Topband: RUSSIAN 160 METER CONTEST
Dear friends, RUSSIAN 160 METER CONTEST will be held from 20.00 to 24.00 UTC, on the 19th December 2014. The Rules of the Contest are at http://www.radio.ru/cq/contest/rule-results/index2012.shtml Current Rules were approximated with RDXC Rules, and any RDXC software may be used in this contest. In previous years, various ideas were discussed, both negative and positive, but finally positive ideas predominated, - even from those who are against Rules changes. Operators from almost 50 Russian oblasts participated in the last Contest. Please note: THERE IS NO 10-minutes rule for club stations. Welcome to participate in RUSSIAN 160 METER CONTEST ! 73! -- С уважением, Vlad / R7LV mailto: r...@dx.ru ua...@dx.ru ua...@mail.ru _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Shunt Feed - Insulated Elements on Yagi
I have never had an issue with this on any tower I have shunt fed that had a Yagi at the top with insulated elements, but then again my insulators are probably a lot better than the average ones used on commerical antennas. I am thinking about shunt feeding a tower that is not mine and wanted to know whether anyone has had any issue runniing 1500 watts to a shunt fed tower that has a Yagi at the top with insulated elements. Im not wanting to ground elements and don't need additional top loading. What I would like to know is anyone has done any damage or melted anything. Thanks...Stan, K5GO _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Non-resonant receive antennas
I noticed JC's comment below about a low dipole as a receiving antenna. Did I interpret that correctly? I've read of a Dipole on the ground as a low noise receive antenna for 160 but.can a non resonant dipole installed at low heights be better, as a receive antenna, than a vertical or L antenna? How about a non-resonant dipole, say, two feet above ground, at a length of 100 feet? Would you feed it with coax or figure out the Zo at 160 and use a suitably wound xfmr to match to 50 ohms??? Just athinkin' of ways to use available low horizontal space, albeit the available space is insufficient for a beverage. Thoughts??? 72, Jim Rodenkirch K9JWV From: n...@comcast.net To: jkaufm...@alum.mit.edu; topband@contesting.com Date: Wed, 17 Dec 2014 23:11:10 -0500 Subject: Re: Topband: 8 circle: DXE vs Hi-Z Hi guys Polarization does play a lot on 160m for two reasons. I can say that because I am using my HWF (two horizontal flags end fire) since 2009. The first one is local man made noise that propagate only vertical due the attenuation on the horizontal component near the ground. And Second the DX signal always come in both polarization. The result form the two reasons is an optimized signal to noise ration using horizontal polarization. I have both WF with the same RDF, during SR or SS there is almost no sky noise coming from the back because of the darkness, however local man made noise comes from any direction, especially if you live in a city lot like I do. Most of the time the noise is coming at the same direction you want to hear the DX, and if you add power line noise the situation deteriorates a lot for the VWF due vertical polarization. Using my HWF I normally get 10 dB better SNR than my VWF that has the same RDF and same aperture of 74 degree measures, I can turn the antenna and measure it, they are not optimized for best F/B, I optimized them for maximum rejection of local man made noise. The HWF is not a dipole. The two phased loops take of angle us 40 degree and there is a huge attenuation for signals above 60 degree. Low dipole is a huge issue if the dipole is resonant, it will interact with all other receiver antennas and will destroy directivity of all of them, if you want to use a low dipole make it not resonant. Gain in not important so it can be short as a 30 m dipole and still will hear the same way. Another issue with low dipoles is the amount of energy absorbed from the TX antenna. If you connect a power meter and a 50 ohms load o the low dipole and transmit KW on the TX antenna, you can measure several WATTS at the low dipole . You can burn you front end with a low resonant dipole. Adding to all that there is another very interesting observation from my last 5 year using a high RDF horizontal RX antenna, when the TX signal refract on the ionosphere the signal split in two waves, that was very well explained by K9LA. What I observed is that these two waves does propagate in different directions. I normally receive VK6 near my SR with better SNR horizontal from 210 degree SSW and with better SNR from 280 degree vertical. Sometimes the horizontal peak is 20 minutes before the vertical peak that is most of the time at my SR. 73's N4IS JC -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of John Kaufmann Sent: Wednesday, December 17, 2014 8:59 PM To: topband@contesting.com Subject: Re: Topband: 8 circle: DXE vs Hi-Z Good points about polarization. If the signals and/or noise are polarized predominantly in one state, then RDF may not be a good predictor of SNR performance, particularly if the antenna receives predominantly in an orthogonal polarization. On the other hand, if the polarization state of the signals and noise evolve randomly with no preference for any one state, which is often assumed for skywave signals, then RDF will be--on average--a good receiving metric, subject to the previous stated qualifications about the spatial distribution of the received noise. However, some of the past discussions on this reflector about preferential polarization of skywave signals on 160 may call into question the assumption of randomly polarized signals. 73, John W1FV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Richard (Rick) Karlquist Sent: Wednesday, December 17, 2014 3:19 PM To: Lee K7TJR; 'Terry Posey'; 'John Kaufmann'; topband@contesting.com Subject: Re: Topband: 8 circle: DXE vs Hi-Z All this discussion about RDF overlooks the issue of polarization. If you make an array of verticals with a certain RDF (assuming noise comes from all directions uniformly), the array will be better than an individual vertical by the RDF factor. However, what I have found is that a horizontally polarized antenna, such as a low dipole frequently receives considerably better than a
Re: Topband: Non-resonant receive antennas
Jim, If the arrival angle of the signals is high, then definitely the low dipole will perform stupendously. At XZ0A in 2000 we were having trouble the first few evenings receiving signals at our sunset and for a couple of hours afterwards. The Beverage RX antennas were working very effectively after that time period, for the entire night time. Our conclusion was that the signals were arriving not only skewed (what signals we were hearing were best on the VK/ZL Beverage and not the direct path on the JA/NA Beverage) but also high arrival angle. I installed a full sized dipole at 20' AGL, suspended by bamboo poles at the center (centered on the helicopter landing zone as we suspected the Myanmar Generals were not going to come visit us) and terminated in the jungle on either side of the helo landing spot. The dipole was oriented east/west, broadside to the N/S. Immediately at the start of that day's Topband operation the NA signals came right up out of the noise floor shortly before sunset. Q5 copy signals on the dipole were barely discernable while listening on the VK/ZL Beverage. For 3 weeks we enjoyed this RX signal capability during the early evening time period. BUT, when it was time for the signal path to change it did so within a 5 minute period every night. It was like someone was disconnecting one antenna and connecting the other, so dramatic was the switch of RX path from skewed, high arrival angle to direct path, much lower arrival angle over a period of a few short minutes. It was like clock work each evening. The low dipole RX antenna allowed an XZ0A 160 M contact to be entered in hundreds of NA log books which most likely would have never happened without it. My personal experience with low (10' AGL), full sized (1/4 WL) horizontal loops at my home station is they work very well for high arrival angle signals but are nearly deaf to low angle signals. Good luck, and YMMV. The low dipole is a specialty RX antenna. And you can never have too many RX antennas. If anyone would like to see photos of the low dipole at XZ0A, send me a direct request. 73 de Milt, N5IA -Original Message- From: James Rodenkirch Sent: Thursday, December 18, 2014 7:26 AM To: Top Band Contesting Subject: Topband: Non-resonant receive antennas I noticed JC's comment below about a low dipole as a receiving antenna. Did I interpret that correctly? I've read of a Dipole on the ground as a low noise receive antenna for 160 but.can a non resonant dipole installed at low heights be better, as a receive antenna, than a vertical or L antenna? How about a non-resonant dipole, say, two feet above ground, at a length of 100 feet? Would you feed it with coax or figure out the Zo at 160 and use a suitably wound xfmr to match to 50 ohms??? Just athinkin' of ways to use available low horizontal space, albeit the available space is insufficient for a beverage. Thoughts??? 72, Jim Rodenkirch K9JWV From: n...@comcast.net To: jkaufm...@alum.mit.edu; topband@contesting.com Date: Wed, 17 Dec 2014 23:11:10 -0500 Subject: Re: Topband: 8 circle: DXE vs Hi-Z Hi guys Polarization does play a lot on 160m for two reasons. I can say that because I am using my HWF (two horizontal flags end fire) since 2009. The first one is local man made noise that propagate only vertical due the attenuation on the horizontal component near the ground. And Second the DX signal always come in both polarization. The result form the two reasons is an optimized signal to noise ration using horizontal polarization. I have both WF with the same RDF, during SR or SS there is almost no sky noise coming from the back because of the darkness, however local man made noise comes from any direction, especially if you live in a city lot like I do. Most of the time the noise is coming at the same direction you want to hear the DX, and if you add power line noise the situation deteriorates a lot for the VWF due vertical polarization. Using my HWF I normally get 10 dB better SNR than my VWF that has the same RDF and same aperture of 74 degree measures, I can turn the antenna and measure it, they are not optimized for best F/B, I optimized them for maximum rejection of local man made noise. The HWF is not a dipole. The two phased loops take of angle us 40 degree and there is a huge attenuation for signals above 60 degree. Low dipole is a huge issue if the dipole is resonant, it will interact with all other receiver antennas and will destroy directivity of all of them, if you want to use a low dipole make it not resonant. Gain in not important so it can be short as a 30 m dipole and still will hear the same way. Another issue with low dipoles is the amount of energy absorbed from the TX antenna. If you connect a power meter and a 50 ohms load o the low dipole and transmit KW on the TX antenna, you can measure several WATTS at the low dipole . You can burn you front end with a
Re: Topband: 8 circle: DXE vs Hi-Z
Hi David and Don I understand your point. Gain is cheap and quite easy to get with a good low noise amplifier, but to keep the common mode noise out of it is very expensive, and could be very complicated. The beverages are very forgiveness and does not requires much amplification. It is an ideal antenna. The noise measured at 500Hz BW on my TX antenna, varies from average -90 dB, when I do not have power line noise to -100 dB few mornings during winter. The noise floor from my HWF is - 120dB (500Hz BW) after a 43db gain preamp (.5dB NF). I have no space for beverages and my station with all antennas uses only 150ft x 100ft. Using 100 Hz BW the noise floor drops to -145dB during the day. Connecting the HWF on the 43db gain increase the noise only 0.2db , you can't hear the increase of noise, I measured it with QS1R SDR, basically the noise is below the sensitivity of the receiver. I can hear very well on 160m. not bragging but just for reference, 4W6, 9M0, 9M4,9M2, HS, DU, XU, and other very weak signals logged in 160 since 2006. Doug worked 292 and I worked 275 on 160m from city lot. The new stuff works. But as I said, it is very expensive. Also the implementation was not possible without the information shared by K9YC, W8JI, and others how to control common mode noise, grounding, shielding and best practices. The list of MUST do things to implement the new stuff is very long The signal above noise is there at the RX array, to bring it at the station and amplify only the signal coming from the RX array without adding common mode noise is very touch. Here is a sort list of must do things 1- Detune all resonant antenna, feed line, rotor cable tower, any metal thing over 90 ft. long . 2- Ground everything at the tower, outside the shack, and in the shack 3- Choke every single cable that enter your radio system, including the preamp. 100's of toroid's is quite common, and few toxoids does not get the job done. 4-All electronics' must be shielded with steel boxes, aluminum does not cut magnetic field and does not help below -120dB noise floor. If possible run all cables inside galvanized grounded water pipes or hot deep galvanized conduit. 5- All cable inside the tower and grounded at the top and at the bottom 6- NO ground loop with the AC lines, isolation transformer and one point ground for the system, your house wires is an effective way to drive noise into the RX system. A good RDF RX antenna does not fix the issues above. There is no allowance here, all points above can deteriorate your RX signal to noise ratio. Using Horizontal antenna does help a lot with interaction with TX antennas but do not eliminate the common mode nose or ground loops problems. Even a single flag is complicated because the feed line can introduce common mode noise, and turn the flag into a loaded vertical. There is only two solution, choke the line overkilling the common mode noise , or use unshielded 100 ohms twisted pair cable. See T6LG results on his web page, only after replacing the coax with twisted pair he was able to work 100's of DX from a military base in YA on 160m. The results using the new RX system varies form excellent to a perfect disaster depending on the points above. 73's N4IS JC -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of David Raymond Sent: Thursday, December 18, 2014 1:01 AM To: Don Moman VE6JY; Topband@Contesting. Com Subject: Re: Topband: 8 circle: DXE vs Hi-Z My experience is similar to Don's outlined below. Both gain and noise figure are important in very low noise environments. In my own case, I have a noise floor from my TX array in the high -120s or -130s assuming a quiet atmosphere. A high RDF performance RX array often brings virtually no improvement. In my case, since the RX arrays lack gain, they often don't have the horsepower (gain) to reach down and hear the super low level signals picked up by the TX array. Switching from the TX antenna to the high RDF receive array not only fails to make the signal jump out of the noise (what noise?) but fails to hear the signal at all. In these circumstance both gain and noise figure become very important factors. 73. . .Dave, W0FLS - Original Message - From: Don Moman VE6JY ve6j...@gmail.com To: Topband@Contesting. Com topband@contesting.com Sent: Wednesday, December 17, 2014 10:53 PM Subject: Re: Topband: 8 circle: DXE vs Hi-Z Well I disagree that gain isn't important. Maybe you topbanders in the better areas of propagation can afford to throw away many db to get a better rdf, but that sure isn't the case up here in mid-northern VE6 land. I have numerous receive antennas including many beverages and Wellbrook loops (large area) and the Hi-Z 4-8PRO 8 element circle. They all work more or less as expected on the easy stuff and show reasonable directivity but when I need help for the weaker dx, there just isn't any signal there to work with.
Re: Topband: Non-resonant receive antennas
Milt, Thanks to share with us your experience during XZ0A. When I started playing with the HWF I was surprised to hear XU7ACY almost every day between 11:10z and 11:20z SSW, during 2010 and 2011 , that happened 50% of the day from October to April. This kind of propagation I called it TELP, Trans Equatorial Long Path. The signals arrive from 40 degree elevation mostly horizontal polarized 20 minutes before SR SSW and 20 minutes after SS SSE. With the HWF I was able to work south Asia almost in a daily base when my colleges nearby only could hear them few day with vertical polarized antennas. The reason why I do believe this propagation is around the equatorial line is due the observation for this kind of propagation from the south hemisphere. Analyzing several long path QSO's from PY's on 160m, there is a common point , in all QSO's the signal was arriving near SS or SR coming from NNW or NNE. In both cases, from north hemisphere or south hemisphere the signal is really coming from the equatorial zone. K9LA demonstrated with a ray trace analyze that the signal refract almost 120 degree at 40 degree angle, you can check that on K9LA web page. I think what I experienced with XU, DU and even JA long path SSW is the same propagation mechanism you mentioned during XZ0A. Very few DX-expeditions uses that propagation mode and do not install any RX antenna to receive SSW and/or SSE. The XU7ACY extravagance QSO's was due the fact Perter was active every day and he installed a SSE /NNW reversible beverage. DU7ET was using a high inverted V broadside N/S that receives horizontal SSE. It is hard d to work DU from Florida until Robert installed that antenna, we worked him Jan, Feb, Mar, Apr, and June this year on 160m, we just missed him during May and I don't know why. By the way Robert worked WAS on 160 with that antenna from DU7ET. 73's N4IS JC -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Milt -- N5IA Sent: Thursday, December 18, 2014 9:56 AM To: James Rodenkirch; Top Band Contesting Subject: Re: Topband: Non-resonant receive antennas Jim, If the arrival angle of the signals is high, then definitely the low dipole will perform stupendously. At XZ0A in 2000 we were having trouble the first few evenings receiving signals at our sunset and for a couple of hours afterwards. The Beverage RX antennas were working very effectively after that time period, for the entire night time. Our conclusion was that the signals were arriving not only skewed (what signals we were hearing were best on the VK/ZL Beverage and not the direct path on the JA/NA Beverage) but also high arrival angle. I installed a full sized dipole at 20' AGL, suspended by bamboo poles at the center (centered on the helicopter landing zone as we suspected the Myanmar Generals were not going to come visit us) and terminated in the jungle on either side of the helo landing spot. The dipole was oriented east/west, broadside to the N/S. Immediately at the start of that day's Topband operation the NA signals came right up out of the noise floor shortly before sunset. Q5 copy signals on the dipole were barely discernable while listening on the VK/ZL Beverage. For 3 weeks we enjoyed this RX signal capability during the early evening time period. BUT, when it was time for the signal path to change it did so within a 5 minute period every night. It was like someone was disconnecting one antenna and connecting the other, so dramatic was the switch of RX path from skewed, high arrival angle to direct path, much lower arrival angle over a period of a few short minutes. It was like clock work each evening. The low dipole RX antenna allowed an XZ0A 160 M contact to be entered in hundreds of NA log books which most likely would have never happened without it. My personal experience with low (10' AGL), full sized (1/4 WL) horizontal loops at my home station is they work very well for high arrival angle signals but are nearly deaf to low angle signals. Good luck, and YMMV. The low dipole is a specialty RX antenna. And you can never have too many RX antennas. If anyone would like to see photos of the low dipole at XZ0A, send me a direct request. 73 de Milt, N5IA -Original Message- From: James Rodenkirch Sent: Thursday, December 18, 2014 7:26 AM To: Top Band Contesting Subject: Topband: Non-resonant receive antennas I noticed JC's comment below about a low dipole as a receiving antenna. Did I interpret that correctly? I've read of a Dipole on the ground as a low noise receive antenna for 160 but.can a non resonant dipole installed at low heights be better, as a receive antenna, than a vertical or L antenna? How about a non-resonant dipole, say, two feet above ground, at a length of 100 feet? Would you feed it with coax or figure out the Zo at 160 and use a suitably wound xfmr to match to 50 ohms??? Just athinkin' of ways to use available low horizontal space, albeit
Re: Topband: Shunt Feed - Insulated Elements on Yagi
Stan - For about 8 years, up until this past spring, my shunt fed tower for 160 had a KT34XA (insulated elements, later upgraded to a KT36XA same insulated elements) at the top and I never experienced any issue at all running 1500 watts, even during a few contests where, as you know, you are running continuous for an extended period. I've read discussion about whether the coax should run inside -vs- outside the tower, mine ran outside. The current arrangement (same tower) has a Cushcraft 40 mtr beam (insulated DE) and an A3WS (insulated DE) on it and the feedlines now run inside the tower. I have developed a problem on 17 meters (12 mtr still OK) with the A3WS so I am trying to assess if it is something caused by the 160 meter shunt feeding or other cause. Still resovling that. But, for years no problem with original set up and now no issue except as noted on 17 meter but most likely NOT related to shunt feed high power. I know some folks have experienced issues but to date (thankfully) I have not. 73 Joel W5ZN I have never had an issue with this on any tower I have shunt fed that had a Yagi at the top with insulated elements, but then again my insulators are probably a lot better than the average ones used on commerical antennas. I am thinking about shunt feeding a tower that is not mine and wanted to know whether anyone has had any issue runniing 1500 watts to a shunt fed tower that has a Yagi at the top with insulated elements. Im not wanting to ground elements and don't need additional top loading. What I would like to know is anyone has done any damage or melted anything. Thanks...Stan, K5GO _ Topband Reflector Archives - http://www.contesting.com/_topband www.w5zn.org _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt Feed - Insulated Elements on Yagi
One of the factors for arc over is the diameter of the tower and top support pipe diameter length. A really FAT 1/4 wave tower may have 1000 ohms at the top, while a skinny tower would have much more. The higher the impedance, the higher the voltage to cause arc overs. 73 Bruce-K1FZ www.qsl.net/k1fz/beveragenotes.html On Thu, 18 Dec 2014 10:05:16 -0600, Joel Harrison w...@w5zn.org wrote: Stan - For about 8 years, up until this past spring, my shunt fed tower for 160 had a KT34XA (insulated elements, later upgraded to a KT36XA same insulated elements) at the top and I never experienced any issue at all running 1500 watts, even during a few contests where, as you know, you are running continuous for an extended period. I've read discussion about whether the coax should run inside -vs- outside the tower, mine ran outside. Thanks...Stan, K5GO _ Topband Reflector Archives - http://www.contesting.com/_topband www.w5zn.org _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
Not wanting to distract from this thread too much, but I'd like to ask a question of the group. If one had the opportunity to install two receiving antennas (such as loops EWE's etc.) for Topband in either a series or parallel configuration, which would be preferred. Since Rick correctly stated that RDF doesn't account for all variables, such as polarization, the same may be said for a pair of antennas in the above configurations. Two receive antennas in parallel will narrow the lobe, but two in series will bring down the upper lobes. Can anyone comment on the advantage or disadvantage of either configuration in real-world practice? Thanks, Jim - KR9U _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: [Bulk] Shunt Feed - Insulated Elements on Yagi
I'm considering insulating elements on large yagis and would like to understand pro's and con's of various boom to element plate insulating materials - RF insulation, physical strength, creep, uv resistance, etc. These raw material properties are easily found, but have some had longer term in use experience worth sharing? 73, Grant KZ1W On 12/18/2014 3:43 AM, Stan Stockton wrote: I have never had an issue with this on any tower I have shunt fed that had a Yagi at the top with insulated elements, but then again my insulators are probably a lot better than the average ones used on commerical antennas. I am thinking about shunt feeding a tower that is not mine and wanted to know whether anyone has had any issue runniing 1500 watts to a shunt fed tower that has a Yagi at the top with insulated elements. Im not wanting to ground elements and don't need additional top loading. What I would like to know is anyone has done any damage or melted anything. Thanks...Stan, K5GO _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt Feed - Insulated Elements on Yagi
Understanding what Bruce has posted would support the theory that a cage feed tower is indeed fatter with a lower impedance and thus less proclivity to arc over on the insulated elements. Herb Schoenbohm, KV4FZ On 12/18/2014 12:33 PM, k...@myfairpoint.net wrote: One of the factors for arc over is the diameter of the tower and top support pipe diameter length. A really FAT 1/4 wave tower may have 1000 ohms at the top, while a skinny tower would have much more. The higher the impedance, the higher the voltage to cause arc overs. 73 Bruce-K1FZ www.qsl.net/k1fz/beveragenotes.html On Thu, 18 Dec 2014 10:05:16 -0600, Joel Harrison w...@w5zn.org wrote: Stan - For about 8 years, up until this past spring, my shunt fed tower for 160 had a KT34XA (insulated elements, later upgraded to a KT36XA same insulated elements) at the top and I never experienced any issue at all running 1500 watts, even during a few contests where, as you know, you are running continuous for an extended period. I've read discussion about whether the coax should run inside -vs- outside the tower, mine ran outside. Thanks...Stan, K5GO _ Topband Reflector Archives - http://www.contesting.com/_topband www.w5zn.org _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
Since Rick correctly stated that RDF doesn't account Jim RDF is everything ! The RX antenna system is the only way to improve signal to noise ratio. All electronic device is not perfect and introduce noise and deteriorate the signal to noise ratio, including your radio too RDF is one way to measure directivity . You may do not need directivity to improve signal to noise ratio if you are operating from a very quiet location or a desert island on the pacific without man made noise. If you deal with noise at your location you will select the antenna with better directivity. That's adds another component how to cover all directions. Better RDF equals to better signal to noise ratio. That's is true for all bands, try to work 20 meter contest with a vertical with 1 kW and compare with a 5 elements Yagi with 100W. Your TX signal will be the same however for sure you will prefer to receive on the Yagi due its directivity. You won't hear much on the vertical Regards JC N4IS _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
Thanks JC, I agree that the RDF number is significant when evaluating a receive antenna. I agree that no one antenna system will work all of the time. Consider we have two scenarios: One RX antenna system that consists of two parallel antennas (Broadside) , and the other is the same antenna configured in-line, toward the desired signal (Delayed series fed). What I am asking is if anyone has any, on-the-air experience and would recommend one antenna system over the other for *most conditions*. In other words, will an antenna that has a less lower elevation pattern generally outperform an antenna that has a narrower beam width, but a higher elevation angle? I think in this we need to consider the arrival angle of atmospheric noise in a broadside array vs. atmospheric noise in a series fed array.Since atmospheric noise propagates and the arrival angle will change, which scenario would provide the general overall better performance? Jim - KR9U _ Jim RDF is everything ! The RX antenna system is the only way to improve signal to noise ratio. All electronic device is not perfect and introduce noise and deteriorate the signal to noise ratio, including your radio too RDF is one way to measure directivity . You may do not need directivity to improve signal to noise ratio if you are operating from a very quiet location or a desert island on the pacific without man made noise. If you deal with noise at your location you will select the antenna with better directivity. That's adds another component how to cover all directions. Better RDF equals to better signal to noise ratio. That's is true for all bands, try to work 20 meter contest with a vertical with 1 kW and compare with a 5 elements Yagi with 100W. Your TX signal will be the same however for sure you will prefer to receive on the Yagi due its directivity. You won't hear much on the vertical Regards JC N4IS _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
Since Rick correctly stated that RDF doesn't account Jim RDF is everything ! The RX antenna system is the only way to improve signal to noise ratio. All electronic device is not perfect and introduce noise and deteriorate the signal to noise ratio, including your radio too RDF is one way to measure directivity . I'm a little tied up with other things like paying work, but I see this is still going on. RDF is directivity, I just called it that to not confuse it with gain that is important to transmitting. I suggested it as a factor in deciding if an antenna is **likely** to be an improvement or not because: 1.) Front gain to rear wide area ratio, based on the null width of the entire rearward pattern, was being used. This method was rarely effective, unless noise largely existed only in the entire rear hemisphere. It is very unlikely to have grossly dominant noise exactly fit a rear hemisphere, and it is impossible to have that condition in more than one direction. 2.) People were using gain as a measure, specifically with closely spaced non-staggered Beverage antennas. If two Beverages are paralleled so close as to not change pattern one bit and not change S/N ratio one bit, gain increases 3 dB! Gain is a useless parameter until the receive system internal noise affects S/N ratio. There certainly are other things that are important, and I weigh more than raw RDF into my selections. (Someday when I have time I may publically document things.) Removing signal from directions where there is no noise or where there is very little noise can make things seem better by RDF when they are really not better, as can RFD improvements by reducing side or back response to levels below where noise or QRM detracts from copy. My preference with large area (not tall height) vertical arrays and Beverage arrays is a very clean pattern with deep nulls elevated above the horizon and maximum overall area removed from the pattern, but I always want to be sure the next direction selected does something useful before I lose too much from the presently selected array. What I have and use is the result of almost 40 years of reading and experimenting, but it only came together here because I have the room I always needed. Most of my life I lived on small lots, and what I did then was ideal. All antennas are compromises, and RDF might be the best (far above gain or other methods) going at the moment, but distribution of noise and QRM has to factor in by looking at the pattern. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
Judging from my own observations and feedback that I get I would say that using a low dipole or horizontal polarity antenna would also depend on what Latitude/Longitude your station is located and how close you are to the sea. Here above 45 degrees Latitude and 200 miles from the sea, I seldom see signals arriving that would benefit from a low horizontal antenna. It does happen however and always early in the a.m.. When FT5XO was on the air I saw their signal change from a very low angle signal received well with verticals to a high angle signal where none of my vertical receiving antennas exhibited any directivity in a couple hours one morning. I have only seen this in the morning when listening West into the Pacific. I have not heard it listening to the East in the evening. So, I say ask around in your area to see what the guys are happy with. I don't think you would hear as many DX signals in my location with a low horizontal as you would with verticals. I am pushing 200 countries on 160 having only used vertical receiving arrays. Or put up both as one can never have enough low-band receiving antennas. Lee K7TJR OR -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of James Wolf Sent: Thursday, December 18, 2014 10:30 AM To: 'JC'; 'Top Band Contesting' Subject: Re: Topband: Non-resonant receive antennas Thanks JC, I agree that the RDF number is significant when evaluating a receive antenna. I agree that no one antenna system will work all of the time. Consider we have two scenarios: One RX antenna system that consists of two parallel antennas (Broadside) , and the other is the same antenna configured in-line, toward the desired signal (Delayed series fed). What I am asking is if anyone has any, on-the-air experience and would recommend one antenna system over the other for *most conditions*. In other words, will an antenna that has a less lower elevation pattern generally outperform an antenna that has a narrower beam width, but a higher elevation angle? I think in this we need to consider the arrival angle of atmospheric noise in a broadside array vs. atmospheric noise in a series fed array.Since atmospheric noise propagates and the arrival angle will change, which scenario would provide the general overall better performance? Jim - KR9U _ Jim RDF is everything ! The RX antenna system is the only way to improve signal to noise ratio. All electronic device is not perfect and introduce noise and deteriorate the signal to noise ratio, including your radio too _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
Jim What I am asking is if anyone has any, on-the-air experience and would recommend one antenna system over the other for *most conditions*. In other words, will an antenna that has a less lower elevation pattern generally outperform an antenna that has a narrower beam width, but a higher elevation angle? I understand your question now. Yes I have exactly that, a low elevation narrow bean VWF, that works best at 20 degree or lower and a same narrow bean but high elevation angle HWF best at 40 degree. I keep a record of new countries worked with one or another. The high elevation angle outperform the low elevation angle 95% of the time, in special near SS or SR. But the low elevation angle was the only antenna that can hear South Asia direct path due north. 9M2AX , BU2AQ, 4W6 over or near the North Pole. Let me say the same thing in another way. For DX signals coming due North 330 to 30 degree , the vertical low angle outperform the high angle always. It is based on the direction the signal is coming from and the interaction with the dip magnetic field. Like 9M4SLL on Mar 13th 2013 was strong 340 degree only heard with VWF, on Mar 17th the signal was coming SSE and the high angle was better, but copy with both antennas. 95% is a big number however the 5% could be a new country. Like 706T in the first and second night only copy on the vertical low angle, after they move to a new location the high angle RX antenna was better. They are complementary to each other, hard to pick one. 73's JC N4IS -Original Message- From: James Wolf [mailto:jbw...@comcast.net] Sent: Thursday, December 18, 2014 1:30 PM To: 'JC'; 'Top Band Contesting' Subject: RE: Topband: Non-resonant receive antennas Thanks JC, I agree that the RDF number is significant when evaluating a receive antenna. I agree that no one antenna system will work all of the time. Consider we have two scenarios: One RX antenna system that consists of two parallel antennas (Broadside) , and the other is the same antenna configured in-line, toward the desired signal (Delayed series fed). What I am asking is if anyone has any, on-the-air experience and would recommend one antenna system over the other for *most conditions*. In other words, will an antenna that has a less lower elevation pattern generally outperform an antenna that has a narrower beam width, but a higher elevation angle? I think in this we need to consider the arrival angle of atmospheric noise in a broadside array vs. atmospheric noise in a series fed array.Since atmospheric noise propagates and the arrival angle will change, which scenario would provide the general overall better performance? Jim - KR9U _ Jim RDF is everything ! The RX antenna system is the only way to improve signal to noise ratio. All electronic device is not perfect and introduce noise and deteriorate the signal to noise ratio, including your radio too RDF is one way to measure directivity . You may do not need directivity to improve signal to noise ratio if you are operating from a very quiet location or a desert island on the pacific without man made noise. If you deal with noise at your location you will select the antenna with better directivity. That's adds another component how to cover all directions. Better RDF equals to better signal to noise ratio. That's is true for all bands, try to work 20 meter contest with a vertical with 1 kW and compare with a 5 elements Yagi with 100W. Your TX signal will be the same however for sure you will prefer to receive on the Yagi due its directivity. You won't hear much on the vertical Regards JC N4IS _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Confusion in ON4UN's Low Band DXing radial length calculations.
Dear OMs and Yls, I am replacing raised radials for 160M inverted L with ground mounted radials mostly because I could not readily get the raised radials up high enough in my wood and also because of maintenance problems. This inverted L goes up 100 feet at its top before levelling out for the final 32' or so. It should I believe have a strong vertical element. ON4UN's book Low-Band DXing 56th edition is generally excellent but I do find the coverage of ground radials both confusing and somewhat contradictory.This surprises me for what is pretty much considered the bible. On page 9-14 the text states that the velocity factor falls for ground mounted radials to the the order of 50-60%, which means that a radial that is physically 20 meters long is actually a half-wave long electrically! This example is for 80M not 160M.However in the examples found on page 9-15 the velocity factor change is ignored.I understand the velocity factor change and have always accepted this. It generally did not pay to try and cut radials precisely to a given wavelength.I accept the radial length vs. radial number charts but is this an electrical length in free space or a length considerably reduced due to velocity factory change?Example 3 ignores velocity factor correction and from what I can see this correction is ignore in most of the text concerning ground radials. What does one do? Who does one believe. While I am talking about a 160M inverted L; I did reference the SteppIR BigIR vertical manual, page 18.Lengths should be scalable.I find no mention of velocity factor and the shortening effect which is experienced. The recommendations are not very different from those in ON4UNs book. So does this mean one ignores the change in velocity factor? I appreciate some guidance with this matter. I would like a radial field which would take me to within 0.5/1 dB of the maximum achievable for reducing near field losses. 73 Doug EI2CN _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Confusion in ON4UN's Low Band DXing radial length calculations.
Hi Doug, As I understand it, the velocity factor of 50% applies for radial wires that are simply laid atop the ground, not buried in any way... But of course, I COULD stand to be corrected..! ~73~ de Eddy VE3CUI - VE3XZ On 2014-12-18, at 4:18 PM, Doug Turnbull wrote: Dear OMs and Yls, I am replacing raised radials for 160M inverted L with ground mounted radials mostly because I could not readily get the raised radials up high enough in my wood and also because of maintenance problems. This inverted L goes up 100 feet at its top before levelling out for the final 32' or so. It should I believe have a strong vertical element. ON4UN's book Low-Band DXing 56th edition is generally excellent but I do find the coverage of ground radials both confusing and somewhat contradictory.This surprises me for what is pretty much considered the bible. On page 9-14 the text states that the velocity factor falls for ground mounted radials to the the order of 50-60%, which means that a radial that is physically 20 meters long is actually a half-wave long electrically! This example is for 80M not 160M.However in the examples found on page 9-15 the velocity factor change is ignored.I understand the velocity factor change and have always accepted this. It generally did not pay to try and cut radials precisely to a given wavelength.I accept the radial length vs. radial number charts but is this an electrical length in free space or a length considerably reduced due to velocity factory change?Example 3 ignores velocity factor correction and from what I can see this correction is ignore in most of the text concerning ground radials. What does one do? Who does one believe. While I am talking about a 160M inverted L; I did reference the SteppIR BigIR vertical manual, page 18.Lengths should be scalable.I find no mention of velocity factor and the shortening effect which is experienced. The recommendations are not very different from those in ON4UNs book. So does this mean one ignores the change in velocity factor? I appreciate some guidance with this matter. I would like a radial field which would take me to within 0.5/1 dB of the maximum achievable for reducing near field losses. 73 Doug EI2CN _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Confusion in ON4UN's Low Band DXing radial lengthcalculations.
Hello Doug, The 50-60% figure depends on your soil conditions, so may vary quite a bit. With my poor, sandy soil, the Vf is 67.7% with the radials laying on the ground. When I buried them 6, the Vf was 39.8%. Using these shortened radials, there wasn't much improvement going beyond 16 radials. To find out your soil conditions, simply lay a temporary dipole on the ground and use an analyzer to find it's resonance. Then trim to length. Now you have your first two radials! Good luck Brian K8BHZ -Original Message- From: Doug Turnbull Sent: Thursday, December 18, 2014 4:18 PM To: topband@contesting.com Subject: Topband: Confusion in ON4UN's Low Band DXing radial lengthcalculations. Dear OMs and Yls, I am replacing raised radials for 160M inverted L with ground mounted radials mostly because I could not readily get the raised radials up high enough in my wood and also because of maintenance problems. This inverted L goes up 100 feet at its top before levelling out for the final 32' or so. It should I believe have a strong vertical element. ON4UN's book Low-Band DXing 56th edition is generally excellent but I do find the coverage of ground radials both confusing and somewhat contradictory.This surprises me for what is pretty much considered the bible. On page 9-14 the text states that the velocity factor falls for ground mounted radials to the the order of 50-60%, which means that a radial that is physically 20 meters long is actually a half-wave long electrically! This example is for 80M not 160M.However in the examples found on page 9-15 the velocity factor change is ignored.I understand the velocity factor change and have always accepted this. It generally did not pay to try and cut radials precisely to a given wavelength.I accept the radial length vs. radial number charts but is this an electrical length in free space or a length considerably reduced due to velocity factory change?Example 3 ignores velocity factor correction and from what I can see this correction is ignore in most of the text concerning ground radials. What does one do? Who does one believe. While I am talking about a 160M inverted L; I did reference the SteppIR BigIR vertical manual, page 18.Lengths should be scalable.I find no mention of velocity factor and the shortening effect which is experienced. The recommendations are not very different from those in ON4UNs book. So does this mean one ignores the change in velocity factor? I appreciate some guidance with this matter. I would like a radial field which would take me to within 0.5/1 dB of the maximum achievable for reducing near field losses. 73 Doug EI2CN _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Iran Topband Emphasis
Preparations Under Way for January DXpedition to Iran Preparations continue on the part of the Rockall DX Group to make Iran -- #33 on ClubLog's DXCC Most Wanted List -- available through a DXpedition to Kish Island (IOTA AS-166). Look for EP6T beginning on January 16. While the emphasis will be on 160 meters, the DXpedition will operate on all bands, 160 through 10 meters. EP6T plans to remain active until January 26. Organizers say the theme of the expedition will be friendship and cultural tolerance. We hope to make a lot of people happy, team member Luc Kerkhofs, ON4IA, said. A dedicated 160 meter station will be on the air starting at local sunrise and sunset for the first two nights, in order to work as many Europeans as possible and to check when signals peak to North America. The planned transmitting antenna is a 26-meter (85.3 feet) vertical with 50 quarter-wave radials. Kerkhofs said the operators will attempt to be fair in giving all continents a crack at working Iran on 160. After that, the operators will concentrate on listening for North American stations, although they concede that paths to North America on Top Band will be dicey and of short duration. Since word first spread of the planned DXpedition, many groups and individuals have offered support, including the Northern California DX Foundation. The organizers say that preparations are progressing smoothly and according to plan. M0URX will be the QSL manager. The EP6T log will be uploaded to Logbook of The World (LoTW) once the DXpedition has concluded. - No virus found in this message. Checked by AVG - www.avg.com Version: 2015.0.5577 / Virus Database: 4253/8762 - Release Date: 12/18/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt Feed - Insulated Elements on Yagi
Concerning voltage breakdowns using yagi-loaded towers on 160 meters... I have heard stories of arcing to beat the band, that included a fair amount of destruction. I have heard stories of nothing needed for good operation, even at QRO. All these stories have to exist in the same logical space. All that you need to lower across-the-insulator voltage stress to a lot of insulated elements is to have just one fairly moderate impedance 160m path from the coax shield to the end of a single half-of-a-driven-element. 500 ohm 160m path through a high band balun to a 20 or 40m driven element would be quite low enough to put the high voltage at the tip of that 1/2 element. You would then have far less voltage across the insulation to the other elements, not enough to arc even at QRO. The controlling length at 160 would be tower plus coax length from tower top to balun plus 1/2 length of that driven element. If the feed arrangement blocks access from the coax to the driven element, and the elements are insulated, for sure there can be arcing. And there are quite a few scenarios for arcing. The mounting plate/u-bolts plus insulation plus insulated element IS a capacitor from the element to the boom. This will constitute a certain amount top loading. My self standing 76 foot tower plus an insulated-element C31XR on top was resonant at 1740. That's a lot of added electrical length for a completely insulated yagi. That's 14 insulated elements to add extra electrical length, which includes three halves of driven elements that are only separated by a high band bead balun from the feed coax. All the entire-lot models for my place have to assume a resonant-on-160 tower back there, which does have a bearing on RX antenna ideas in that part of the lot. 73, Guy K2AV On Thu, 18 Dec 2014 10:05:16 -0600, Joel Harrison w...@w5zn.org wrote: Stan - For about 8 years, up until this past spring, my shunt fed tower for 160 had a KT34XA (insulated elements, later upgraded to a KT36XA same insulated elements) at the top and I never experienced any issue at all running 1500 watts, even during a few contests where, as you know, you are running continuous for an extended period. I've read discussion about whether the coax should run inside -vs- outside the tower, mine ran outside. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: RUSSIAN 160 METER CONTEST
My question is; If this is a contest inviting worldwide participation, why is there not at the minimum a full 24 hours of competition period? Same questions from me and others UA0/RA0 Russian stations... 73! de Eugene RA0FF http://www.qsl.net/ra0ff/ Thu, 18 Dec 2014 08:10:46 -0700 от Milt -- N5IA n...@zia-connection.com: Vlad, Although it is difficult to work Russian stations (UA0 excepted) from my location in southwest USA, I find it very strange that the hours of the contest operation do NOT include any night time hours at my location. The sun sets at 0010 UTC at my location this time of the year. Consequently there is absolutely no opportunity to effectively participate in this 'WORLDWIDE' CONTEST. My question is; If this is a contest inviting worldwide participation, why is there not at the minimum a full 24 hours of competition period? 73 de Milt, N5IA -- Also operator of N7GP == -Original Message- From: R7LV Sent: Thursday, December 18, 2014 2:23 AM To: topband@contesting.com Subject: Topband: RUSSIAN 160 METER CONTEST Dear friends, RUSSIAN 160 METER CONTEST will be held from 20.00 to 24.00 UTC, on the 19th December 2014. The Rules of the Contest are at http://www.radio.ru/cq/contest/rule-results/index2012.shtml Current Rules were approximated with RDXC Rules, and any RDXC software may be used in this contest. In previous years, various ideas were discussed, both negative and positive, but finally positive ideas predominated, - even from those who are against Rules changes. Operators from almost 50 Russian oblasts participated in the last Contest. Please note: THERE IS NO 10-minutes rule for club stations. Welcome to participate in RUSSIAN 160 METER CONTEST ! 73! -- С уважением, Vlad / R7LV mailto: r...@dx.ru ua...@dx.ru ua...@mail.ru - No virus found in this message. Checked by AVG - www.avg.com Version: 2015.0.5577 / Virus Database: 4253/8759 - Release Date: 12/18/14 _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
A few years ago, I put up a low, non-resonant dipole, about 150 feet long and 10 feet high for use as an auxiliary receiving antenna on 160. My main receiving antenna was and still is an array of short verticals. What I found at my W1 location after I installed the dipole is similar to what N5IA described at XZ0A. If the band was open before my local sunrise (not always the case!), the verticals would always outperform the dipole by a large amount. However, as soon as we hit sunrise, the dipole would suddenly start equaling and then outperforming the verticals. The transition would take place in a matter of a few short minutes. Past sunrise, DX signals would drop into the noise on the verticals but would continue to hang in on the dipole. The dipole would sometimes extend the opening for me by 5 to 15 minutes, allowing me to make some contacts (mainly JA and VK, if the band was open in those directions) that would not have been possible with the vertical array. Sometimes the DX would be virtually inaudible on the verticals but Q5, although not strong, on the dipole. What is rather interesting, however, is that in the winter seasons of 2012-2013 and 2013-2014, this dipole advantage became non-existent. The dipole was never even close to the verticals, either before or after sunrise. It caused me to go outside a number of times to see if the dipole had fallen down, but that was never the case. Evidently the propagation mechanisms at work around sunrise have changed from a few years ago, at least at my QTH. So far in the 2014-2015 season, the dipole has still not provided any receiving advantage around sunrise. I generally don't operate much around local sunset, but I have never seen any dipole advantage at sunset. 73, John W1FV _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt Feed - Insulated Elements on Yagi
On Thu,12/18/2014 4:59 PM, Ralph Parker wrote: I have a 64' self-standing tower with a 3 el Steppir on it (insulated elements) and a 40m linear loaded dipole (also insulated) on top of that. I've worried that any high voltage on the ends of the boom might be harmful to the drive motors in the dir/ref boxes. So I've chickened out and avoided loading the tower on 160. I have a 3-el SteppIR on a 120 ft tower. I don't load the tower, but the tower is a reflector for a wire that is suspended from it, insulated from it, and slopes to a point on the ground about 50 ft from the tower where it is fed against four elevated radials (about 18 ft). This makes the top of the tower a high voltage point, although probably not as high as it would be if I were loading it). There are two antennas rigged like this, one facing the east coast and one facing west. I've been using them for about three years, mostly running legal limit, and the SteppIR still works fine. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Confusion in ON4UN's Low Band DXing radial length calculations.
On Thu,12/18/2014 1:18 PM, Doug Turnbull wrote: I appreciate some guidance with this matter. I would like a radial field which would take me to within 0.5/1 dB of the maximum achievable for reducing near field losses. Some of the best work I've seen published on this topic is by Rudy Severns, N6LF. Look for the 2-part QEX piece he did about 3 years ago. It's on his website and is well worth studying. For my part, I modeled a half-wave 160M dipole parallel to the earth starting at heights of about 5 ft down to a few inches, varied the length so that the antenna was resonant at each height, computed Vf from the result, and plotted it. That work is slides 40 and 41 in http://k9yc.com/160MPacificon.pdf Obviously what happens in the real world will depend on soil conditions. Think about this in the light of Rudy's work -- the standard for broadcast radials has been a half wave length. Taking Vf into account, they would be more like 3/4 wavelength or even longer. Rudy observes that current distribution will depend on the length of the radial, and the boundary condition is that it must be minimum at the end. He notes that if a radial is some length between 0.25 and 0.5 wavelength, the current will peak 0.25 from the far end, and that peak will be greater than the current at the tower base, and because that current is greater, the loss will be greater. He observes that loss will be minimized when the peak current is at the feedpoint. He also observes that loss will be minimized by making the all the radial currents as nearly equal as possible (again, because loss is I squared R), and by sharing that current by more radials (again because loss is I squared R). Rudy further observes that radial current can be unbalanced by variations in soil conditions, including factors like variations in skin depth, and by their electrical length. Like I said, it's REALLY GOOD reading, and it all makes sense. And thanks for the QSO on 10M. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
