Home |
Search |
Today's Posts |
#11
|
|||
|
|||
On Fri, 7 Jan 2005 13:23:24 -0600, "Charlie"
wrote: |What about the Hustler antenna instructions which provide the "correct |lengths" for cutting radials? Moreover they need not be "buried 2 inches" in |the ground but can safely remain on the ground once grass growth effectively |buries them. Also DX Engineering www.dxengineering.com has ground radials |for sale which are "pre-cut to length". I assume they know what they are |doing. Of course they do.... they are separating fools from their money. |Force 12 also recommends using "tuned radials" with their line of |vertical antennas. I assume they too know more about antennas then I do. I'm sure. And they say, among other things (including some advertising hype) at: http://force12inc.com/brvinfo.htm "The most efficient radial system is one that is elevated above ground." Only then, does it pay (or matter) to tune the radials. |
#12
|
|||
|
|||
I just want to thank all of you for your kindness and speediness in pointing
out my error as a new vertical antenna user. I am glad several of you had a laugh on me for burying tuned radials. Thank you for your kindness and courtesy. Hope to catch each and every one of you on the bands. I am grateful for the tact and diplomacy that many of you showed me. True Ham Spirit at it's best. Based on what I have been told by the gentlemen in this great group I could have used much shorter radials than any "tuned length". If that is right then I have achieved a much more effective radial system then what I would have had I not erred. Is this right? In other words I have more wire in the ground then I need..right? Now if that is so..does that hurt or help TY Roy 73 / DX -- Charlie Ham Radio - AD5TH www.ad5th.com Live Blues Music www.492acousticblues.com "Wes Stewart" wrote in message ... On Fri, 7 Jan 2005 13:23:24 -0600, "Charlie" wrote: |What about the Hustler antenna instructions which provide the "correct |lengths" for cutting radials? Moreover they need not be "buried 2 inches" in |the ground but can safely remain on the ground once grass growth effectively |buries them. Also DX Engineering www.dxengineering.com has ground radials |for sale which are "pre-cut to length". I assume they know what they are |doing. Of course they do.... they are separating fools from their money. |Force 12 also recommends using "tuned radials" with their line of |vertical antennas. I assume they too know more about antennas then I do. I'm sure. And they say, among other things (including some advertising hype) at: http://force12inc.com/brvinfo.htm "The most efficient radial system is one that is elevated above ground." Only then, does it pay (or matter) to tune the radials. |
#13
|
|||
|
|||
Nobody's laughing at you -- it's a topic that's very poorly understood.
Here's how it works with buried radials. . . It never hurts to make them longer. But beyond some distance, it doesn't help appreciably -- if the current on a radial has dropped to a negligible value at its end, extending it won't do anything. What is this distance? Well, like so many other things, the only really honest answer is that it depends. As it turns out, the current fades more rapidly if you have only a few radials. So if you only have a few, it doesn't help to make them super long. If you have a lot (say, 60 or more), increasing the length has more effect -- but your system will already be so efficient that it won't make much difference. The classic set of measurements of various ground systems was published in 1937 as "Ground Systems as a Factor in Antenna Efficiency" by Brown, Lewis, and Epstein. Their paper has many graphs of the effectiveness of various combinations of radial lengths and number of radials for various vertical heights -- for the particular ground at the place of their experiments, the characteristics of which weren't recorded. Their data have been interpreted and reorganized countless times and in countless ways -- a web search should bring you a lot of hits. But some rules of thumb (and only rules of thumb) for amateurs(*) emerge: 1. There's not much point in making radials much longer than a free-space quarter wavelength or so. 2. Increasing the number of radials from 16 to 120 or more will probably net you less than a couple of dB. That might be worth it to you, it might not. These assume more-or-less average soil. If your soil is very dry, you might benefit from more and/or longer radials. And of course, there's no point in fussing over exact lengths. There's no need to even make them the same length. Put down what you can and don't worry about it. Putting in more won't hurt, nor will making them longer. But you're not likely to notice much difference between a big installation and a fairly simple one, unless your ground is extraordinarily poor. Roy Lewallen, W7EL (*) An increase in field strength of a few percent is a worthwhile pursuit for AM broadcasters, because it increases the size of their audience and hence the value of their advertising. Small increments like that are completely useless for amateurs, though, so our goals are somewhat different. Keep that in mind when looking through various analyses and recommendations, since most are oriented toward broadcasters. Charlie wrote: I just want to thank all of you for your kindness and speediness in pointing out my error as a new vertical antenna user. I am glad several of you had a laugh on me for burying tuned radials. Thank you for your kindness and courtesy. Hope to catch each and every one of you on the bands. I am grateful for the tact and diplomacy that many of you showed me. True Ham Spirit at it's best. Based on what I have been told by the gentlemen in this great group I could have used much shorter radials than any "tuned length". If that is right then I have achieved a much more effective radial system then what I would have had I not erred. Is this right? In other words I have more wire in the ground then I need..right? Now if that is so..does that hurt or help TY Roy 73 / DX |
#14
|
|||
|
|||
On Fri, 7 Jan 2005 21:18:45 -0600, "Charlie"
wrote: I just want to thank all of you for your kindness and speediness in pointing out my error as a new vertical antenna user. I am glad several of you had a laugh on me for burying tuned radials Don't feel bad Charlie, we read the book. G I would really suggest you consider purchasing the current edition of the ARRL Antenna book. There is a whole chapter (3) devoted to the effects of ground. You'll find in more reliable information in that book than you ever see in antenna manufacturers' statements and claims. Oh, yes when it comes to radials you can't have too much wire in the ground, but you can hit the wall of diminishing returns. Bust of luck and 73 Danny, K6MHE |
#15
|
|||
|
|||
Thanks Roy for a great yet concise answer to this matter. I misunderstood
about tuned radials. I wish I would have done more then a cursory look at the matter. Basically all I saw was "tuned radials" and "you can't have too many". Had I read more I would have eventually seen that buried radials need not be tuned and that a 1/4 lambda would have been adequate. I have over 1300 ft of radials! Don't ask what my pre-cut "tuned radials" cost me!! I made sure I had plenty and now that this cabbage is boiled I am glad to see at least I did not do my station a disservice. Most importantly I learned something.I am not a new ham but am new to this vertical antenna scene. I am aware of your reputation in this field Roy and I appreciate your warm, courteous and most of all informative replies. 73 / DX -- Charlie Ham Radio - AD5TH www.ad5th.com Live Blues Music www.492acousticblues.com "Roy Lewallen" wrote in message ... Nobody's laughing at you -- it's a topic that's very poorly understood. Here's how it works with buried radials. . . It never hurts to make them longer. But beyond some distance, it doesn't help appreciably -- if the current on a radial has dropped to a negligible value at its end, extending it won't do anything. What is this distance? Well, like so many other things, the only really honest answer is that it depends. As it turns out, the current fades more rapidly if you have only a few radials. So if you only have a few, it doesn't help to make them super long. If you have a lot (say, 60 or more), increasing the length has more effect -- but your system will already be so efficient that it won't make much difference. The classic set of measurements of various ground systems was published in 1937 as "Ground Systems as a Factor in Antenna Efficiency" by Brown, Lewis, and Epstein. Their paper has many graphs of the effectiveness of various combinations of radial lengths and number of radials for various vertical heights -- for the particular ground at the place of their experiments, the characteristics of which weren't recorded. Their data have been interpreted and reorganized countless times and in countless ways -- a web search should bring you a lot of hits. But some rules of thumb (and only rules of thumb) for amateurs(*) emerge: 1. There's not much point in making radials much longer than a free-space quarter wavelength or so. 2. Increasing the number of radials from 16 to 120 or more will probably net you less than a couple of dB. That might be worth it to you, it might not. These assume more-or-less average soil. If your soil is very dry, you might benefit from more and/or longer radials. And of course, there's no point in fussing over exact lengths. There's no need to even make them the same length. Put down what you can and don't worry about it. Putting in more won't hurt, nor will making them longer. But you're not likely to notice much difference between a big installation and a fairly simple one, unless your ground is extraordinarily poor. Roy Lewallen, W7EL (*) An increase in field strength of a few percent is a worthwhile pursuit for AM broadcasters, because it increases the size of their audience and hence the value of their advertising. Small increments like that are completely useless for amateurs, though, so our goals are somewhat different. Keep that in mind when looking through various analyses and recommendations, since most are oriented toward broadcasters. Charlie wrote: I just want to thank all of you for your kindness and speediness in pointing out my error as a new vertical antenna user. I am glad several of you had a laugh on me for burying tuned radials. Thank you for your kindness and courtesy. Hope to catch each and every one of you on the bands. I am grateful for the tact and diplomacy that many of you showed me. True Ham Spirit at it's best. Based on what I have been told by the gentlemen in this great group I could have used much shorter radials than any "tuned length". If that is right then I have achieved a much more effective radial system then what I would have had I not erred. Is this right? In other words I have more wire in the ground then I need..right? Now if that is so..does that hurt or help TY Roy 73 / DX |
#16
|
|||
|
|||
If length means nothing I could have gone with 6 inch
radials if I followed your logic...eh? I thought my "logic" said "make them all as log as possible". If the manufacturs say cut radials to X length then lay them on the ground...then they need to go back to school. One rule of thumb is: Try to make the radial length at least equal to the heigth of the vertical. If the Hustler is 20' tall, make the radials at least 20' long and use lots of them. Having 50 radials 20' long is better than 8 radials 500' long etc. N4LQ -- Steve N4LQ "Charlie" wrote in message ... What about the Hustler antenna instructions which provide the "correct lengths" for cutting radials? Moreover they need not be "buried 2 inches" in the ground but can safely remain on the ground once grass growth effectively buries them. Also DX Engineering www.dxengineering.com has ground radials for sale which are "pre-cut to length". I assume they know what they are doing. Force 12 also recommends using "tuned radials" with their line of vertical antennas. I assume they too know more about antennas then I do. I researched this topic before installing my 5-BTV and tuned radials were always recommended. If length means nothing I could have gone with 6 inch radials if I followed your logic...eh? My 5-BTV installation with 72 "tuned" radials at this page 1. http://www.ad5th.com/5-BTV.html I am getting great reports so far but have only been on the air at this qth for a couple weeks. A new AL-80B arrives in 3 days which should improve my signal greatly. 73 / DX -- Charlie Ham Radio - AD5TH www.ad5th.com Live Blues Music www.492acousticblues.com "N4LQ" wrote in message ... Why do hams persist on using "tuned" radials on the ground? They cut them to "resonance" which means nothing. A wire cut for resonance on 40 meters and buried under 2 inches of soil is no where near resonant 7mhz. It would be much more effective if they just made all the radials as long as possible and forget this resonance stuff but no one listens. -- Steve N4LQ "Roger Adam" wrote in message ... Andy, check out this site, it may you/someone else, regards http://www.ad5th.com/5-BTV.html http://www.ad5th.com/5-BTV.html I choose Polesoft Lockspam to fight spam, and you? http://www.polesoft.com/refer.html |
#17
|
|||
|
|||
Thx Steve for that .....73
-- Charlie Ham Radio - AD5TH www.ad5th.com Live Blues Music www.492acousticblues.com "N4LQ" wrote in message ... If length means nothing I could have gone with 6 inch radials if I followed your logic...eh? I thought my "logic" said "make them all as log as possible". If the manufacturs say cut radials to X length then lay them on the ground...then they need to go back to school. One rule of thumb is: Try to make the radial length at least equal to the heigth of the vertical. If the Hustler is 20' tall, make the radials at least 20' long and use lots of them. Having 50 radials 20' long is better than 8 radials 500' long etc. N4LQ -- Steve N4LQ "Charlie" wrote in message ... What about the Hustler antenna instructions which provide the "correct lengths" for cutting radials? Moreover they need not be "buried 2 inches" in the ground but can safely remain on the ground once grass growth effectively buries them. Also DX Engineering www.dxengineering.com has ground radials for sale which are "pre-cut to length". I assume they know what they are doing. Force 12 also recommends using "tuned radials" with their line of vertical antennas. I assume they too know more about antennas then I do. I researched this topic before installing my 5-BTV and tuned radials were always recommended. If length means nothing I could have gone with 6 inch radials if I followed your logic...eh? My 5-BTV installation with 72 "tuned" radials at this page 1. http://www.ad5th.com/5-BTV.html I am getting great reports so far but have only been on the air at this qth for a couple weeks. A new AL-80B arrives in 3 days which should improve my signal greatly. 73 / DX -- Charlie Ham Radio - AD5TH www.ad5th.com Live Blues Music www.492acousticblues.com "N4LQ" wrote in message ... Why do hams persist on using "tuned" radials on the ground? They cut them to "resonance" which means nothing. A wire cut for resonance on 40 meters and buried under 2 inches of soil is no where near resonant 7mhz. It would be much more effective if they just made all the radials as long as possible and forget this resonance stuff but no one listens. -- Steve N4LQ "Roger Adam" wrote in message ... Andy, check out this site, it may you/someone else, regards http://www.ad5th.com/5-BTV.html http://www.ad5th.com/5-BTV.html I choose Polesoft Lockspam to fight spam, and you? http://www.polesoft.com/refer.html |
#18
|
|||
|
|||
On Fri, 7 Jan 2005 21:18:45 -0600, "Charlie"
wrote: |I just want to thank all of you for your kindness and speediness in pointing |out my error as a new vertical antenna user. I am glad several of you had a |laugh on me for burying tuned radials. Thank you for your kindness and |courtesy. Hope to catch each and every one of you on the bands. I am |grateful for the tact and diplomacy that many of you showed me. True Ham |Spirit at it's best. | |Based on what I have been told by the gentlemen in this great group I could |have used much shorter radials than any "tuned length". If that is right |then I have achieved a much more effective radial system then what I would |have had I not erred. Is this right? In other words I have more wire in the |ground then I need..right? Now if that is so..does that hurt or help I haven't followed this thread since its inception, but I did read comments from you such as: "If length means nothing I could have gone with 6 inch radials if I followed your logic...eh?" and "You're entitled to your opinion on this seemingly controversial topic." This came across as an attitude problem (further exemplified by your sarcasm above) that precluded gentler handling of your inexperience, by me anyway. In the future, I suggest a more receptive attitude on your part might elicit less hostile advice. You did do a great installation job, however, and while you expended more effort than necessary, it is not for naught. |
#19
|
|||
|
|||
Thanks for the kind words Wes.
Please fax me a copy of your medical credentials and I'll more genuinely consider your diagnosis. Most of the others have been courteous and respectful. Maybe you were absent that day....73 -- Charlie Ham Radio - AD5TH www.ad5th.com Live Blues Music www.492acousticblues.com "Wes Stewart" wrote in message ... On Fri, 7 Jan 2005 21:18:45 -0600, "Charlie" wrote: |I just want to thank all of you for your kindness and speediness in pointing |out my error as a new vertical antenna user. I am glad several of you had a |laugh on me for burying tuned radials. Thank you for your kindness and |courtesy. Hope to catch each and every one of you on the bands. I am |grateful for the tact and diplomacy that many of you showed me. True Ham |Spirit at it's best. | |Based on what I have been told by the gentlemen in this great group I could |have used much shorter radials than any "tuned length". If that is right |then I have achieved a much more effective radial system then what I would |have had I not erred. Is this right? In other words I have more wire in the |ground then I need..right? Now if that is so..does that hurt or help I haven't followed this thread since its inception, but I did read comments from you such as: "If length means nothing I could have gone with 6 inch radials if I followed your logic...eh?" and "You're entitled to your opinion on this seemingly controversial topic." This came across as an attitude problem (further exemplified by your sarcasm above) that precluded gentler handling of your inexperience, by me anyway. In the future, I suggest a more receptive attitude on your part might elicit less hostile advice. You did do a great installation job, however, and while you expended more effort than necessary, it is not for naught. |
#20
|
|||
|
|||
On Sat, 8 Jan 2005 11:30:51 -0600, "Charlie"
wrote: |Thanks for the kind words Wes. |Please fax me a copy of your medical credentials and I'll more genuinely |consider your diagnosis. |Most of the others have been courteous and respectful. Maybe you were absent |that day.... Perhaps. But I can be as kind and courteous as the next guy when it is reciprocal. Over one hundred hams got their Novice tickets via classes that I taught at the local community college and I *never* had a complaint about disrespecting any of them because of their ignorance. Some of them even repeated the course just for the fun of it...and I might add they were paying tuition. Likewise the tech course I taught at the local Air Force base and the grad students I tutored in a microwave measurements course my boss taught at the U of Az. That said, if one of them had told me "You're entitled to your opinion on this seemingly controversial topic", I would have shown him the door. I actually like helping the inexperienced, but I don't suffer fools gladly. |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Inverted ground plane antenna: compared with normal GP and low dipole. | Antenna | |||
Yaesu FT-857D questions | Equipment | |||
Mobile Ant L match ? | Antenna | |||
EH Antenna Revisited | Antenna | |||
Poor quality low + High TV channels? How much dB in Preamp? | Antenna |