local noise in any RX antenna. He has addressed this many times. Keep us posted Jamie if you need more information. Lee K7TJR Hi-Z Antennas Hi Jaime The only way to really improve signal to noise ratio is with directivity. Better directivity better signal to noise ratio. Everything else is just less deterioration or more deterioration. The only thing that makes a difference is how narrow the front lobe really is. Your 40m array plus the integration with your tower and inverted L is giving you a better directivity. Probably if you try another direction the results should be very different. Things that people believe but does not impact signal to noise ratio. 1- Front back. 2- Noise canceling devices , (only help with weak signal it its narrow the front lobe) 3- Vertical array, if you live downtown, or a city lot like mine, 150x 100 ft back yard. The manmade noise is only vertical polarized, vertical array may help you to hear more noise. If you want your vertical RX array to work, it is necessary to detune your TX antenna, and any other vertical structure above 1/8 wave high, even it is 300 ft away. 160m one wave length is 480ft long, don't full yourself. Get common mode out of your RX system input, good shield is a must, never use plastic box for any RX system part. Open frame relay is also a big problem, DC bringing noise to the amplifier, another thing. Choke and shield is your friend, but only works with a good ground. RDF
Re: Topband: 40m array as RX antenna
JC thanks for helping Jamie, I agree with most things you have pointed out however I must take issue with you on never use plastic boxes. I have used plastic boxes on my arrays for many years now and it has been very successful. The decision to use a plastic box or not depends mostly on the signal levels expected in the circuitry. My take on this is that the Waller flags have a very low signal output which requires extreme low noise and high gain amplification. The phased vertical arrays such as I make have a much greater signal output level and have never shown any ill affects using plastic. There is no need for my customers to go on a mission to change all their arrays to metal boxes. As far as DX is concerned I wish my very good friend Dale N4NN from Florida was still around because he and I would compare what you were hearing and what he was hearing. He always reported to me he would hear everything you did with his Hi-Z 8 array. I suspect the difference as you say was he was in the country without a lot of vertically polarized noise where your recording clearly indicate considerable power line noise on your VWF compared to your HWF. Eliminating local noise is quite a process of peeling back the layers one at a time. Without any other tools your best noise finding friend is a small transistorized BC band radio. It is amazing what you hear when you place one near different powered objects in your area. Put one next to your TX antenna and you will find noises and signals that are reradiated. Put one next to your computer monitor and you are likely to faint. The biggest problem we see is RG-6 coaxial cable that has been contaminated and the shield connection is damaged. To a great degree that causes all directivity to be compromised as the array then electrically looks just like a bunch of wire laying on the ground. Interesting that you indicate some say front to back does not affect RDF but this I will assure you, if you have an array that does not show significant front to back you can be rest assured the array will not have much RDF. The writings of Jim K9YC are very valuable for knocking down local noise in any RX antenna. He has addressed this many times. Keep us posted Jamie if you need more information. Lee K7TJR Hi-Z Antennas Hi Jaime The only way to really improve signal to noise ratio is with directivity. Better directivity better signal to noise ratio. Everything else is just less deterioration or more deterioration. The only thing that makes a difference is how narrow the front lobe really is. Your 40m array plus the integration with your tower and inverted L is giving you a better directivity. Probably if you try another direction the results should be very different. Things that people believe but does not impact signal to noise ratio. 1- Front back. 2- Noise canceling devices , (only help with weak signal it its narrow the front lobe) 3- Vertical array, if you live downtown, or a city lot like mine, 150x 100 ft back yard. The manmade noise is only vertical polarized, vertical array may help you to hear more noise. If you want your vertical RX array to work, it is necessary to detune your TX antenna, and any other vertical structure above 1/8 wave high, even it is 300 ft away. 160m one wave length is 480ft long, don't full yourself. Get common mode out of your RX system input, good shield is a must, never use plastic box for any RX system part. Open frame relay is also a big problem, DC bringing noise to the amplifier, another thing. Choke and shield is your friend, but only works with a good ground. RDF measure directivity, more RDF better reception, but every single wire , cable, tower can deteriorate RDF, you need to control that. You can hear my webinar at WWW.WWROF.ORG >> https://wwrof.org/webinar-archive/n4is-waller-flag-construction/ >> https://wwrof.org/webinar-archive/high-performance-rx-antennas-for-a-small-l ot/ Just an update from that Webinar . NX4D using a Waller Flag from a 1/5 acre lot is now at #311, confirmed on 160m. My Horizontal Waller Flag, HWF, is working very well, I can hear 4K6FO , FR , VU almost every time they are on the band.. I Heard 316 countries on 160m since 2006, but the HWF was operational only after 2010. Now I am at #299 on 160m. This is a thing people only believe when they see it happening. Almost 100 people is using WHF and VWF around the world, all of them delivering excellent performance. However it is a huge project, not plug an play at all, and it works! 73's JC N4IS _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 40m array as RX antenna
I have 2x6 switch at the tower, that the inv l feeds thru, choosing a different antenna makes no difference in the noise level, but I suspect there is more to detuning it than just disconnecting it. Sent from my iPad > On Nov 14, 2018, at 4:00 PM, wrote: > > > If you want your vertical RX array to work, it is necessary to detune your > TX antenna, and any other vertical structure above 1/8 wave high, even it is > 300 ft away. 160m one wave length is 480ft long, don't full yourself. > > > > > > > -Original Message- > From: Topband On Behalf Of Jamie WW3S > Sent: Wednesday, November 14, 2018 2:10 PM > To: topband > Subject: Topband: 40m array as RX antenna > > I'm plagued with local noise, I live in a sub division, and have a small > loet (80x180), 2 yrs ago, I tried a reversible EWE and had pretty good > sucess with it, last year I tried a HI-Z 3L, and wasnt really any better > than the EWE. I put the EWE up again this season, and its so-so, but have > discovered that my 2 ele 40m phased verticals work great as a RC > antenna.there is literraly no noise on this.signal are weak, but as > this noise is S0, I can hear just about everything (OK I couldnt hear the FR > last night but I heard a bunch of EU calling him)..wondering why the > noise is so lowoh this array compared to my other antennas, and if thats a > clue as to what may be wrong (if anything) with the others.my 160 inv l > is S9 noise level, and my EWE is about S3. > _ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: 40m array as RX antenna
Hi Jaime The only way to really improve signal to noise ratio is with directivity. Better directivity better signal to noise ratio. Everything else is just less deterioration or more deterioration. The only thing that makes a difference is how narrow the front lobe really is. Your 40m array plus the integration with your tower and inverted L is giving you a better directivity. Probably if you try another direction the results should be very different. Things that people believe but does not impact signal to noise ratio. 1- Front back. 2- Noise canceling devices , (only help with weak signal it its narrow the front lobe) 3- Vertical array, if you live downtown, or a city lot like mine, 150x 100 ft back yard. The manmade noise is only vertical polarized, vertical array may help you to hear more noise. If you want your vertical RX array to work, it is necessary to detune your TX antenna, and any other vertical structure above 1/8 wave high, even it is 300 ft away. 160m one wave length is 480ft long, don't full yourself. Get common mode out of your RX system input, good shield is a must, never use plastic box for any RX system part. Open frame relay is also a big problem, DC bringing noise to the amplifier, another thing. Choke and shield is your friend, but only works with a good ground. RDF measure directivity, more RDF better reception, but every single wire , cable, tower can deteriorate RDF, you need to control that. You can hear my webinar at WWW.WWROF.ORG >> https://wwrof.org/webinar-archive/n4is-waller-flag-construction/ >> https://wwrof.org/webinar-archive/high-performance-rx-antennas-for-a-small-l ot/ Just an update from that Webinar . NX4D using a Waller Flag from a 1/5 acre lot is now at #311, confirmed on 160m. My Horizontal Waller Flag, HWF, is working very well, I can hear 4K6FO , FR , VU almost every time they are on the band.. I Heard 316 countries on 160m since 2006, but the HWF was operational only after 2010. Now I am at #299 on 160m. This is a thing people only believe when they see it happening. Almost 100 people is using WHF and VWF around the world, all of them delivering excellent performance. However it is a huge project, not plug an play at all, and it works! 73's JC N4IS -Original Message- From: Topband On Behalf Of Jamie WW3S Sent: Wednesday, November 14, 2018 2:10 PM To: topband Subject: Topband: 40m array as RX antenna I'm plagued with local noise, I live in a sub division, and have a small loet (80x180), 2 yrs ago, I tried a reversible EWE and had pretty good sucess with it, last year I tried a HI-Z 3L, and wasnt really any better than the EWE. I put the EWE up again this season, and its so-so, but have discovered that my 2 ele 40m phased verticals work great as a RC antenna.there is literraly no noise on this.signal are weak, but as this noise is S0, I can hear just about everything (OK I couldnt hear the FR last night but I heard a bunch of EU calling him)..wondering why the noise is so lowoh this array compared to my other antennas, and if thats a clue as to what may be wrong (if anything) with the others.my 160 inv l is S9 noise level, and my EWE is about S3. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: 40m array as RX antenna
I'm plagued with local noise, I live in a sub division, and have a small loet (80x180), 2 yrs ago, I tried a reversible EWE and had pretty good sucess with it, last year I tried a HI-Z 3L, and wasnt really any better than the EWE. I put the EWE up again this season, and its so-so, but have discovered that my 2 ele 40m phased verticals work great as a RC antenna.there is literraly no noise on this.signal are weak, but as this noise is S0, I can hear just about everything (OK I couldnt hear the FR last night but I heard a bunch of EU calling him)..wondering why the noise is so lowoh this array compared to my other antennas, and if thats a clue as to what may be wrong (if anything) with the others.my 160 inv l is S9 noise level, and my EWE is about S3. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
