Re: Topband: RX 4 SQ Phasing
On 8/11/2012 5:00 AM, Pete Smith N4ZR wrote: > I'm not sure I'd go too far with the FCC map. At my QTH, which is shown > as average, actual ground/earth varies within a hundred feet from deep Yes, but I have also measured the current drop off with distance on my beverages and it agrees with the high conductivity assumption. Any wire beyond 400 feet on a beverage is ineffective here; I installed a relay at 400 feet and listened as more wire was switched in. I have room for much longer Beverages. This clearly indicates too much conductivity for optimum beverage operation. Yet they still do interesting things on 160 and BCB. The ground here is all clay, no rock, with cemented hard pan a few feet down. The clay goes down about 40 feet, as determined by well drilling. Rick N6RK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
> This for instance > http://www.aytechnologies.com/TechData/ShortBev.htm There isn 't enough detail in the description to understand the model and the plots fully. A 560 foot long "beverage" on 175 kHz has about 15 dB null off the sides at 5 degrees wave angle, and a few dB F/B at low angles. The mode is the same as the K9AY, flag, EWE, and many other antennas use. It acts like two short top-loaded verticals phased, and fires opposite normal direction. You can find bad places as frequency is varied, at different angles and directions, but it is pretty tough to find a spot where any antenna has no nulls at all. > >It isn't in "Beverage mode", but it is in a mode that offers >> directivity. >> >> They work that way, too. > > And what mode is that? Yes they work suprisingly well at LF, so well in > fact that I can seperate stations on the same frequency, NDB's or the LF > BCB. No doubt. It models to be able to do that with 15 mS/m earth, or 1 mS/m earth. Mine act that way too, and they acted that way every place I ever lived. >> Certainly they are not good antennas in comparison to something full >> size, >> and are not acting as a Beverage, but they do have pronounced directivity >> at >> lower wave angles. > > > At LF its not much different than a BOG on 160 and its obvious that no > pattern reversal takes place. > Prior to these antennas the 175' Slinky also had good directivity on LF. > > Ive seen no models that explain this. Everything is explainable. Nothing is magic, and very little (much to all of our regrets) is a special gift, except being out away from noise, or moving close to where we want to communicate. > Thats always been my starting point, try it, then understand why, and then > improve it. It's all about phase shift and current. Nothing is magic. For example, we sometimes feel good because an antenna has noticeable F/B over 10 octaves. That really tells different people different things. It tells me the phasing is far from optimum directivity phase at the high end of the pattern frequency range. If I wanted the best 160 and 80 meter antenna, I would intentionally forego a significant back null on 400 meters. If I wanted a wideband null to never hear a certain direction more than raw S/N ratio on 160 and 80, I'd use that delay. It really all depends on what our goal is. 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
Please elaborate! The LF stations you are likely to receive would all be from Europe or Mediteranean countries in N. Africa. From your location, I wonder how you would get enough directivity to separate them. Chuck On 8/11/2012 9:40 AM, ZR wrote: > And what mode is that? Yes they work suprisingly well at LF, so well in fact > that I can seperate stations on the same frequency, NDB's or the LF BCB. > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
On Sat, 2012-08-11 at 09:44 -0400, Tom W8JI wrote: ---snip--- > > Mostly what we find, when we cut through all the emotion, is we try to find > a way to justify why our locations and antennas are somehow "special". ---snip--- > 73 Tom > Hi, My antennas are indeed special. They fit in a rectangle 100 feet long by 35 feet wide. That I can work any stations at all on 160 and hear stations on 600 meters is - *special*. I have been taking notes to see what I can adapt to my postage stamp for improvements. 73, Bill ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
- Original Message - From: "Tom W8JI" To: Sent: Saturday, August 11, 2012 11:43 AM Subject: Re: Topband: RX 4 SQ Phasing >> ** That doesnt make sense since the books, etc claim virtually no >> directivity at a 1/4 wave. At 175 KHz a 1/4 wave is 1406'. > > > I don't know what "books, etc" that comes from, but even over fairly good > soil a 600-foot "Beverage" models to have about 18 dB side null and a few > dB > F/B at 175 kHz. This for instance http://www.aytechnologies.com/TechData/ShortBev.htm >It isn't in "Beverage mode", but it is in a mode that offers > directivity. > > They work that way, too. And what mode is that? Yes they work suprisingly well at LF, so well in fact that I can seperate stations on the same frequency, NDB's or the LF BCB. > Certainly they are not good antennas in comparison to something full size, > and are not acting as a Beverage, but they do have pronounced directivity > at > lower wave angles. At LF its not much different than a BOG on 160 and its obvious that no pattern reversal takes place. Prior to these antennas the 175' Slinky also had good directivity on LF. Ive seen no models that explain this. > > This is why people should never give up, and should experiment with the > best > they can do. Even if it doesn't work close to right, it can make people > happy. > > 73 Tom Thats always been my starting point, try it, then understand why, and then improve it. Carl KM1H ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
> ** That doesnt make sense since the books, etc claim virtually no > directivity at a 1/4 wave. At 175 KHz a 1/4 wave is 1406'. I don't know what "books, etc" that comes from, but even over fairly good soil a 600-foot "Beverage" models to have about 18 dB side null and a few dB F/B at 175 kHz. It isn't in "Beverage mode", but it is in a mode that offers directivity. They work that way, too. Certainly they are not good antennas in comparison to something full size, and are not acting as a Beverage, but they do have pronounced directivity at lower wave angles. This is why people should never give up, and should experiment with the best they can do. Even if it doesn't work close to right, it can make people happy. 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
- Original Message - From: "Tom W8JI" To: Sent: Friday, August 10, 2012 11:45 PM Subject: Re: Topband: RX 4 SQ Phasing > >I use 5 two wire Beverages for 10 directions and have good directivity > >down >> to the 175 KHz LF BCB and they are only 500-700' long. Performance seems >> to >> exceed published info. On the US BCB its like aiming a long yagi on 2M, >> multiple stations on the same frequency can be heard with ease during the >> day. > > If any of us **really** had an antenna as sharp as a long Yagi, we'd need > 16 > or more antennas to cover useful directions. ** More like 24, my 70cm yagis are 15 degrees. > > That's pretty typical behavior for a properly installed Beverage no matter > what the location, unless you park it over saltwater. > > 73 Tom ** That doesnt make sense since the books, etc claim virtually no directivity at a 1/4 wave. At 175 KHz a 1/4 wave is 1406'. Carl KM1H > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1424 / Virus Database: 2437/5192 - Release Date: 08/10/12 > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
> I'm not sure I'd go too far with the FCC map. At my QTH, which is shown > as average, actual ground/earth varies within a hundred feet from deep > old riverbottom loam to limestone with a thin covering of topsoil (or > sometimes none). While I don't know how this affects electrical ground > conditions, the difference must be fairly pronounced - and I am very > glad my shunt fed tower is based in the old riverbed. If you only use ground rods or depend on earth as a counterpoise, where you place the antenna locally can matter. With a reasonably good ground, most of the losses are in the Fresnel region outside the area you can control. The result is a mean value of all the variables combined, local soil under the antenna doesn't matter much. Since Rick's Beverages are long and likely cross a big sample area of soil, most likely they do a good job of averaging ground. Not that ground is all that important for a Beverage. Mostly what we find, when we cut through all the emotion, is we try to find a way to justify why our locations and antennas are somehow "special". In truth, the description of sorting multiple stations or having directivity in the BCB being somehow exceptional, like a "long Yagi", is just common performance. I lived in NW Ohio in an area with deep rich sandy black loam with water near the surface, and BC conductivity estimates from local AM station proof of performances placed that soil above 20 mS/ meter for that whole area, but nothing totally off the charts. The seriously flawed ground rod test using 60 Hz was off the charts for conductivity, because the top black soil layer was saturated with contaminated water. What we forget is skin depth can be many dozens of feet, and the wavelength is so long we get an averaged effect of all the stuff going on. We look at one tiny area near the surface, or look 1000 feet deep, and assume that defines something one way or another, usually to unintentionally make a system "special". My Beverages over that good very uniform soil worked exactly as described over rocky poor soil. As a matter of fact, they worked the same in Cleveland over clay, and in Rockdale County GA over rock. They work that way here, too. I could always go to the AM band with any properly installed Beverage of 400-500 feet or longer and change directions, and sort multiple AM stations on one frequency. It is common antenna behavior, because the "test" being used is so non-critical. It always fascinates people who listen, when several stations can be sorted on one AM BCB channel. That a normal reaction to a common non-special result where just 10 dB of response variation over nearly equal signal levels arriving from widely separated directions shows up as "changing audio like a switch". It's human nature, just like we commonly see when antenna systems are changed, and why we should make measurements. The best example of this common very human effect is to change the battery in your car, clean it , and wax it. It will run better, and get better fuel mileage. (A popular Ham author actually put that in an article on mobile installations!) I think this is what Rick was driving at. 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
>>>N4ZR wrote: >>>I'm not sure I'd go too far with the FCC map. You might look at your local soil surveys for better information, or contact your local NRCS office. I use the online Web Soil Survey. http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm Once you select your area of interest and your soil type(s), you can navigate to 'Soil Properties and Qualities' and then to 'Soil Chemical Properties" and find Electrical Conductivity 'EC'. It is listed as millimhos per centimeter (same as millisiemens per centimeter if you prefer). You can look around at EC for your near and far fields and hopefully have something of greater confidence than the FCC map. Steve KK7UV ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
I'm not sure I'd go too far with the FCC map. At my QTH, which is shown as average, actual ground/earth varies within a hundred feet from deep old riverbottom loam to limestone with a thin covering of topsoil (or sometimes none). While I don't know how this affects electrical ground conditions, the difference must be fairly pronounced - and I am very glad my shunt fed tower is based in the old riverbed. 73, Pete N4ZR The World Contest Station Database, at www.conteststations.com The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com, spots at telnet.reversebeacon.net, port 7000 and arcluster.reversebeacon.net, port 7000 On 8/10/2012 8:14 PM, Rick Karlquist wrote: > ZR wrote: >> Sometimes I wonder if its my very poor RF ground conditions that tilt the >> wave more and result in the performance of a much longer antenna. >> >> Carl >> KM1H > My ground is high conductivity according to the FCC map, so > maybe that doesn't explain the performance. > > Rick > N6RK > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
>I use 5 two wire Beverages for 10 directions and have good directivity down > to the 175 KHz LF BCB and they are only 500-700' long. Performance seems > to > exceed published info. On the US BCB its like aiming a long yagi on 2M, > multiple stations on the same frequency can be heard with ease during the > day. If any of us **really** had an antenna as sharp as a long Yagi, we'd need 16 or more antennas to cover useful directions. That's pretty typical behavior for a properly installed Beverage no matter what the location, unless you park it over saltwater. 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
How does it work way down into LF? Carl - Original Message - From: "Rick Karlquist" To: "ZR" Cc: ; Sent: Friday, August 10, 2012 8:14 PM Subject: Re: Topband: RX 4 SQ Phasing > ZR wrote: >> >> Sometimes I wonder if its my very poor RF ground conditions that tilt the >> wave more and result in the performance of a much longer antenna. >> >> Carl >> KM1H > > My ground is high conductivity according to the FCC map, so > maybe that doesn't explain the performance. > > Rick > N6RK > > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1424 / Virus Database: 2437/5192 - Release Date: 08/10/12 > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
ZR wrote: > > Sometimes I wonder if its my very poor RF ground conditions that tilt the > wave more and result in the performance of a much longer antenna. > > Carl > KM1H My ground is high conductivity according to the FCC map, so maybe that doesn't explain the performance. Rick N6RK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
I use 5 two wire Beverages for 10 directions and have good directivity down to the 175 KHz LF BCB and they are only 500-700' long. Performance seems to exceed published info. On the US BCB its like aiming a long yagi on 2M, multiple stations on the same frequency can be heard with ease during the day. It more jumbled at night Sometimes I wonder if its my very poor RF ground conditions that tilt the wave more and result in the performance of a much longer antenna. Carl KM1H - Original Message - From: "Rick Karlquist" To: "Larry Molitor" Cc: ; "Dennis W0JX" Sent: Friday, August 10, 2012 1:59 PM Subject: Re: Topband: RX 4 SQ Phasing Larry Molitor wrote: > However, the lower frequency limit of usefulness extends WAY below the AM > broadcast band. For example I currently use a two element Hi-Z array with > 60 foot spacing and can see as much as 30 dB F/B as low as 150 kHz!. The A while back, I built a 4X2 low band array of receive verticals aimed at Europe via Canada, but reversible to beam over San Francisco. I could tune to 960 kHz and listen to a San Francisco station 70 miles away on ground wave with armchair copy or reverse the array and listen to a Canadian station also on 960 kHz again with armchair copy. The array seemed to be on a par with my NE beverage. BTW, my beverages are only 400 feet long but often work quite well on the broadcast band. Rick N6RK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2437/5191 - Release Date: 08/10/12 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
Larry Molitor wrote: > However, the lower frequency limit of usefulness extends WAY below the AM > broadcast band. For example I currently use a two element Hi-Z array with > 60 foot spacing and can see as much as 30 dB F/B as low as 150 kHz!. The A while back, I built a 4X2 low band array of receive verticals aimed at Europe via Canada, but reversible to beam over San Francisco. I could tune to 960 kHz and listen to a San Francisco station 70 miles away on ground wave with armchair copy or reverse the array and listen to a Canadian station also on 960 kHz again with armchair copy. The array seemed to be on a par with my NE beverage. BTW, my beverages are only 400 feet long but often work quite well on the broadcast band. Rick N6RK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: RX 4 SQ Phasing
Dennis, W0JX, is nearly correct but didn't go far enough. In the last few years I've had up several Hi-Z two element arrays, a Hi-Z 4-sq, and a Hi-Z 2-3 array. They all exhibit the same characteristics. Depending on the element spacing used, the upper frequency limit may be over 7 MHz. For instance the 4-sq at 50 foot on a side worked nearly as well as my full size 40 meter 4-sq. On the other hand, the 2 element array at 60 foot spacing is worthless on 40 meters. However, the lower frequency limit of usefulness extends WAY below the AM broadcast band. For example I currently use a two element Hi-Z array with 60 foot spacing and can see as much as 30 dB F/B as low as 150 kHz!. The 4-sq worked well as low as 350 kHz, maybe lower, never checked. The two element (and the 2-3 array) show outstanding performance on the new 630 meter band as well as NAVTEX and NDB frequencies. Be aware that due to the long wave lengths and and the fact that a 70 foot tower with yagis on top is usually resonant in the BC band, when tuning around you may find frequencies that show little or no F/B. Pay attention to "arrival angle" as well. High angle signals will show little or no F/B and possibly even reversed direction. The best way to test your array to see if it is actually working correctly is to look at local groundwave signals because the "arrival angle" of DX signals is usually unknown. It's pretty easy to tune local AM stations and check F/B when you know that the array will work down there about the same as on 160. FWIW, the Flag, as built to K6SE's original spec also performs quite well as low as 100 kHz. 73, Larry - W7IUV > > From: Dennis W0JX > As far as phasing relationships, the HiZ antenna system uses "Cross Fire" >phasing, an approach that maintains a balanced relationship in the delay lines over at least a 2 to 1 frequency range, so that the system works very well on 160 and 80 meters. > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: RX 4 SQ Phasing
Bob, for a good understanding of the concepts of phasing in these RX antennas, read Chapter Seven of ON4UN's "Low Band DXing." The length of the delay lines primarily affects the placement of the nulls of the array while the voltage output of the antennas and amplifiers controls the depth of the nulls. The more perfect the balance of the output of each antenna and amplifier, (i.e., equal), the deeper the nulls. That is why when conductors interact with the elements, the pattern gets screwed up. They mess up the balance of outputs of the antennas. The spacing of the antenna elements is generally optimum on one band. If selected for 160 meters, the 4 SQ pattern deteriorates as you go up in frequency since the spacing becomes wider electrically. At 30 meters, there is practically no pattern although the array hears very well. As far as phasing relationships, the HiZ antenna system uses "Cross Fire" phasing, an approach that maintains a balanced relationship in the delay lines over at least a 2 to 1 frequency range, so that the system works very well on 160 and 80 meters. 73, Dennis W0JX/8 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
