Re: Topband: Skimmer calibration
Iceland: three people per square km - Original Message - From: Tracey GardnerTo: topband@contesting.com Sent: Wed, 20 Aug 2014 02:30:49 -0400 (EDT) Subject: Topband: Skimmer calibration Hello Mike You forget that on this side of the pond, the majority of us live on pocket handkerchief sized plots. :-) The representative of a major building company in the UK was on TV yesterday saying that 1000 sq ft was plenty big enough for a three bedroomed house. I imagine that would be the area of one room in a lot of houses in the USA. Even a K9AY needs a 30ft by 30ft space with a central support and a lot of new builds here don't even have gardens that size. You've only got to look at the population densities to begin to see the problem Population density (people per sq. km of land area) USA - 35 UK- 265 Netherlands - 498 France - 121 Germany - 231 Italy - 203 We'd all love to have the space to put up phased arrays or Beverages and even a Flag, K9AY, EWE, is out of the question for a large number of us. And as for quiet locations well for the vast majority of us those again are a thing of the past unless you go out portable. Switched mode power supplies and cheap plasma TVs etc have seen to that. Nothing comes with a good old linear power supply nowadays and any power supply coming out of the Far East has got to be suspect 73s Tracey G5VU On Tue, Aug 19, 2014 at 5:33 AM, Mike Waters wrote: > When I last investigated, all the skimmers and Web SDRs that were outside > of North America all had terrible receive antennas for copying DX signals > on 160. (And who knows how many of them are in quiet locations?) > > When I say "terrible", I mean small "magnetic" loops, very short whips, > low dipoles, a random end-fed wire, etc. No phased arrays or Beverages, > and not even a Flag, K9AY, EWE, etc. > > Does anyone know if that is still the case? > > 73, Mike > www.w0btu.com > _ > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Skimmer calibration
Iceland: three people per square km. :) - Original Message - From: Tracey GardnerTo: topband@contesting.com Sent: Wed, 20 Aug 2014 02:30:49 -0400 (EDT) Subject: Topband: Skimmer calibration Hello Mike You forget that on this side of the pond, the majority of us live on pocket handkerchief sized plots. :-) The representative of a major building company in the UK was on TV yesterday saying that 1000 sq ft was plenty big enough for a three bedroomed house. I imagine that would be the area of one room in a lot of houses in the USA. Even a K9AY needs a 30ft by 30ft space with a central support and a lot of new builds here don't even have gardens that size. You've only got to look at the population densities to begin to see the problem Population density (people per sq. km of land area) USA - 35 UK- 265 Netherlands - 498 France - 121 Germany - 231 Italy - 203 We'd all love to have the space to put up phased arrays or Beverages and even a Flag, K9AY, EWE, is out of the question for a large number of us. And as for quiet locations well for the vast majority of us those again are a thing of the past unless you go out portable. Switched mode power supplies and cheap plasma TVs etc have seen to that. Nothing comes with a good old linear power supply nowadays and any power supply coming out of the Far East has got to be suspect 73s Tracey G5VU On Tue, Aug 19, 2014 at 5:33 AM, Mike Waters wrote: > When I last investigated, all the skimmers and Web SDRs that were outside > of North America all had terrible receive antennas for copying DX signals > on 160. (And who knows how many of them are in quiet locations?) > > When I say "terrible", I mean small "magnetic" loops, very short whips, > low dipoles, a random end-fed wire, etc. No phased arrays or Beverages, > and not even a Flag, K9AY, EWE, etc. > > Does anyone know if that is still the case? > > 73, Mike > www.w0btu.com > _ > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Modeling the proverbial "vertical on a beach"
It's not necessary to place a vertical antenna at waters edge to gain the low angle efficiency advantages of an oceanfront site. There are two zones of interest: the area immediately adjacent to the antenna which primarily affects efficiency (very important for transmitting and very unimportant for top band receiving) and the Fresnel Zone which is very important for the very low angles that difficult to achieve at most land sites. Salt marshes (e.g., W1KM) are practical for long term installation but antennas over ocean water are rarely practical except on ships. The most practical ocean front permanent transmitting antenna is a land based vertical over an extensive radial system sited so that most of its Fresnel Zone is over salt water. 73 Frank W3LPL - Original Message - From: Guy Olinger K2AVTo: Tom W8JI Cc: Mark Connelly , TopBand List Sent: Tue, 19 Aug 2014 21:21:03 -0400 (EDT) Subject: Re: Topband: Modeling the proverbial "vertical on a beach" On Tue, Aug 19, 2014 at 11:24 AM, Tom W8JI wrote: > Why would it matter? > > The receiving antenna does not matter, provided it responds to the wave > angle at the receive site. It doesn't matter if it is loop, a 10 foot > vertical, or a 200 foot vertical so long as the antenna does not null the > primary wave angle for the incoming signal. It does not matter if it is a > large receiving array or a whip, provided each are not nulling the primary > signal arrival. Or giving advantage to one or the other incoming angle in effect setting the primary signal arrival Not using a small omni RX antenna for this experiment introduces some serious calculation issues. E.g. if the RX setup has pattern and gain, we first have to know what incoming angle and direction a signal is arriving at and then divide the pattern out BEFORE any comparisons are made. So how do we know that? VOACAP has that built in where you are supposed to supply the RX pattern, which otherwise defaults to omni. No pattern is required to eliminate direction and elevation arrival adjustments to reported readings if the antenna is truly omni. If the RX antenna is "omni" and low enough then any enhancements are due to the propagation or environment or the TX station's antennas, which is what you WANT to see. FURTHER, since nearly all ham TX antennas are NOT at water's edge, then any tests looking for water's edge enhancement must do so by placing RX at water's edge and placing another identical RX/antenna back on the beach a few hundred feet off and another identical RX/antenna at typical shore site antenna-distance-from-actual-water's edge as in 1500 feet for W2GD and K3ZM. Putting up and maintaining TX antennas right at water's edge and feedline back to safe location for transceivers, etc, is something that likely unworkable or will not be tolerated by those controlling public beach fronts, would be a maintenance nightmare to begin with. These include such things as guy anchors under water on the beach, that will not come loose under typical random sand rearrangement underwater. Or continuous corrosive/shorting salt spray on metal and insulators. Or exposure to vandalism. RX skimmers with a short antenna can be made very small, battery charged by solar power, completely enclosed in smallish sealed box and communicating with the internet via wifi back off the beach. They can be put on top of pier poles, etc, and completely controlled remotely. 73, Guy _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Low-angle radiation from vertical antennas
This is somewhat related to the "vertical on a beach" thread but I figured if I put that in the subject line I might get lynched. In the past there have been questions about the accuracy of NEC far field calculations at low take-off angles for vertical antennas since the far field does not include the ground wave. To help resolve the issue I modeled a λ/4 vertical with and without the ground wave at multiple slant (radial) distances and plotted the results. This is for the 160m band at 10°, 1°, and 0.1° take-off angles with slant (radial) distances varying from 100 m to 100 km: http://ac6la.com/adhoc/VertFlds9.png And this is for 40m: http://ac6la.com/adhoc/VertFlds10.png As expected, the far field values decay at a "1/r" rate. With log-log scales that's a one decade decrease for every one decade increase in radial distance. At close-in distances the far field does indeed under-estimate the total field which includes ground wave. However, for typical sky wave propagation the difference has vanished (plot lines converged) long before the ionosphere has been reached. For each of the 3 take-off angles, calculations were done at 100 different distances in order to get smooth curves. Obviously I didn't do those one at a time; I used AutoEZ with 100 test cases. Each test case generated an EZNEC "Setups > Near Field" like this. http://ac6la.com/adhoc/VertFlds5.png Near Field calculations report the total field, including the ground wave, and are valid at any distance from the antenna. For the Far Field, also done for each test case, AutoEZ can convert the dBi values produced by EZNEC to the corresponding mV/m field strengths. Dan, AC6LA http://ac6la.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Switching Pennants
Hi Dwight, I have 3 point fed pennants that share the same feedpoint and use only one BN-73-202 Binocular Core Transformer matching transformer at the feedpoint (one pennant pointing 40 degrees, one pointing 160 degrees, and one pointing 300 degrees) and have been using this system for over 3 years now with no problems. I use two relays (located at the common center location of the pennants to select the active pennant, and disconnect both sides of the pennants that are not active from the matching transformer. Switching 3 pennants is very easy as it only requires one isolated 12 volt supply and a two conductor control cable from the shack out to the relay box which is located at the feedpoint. 0 volts over the feedline selects one pennant, +12 volts selects the second pennant, and -12 volts (just reversing polarity of the power supply connected to the control line) selects the 3rd pennant. Here is a link to a simple website I have that documents my 3 pennant system, and you can see a picture of the inside of my relay box on this website. http://sites.google.com/site/pennantflagantennas/ Simple and see no reason to do it any other way if using 3 pennants that have a common center point location. 73, Don On Tue, Aug 19, 2014 at 7:59 PM, Tom W8JI wrote: > I would not switch high impedance lines without very special precautions. > > I really do not think it is worth the small parts savings. > > - Original Message - From: "DGB" > To: > Sent: Tuesday, August 19, 2014 4:38 PM > Subject: Topband: Switching Pennants > > > I am wanting a simple way of switching 3 or 4 pennants. Anyone done this? >> >> Quote From K6SEE ... All four Pennants would be installed with their >> points all adjacent to each other. Only one feedline would be necessary >> and only one >> transformer would be necessary, with the high impedance winding of the >> transformer being switched to the feedpoint of the Pennant in the desired >> direction ... 73, de Earl, K6SE >> >> 73 Dwight NS9I >> _ >> Topband Reflector Archives - http://www.contesting.com/_topband >> >> >> - >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2014.0.4745 / Virus Database: 4007/8063 - Release Date: 08/19/14 >> >> _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Switching Pennants
Dwight, Correction, I should have said 0 volts over the control line (not feedline) selects one pennant, +12 volts selects the second pennant, and -12 volts (just reversing polarity of the power supply connected to the control line) selects the 3rd pennant. Don On Wed, Aug 20, 2014 at 7:11 AM, Don Kirk wrote: > Hi Dwight, > > I have 3 point fed pennants that share the same feedpoint and use only one > BN-73-202 Binocular Core Transformer matching transformer at the feedpoint > (one pennant pointing 40 degrees, one pointing 160 degrees, and one > pointing 300 degrees) and have been using this system for over 3 years now > with no problems. I use two relays (located at the common center location > of the pennants to select the active pennant, and disconnect both sides of > the pennants that are not active from the matching transformer. > > Switching 3 pennants is very easy as it only requires one isolated 12 volt > supply and a two conductor control cable from the shack out to the relay > box which is located at the feedpoint. 0 volts over the feedline selects > one pennant, +12 volts selects the second pennant, and -12 volts (just > reversing polarity of the power supply connected to the control line) > selects the 3rd pennant. > > Here is a link to a simple website I have that documents my 3 pennant > system, and you can see a picture of the inside of my relay box on this > website. > http://sites.google.com/site/pennantflagantennas/ > > Simple and see no reason to do it any other way if using 3 pennants that > have a common center point location. > > 73, > Don > > > > On Tue, Aug 19, 2014 at 7:59 PM, Tom W8JI wrote: > >> I would not switch high impedance lines without very special precautions. >> >> I really do not think it is worth the small parts savings. >> >> - Original Message - From: "DGB" >> To: >> Sent: Tuesday, August 19, 2014 4:38 PM >> Subject: Topband: Switching Pennants >> >> >> I am wanting a simple way of switching 3 or 4 pennants. Anyone done this? >>> >>> Quote From K6SEE ... All four Pennants would be installed with their >>> points all adjacent to each other. Only one feedline would be necessary >>> and only one >>> transformer would be necessary, with the high impedance winding of the >>> transformer being switched to the feedpoint of the Pennant in the desired >>> direction ... 73, de Earl, K6SE >>> >>> 73 Dwight NS9I >>> _ >>> Topband Reflector Archives - http://www.contesting.com/_topband >>> >>> >>> - >>> No virus found in this message. >>> Checked by AVG - www.avg.com >>> Version: 2014.0.4745 / Virus Database: 4007/8063 - Release Date: 08/19/14 >>> >>> _ >> Topband Reflector Archives - http://www.contesting.com/_topband >> > > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Skimmer calibration
- Original Message - From: "Tom W8JI" To: "topband" Sent: Tuesday, August 19, 2014 10:08 PM Subject: Re: Topband: Skimmer calibration BC antennas have the elaborate radial system in order to get that groundwave while the typical on ground ham vertical loses a lot of the 0-10 degree (or more) radiation. Go to the beach to get it back.or go with elevated radials. That just isn't factual at all. Radials under the vertical antenna have virtually no effect on wave angle unless they are sparse and grossly unbalanced, allowing them to radiate like a low horizontal antenna. Radials change the efficiency, not the pattern, unless the radials radiate like a dipole. 73 Tom Note that I didnt say anything about changing the pattern, just the energy included at low angles and where the efficiency starts at the base and at the often poorly understood Fresnel Zone if you really want more power in those low angles and not heating worms or sand granules. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Switching Pennants
Hi Dwight, I just added the schematic of my 3 Pennant RX antenna switching system to my website. http://sites.google.com/site/pennantflagantennas/ Just FYI, Don (wd8dsb) _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Switching Pennants
Most common K9AY relay-switching configuration involves a single transformer, with relay-switching at the high impedance side, and just inches of run from the transformer to the relays to the loops. The unused loops are left open (not connected either side). The proposed single-transformer pennant relay configuration sounds almost exactly the same. (Except no "reversing relay" as termination is symmetrical.) Pennants are typically just a little bit higher impedance than K9AY, yes? Tim N3QE On Tue, Aug 19, 2014 at 7:59 PM, Tom W8JI wrote: > I would not switch high impedance lines without very special precautions. > > I really do not think it is worth the small parts savings. > > - Original Message - From: "DGB" > To: > Sent: Tuesday, August 19, 2014 4:38 PM > Subject: Topband: Switching Pennants > > > I am wanting a simple way of switching 3 or 4 pennants. Anyone done this? >> >> Quote From K6SEE ... All four Pennants would be installed with their >> points all adjacent to each other. Only one feedline would be necessary >> and only one >> transformer would be necessary, with the high impedance winding of the >> transformer being switched to the feedpoint of the Pennant in the desired >> direction ... 73, de Earl, K6SE >> >> 73 Dwight NS9I >> _ >> Topband Reflector Archives - http://www.contesting.com/_topband >> >> >> - >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2014.0.4745 / Virus Database: 4007/8063 - Release Date: 08/19/14 >> >> _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Skimmer calibration
I said: That just isn't factual at all. Radials under the vertical antenna have virtually no effect on wave angle unless they are sparse and grossly unbalanced, allowing them to radiate like a low horizontal antenna. Radials change the efficiency, not the pattern, unless the radials radiate like a dipole. 73 Tom Note that I didnt say anything about changing the pattern, just the energy included at low angles and where the efficiency starts at the base and at the often poorly understood Fresnel Zone if you really want more power in those low angles and not heating worms or sand granules. That, by definition, is a pattern change. You said it improves groundwave. What you think happen just does not happen. It improves efficiency. It does not change elevation pattern, it does not change Fresnel zone losses significantly. It does not improve groundwave any significant amount more than it changes sky wave. This is because the "often poorly understood" Fresnel zone extends far beyond practical radial field area, and virtually all of the ground wave attenuation from soil losses is miles from the antenna over the entire long length of a path. It is not localized loss. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Skimmer calibration
I said: That just isn't factual at all. Radials under the vertical antenna have virtually no effect on wave angle unless they are sparse and grossly unbalanced, allowing them to radiate like a low horizontal antenna. Radials change the efficiency, not the pattern, unless the radials radiate like a dipole. 73 Tom Note that I didnt say anything about changing the pattern, just the energy included at low angles and where the efficiency starts at the base and at the often poorly understood Fresnel Zone if you really want more power in those low angles and not heating worms or sand granules. That, by definition, is a pattern change. You said it improves groundwave. What you think happen just does not happen. It improves efficiency. It does not change elevation pattern, it does not change Fresnel zone losses significantly. It does not improve groundwave any significant amount more than it changes sky wave. This is because the "often poorly understood" Fresnel zone extends far beyond practical radial field area, and virtually all of the ground wave attenuation from soil losses is miles from the antenna over the entire long length of a path. It is not localized loss. 73 Tom All of which is well known and well published. You might ask Frank, W3LPL, or Richard Fry to explain it to you better than I seem to do since you appear to get hung up on the semantics. Looking at the coastal AM BCB patterns I mentioned a week (WGBB 1240) ago or others recently will show you the effects of salt water and land. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Skimmer calibration
On Tue,8/19/2014 7:08 PM, Tom W8JI wrote: Radials under the vertical antenna have virtually no effect on wave angle unless they are sparse and grossly unbalanced, allowing them to radiate like a low horizontal antenna. Radials change the efficiency, not the pattern, unless the radials radiate like a dipole. On Wed,8/20/2014 9:05 AM, Tom W8JI wrote: This is because the "often poorly understood" Fresnel zone extends far beyond practical radial field area, and virtually all of the ground wave attenuation from soil losses is miles from the antenna over the entire long length of a path. It is not localized loss. I agree completely with both of Tom's posts. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Skimmer calibration
- Original Message - From: "Jim Brown" To: Sent: Wednesday, August 20, 2014 12:48 PM Subject: Re: Topband: Skimmer calibration On Tue,8/19/2014 7:08 PM, Tom W8JI wrote: Radials under the vertical antenna have virtually no effect on wave angle unless they are sparse and grossly unbalanced, allowing them to radiate like a low horizontal antenna. Radials change the efficiency, not the pattern, unless the radials radiate like a dipole. On Wed,8/20/2014 9:05 AM, Tom W8JI wrote: This is because the "often poorly understood" Fresnel zone extends far beyond practical radial field area, and virtually all of the ground wave attenuation from soil losses is miles from the antenna over the entire long length of a path. It is not localized loss. I agree completely with both of Tom's posts. 73, Jim K9YC You should, he didnt say anything wrong. _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Ferrite beads
Anyone know if the ferrite beads that are encased on the cables of older CRT monitors are any good for use in the shack. This has probably been asked before but I can not find any info. Thanks , Joe K2UF _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Low-angle radiation from vertical antennas
Dan AC6LA wrote: ...To help resolve the issue I modeled a ?/4 vertical with and without the ground wave at multiple slant (radial) distances and plotted the results. etc Dan's AutoEZ charts remove all doubt about the issue of whether or not the ground wave contributes to monopole radiation reaching the ionosphere. Clearly, it doesn't. R. Fry _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Ferrite beads
Anyone know if the ferrite beads that are encased on the cables of older CRT monitors are any good for use in the shack. This has probably been asked before but I can not find any info. Thanks , Joe K2UF Since most of those come from Asia it is anyones guess what mixes are used by who. It would be simple enough to wind 10 turns, measure inductance and then zero in on the Al value using the published formula. Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Low-angle radiation from vertical antennas
So now NEC is definitive? Even with all it's known defects around the edges? NEC is the process that indicates the unproven/undisproven notch. Measurements at aircraft altitudes and 25-50 km or hold one's peace. 73, Guy On Wed, Aug 20, 2014 at 2:36 PM, Richard Fry wrote: > Dan AC6LA wrote: > >> ...To help resolve the issue I modeled a ?/4 vertical with and without >> the ground wave at multiple slant (radial) distances and plotted the >> results. etc >> > > Dan's AutoEZ charts remove all doubt about the issue of whether or not the > ground wave contributes to monopole radiation reaching the ionosphere. > > Clearly, it doesn't. > > R. Fry > > > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: New 3 el 160m yagi at 7J4AAL
We went to Japan for our honeymoon in 2010 and were invited to visit 7J4AAL for a few days.. I have heard about his 160m-Yagi plan at this time and was very excited all the years until now. I talk to him and Masaru JA5AQC (with whom I went on a 23 day-round trip in Europe 2012) frequently on 80m. Kan lives in a more quiet location compared to other JA QTH's . Both large Yagis are on hill tops but there are also other hills around, so it is not a hill top location with a flat terrain around. He has multiple beverages, too. The QTH is 200m or so next to a large hospital, other houses are further away. I enjoyed operating 80m with his 5 el yagi. Signals from EU were loud enough, no need for special RX antennas at that time. (guess different in other special static conditions) You can see some pictures of the surroundings as well as from his 5el 80m Yagi here.. http://www.dm9ee.de/operating_7J4AAL.html I am looking forward to hear Kan on 160m 73 de Tom www.DM9EE.de( ex DL2OBO ) PS: check my homepage for other DX station QTHs -Ursprüngliche Nachricht- Von: Topband [mailto:topband-boun...@contesting.com] Im Auftrag von Gary and Kathleen Pearse Gesendet: Dienstag, 19. August 2014 22:13 An: topband List Betreff: Re: Topband: New 3 el 160m yagi at 7J4AAL I guess well hear this 160 season from 7J4AAL. Living mid-path USA-JA affords KL7s the opportunity to receive both as Ws and others turn their attention to JA. Why not give it a try if one has the motivation, real estate, and resources? And about which antenna is better? His 160 beam on a hill will outperform what most of us will ever have available. I wonder what his noise floor will be, and if he employs receiving arrays? Source: http://www.cd-corp.com/english/ http://www3.ocn.ne.jp/~kan1/cy163tower.html 73, Gary NL7Y _ Topband Reflector Archives - http://www.contesting.com/_topband --- Diese E-Mail ist frei von Viren und Malware, denn der avast! Antivirus Schutz ist aktiv. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: New 3 el 160m yagi at 7J4AAL
Yes, the boom of the 5el 80m yagi is used as a 160m dipole. 160m and 80m yagis are on separate towers While discussing about efficiency between yagis and vertical arrays it was more the question, what Kan WANTED to build. Sure he could have built a vertical array instead, but he didn't want to. Otoh, the terrain for a 9 circle etc. is not really good at his QTH 73 Tom www.DM9EE.de ( ex DL2OBO ) -Ursprüngliche Nachricht- Von: Topband [mailto:topband-boun...@contesting.com] Im Auftrag von Peter Voelpel Gesendet: Dienstag, 19. August 2014 19:48 An: 'Topband Reflector' Betreff: Re: Topband: New 3 el 160m yagi at 7J4AAL His CL75 CX-M 5-element 80m yagi is on the other tower and still in use. The new 160m antenna was built on order by Create. 73 Peter -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Richard (Rick) Karlquist Sent: Dienstag, 19. August 2014 19:29 To: Jim N7US; 'Topband Reflector'; CADXA Reflector Subject: Re: Topband: New 3 el 160m yagi at 7J4AAL The web site talks about a CL-75 Yagi, which operates as a dipole on 160 meters, and has 5 elements on 80. Is there also some different antenna that is actually 3 elements on 160 meters? My Japanese is a little rusty :-) Rick N6RK On 8/19/2014 9:22 AM, Jim N7US wrote: >>From the reflector of the Northern IL DX Association. > > 73, Jim N7US > > > From: ni...@yahoogroups.com [mailto:ni...@yahoogroups.com] > Sent: August 19, 2014 07:49 > To: ni...@yahoogroups.com > Subject: [NIDXA] New 3 el 160m yagi at 7J4AAL > > > Now that is an antenna! > > http://www3.ocn.ne.jp/~kan1/newmonsterantenna2.html > > The three SteppIR DB42's look small! > > > 73, John > K9EL > > Posted by: "John, K9EL" > > > > _ > Topband Reflector Archives - http://www.contesting.com/_topband > > _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband --- Diese E-Mail ist frei von Viren und Malware, denn der avast! Antivirus Schutz ist aktiv. http://www.avast.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Low-angle radiation from vertical antennas
Guy Olinger wrote: NEC is the process that indicates the unproven/undisproven notch. Based on the AutoEZ charts linked here by AC6LA, the existence of this "notch" is true only if NEC is misused and/or misunderstood. _ Topband Reflector Archives - http://www.contesting.com/_topband