OT: Elevated vs. Buried Radials
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A lot of talk has been going on about radials on the KX3 Yahoogroups
Reflector, but there is so much FOD on that reflector, I usually delete most of the messages. Although it may have been mentioned there, I have probably missed it. Other than for portability, why are elevated radials so important? I have a ground-mounted 6BTV (not my main antenna) in my backyard. I have four radials for each band and they were all put in with yard staples. I did this in the Fall after the last grass cutting. By Spring, the grass had grown over them. Now, several years later, there is at least one inch of dirt over them. In all honesty, it's only a backup antenna and probably needs some radials replaced. Now, in my situation, there was no way I was going to use elevated radials. Someone recently posted a link to the SteppIR vertical - the CrankIR. Looking at the one page from the link, it only mentions elevated radials. Now, I've never seen a loaded-tower broadcast antenna with elevated radials either. Is the only benefit portability? Please, I do not want to also be accused of perpetuating FOD on another reflector. I'd prefer you reply directly to me. If needed, I'll summarize and repost. Thanks, Joel - W4JBB ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: OT: Elevated vs. Buried Radials
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The cleanest installation is to put the radials in the ground - but, not
portable at all. The idea is a capacitance connection with the earth. I have used welded steel cattle fence in the past - I build a mat that is about 30 or 40 feet out from the base of the antenna. For raised radials - they must be resonate to function properly. Three or four per band or related band. They have to be high enough that they present no danger to anyone roaming around your antenna field. They can be drooping or horizontal - both work well. Personally, I do wonder about the new fangled "no radials required" antennas. But, I have an old R5 and it works well. Perhaps the way to go is a new antenna that just gets bolted to a post and a feedline attached. Sure makes life easier and from folks I talk to all the time - they do work. Forget that they are a little expensive. You buy an antenna to use for years. Read the eHam reviews and see what other users are saying before you buy anything. Ask on the air. The best I ever had was a Butternut of some kind over a bunch of buried fence. Might still be the way to go. But, if I was doing it now, I'd be looking at a "no radials required" antenna. My reasoning is somewhat age related. Be looking forward to the sage advice that will come from this post. It is summer - so it is antenna time. Bill W2BLC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: OT: Elevated vs. Buried Radials
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> Personally, I do wonder about the new fangled "no radials required" > antennas. But, I have an old R5 and it works well. The "no radials" antennas are basically a vertical OCF - the short decoupling radials are the short leg and the vertical is adjusted through the use of traps, stubs and/or loading to resonate on the desired band with the fixed length (typically 42") of the short "radials". 73, ... Joe, W4TV On 5/18/2013 9:25 AM, Bill wrote: > The cleanest installation is to put the radials in the ground - but, not > portable at all. The idea is a capacitance connection with the earth. I > have used welded steel cattle fence in the past - I build a mat that is > about 30 or 40 feet out from the base of the antenna. > > For raised radials - they must be resonate to function properly. Three > or four per band or related band. They have to be high enough that they > present no danger to anyone roaming around your antenna field. They can > be drooping or horizontal - both work well. > > Personally, I do wonder about the new fangled "no radials required" > antennas. But, I have an old R5 and it works well. Perhaps the way to go > is a new antenna that just gets bolted to a post and a feedline > attached. Sure makes life easier and from folks I talk to all the time - > they do work. Forget that they are a little expensive. You buy an > antenna to use for years. > > Read the eHam reviews and see what other users are saying before you buy > anything. Ask on the air. > > The best I ever had was a Butternut of some kind over a bunch of buried > fence. Might still be the way to go. But, if I was doing it now, I'd be > looking at a "no radials required" antenna. My reasoning is somewhat age > related. > > Be looking forward to the sage advice that will come from this post. It > is summer - so it is antenna time. > > Bill W2BLC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by W4JBB
Hi Joel,
You've asked "why are elevated radials so important". If a vertical is elevated above ground (perhaps on a post or on a roof) elevated radials are a necessity because in order to use ground mounted radials you would have to run a long length of wire down to the ground mounted radial field. In doing this that wire becomes part of your antenna with an effect on resonant frequency and radiation pattern. For ground mounted verticals, elevated radials might be desired if the installation is temporary/portable or if laying ground radials is too difficult. The CrankIR is being marketed as a portable antenna so elevated radials are the logical choice. I'm sure once the antenna becomes available we'll read about folks ground mounting the antenna and laying traditional radial fields. And why not. I can see HOA restricted hams laying an invisible radial field in the grass and bringing out the CrankIR for a few hours use while the HOA police are napping. 73, Mike K2MK
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In reply to this post by W4JBB
Hi Joel,
The ground beneath the antenna can have two effects: 1. It can become a part of the antenna's equivalent electrical circuit. 2. It has an effect on the antenna's far field due to "reflection" of the antenna's field By burying the radials and mounting the antenna on the ground, you increase the losses of the antenna itself, but improve the reflection coefficient of the ground, because most of the field is reflected very close to the antenna (where conductivity is high because of the radials). By increasing the antenna's feedpoint height, you start to "decouple" the ground from the antenna's equivalent circuit (the capacity between the radiator and the ground decreases) but at the same time, the reflection point is further away from the antenna, so the field "sees" a ground with lower conductivity. This reduces the far field at low elevation angles due to a nearly 180 deg phase shift (related to "pseudo-Brewster angle"), if the antenna is low in terms of the wavelength. So, the "best" verticals are ground-mounted (if you have something like 15 radials at least and there are no large structures around the antenna) but antennas up about 1 wavelength are also very good if ground conductivity is rather low, because at low angles, the fields experience about the same 180deg phase shift that horizontal antennas see. If the antenna is high enough, the incident and reflected fields add up by almost 6dB at low angles. In ON4UN's book "low band dxing", he refers to some measurements performed by W8IJ and what he found was that low antennas with few elevated radials are inferior to antennas with (many) buried radials and that the difference was higher than could be expected from NEC modelling. I think he gave the recommendation to put up the feedpoint at least 1/8 lambda above the ground. In these "no radial" verticals, the feedline becomes the counterpart of the antenna, however, the current can be low, so that this is not necessarily a problem (depending on the feedline length), but basically you need a counterpoise because your trx does nothing more than periodically moving charges from one point in space to another. If there is no counterpoise, it has to take and move the charges on the feed line's shield (maybe by capacitive coupling) , the trx housing or the ac-mains (it only moves charges, but doesn't create or destroy them, so charge conservation applies). So, there is a counterpoise, even if you don't see it, there has to be one if the feed point current is not equal zero (which would mean tx off or infinite impedance). I don't remember for the R5, but I think the R7 had very short "radials". In these antennas, the short radials are part of the antenna, radials + radiator together form a resonant structure (like in the off-center-fed dipole antenna), so they are not truly end-fed, and require some broadband impedance transform plus a current choke because of the imbalance of the load (that is what is in the box at the feed point). If you provide a current choke, you may have shorter radials plus longer radiator, both together have to be lambda/half (electrically, taking all traps into account), however the feedpoint resistance is higher than 50 Ohms and some matching is required. Vy 73 Ralf, DL6OAP Am 18.05.2013 um 14:37 schrieb Joel Black <[hidden email]>: > A lot of talk has been going on about radials on the KX3 Yahoogroups Reflector, but there is so much FOD on that reflector, I usually delete most of the messages. Although it may have been mentioned there, I have probably missed it. > > Other than for portability, why are elevated radials so important? I have a ground-mounted 6BTV (not my main antenna) in my backyard. I have four radials for each band and they were all put in with yard staples. I did this in the Fall after the last grass cutting. By Spring, the grass had grown over them. Now, several years later, there is at least one inch of dirt over them. In all honesty, it's only a backup antenna and probably needs some radials replaced. > > Now, in my situation, there was no way I was going to use elevated radials. Someone recently posted a link to the SteppIR vertical - the CrankIR. Looking at the one page from the link, it only mentions elevated radials. Now, I've never seen a loaded-tower broadcast antenna with elevated radials either. > > Is the only benefit portability? > > Please, I do not want to also be accused of perpetuating FOD on another reflector. I'd prefer you reply directly to me. If needed, I'll summarize and repost. > > Thanks, > Joel - W4JBB > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: OT: Elevated vs. Buried Radials
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In reply to this post by W4JBB
Joel,
Very simply put. When you have elevated radials, > 0.1 wavelength, your system uses the radials as intended. However, with radials on the ground, your system will see the vector summation of the radials and the ground. What that means is your ground losses will be greater with ground based radials. And you are going to miss out on gain at the much lower angles. I hope this helps. 73, Barry K3NDM ----- Original Message ----- From: "Joel Black" <[hidden email]> To: "elecraft" <[hidden email]> Sent: Saturday, May 18, 2013 8:37:15 AM Subject: [Elecraft] OT: Elevated vs. Buried Radials A lot of talk has been going on about radials on the KX3 Yahoogroups Reflector, but there is so much FOD on that reflector, I usually delete most of the messages. Although it may have been mentioned there, I have probably missed it. Other than for portability, why are elevated radials so important? I have a ground-mounted 6BTV (not my main antenna) in my backyard. I have four radials for each band and they were all put in with yard staples. I did this in the Fall after the last grass cutting. By Spring, the grass had grown over them. Now, several years later, there is at least one inch of dirt over them. In all honesty, it's only a backup antenna and probably needs some radials replaced. Now, in my situation, there was no way I was going to use elevated radials. Someone recently posted a link to the SteppIR vertical - the CrankIR. Looking at the one page from the link, it only mentions elevated radials. Now, I've never seen a loaded-tower broadcast antenna with elevated radials either. Is the only benefit portability? Please, I do not want to also be accused of perpetuating FOD on another reflector. I'd prefer you reply directly to me. If needed, I'll summarize and repost. Thanks, Joel - W4JBB ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: OT: Elevated vs. Buried Radials
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In reply to this post by W4JBB
At 08:37 AM 5/18/2013, Joel Black wrote:
>Is the only benefit portability? > > >Thanks, >Joel - W4JBB Hi Joel As you mentioned ... physical, portable, and safety issues aside the difference between raised and buried radials is the difference in how they perform their function; that is how they effectively balance the antenna currents in the vertical radiating element and allow maximum radiation (usually vertically oriented). Example: imagine a 1/2 wave dipole horizontally oriented in free space above earth producing a horizontal oriented radiation pattern. Now bend the 1/2 wave 90 deg so one side is vertical while the other side remains horizontal and you now have a combination of horizontal and vertical radiation while the radiation efficiency remains the same. In order to eliminate the horizontal component install a second horizontal 1/4 wave element installed 180 deg opposite the first horizontal wire and the horizontal radiation component cancels leaving only the vertical component. This configuration is a vertical ground plane antenna and is quite efficient even though approximately half the radiated power is lost in the cancelled out horizontal portion. Now assume for whatever reason you want the feed point to be at ground level and you lower it more and more. As you do so the efficient 2 element ground plane (1/4 wave each) comes closer and closer to ground level and the resonant efficiency of the ground plane becomes lower and lower due to the interaction with the earth until the resonant length of the ground plane becomes irrelevant. Now in order to handle the RF current flow necessary to allow maximum current flow in the vertical radiating element a different method is required..... you now actually need to allow current to flow from the "ground System" to the earth itself. Different radial properties are required and resonance is no longer required.. To a large degree RF current flow now depends on characteristics of the earth and the mass of the coupling material that you use to come in contact with it. This is true of all vertical antennas. Some tricks are employed to reduce this ground effect which is at maximum if the vertical element is 1/4 wave (low impedance feed point). For example if the element length is increased the feed point impedance is increased and the current flow required for a given power is reduced. There are any number of articles on how to do this. 73 Jim, VE3CI ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: OT: Elevated vs. Buried Radials
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In reply to this post by W4JBB
The SteppIR information is overly simplified. For the best current analysis of elevated vs. on ground radials see the extensive data from N6LF - http://www.antennasbyn6lf.com In particular, read the comments on elevated radials: http://www.antennasbyn6lf.com/2011/02/comments-on-elevated-radials.html studies on ground systems: <http://www.antennasbyn6lf.com/2009/12/series-of-qex-articles-on-ground-system-experiments.html> and studies on elevated radial systems: <http://www.antennasbyn6lf.com/2012/02/elevated-radial-ground-systems-some-cautions.html> One of the major red flags with elevated radials - they must be a major fraction of a wavelength (1/8 wave is a good rule of thumb) before they really act independently of the "dirt". Even then, nothing will reduce the losses in the 1 to 10 wavelength area responsible for forming the low take off angle lobe. 73, ... Joe, W4TV On 5/18/2013 1:36 PM, Ron D'Eau Claire wrote: > Hi Joel: > > This is a very good summary that clearly shows the difference between > elevated and in-ground radials. (See Figure 1 on the second page) > > http://www.steppir.com/wp-content/uploads/2011/10/radial-systems-for-vertica > l-antennas.pdf > > Bottom line, if you can install a LOT of in-ground radials (the A.M. > broadcast stations use about 100), the efficiency of the antenna will be > high. If you can install resonant elevated radials, a much small number will > produce even higher efficiencies. > > In ground radials do not need to be very long. About 0.2 wavelengths seems > to be as good as a much longer radial. Above ground resonant (1/4 wave long) > radials take up a lot more room. > > Some A.M. Broadcast stations in the USA have used elevated radials with > great results. At least one was described in an A.R.R.L. antenna compendium > a few years ago. However, their antenna configurations are controlled by the > F.C.C. so they must go through approvals for the design. And resonant > elevated radials at those frequencies are rather long! > > 73, Ron AC7AC > > P.S. The only FOD I know about is "Foreign Object Damage" - the nemeses of > jet engines. Haven't a clue how that applies here, Hi! > > > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Joel Black > Sent: Saturday, May 18, 2013 5:37 AM > To: elecraft > Subject: [Elecraft] OT: Elevated vs. Buried Radials > > A lot of talk has been going on about radials on the KX3 Yahoogroups > Reflector, but there is so much FOD on that reflector, I usually delete most > of the messages. Although it may have been mentioned there, I have probably > missed it. > > Other than for portability, why are elevated radials so important? I have a > ground-mounted 6BTV (not my main antenna) in my backyard. I have four > radials for each band and they were all put in with yard staples. > I did this in the Fall after the last grass cutting. By Spring, the grass > had grown over them. Now, several years later, there is at least one inch > of dirt over them. In all honesty, it's only a backup antenna and probably > needs some radials replaced. > > Now, in my situation, there was no way I was going to use elevated radials. > Someone recently posted a link to the SteppIR vertical - the CrankIR. > Looking at the one page from the link, it only mentions elevated radials. > Now, I've never seen a loaded-tower broadcast antenna with elevated radials > either. > > Is the only benefit portability? > > Please, I do not want to also be accused of perpetuating FOD on another > reflector. I'd prefer you reply directly to me. If needed, I'll summarize > and repost. > > Thanks, > Joel - W4JBB > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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How can ya'll worry about this when the burning issues of free hats and
discounts remain unsolved? -W4SK ________________________________ John T. Gwin [hidden email] [hidden email] ----- Original Message ----- From: "Ron D'Eau Claire" <[hidden email]> To: <[hidden email]> Sent: Saturday, May 18, 2013 2:31 PM Subject: Re: [Elecraft] OT: Elevated vs. Buried Radials > Joe, the article I referenced clearly said to use 1/4 wavelength radials > when they are elevated. That's agrees with everything I've read and done > over years as well. > > I'll stand behind that SteppIR article as showing how to put up a vertical > that avoids the worst pitfalls. (And it's basically a repeat of what's in > every Antenna Handbook I've read over the years.) > > Can one tweak it even further? Perhaps. The articles you reference study > some ideal situations that most Hams cannot emulate that do so, especially > in producing a perfectly omnidirectional pattern with a minimum of 4 > radials. And they confirm the basic rules covered in the SteppIR article. > > 73, Ron AC7AC > > > > -----Original Message----- > From: [hidden email] > [mailto:[hidden email]] On Behalf Of Joe Subich, W4TV > Sent: Saturday, May 18, 2013 11:53 AM > To: [hidden email] > Subject: Re: [Elecraft] OT: Elevated vs. Buried Radials > > > The SteppIR information is overly simplified. For the best current > analysis > of elevated vs. on ground radials see the extensive data from N6LF - > http://www.antennasbyn6lf.com > > In particular, read the comments on elevated radials: > http://www.antennasbyn6lf.com/2011/02/comments-on-elevated-radials.html > studies on ground systems: > <http://www.antennasbyn6lf.com/2009/12/series-of-qex-articles-on-ground-syst > em-experiments.html> > and studies on elevated radial systems: > <http://www.antennasbyn6lf.com/2012/02/elevated-radial-ground-systems-some-c > autions.html> > > One of the major red flags with elevated radials - they must be a major > fraction of a wavelength (1/8 wave is a good rule of thumb) before they > really act independently of the "dirt". Even then, nothing will reduce > the > losses in the 1 to 10 wavelength area responsible for forming the low take > off angle lobe. > > 73, > > ... Joe, W4TV > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2013.0.2904 / Virus Database: 3162/6329 - Release Date: 05/16/13 > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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I like a guy who can get to the essence of an issue.
On May 18, 2013, at 2:34 PM, "W4SK" <[hidden email]> wrote: > How can ya'll worry about this when the burning issues of free hats and discounts remain unsolved? > -W4SK > ________________________________ > John T. Gwin > [hidden email] > [hidden email] > ----- Original Message ----- From: "Ron D'Eau Claire" <[hidden email]> > To: <[hidden email]> > Sent: Saturday, May 18, 2013 2:31 PM > Subject: Re: [Elecraft] OT: Elevated vs. Buried Radials > > >> Joe, the article I referenced clearly said to use 1/4 wavelength radials >> when they are elevated. That's agrees with everything I've read and done >> over years as well. >> >> I'll stand behind that SteppIR article as showing how to put up a vertical >> that avoids the worst pitfalls. (And it's basically a repeat of what's in >> every Antenna Handbook I've read over the years.) >> >> Can one tweak it even further? Perhaps. The articles you reference study >> some ideal situations that most Hams cannot emulate that do so, especially >> in producing a perfectly omnidirectional pattern with a minimum of 4 >> radials. And they confirm the basic rules covered in the SteppIR article. >> >> 73, Ron AC7AC >> >> >> >> -----Original Message----- >> From: [hidden email] >> [mailto:[hidden email]] On Behalf Of Joe Subich, W4TV >> Sent: Saturday, May 18, 2013 11:53 AM >> To: [hidden email] >> Subject: Re: [Elecraft] OT: Elevated vs. Buried Radials >> >> >> The SteppIR information is overly simplified. For the best current analysis >> of elevated vs. on ground radials see the extensive data from N6LF - >> http://www.antennasbyn6lf.com >> >> In particular, read the comments on elevated radials: >> http://www.antennasbyn6lf.com/2011/02/comments-on-elevated-radials.html >> studies on ground systems: >> <http://www.antennasbyn6lf.com/2009/12/series-of-qex-articles-on-ground-syst >> em-experiments.html> >> and studies on elevated radial systems: >> <http://www.antennasbyn6lf.com/2012/02/elevated-radial-ground-systems-some-c >> autions.html> >> >> One of the major red flags with elevated radials - they must be a major >> fraction of a wavelength (1/8 wave is a good rule of thumb) before they >> really act independently of the "dirt". Even then, nothing will reduce the >> losses in the 1 to 10 wavelength area responsible for forming the low take >> off angle lobe. >> >> 73, >> >> ... Joe, W4TV >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> Version: 2013.0.2904 / Virus Database: 3162/6329 - Release Date: 05/16/13 > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Joe Subich, W4TV-4
ELEVATED RADIALS: I think Joe hits it on the head here. A vertical with elevated "radials" is essentially an OCF dipole. There is no particular reason for the "radials" to be a quarter wavelength. They should be whatever length lets you resonate the antenna with a feed impedance you can live with.
IMPT POINT: If you want your antenna actually to have a vertical radiation pattern (low angle, omni-directional) then the elevated radials must be symmetric. If there are two, they must be of exactly equal length and point in exactly opposite directions. If there are four, they must be equal and point in directions 90 degrees from one another. This symmetry guarantees that the "radials" do not radiate. The do carry currents, they do help resonate the antenna, but if they are symmetric radiation from them cancels and they therefore do not radiate appreciably. 73, Oliver W6ODJ On 18 Jan. 2013, at 06:46 AM, "Joe Subich, W4TV" <[hidden email]> wrote: > > > Personally, I do wonder about the new fangled "no radials required" > > antennas. But, I have an old R5 and it works well. > > The "no radials" antennas are basically a vertical OCF - the short > decoupling radials are the short leg and the vertical is adjusted > through the use of traps, stubs and/or loading to resonate on the > desired band with the fixed length (typically 42") of the short > "radials". > > 73, > > ... Joe, W4TV > > > On 5/18/2013 9:25 AM, Bill wrote: >> The cleanest installation is to put the radials in the ground - but, not >> portable at all. The idea is a capacitance connection with the earth. I >> have used welded steel cattle fence in the past - I build a mat that is >> about 30 or 40 feet out from the base of the antenna. >> >> For raised radials - they must be resonate to function properly. Three >> or four per band or related band. They have to be high enough that they >> present no danger to anyone roaming around your antenna field. They can >> be drooping or horizontal - both work well. >> >> Personally, I do wonder about the new fangled "no radials required" >> antennas. But, I have an old R5 and it works well. Perhaps the way to go >> is a new antenna that just gets bolted to a post and a feedline >> attached. Sure makes life easier and from folks I talk to all the time - >> they do work. Forget that they are a little expensive. You buy an >> antenna to use for years. >> >> Read the eHam reviews and see what other users are saying before you buy >> anything. Ask on the air. >> >> The best I ever had was a Butternut of some kind over a bunch of buried >> fence. Might still be the way to go. But, if I was doing it now, I'd be >> looking at a "no radials required" antenna. My reasoning is somewhat age >> related. >> >> Be looking forward to the sage advice that will come from this post. It >> is summer - so it is antenna time. >> >> Bill W2BLC >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: OT: Elevated vs. Buried Radials
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Further to that, if you desire, as I might, to have more radiation in one
direction, eg from here to North America, I would have one elevated radial pointing that way and the radiation pattern tilts that way a little. One further point not brought out so far: the antenna itself does not have to be resonant; as long as the impedance is transformed to match the tx, it will accept power and radiate, minus the transformation and system losses. Since ocf has been mentioned a few times: I've seen VNA sweeps of ocf aerials in which the vswr dips nicely in band but the resonance as shown by X passing thro zero is often nowhere near. David G3UNA > > IMPT POINT: If you want your antenna actually to have a vertical > radiation pattern (low angle, omni-directional) then the elevated radials > must be symmetric. If there are two, they must be of exactly equal length > and point in exactly opposite directions. If there are four, they must be > equal and point in directions 90 degrees from one another. This symmetry > guarantees that the "radials" do not radiate. The do carry currents, they > do help resonate the antenna, but if they are symmetric radiation from > them cancels and they therefore do not radiate appreciably. > > 73, > > Oliver > W6ODJ > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by W6ODJ
Can we possibly get back to topics that are relevant to Elecraft
equipment. Find a different forum to talk antennas! 73,Tom (K7ZZ) On Sat, May 18, 2013 at 11:36 PM, Oliver Johns <[hidden email]>wrote: > ELEVATED RADIALS: I think Joe hits it on the head here. A vertical with > elevated "radials" is essentially an OCF dipole. There is no particular > reason for the "radials" to be a quarter wavelength. They should be > whatever length lets you resonate the antenna with a feed impedance you can > live with. > > IMPT POINT: If you want your antenna actually to have a vertical > radiation pattern (low angle, omni-directional) then the elevated radials > must be symmetric. If there are two, they must be of exactly equal length > and point in exactly opposite directions. If there are four, they must be > equal and point in directions 90 degrees from one another. This symmetry > guarantees that the "radials" do not radiate. The do carry currents, they > do help resonate the antenna, but if they are symmetric radiation from them > cancels and they therefore do not radiate appreciably. > > 73, > > Oliver > W6ODJ > > > On 18 Jan. 2013, at 06:46 AM, "Joe Subich, W4TV" <[hidden email]> wrote: > > > > > > Personally, I do wonder about the new fangled "no radials required" > > > antennas. But, I have an old R5 and it works well. > > > > The "no radials" antennas are basically a vertical OCF - the short > > decoupling radials are the short leg and the vertical is adjusted > > through the use of traps, stubs and/or loading to resonate on the > > desired band with the fixed length (typically 42") of the short > > "radials". > > > > 73, > > > > ... Joe, W4TV > > > > > > On 5/18/2013 9:25 AM, Bill wrote: > >> The cleanest installation is to put the radials in the ground - but, not > >> portable at all. The idea is a capacitance connection with the earth. I > >> have used welded steel cattle fence in the past - I build a mat that is > >> about 30 or 40 feet out from the base of the antenna. > >> > >> For raised radials - they must be resonate to function properly. Three > >> or four per band or related band. They have to be high enough that they > >> present no danger to anyone roaming around your antenna field. They can > >> be drooping or horizontal - both work well. > >> > >> Personally, I do wonder about the new fangled "no radials required" > >> antennas. But, I have an old R5 and it works well. Perhaps the way to go > >> is a new antenna that just gets bolted to a post and a feedline > >> attached. Sure makes life easier and from folks I talk to all the time - > >> they do work. Forget that they are a little expensive. You buy an > >> antenna to use for years. > >> > >> Read the eHam reviews and see what other users are saying before you buy > >> anything. Ask on the air. > >> > >> The best I ever had was a Butternut of some kind over a bunch of buried > >> fence. Might still be the way to go. But, if I was doing it now, I'd be > >> looking at a "no radials required" antenna. My reasoning is somewhat age > >> related. > >> > >> Be looking forward to the sage advice that will come from this post. It > >> is summer - so it is antenna time. > >> > >> Bill W2BLC > >> ______________________________________________________________ > >> Elecraft mailing list > >> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >> Help: http://mailman.qth.net/mmfaq.htm > >> Post: mailto:[hidden email] > >> > >> This list hosted by: http://www.qsl.net > >> Please help support this email list: http://www.qsl.net/donate.html > >> > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Exactly... Talking about Dayton discounts and hats (are they "equipment"?), that is why I became radio amateur ...
73, Ralf, DL6OAP Am 19.05.2013 um 16:19 schrieb "tomk7zz ." <[hidden email]>: > Can we possibly get back to topics that are relevant to Elecraft > equipment. Find a different forum to talk antennas! > > 73,Tom (K7ZZ) > > > On Sat, May 18, 2013 at 11:36 PM, Oliver Johns <[hidden email]>wrote: > >> ELEVATED RADIALS: I think Joe hits it on the head here. A vertical with >> elevated "radials" is essentially an OCF dipole. There is no particular >> reason for the "radials" to be a quarter wavelength. They should be >> whatever length lets you resonate the antenna with a feed impedance you can >> live with. >> >> IMPT POINT: If you want your antenna actually to have a vertical >> radiation pattern (low angle, omni-directional) then the elevated radials >> must be symmetric. If there are two, they must be of exactly equal length >> and point in exactly opposite directions. If there are four, they must be >> equal and point in directions 90 degrees from one another. This symmetry >> guarantees that the "radials" do not radiate. The do carry currents, they >> do help resonate the antenna, but if they are symmetric radiation from them >> cancels and they therefore do not radiate appreciably. >> >> 73, >> >> Oliver >> W6ODJ >> >> >> On 18 Jan. 2013, at 06:46 AM, "Joe Subich, W4TV" <[hidden email]> wrote: >> >>> >>>> Personally, I do wonder about the new fangled "no radials required" >>>> antennas. But, I have an old R5 and it works well. >>> >>> The "no radials" antennas are basically a vertical OCF - the short >>> decoupling radials are the short leg and the vertical is adjusted >>> through the use of traps, stubs and/or loading to resonate on the >>> desired band with the fixed length (typically 42") of the short >>> "radials". >>> >>> 73, >>> >>> ... Joe, W4TV >>> >>> >>> On 5/18/2013 9:25 AM, Bill wrote: >>>> The cleanest installation is to put the radials in the ground - but, not >>>> portable at all. The idea is a capacitance connection with the earth. I >>>> have used welded steel cattle fence in the past - I build a mat that is >>>> about 30 or 40 feet out from the base of the antenna. >>>> >>>> For raised radials - they must be resonate to function properly. Three >>>> or four per band or related band. They have to be high enough that they >>>> present no danger to anyone roaming around your antenna field. They can >>>> be drooping or horizontal - both work well. >>>> >>>> Personally, I do wonder about the new fangled "no radials required" >>>> antennas. But, I have an old R5 and it works well. Perhaps the way to go >>>> is a new antenna that just gets bolted to a post and a feedline >>>> attached. Sure makes life easier and from folks I talk to all the time - >>>> they do work. Forget that they are a little expensive. You buy an >>>> antenna to use for years. >>>> >>>> Read the eHam reviews and see what other users are saying before you buy >>>> anything. Ask on the air. >>>> >>>> The best I ever had was a Butternut of some kind over a bunch of buried >>>> fence. Might still be the way to go. But, if I was doing it now, I'd be >>>> looking at a "no radials required" antenna. My reasoning is somewhat age >>>> related. >>>> >>>> Be looking forward to the sage advice that will come from this post. It >>>> is summer - so it is antenna time. >>>> >>>> Bill W2BLC >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by W6ODJ
My today's experience was that my nice KX3/ATU which happily tuned my random wire when running from a power supply two weeks ago refused to load the same wire at the same location on all bands below 10 megs when running from the internal battery. However, I could convince it to tune the antenna while I was touching the case of the transceiver (I have been doing some simulations In order to gain some understanding why the german "Multiband-Fuchskreis" sold by a german Elecraft reseller seems to work in some situations and doesn't work for others and just used what I learned from my simulations)
Obviously the "counterpoise" was missing (or in my words the capacitance of the case to ground was not high enough). I could not test if plugging the headphones in and using them is sufficient to increase the capacitance sufficiently ;-) So, although not directly related to elevated radials, this former OT post has a relation to Elecraft equipment now ;-) BTW, is there any idea concerning the order of magnitude of the capacitance of a human body (6ft tall, normal weight) with respect to ground? Vy 73, Ralf, DL6OAP Am 19.05.2013 um 17:28 schrieb Walter Underwood <[hidden email]>: > A vertical dipole can be balanced with the lower element shorter. It will have more capacitance to ground, which makes it electrically longer. This is like putting a capacitance hat on the end of an element. > > wunder > K6WRU > > On May 18, 2013, at 11:36 PM, Oliver Johns wrote: > >> ELEVATED RADIALS: I think Joe hits it on the head here. A vertical with elevated "radials" is essentially an OCF dipole. There is no particular reason for the "radials" to be a quarter wavelength. They should be whatever length lets you resonate the antenna with a feed impedance you can live with. >> >> IMPT POINT: If you want your antenna actually to have a vertical radiation pattern (low angle, omni-directional) then the elevated radials must be symmetric. If there are two, they must be of exactly equal length and point in exactly opposite directions. If there are four, they must be equal and point in directions 90 degrees from one another. This symmetry guarantees that the "radials" do not radiate. The do carry currents, they do help resonate the antenna, but if they are symmetric radiation from them cancels and they therefore do not radiate appreciably. >> >> 73, >> >> Oliver >> W6ODJ >> >> >> On 18 Jan. 2013, at 06:46 AM, "Joe Subich, W4TV" <[hidden email]> wrote: >> >>> >>>> Personally, I do wonder about the new fangled "no radials required" >>>> antennas. But, I have an old R5 and it works well. >>> >>> The "no radials" antennas are basically a vertical OCF - the short >>> decoupling radials are the short leg and the vertical is adjusted >>> through the use of traps, stubs and/or loading to resonate on the >>> desired band with the fixed length (typically 42") of the short >>> "radials". >>> >>> 73, >>> >>> ... Joe, W4TV >>> >>> >>> On 5/18/2013 9:25 AM, Bill wrote: >>>> The cleanest installation is to put the radials in the ground - but, not >>>> portable at all. The idea is a capacitance connection with the earth. I >>>> have used welded steel cattle fence in the past - I build a mat that is >>>> about 30 or 40 feet out from the base of the antenna. >>>> >>>> For raised radials - they must be resonate to function properly. Three >>>> or four per band or related band. They have to be high enough that they >>>> present no danger to anyone roaming around your antenna field. They can >>>> be drooping or horizontal - both work well. >>>> >>>> Personally, I do wonder about the new fangled "no radials required" >>>> antennas. But, I have an old R5 and it works well. Perhaps the way to go >>>> is a new antenna that just gets bolted to a post and a feedline >>>> attached. Sure makes life easier and from folks I talk to all the time - >>>> they do work. Forget that they are a little expensive. You buy an >>>> antenna to use for years. >>>> >>>> Read the eHam reviews and see what other users are saying before you buy >>>> anything. Ask on the air. >>>> >>>> The best I ever had was a Butternut of some kind over a bunch of buried >>>> fence. Might still be the way to go. But, if I was doing it now, I'd be >>>> looking at a "no radials required" antenna. My reasoning is somewhat age >>>> related. >>>> >>>> Be looking forward to the sage advice that will come from this post. It >>>> is summer - so it is antenna time. >>>> >>>> Bill W2BLC >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > > -- > Walter Underwood > [hidden email] > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by W4JBB
Thanks for all the answers. I have a lot to read through, but I think I
have enough for now. 73, Joel - W4JBB On 5/18/13 7:37 AM, Joel Black wrote: > Other than for portability, why are elevated radials so important? ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by DL6OAP
An oft overlooked advantage to elevated radials is that, properly
terminated, they will keep your hat from blowing off. ________________________________ John T. Gwin [hidden email] [hidden email] ----- Original Message ----- From: "Ralf Wilhelm" <[hidden email]> Cc: "elecraft List" <[hidden email]> Sent: Sunday, May 19, 2013 3:59 PM Subject: Re: [Elecraft] OT: Elevated vs. Buried Radials > My today's experience was that my nice KX3/ATU which happily tuned my > random wire when running from a power supply two weeks ago refused to load > the same wire at the same location on all bands below 10 megs when running > from the internal battery. However, I could convince it to tune the > antenna while I was touching the case of the transceiver (I have been > doing some simulations In order to gain some understanding why the german > "Multiband-Fuchskreis" sold by a german Elecraft reseller seems to work in > some situations and doesn't work for others and just used what I learned > from my simulations) > > Obviously the "counterpoise" was missing (or in my words the capacitance > of the case to ground was not high enough). I could not test if plugging > the headphones in and using them is sufficient to increase the capacitance > sufficiently ;-) > > So, although not directly related to elevated radials, this former OT post > has a relation to Elecraft equipment now ;-) > > BTW, is there any idea concerning the order of magnitude of the > capacitance of a human body (6ft tall, normal weight) with respect to > ground? > > Vy 73, Ralf, DL6OAP > > Am 19.05.2013 um 17:28 schrieb Walter Underwood <[hidden email]>: > >> A vertical dipole can be balanced with the lower element shorter. It will >> have more capacitance to ground, which makes it electrically longer. This >> is like putting a capacitance hat on the end of an element. >> >> wunder >> K6WRU >> >> On May 18, 2013, at 11:36 PM, Oliver Johns wrote: >> >>> ELEVATED RADIALS: I think Joe hits it on the head here. A vertical >>> with elevated "radials" is essentially an OCF dipole. There is no >>> particular reason for the "radials" to be a quarter wavelength. They >>> should be whatever length lets you resonate the antenna with a feed >>> impedance you can live with. >>> >>> IMPT POINT: If you want your antenna actually to have a vertical >>> radiation pattern (low angle, omni-directional) then the elevated >>> radials must be symmetric. If there are two, they must be of exactly >>> equal length and point in exactly opposite directions. If there are >>> four, they must be equal and point in directions 90 degrees from one >>> another. This symmetry guarantees that the "radials" do not radiate. >>> The do carry currents, they do help resonate the antenna, but if they >>> are symmetric radiation from them cancels and they therefore do not >>> radiate appreciably. >>> >>> 73, >>> >>> Oliver >>> W6ODJ >>> >>> >>> On 18 Jan. 2013, at 06:46 AM, "Joe Subich, W4TV" <[hidden email]> >>> wrote: >>> >>>> >>>>> Personally, I do wonder about the new fangled "no radials required" >>>>> antennas. But, I have an old R5 and it works well. >>>> >>>> The "no radials" antennas are basically a vertical OCF - the short >>>> decoupling radials are the short leg and the vertical is adjusted >>>> through the use of traps, stubs and/or loading to resonate on the >>>> desired band with the fixed length (typically 42") of the short >>>> "radials". >>>> >>>> 73, >>>> >>>> ... Joe, W4TV >>>> >>>> >>>> On 5/18/2013 9:25 AM, Bill wrote: >>>>> The cleanest installation is to put the radials in the ground - but, >>>>> not >>>>> portable at all. The idea is a capacitance connection with the earth. >>>>> I >>>>> have used welded steel cattle fence in the past - I build a mat that >>>>> is >>>>> about 30 or 40 feet out from the base of the antenna. >>>>> >>>>> For raised radials - they must be resonate to function properly. Three >>>>> or four per band or related band. They have to be high enough that >>>>> they >>>>> present no danger to anyone roaming around your antenna field. They >>>>> can >>>>> be drooping or horizontal - both work well. >>>>> >>>>> Personally, I do wonder about the new fangled "no radials required" >>>>> antennas. But, I have an old R5 and it works well. Perhaps the way to >>>>> go >>>>> is a new antenna that just gets bolted to a post and a feedline >>>>> attached. Sure makes life easier and from folks I talk to all the >>>>> time - >>>>> they do work. Forget that they are a little expensive. You buy an >>>>> antenna to use for years. >>>>> >>>>> Read the eHam reviews and see what other users are saying before you >>>>> buy >>>>> anything. Ask on the air. >>>>> >>>>> The best I ever had was a Butternut of some kind over a bunch of >>>>> buried >>>>> fence. Might still be the way to go. But, if I was doing it now, I'd >>>>> be >>>>> looking at a "no radials required" antenna. My reasoning is somewhat >>>>> age >>>>> related. >>>>> >>>>> Be looking forward to the sage advice that will come from this post. >>>>> It >>>>> is summer - so it is antenna time. >>>>> >>>>> Bill W2BLC >>>>> ______________________________________________________________ >>>>> Elecraft mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:[hidden email] >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >> >> -- >> Walter Underwood >> [hidden email] >> >> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2013.0.2904 / Virus Database: 3162/6329 - Release Date: 05/16/13 > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by DL6OAP
On Sun, 19 May 2013 22:59:50 +0200, Ralf Wilhelm wrote:
> Obviously the "counterpoise" was missing (or in my words the capacitance of the case to ground was not high enough). I could not test if plugging the headphones in and using them is sufficient to increase the capacitance sufficiently ;-) Sounds to me like you don't have your radio properly grounded (earthed?) in the first place. Gary -- http://ag0n.net 3055: http://ag0n.net/irlp/3055 NodeOp Help Page: http://ag0n.net/irlp ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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Exactly.
Well, I don't "believe" in grounding except for safety reasons, because a good rf to earth connection is so difficult to obtain ;-) My "believe" is that if I am pushing some electrons into the wire, I have to take them from somewhere else (my rig can't create or destroy them), and if there is no obvious counterpoise (or good rf connection to earth turning this huge electron reservoir into a counterpoise) I take them from the TRX's case. So, in my situation, my antenna's two "poles" are formed by the wire on one end and the trx housing on the other end. My wire has a capacitance to earth and a capacitance to the rig, my rig has a capacitance to earth and by touching the rig I increase the former two of them (but become part of the antenna). A good rf ground would be the best choice (if ground conductivity is high enough so that the capacitance between antenna and ground is not too lossy), but in general I prefer to increase the capacity between antenna wire and counterpoise (because the lossy antenna to ground capacitance becomes less important). Yes, I know putting 1000 sq ft of chicken wire fence onto e arth would be slightly better, but I am a "quick and dirty guy" ;-) Actually it is something I was always expecting to happen earlier (so no big surprise for me, I immediately knew what to do: touch the rig!) but never happened to me. I have been using this same piece of wire for something like 10 years now, and have used it with a FT817+ ZM2 atu, a K2 + internal atu, and now with the KX3. I was always expecting it to behave differently when using a battery powered rig instead of a rig connected to the power supply. I could not determine a different behaviour with the ZM2, because this thing tunes almost everything with very similar knob settings (so I would not be able to tell) but with high losses due to its high Q in some situations. The K2 could tune this same wire in the same situation even when battery powered and w/o ground. However, the impedance range of the K2 tuner should be higher (I think I noticed from the diagrams it uses larger inductivities, but still have to check), as the K2 with ground can tune the wire on 160 which the KX 3 can't (I don't care because it is a dummy load on 160 anyway). So, if you can't tune 20 mtrs of wire on 10 meg and below, try touching the rig, and then probably follow the manual (or your licence course materials) and connect at least this "pedestrian trailing wire" to it and don't blame it on the tuner (or Elecraft) ;-) Vy 73 Ralf, DL6OAP Am 19.05.2013 um 23:14 schrieb AG0N-3055 <[hidden email]>: > On Sun, 19 May 2013 22:59:50 +0200, Ralf Wilhelm wrote: > >> Obviously the "counterpoise" was missing (or in my words the capacitance of the case to ground was not high enough). I could not test if plugging the headphones in and using them is sufficient to increase the capacitance sufficiently ;-) > > Sounds to me like you don't have your radio properly grounded (earthed?) > in the first place. > > Gary > -- > http://ag0n.net > 3055: http://ag0n.net/irlp/3055 > NodeOp Help Page: http://ag0n.net/irlp > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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