Topband: The Russian 160M contest
Dear OMs and Yls, Last night I came back from dinner at our local with the XYL. I sat down at the radio and heard F5IN at about 21:06 UTC working a contest. Ah it is the Russian 160M contest -hmm. Oh it seems that one does not just work UA land. This is good as there would not be enough activity to keep going. It would just be a bore.Okay another good thing is that the contest is over at 24:00 so I could stay up for it. An hour and six minutes of the four hours is lost but I am still pretty sober not having consumed too much - thank God. Lets give it a try. Well this contest was an absolute toot - I enjoyed it from start to finish. I like short contests!I worked 130 QSOs, in 32 DXCC and 27 Russian regions for a score of 43,011.At the start I was not hearing any of the Russians who were spotted so worked some EU stations, then I started a run and gradually Russian stations started calling in.During this time I worked Greece and the UAE. Later things started to flag and the USA was coming in so about ten North American QSOs were added of course including VE1ZZ, Jack as a starter. This activity from W/VE was good as for the last hour the contests really flagged. There were not that many Russian or EU entrants but it was a most agreeable evening and all the more so as it was not expected. Post Contest by a couple of minutes V5/DL3DXX in Namibia was worked for a new 160M entity. It seems that the inverted L on the original SteppIR radial field is not doing too poorly.I hope to improve this before the Stew Perry. Thanks to all. 73 Doug EI2CN _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: The Russian 160M contest
On Sat,12/20/2014 3:42 AM, Doug Turnbull wrote: Last night I came back from dinner at our local with the XYL. I sat down at the radio and heard F5IN at about 21:06 UTC working a contest. The only CW activity heard here was an N6 with a very broad signal calling CQ Cent working 2-3 guys. But I heard a LOT of activity on JT65 and JT9 -- copied more than 30 calls in a few hours, including more than a half dozen W1/W2,W3. 73, Jim K9YC (south of San Francisco) _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
This is almost the way it worked here just at sunrise, both transmitting and receiving, except after sunrise the vertical hung in longest here. The brief and unpredictable window of horizontal superiority at this location is why I eventually just let the horizontal antennas all fall apart. The pattern was true for both high (~300 ft) and low (less than 150 ft) dipoles. We would get beat all the time in 160 pileups using a high dipole in contests on the second station, so much that I just took that antenna out of the selections. At this location, when the horizontal was good the verticals were still workable. So the horizontals never really extended anything, they just were better. The exception was during solar storms, where sometimes the verticals were poor compared to the horizontals for extended periods. 73 Tom 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 - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4794 / Virus Database: 4235/8762 - Release Date: 12/18/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fw: Shortened Radial Experiments
Actually, I don't believe the Brown et al experiments showed this conclusion at all. Their extensive experiments showed an optimal radial length of about 3/8 wavelength (actually 0.41). This, with ON4UN's typical soil Vf of 0.5, would yield an rf length of 3/4 wavelength. This 3/4 wavelength has the same properties as a quarter wavelength, just for taller vertical antennas. My write-up was specifically about shortened radials for 160 meter inverted L antennas with 50' vertical sections, and the resonant radials are 48 to 49 feet, so the fit is good. I clearly stated that if I was to use a taller vertical, I would use a 3/4 length radial (modified by Vf, of course). If you wish to upgrade your thinking to today, try using the EZNEC model for a simple VHF ground plane antenna (vertical antenna with 4 ground radials). Then change the radial length to something other than 1/4 wavelength or some odd multiple of it. I don't think you'll like the resultsOf course, the VHF ground plane is in free space. If you lower it to the ground, the radial lengths would be affected by Vf would have to be shortened (just like lowering a dipole requires pruning). If you are thinking that a buried radial wouldn't be the same anymore, I would point out that the soil penetration depth of rf at 1.8 MHz is considered to be 30 to 50 feet, so the radials are very visible to the vertical. Recalling Jim Brown's posting yesterday of Rudy Severn's excellent recent work, the current maximum in a radial occurs at 0.25 wavelength from it's open end loss will be minimized when that current maximum is at the feedpoint. Brian K8BHZ -Original Message- From: Richard Fry Sent: Friday, December 19, 2014 7:18 PM To: topband@contesting.com Subject: Topband: Fw: Shortened Radial Experiments RE: Brian Mattson's post of Friday, 19 Dec 2014 12:23:52 -0500 The velocity of propagation in the MF and HF bands along radial conductors that lie on, or are buried several inches in the earth is inconsequential. What DOES matter is the free space wavelength, and the number of those radial conductors. This was shown in the real-world experiments of Brown, Lewis Epstein of RCA Laboratories, published in the Proceedings of the Institute of Radio Engineers in 1937. Those BLE findings established the requirements for such radial systems required of AM broadcast stations subject to FCC jurisdiction, to the present day. R. Fry, CPBE _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Shunt Feed - Insulated Elements on Yagi
You can model this two ways: 1.) As a very high impedance load between the elements and the boom and look at the load data to see voltage between the boom and elements 2.) With a source between the element and boom, and set the source to zero current. Then look at source data and see what the voltage is to have zero current. This will tell you the peak voltage. Arcing and damage absolutely can be a problem, and not just on 160. I know a few people who have an insulated element antenna stacked above or below a differently rotating antenna, and when the second antenna's elements are near parallel to the boom the boom is excited so much it arcs to the elements. This is an issue when a boom length near 1/2 wave on the second band is excited by the second band. It is also an issue on 160. The less other large stuff at the top and the more power, the more of an issue it becomes. - Original Message - From: Ralph Parker ve...@dccnet.com To: topband@contesting.com Sent: Thursday, December 18, 2014 7:59 PM Subject: Topband: Shunt Feed - Insulated Elements on Yagi Good question, Stan. I've wondered the same thing. 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. VE7XF _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4794 / Virus Database: 4235/8762 - Release Date: 12/18/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: 160m RX antenna testing surrogates?
Here in the US we have the AM broadcast band which I assume other countries can use as 160m testing surrogates to some degree. Are there other DX broadcasters either just above or below 160m that I could use for testing my RX antennas when ham sigs aren't available? My QTH is Maryland, USA. I'm particularly interested in EU and SA as those directions are my best opportunities for adding to my DXCC list. It would be nice if the system of beacons included 160m some day. I've been using those on the upper bands and found them very useful. 73 jim ab3cv _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Fw: Shortened Radial Experiments
Recalling Jim Brown's posting yesterday of Rudy Severn's excellent recent work, the current maximum in a radial occurs at 0.25 wavelength from it's open end loss will be minimized when that current maximum is at the feedpoint. _ For consideration: The first link below is from a recent paper of Valentino Trainotti, a highly-regarded antenna engineering professor at the University of Buenos Aires. He shows that it is the quality of the ground plane within 1/2 of a free-space wavelength surrounding the base of a monopole (regardless of its electrical height) that is important in its operation. He states that the conductivity of the ground plane within a 1/2-wave radius of a monopole is part of the wave generator, and its r-f loss must be low in order to maximize the radiation efficiency of the antenna system. No requirement or effect is stated for the v.p. along any buried radial wires used in that boundary area. RF currents entering the earth from radiation by the monopole out to a radius of 1/2-wavelength need to travel back to the ground terminal of the antenna system in order for the monopole to radiate. The conductivity of the ground plane in that region needs to be minimized, no matter what the presence of the earth around buried radial wires does to their v.p. So the wires ideally should extend out to 1/2 of a free space wavelength, no matter what electrical length they may have due to their v.p. when buried. http://s20.postimg.org/xviw4hrot/Trainotti_Clip.jpg Here is a quote from the 1937 BLE paper on ground systems. Note especially the last sentence there. \\ Brown, Lewis, and Epstein: Ground Systems (p. 757) These losses are due to conduction of earth currents through a high resistance earth and to dielectric losses in the base insulator of the antenna. We shall next consider the earth currents flowing toward the antenna. The earth currents are set up in the following manner. Displace- ment currents leave the antenna, flow through space, and finally flow into the earth where they become conduction currents. If the earth is homogeneous, the skin effect phenomena keep the current concentrated near the surface of the earth as it flows back to the antenna along radial lines. Where there are radial ground wires present, the earth current consists of two components, part of which flows in the earth itself and the remainder of which flows in the buried wires. As the current flows in toward the antenna, it is continually added to by more displacement currents flowing into the earth. It is not necessarily true that the earth currents will increase because of this additional displacement current, since all the various components differ in phase. // Below are two clips from the BLE paper showing the distribution of r-f current in the earth around the base of monopoles of heights from 22 degrees to 99 degrees, and the current distribution along buried radial wires of 0.41 wavelength (in free space). Note that current is not maximized at a distance of 1/4-wavelength (free space) from the open ends of those buried radials. It is maximized near the common point of those radials, adjacent to the base of the monopole. http://s20.postimg.org/qji1coyul/Earth_Currents_near_Monopole.gif http://s20.postimg.org/zfstgmpgt/Currents_in_Radials.gif R. Fry, CPBE _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 160m RX antenna testing surrogates?
The fact that the world outside the Americas has 9kHz rather than 10 kHz separation between broadcasters could help you here Jim. Not as much help for South America, though there is an Argentinian on 1710kHz, but there are US pirates there also. I believe Mark Connelly WA1ION is on this list, and has suggested medium wave broadcast beacons in the past? In Maryland, Asia on 160m would be a longer shot, but you could see if you can hear at least a carrier on 1566kHz from HLAZ South Korea, 1575kHz VoA Thailand, maybe 1593 CNR1 China, 1557 Taiwan. (listening when you have a darkness path of course). These are all high power stations, and tend to dominate their frequencies. North Korea still broadcasts on 2350 and 2850kHz, though they may be more relevant for 80m DX. If you are searching for Australia, 1548 4QD. best wishes, Nick VE7DXR (if you have access to QEX July/August 2001, I did an article on the possibilities of using such stations as beacons for 160m propagation studies, but not as much for your regions of interest unfortunately) At 17:32 20-12-14, you wrote: Here in the US we have the AM broadcast band which I assume other countries can use as 160m testing surrogates to some degree. Are there other DX broadcasters either just above or below 160m that I could use for testing my RX antennas when ham sigs aren't available? My QTH is Maryland, USA. I'm particularly interested in EU and SA as those directions are my best opportunities for adding to my DXCC list. It would be nice if the system of beacons included 160m some day. I've been using those on the upper bands and found them very useful. 73 jim ab3cv _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 160m RX antenna testing surrogates?
The AM BCB band is unique in that it is virtually never limited by noise; rather every channel has deep layers of QRM to deal with. The BCB is very useful as a sanity check for beverages, because they are still very directional in the BCB. If I have a broken beverage, the directionality will be off and/or signals will be down. None of this guarantees that the beverage will actually hear weak signals better than some other antenna. For that, I use WWV/WWVH on 2.5 MHz. I can compare signal to noise ratios of antennas to be tested. I make sure that my tuned loops can tuned to 2.5 MHz. Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
John, My experience mirrors your comments. In the mornings to JA and VK on 160M, the signals are usually best on my end-fire loop arrays, but around SR there is often a rapid shift to my inverted L transmitting antenna. The signals may or may not hold up on the loops. I guess I should try a low dipole and see what happens. Dick, K4IQJ .. On Dec 19, 2014, at 1:43 AM, John Kaufmann wrote: 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 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 160m RX antenna testing surrogates?
Jim, For this direction there are many in the Eastern Caribbean that may be of value for testing RX antenna's. I suggest the 50KW on 1610 in Anguilla and WDHP St. Croix on 1620. (They are licensed for 1KW Night times.). If you can pick up 1500KHZ from Caracas on your South Beverage and null out KSTP in St. Paul's 50KW to a Franklyn antenna in the process, you can be assured that your antenna has some good directive qualities late at night. Also there are many AM station overseas that operate on 5KZ separation and you can get the list on line of some of the more popular ones. Am Radio DX-ing is a very popular SWL hobby especially in Europe and there are web sites devoted to this. Herb Schoenbohm, KV4FZ On 12/20/2014 1:32 PM, Jim Miller wrote: Here in the US we have the AM broadcast band which I assume other countries can use as 160m testing surrogates to some degree. Are there other DX broadcasters either just above or below 160m that I could use for testing my RX antennas when ham sigs aren't available? My QTH is Maryland, USA. I'm particularly interested in EU and SA as those directions are my best opportunities for adding to my DXCC list. It would be nice if the system of beacons included 160m some day. I've been using those on the upper bands and found them very useful. 73 jim ab3cv _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Non-resonant receive antennas
On 2014-12-20 13:06, Richard Jaeger wrote: I guess I should try a low dipole and see what happens. Dick, K4IQJ .. When talking about a low dipole, the question comes up as to why it must be low to work. Actually we don't know that it must be low to work. Very few of us are in a position to put up a high dipole, so the question is basically moot. However, in an attempt to gauge the influence of height, I A/B'ed two full size dipoles at 30 and 60 foot heights over a period of 6 months. The one not in use was floating to avoid interaction with the active one. I never noticed any difference in receiving performance. What seems to happen is that the signals are a few dB higher on the 60 foot wire, but the noise is commensurately higher. 30 feet was chosen for the minimum so that the wires didn't look like beverages (and because I have a bunch of 30 foot lengths of pipe). Rick N6RK _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: 160m RX antenna testing surrogates?
Here's a list I compiled two or three years ago: http://www.w0btu.com/AM-longwaveStations.html 73, Mike www.w0btu.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Modeling W8JI and Hi-Z 8 Circles
The recent thread on 8 circle arrays prompted me to create a few different AutoEZ models, mostly because I was curious about the relationship between array size, element phasing, and number of active elements (4 with W8JI, 8 with Hi-Z). First thing I did was educate myself. For W8JI type arrays: http://w8ji.com/small_vertical_arrays.htm http://n3ujj.com/manuals/8%20Circle%20Vertical%20Array%20for%20Low%20Band%20Receiving.pdf http://www.dxengineering.com/parts/dxe-rca8b-sys-3p http://static.dxengineering.com/global/images/instructions/dxe-rca8b-sys-3p-rev3.pdf Low-Band DXing, 4th ed, ON4UN, Chapter 7, Sections 1-21 and 1-30 And for Hi-Z type arrays: http://www.k7tjr.com/need.htm http://www.kkn.net/dayton2014/HiZ_DAYTON_2014_7n2.pdf http://www.hizantennas.com/HiZ8-16080_users_guide.pdf http://www.hizantennas.com/Hiz_8_16080_manual.pdf http://www.dxengineering.com/parts/hiz-8a-lv2-160-2 Then I created models where the array size (diameter) can be controlled via a single variable, along with another variable to control the phasing. For example, here's the AutoEZ Variables sheet tab for a W8JI type array. The Hi-Z is similar except that array size is specified in feet (or meters) rather than wavelengths. http://ac6la.com/adhoc/8circle1.png Since everything is controlled by variables you can run variable sweeps changing one or more parameters. Here's the W8JI array with the spacing (B) held constant while the phase delay (P) is swept from 80 to 140 degrees. For each test case AutoEZ will automatically calculate the RDF (last column). http://ac6la.com/adhoc/8circle2.png When the calculations finish you can step through the 2D patterns. Here are the elevation and azimuth (at 20° TOA) patterns for 0.604 wl broadside spacing and 125 degree phasing, as shown by B and P in the lower right corner. http://ac6la.com/adhoc/8circle3.png You can run similar sweeps changing the array size while holding the phase delay constant, or hold both size and phase constant and do a frequency sweep, or use the Generate Test Cases button to create any combination. For example, the setup below would vary broadside spacing B from 0.50 to 0.70 wavelengths; for each B the phase delay P would be varied from 115 to 135 degrees; all at a constant frequency of 1.85 MHz. That would be 25 test cases. You can run thousands if you like. http://ac6la.com/adhoc/8circle4.png You can also show 3D patterns. Here's an example of a Hi-Z array, diameter 200 ft with ±106 degree phasing, along with the 2D elevation pattern. http://ac6la.com/adhoc/8circle5.png And here's how the RDF for a 200 ft Hi-Z array varies as the phase is swept from ±100 to ±112 degrees. http://ac6la.com/adhoc/8circle6.png For both of the array types, I created one model using W8JI-style top hat loaded vertical elements (per the sample model on Tom's site) and a second model using simple aluminum tube elements (per the four-section, 23.25 ft, Hi-Z AL-24). Here are the models. Save to your computer then use the AutoEZ Open Model File button. http://ac6la.com/adhoc/W8JI_8_Circle__TopHat.weq http://ac6la.com/adhoc/W8JI_8_Circle__AL-24.weq http://ac6la.com/adhoc/Hi-Z_8_Circle__TopHat.weq http://ac6la.com/adhoc/Hi-Z_8_Circle__AL-24.weq Please note that these models have not been reviewed or approved by the authors of the references cited above. Any mistakes or misinterpretations are strictly mine. And the models may or may not be an accurate representation of any given commercial package. In all the models, a single variable (X) controls the segmentation. You can reduce that to speed up the calculations. You can also run a sweep on X to do a convergence test for model accuracy. For comparison with the 8 circle arrays, here's the W8WWV Benchmark Beverage model. With this one you can sweep the length and/or other parameters. http://ac6la.com/adhoc/W8WWV_Beverage.weq Greg's Beverage page for reference. http://www.seed-solutions.com/gregordy/Amateur%20Radio/Experimentation/Beverage.htm Calculated results for this Beverage are shown in section Calculate 3D Data here. http://ac6la.com/aeuse3d.html === AutoEZ is an antenna modeling program which uses Microsoft Excel in combination with EZNEC. http://ac6la.com/autoez.html Current AutoEZ users, see here for recent maintenance updates and instructions on how to get the latest release. http://ac6la.com/aechanges.html Dan, AC6LA _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: BOG constructed from uninsulated electric fence wire
Has anyone ever actually tried this? If so it works, does it only work when it's not raining? If I wanted to construct this antenna compare it with one made from insulated wire, can the two antennas run parallel to each other and if so how far apart shud they be? If not, then how shud they be constructed for comparison? Tks, Fritz K4OAQ _ Topband Reflector Archives - http://www.contesting.com/_topband
