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vertical antenna loading coil vs toroid
I am doing some design with vertical antennas for the low bands
40/80/160M. I require a somewhat large reactance on the element to help load it on 160M, (40&80M) are working somewhat satisfactory now with the design i am using. The required reactance that i need and the size it would be using a coil (with the materials that i have right now) may not last a winter storm in VO1 land when loaded with ice or snow in 90km/h wind, so my question is, has anyone had experience using a toroid wound with the correct amount of reactance installed on the element to to achieve resonance instead of a coil and how it has been for them. |
vertical antenna loading coil vs toroid
On Mar 28, 2:10*pm, Cecil Moore wrote:
wrote: ... has anyone had experience using a *toroid wound with the correct amount of reactance installed on the element to to achieve resonance instead of a coil and how it has been for them. I've only one data point based on measurements made at a California 75m mobile shootout. K7JEB had this one mounted on a full-sized pickup. An 8.5 foot whip using a 75m Texas Bugcatcher coil at the base outperformed my antenna by +7dB. I had this one mounted on a full-sized pickup. An 11.5 foot whip using an SG-230 autotuner at the base. Not exactly the comparison you are seeking but the SG-230 did use #2 iron powder toroidal inductors. One might assume that the 6 inch long air-core bugcatcher coil contributed more radiation than the toroidal inductors. Seems to me the large air-core coil occupies a greater number of degrees of antenna than does toroidal inductor. This could be proved (or disproved) by making delay measurements on both coils using traveling wave current. Previous such measurements are worthless for such because the total current used was primarily standing- wave current and was changing phase by only ~1 deg for every ~30 degrees of antenna wire or coil. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com Thanks for your reply and the information you provided, it was very useful as well as the link, it will take me a bit to check it out LOTS of info there as well. I'm trying 40/80/160M trap vertical ,i'm experimenting with the low pass filters in the vertical as coil and cap hats as opposed to coils and coax capacitors or mica caps which ever. I would like to use the hats to distribute the current along the radiators more uniform as opposed to linear. The insulator i have on hand for the top hat is physically not long enough for the air core inductor, this is why i was wondering about the toroid at the top. 40/80M works great for dx with a 100W not bad on 15M either despite propagation lately. I should also mention its noisy on rx, i see it sometimes has 40db more noise then the loops that i used for rx, thanks again, 73 vo1bbn |
vertical antenna loading coil vs toroid
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vertical antenna loading coil vs toroid
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vertical antenna loading coil vs toroid
On Mar 28, 3:00*pm, wrote:
wrote: I am doing some design with vertical antennas for the low bands 40/80/160M. I require a somewhat large reactance on the element to help load it on 160M, (40&80M) are working somewhat satisfactory now with the design i am using. The required reactance that i need and the size it would be using a coil (with the materials that i have right now) *may not last a winter storm in VO1 land when loaded with ice or snow in 90km/h wind, so my question is, has anyone had experience using a *toroid wound with the correct amount of reactance installed on the element to to achieve resonance instead of a coil and how it has been for them. I have something simular and used a FT-240-61 torroid which I happened to have to build a tapped inductor with a pair of relays to switch it in/out for 80/160. The antenna analyzer and radio say it seems to work OK. Just be sure to pick a material appropriate for an inductor at those frequencies and a size appropriate for the power you intend to run. -- Jim Pennino Remove .spam.sux to reply. Thanks for the information, nice to see others have done some work with this in the past.I could do the switch relay and use the same hat on 160 as i am now on 80, this overhaul length would be about 45 feet not bad on 80 but i'm think a little short for efficiency on 160, with the insulator i have on top of the 45 feet i can go another 12 feet to the 160M hat. 57 feet overhaul to see how that works out. I do have an option for an 18 feet fiberglass on that for 75 feet total but would like to stick to 57 feet max any higher than that it will be quite noticeable with the sun on the fiberglass over the tree line, i will consider though your thought maybe not worth the gain in efficiency to go the other 12 feet to the 160M hat, its maybe about 8-10 electrical degrees in vertical radiator to the 160M top hat, thanks again great info,73 vo1bbn |
vertical antenna loading coil vs toroid
On Mar 28, 3:09*pm, Roy Lewallen wrote:
wrote: I am doing some design with vertical antennas for the low bands 40/80/160M. I require a somewhat large reactance on the element to help load it on 160M, (40&80M) are working somewhat satisfactory now with the design i am using. The required reactance that i need and the size it would be using a coil (with the materials that i have right now) *may not last a winter storm in VO1 land when loaded with ice or snow in 90km/h wind, so my question is, has anyone had experience using a *toroid wound with the correct amount of reactance installed on the element to to achieve resonance instead of a coil and how it has been for them. In most applications you'd be concerned about the inductor Q, since higher Q means less loss for the same inductance. You probably won't be able to get as high Q with a toroid as you will with a good air core inductor. But Tom, W8JI pointed out that with mobile antennas on the low frequency bands, the ground loss is so much greater than loading inductor loss, the latter isn't usually an important factor. It'll be difficult to get really low ground loss with a fixed antenna, too, so a toroid should work just about as well in practice unless you have a very good ground system. You don't, though, want the Q to be outrageously low. And that can happen if water gets between the turns. (That's also true of an air wound inductor.) So I recommend putting it into a container or coating it to keep that from happening. I built a toroid-loaded quarter wavelength (half length) 40 meter dipole for Field Day, and measured the gain relative to a full size dipole. The loss due to the inductors was less than a dB. Expect a very narrow bandwidth if the loss is low. Roy Lewallen, W7EL thanks for the consideration on the topic of the Q, for the 40M vertical i have over 0220khz of 2:1 swr on 80M about 160khz, i've tried a shunt resistor to change the bw on the 80M but didn;t really do much with it before 160M was going through my mind. If I get 50-80khz bw on 160M, i can work with that to do some testing it was orginally designed for 40/80M which works ok but now i would like to try 160, thanks again for the info, 73 vo1bbn |
vertical antenna loading coil vs toroid
Cecil Moore wrote:
Seems to me the large air-core coil occupies a greater number of degrees of antenna than does the toroidal inductor. I've received a number of emails requesting that I explain what I meant by this statement. It is easiest understood by people who can solve the following problem. How can the impedance looking into the following physical 45 degree, dual-Z0 stub be purely resistive, i.e. electrically 90 degrees and resonant? ---22.5 deg 300 ohm twinlead---+---22.5 deg 50 ohm coax---open -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
vertical antenna loading coil vs toroid
On Mar 30, 4:39*pm, Cecil Moore wrote:
Cecil Moore wrote: Seems to me the large air-core coil occupies a greater number of degrees of antenna than does the toroidal inductor. I've received a number of emails requesting that I explain what I meant by this statement. It is easiest understood by people who can solve the following problem. How can the impedance looking into the following physical 45 degree, dual-Z0 stub be purely resistive, i.e. electrically 90 degrees and resonant? ---22.5 deg 300 ohm twinlead---+---22.5 deg 50 ohm coax---open -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com Exactly as my tests have shown me. Using a coil and toroid with given same inductance say 20uH to achieve the same resonance the top part of the vertical over the toroid was about 8" longer, then the top portion of the vertical over the coil, just as you stated, More electrical degrees in the coil than the toroid. I was wondering if the self shielding properties of the toroid would have contributed to this conclusion, and because of these properties, the toroid not have any electrical degrees, so to speak, so when it come to the radiating element it would need to be slightly longer to see the electrical degrees for the wavelength or resonance frequency injected into it. thanks again for the info. |
vertical antenna loading coil vs toroid
wrote:
I was wondering if the self shielding properties of the toroid would have contributed to this conclusion, and because of these properties, the toroid not have any electrical degrees, so to speak, so when it come to the radiating element it would need to be slightly longer to see the electrical degrees for the wavelength or resonance frequency injected into it. thanks again for the info. I suspect that the VF of the toroidal loading coil is much higher than the VF of an air-core loading coil, i.e. the toroidal loading coil occupies fewer electrical degrees of the antenna. It makes sense that if the toroidal loading coil occupies fewer electrical degrees of the antenna that those degrees must be furnished somewhere else. The toroidal loading coil seems to be closer to the lumped circuit model than is the large air-core loading coil which generally requires analysis using distributed network techniques. http://www.ttr.com/TELSIKS2001-MASTER-1.pdf There are two things happening with a base loading coil. The loading coil occupies a certain number of degrees, e.g. ~36 degrees for a 75m bugcatcher coil. The stinger occupies maybe ~11 degrees for a total of ~47 degrees. The other ~43 degrees comes from the phase shift at the impedance discontinuity between the coil and the stinger. With a center loading coil, a few degrees are lost at the impedance discontinuity between the base section and the coil. That's why a larger coil is needed for a center-loaded mobile antenna. -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
vertical antenna loading coil vs toroid
On Apr 2, 8:33*am, Cecil Moore wrote:
wrote: I was wondering if the self shielding properties of the toroid would have contributed to this conclusion, and because of these properties, the toroid not have any electrical degrees, so to speak, so when it come to the radiating element it would need to be slightly longer to see the electrical degrees for the wavelength or resonance frequency injected into it. thanks again for the info. I suspect that the VF of the toroidal loading coil is much higher than the VF of an air-core loading coil, i.e. the toroidal loading coil occupies fewer electrical degrees of the antenna. It makes sense that if the toroidal loading coil occupies fewer electrical degrees of the antenna that those degrees must be furnished somewhere else. The toroidal loading coil seems to be closer to the lumped circuit model than is the large air-core loading coil which generally requires analysis using distributed network techniques. http://www.ttr.com/TELSIKS2001-MASTER-1.pdf There are two things happening with a base loading coil. The loading coil occupies a certain number of degrees, e.g. ~36 degrees for a 75m bugcatcher coil. The stinger occupies maybe ~11 degrees for a total of ~47 degrees. The other ~43 degrees comes from the phase shift at the impedance discontinuity between the coil and the stinger. With a center loading coil, a few degrees are lost at the impedance discontinuity between the base section and the coil. That's why a larger coil is needed for a center-loaded mobile antenna. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com I am a little confused, you say about the coil and the stinger occupying a portion of the total 90 degrees, (I can follow this not a problem), however I thought the purpose of the coil was to add inductive reactance, due to the shortened length of the radiator, less than 1/4 wave, therefore having a capacitive reactance overhaul. Let the shortened vertical be 34-j234 ohms. My understanding is that depending on on what the reactance is at some freq, I need to offset this negative reactance with an equal positive reactance. I wasn't looking at from a degrees point for view. Or is it just 6 of one, half dozen of the other, both be equal just expressed differently, I like the degrees point of view for a couple of other arrays I am experimenting with. (long wires) I think it will simplify things a whole lot. thanks again for the info and the links, very valuable info. 73 brett |
vertical antenna loading coil vs toroid
wrote:
My understanding is that depending on on what the reactance is at some freq, I need to offset this negative reactance with an equal positive reactance. I wasn't looking at from a degrees point for view. It depends upon which math model is being used and whether the math model is valid under the existing conditions. We can neutralize capacitive reactance with a lumped inductance or with a stub or with a helical coil. The results are approximately the same but there are differences. If the current amplitude changes significantly between the bottom and top of the loading coil, the lumped circuit model is not valid because the coil is an appreciable percentage of a wavelength more akin to a transmission line than a lumped circuit. -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
vertical antenna loading coil vs toroid
On Apr 2, 7:17*pm, Cecil Moore wrote:
It depends upon which math model is being used and whether the math model is valid under the existing conditions. We can neutralize capacitive reactance with a lumped inductance or with a stub or with a helical coil. The results are approximately the same but there are differences. If the current amplitude changes significantly between the bottom and top of the loading coil, the lumped circuit model is not valid because the coil is an appreciable percentage of a wavelength more akin to a transmission line than a lumped circuit. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com Now it is clearer to me. I understand why there is a difference using lumped circuit analysis as opposed to the the actual coil or stub analysis. You have provided much valuable info on this subject. Thanks again. I will load some math program on my pc any do some of the analzsis of my design and compare it to what I have measured now with the ones I have built The reason this came about to me was to use some very short but extremely strong 1.5" insulators that I have.In order to get the required inductance with the length of insulators that I have the losses in the coil would be large, that is why I chose the toroid. Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , would it somewhat have a larger inductance then the expected air wound value, similar to a coil with a ferite inside it (tuning slug) or would the radiator not even see the amount of the coil that it covered therefore have a lower inductance. I was thinking, instead of spreading the turns on the coil to adjust amount of inductance simply move the vertical element in and out of the coil to adjust it. There discussions before were for a center loading coil which will be constant, but this last part of discussion I would like to try for base loaded coil and make it variable but not tap it conventionally . Hope I described well enough for you see what I have in mind, Again thanks for the info.73 brett |
vertical antenna loading coil vs toroid
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vertical antenna loading coil vs toroid
wrote:
Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
vertical antenna loading coil vs toroid
Richard Clark wrote:
One inductance value (however it is wound) is not equivalent everywhere - hence the proposition of a coil having an equivalent length is rather preposterous. Nobody said one inductance value is equivalent everywhere. In fact, just the opposite is true. The equivalent length for different coils with the same inductance depends upon their physical configurations. For instance, w8ji's loading coil (100t, 10tpi, 2"dia) calculates to have a VF of 0.0328 while my 75m Texas Bugcatcher coil with approximately the same inductance calculates to have a VF of 0.0198, a 66% difference proving your above premise to be false. ************************************************** ***** THERE IS NO REQUIREMENT THAT TWO COILS WITH THE SAME INDUCTANCE OCCUPY THE SAME NUMBER OF DEGREES OF ANTENNA. ************************************************** ***** To understand the details, just compare the following 1/4WL resonant stubs: ---25.3 deg Z0=600 ohm---+---10 deg Z0=50 ohm---open ---70.6 deg Z0=100 ohm---+---10 deg Z0=50 ohm---open Both stubs are electrically 1/4WL = 90 degrees long. How can 35.3 physical degrees of stub perform a 90 degree stub function? Hint: There is a 54.7 degree phase shift at the '+' junction. Why does the second example require 80.6 physical degrees of feedline? Hint: There is only a 9.4 degree phase shift at the '+' junction. Why does it take 70.6 degrees of Z0=100 ohm feedline to perform exactly the same function as 25.3 degrees of Z0=600 ohm feedline? Both stub segments, Z0=600 and Z0=100, are providing the same inductance at the '+' junction point, yet one is 2.8 times longer than the other. Is "the proposition of a piece of transmission line having an equivalent length rather preposterous"? -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
vertical antenna loading coil vs toroid
Cecil Moore wrote:
wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. some times a hack saw *can* be a fine tuning tool. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. Ahh, I had the idea of doing such a thing (add vertical travel) for my bugcatcher to fine tune swr if it needs tweaked a little. But it looks like I'll be hopping outside the car a lot after all. For 75/80 meters, I have like 4 separate taps. - 73 de Mike N3LI - |
vertical antenna loading coil vs toroid
On Apr 2, 10:34*pm, Richard Clark wrote:
On Thu, 2 Apr 2009 16:42:32 -0700 (PDT), wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil Hi Brett, After following Cecil's pet theory, and your statement of finding it useful, your question above becomes a remarkably perplexing application of that knowledge. The theory should have answered your question before hand. * Thanks very much for the information you provided to my posting. The theory to the question was answered, I was asking the question once again to the group to see if others have input on the subject I posted. Knowing me I will probably ask many more questions that I have already have the answer to, just to raise conversation and debate to get other views on the subject. Thanks again for the info on the subject, much appreciated. 73, vo1bbn Brett |
vertical antenna loading coil vs toroid
On Apr 2, 10:34*pm, Richard Clark wrote:
On Thu, 2 Apr 2009 16:42:32 -0700 (PDT), wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil Hi Brett, After following Cecil's pet theory, and your statement of finding it useful, your question above becomes a remarkably perplexing application of that knowledge. The theory should have answered your question before hand. * Thanks very much for the information you provided to my posting. The theory to the question was answered, I was asking the question once again to the group to see if others have input on the subject I posted. Knowing me I will probably ask many more questions that I have already have the answer to, just to raise conversation and debate to get other views on the subject. Thanks again for the info on the subject, much appreciated. 73, vo1bbn Brett |
vertical antenna loading coil vs toroid
On Fri, 03 Apr 2009 10:39:37 -0800, Richard Clark
wrote: On Fri, 03 Apr 2009 07:34:20 -0500, Cecil Moore wrote: Richard Clark wrote: One inductance value (however it is wound) is not equivalent everywhere - Nobody said one inductance value is equivalent everywhere. Nobody is not very many people which should make this a short list. But I don't see any names - strange. In fact, just the opposite is true. which must mean Nobody said one inductance value is NOT equivalent everywhere. or, perhaps: EVERYBODY said one inductance value is equivalent everywhere. or, perhaps: EVERYBODY said one inductance value is NOT equivalent everywhere. or, perhaps: Nobody said one inductance value is equivalent NO where. or, perhaps: Nobody said NO inductance value is equivalent everywhere. or, perhaps: EVERBODY said NO inductance value is equivalent NO where. ... proving your above premise to be false. Which apparently nobody (somebody, everbody?) said. The power of persuasion (Cecil's Degenerative form of the Sub-optimal Hypothesis of Information Transformation) at its inventive best to be able to wrestle two contradictory claims together and prove them both true and false simultaneously! Cecil must have been posed some very difficult advice as a little nipper: "Nobody jumped off the roof because everone did - wouldn't you?" 73's Richard Clark, KB7QHC This reminds me of a quote from Yogi Berra (as I recall) about a retaurant in New York City: "The place is so crowded, nobody goes there anymore". W0BF |
vertical antenna loading coil vs toroid
On Fri, 03 Apr 2009 07:34:20 -0500, Cecil Moore
wrote: Richard Clark wrote: One inductance value (however it is wound) is not equivalent everywhere - Nobody said one inductance value is equivalent everywhere. Nobody is not very many people which should make this a short list. But I don't see any names - strange. In fact, just the opposite is true. which must mean Nobody said one inductance value is NOT equivalent everywhere. or, perhaps: EVERYBODY said one inductance value is equivalent everywhere. or, perhaps: EVERYBODY said one inductance value is NOT equivalent everywhere. or, perhaps: Nobody said one inductance value is equivalent NO where. or, perhaps: Nobody said NO inductance value is equivalent everywhere. or, perhaps: EVERBODY said NO inductance value is equivalent NO where. .... proving your above premise to be false. Which apparently nobody (somebody, everbody?) said. The power of persuasion (Cecil's Degenerative form of the Sub-optimal Hypothesis of Information Transformation) at its inventive best to be able to wrestle two contradictory claims together and prove them both true and false simultaneously! Cecil must have been posed some very difficult advice as a little nipper: "Nobody jumped off the roof because everone did - wouldn't you?" 73's Richard Clark, KB7QHC |
vertical antenna loading coil vs toroid
On Apr 3, 8:22*am, Cecil Moore wrote:
wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com I have the top portion of the antenna put togather, ready to go up in the next couple of days depending on wx, after I got it put together I realized that when I got the toroids I was only concerned about 40 & 80M, and then wanted 160M, should these be some what acceptable on 160M with 100watts Their red on the inner, outer, and top, the bottom is some color of a green or brown. It measures very close to 26mm outside,15mm inside and 10mm high. No markings what soever. Any thoughts on if it should work or not. thanks 73, brett |
vertical antenna loading coil vs toroid
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vertical antenna loading coil vs toroid
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vertical antenna loading coil vs toroid
wrote:
On Apr 3, 8:22Â*am, Cecil Moore wrote: wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. -- 73, Cecil, IEEE, OOTC, Â*http://www.w5dxp.com I have the top portion of the antenna put togather, ready to go up in the next couple of days depending on wx, after I got it put together I realized that when I got the toroids I was only concerned about 40 & 80M, and then wanted 160M, should these be some what acceptable on 160M with 100watts Their red on the inner, outer, and top, the bottom is some color of a green or brown. It measures very close to 26mm outside,15mm inside and 10mm high. No markings what soever. Any thoughts on if it should work or not. thanks 73, brett They aren't usually color coded on the "bottom". If they are iron-powder, red is material #2, which is good for .5 Mhz to 10 Mhz. The size seems closest to T-106, which in inches is 1.060 X 0.570 X 0.437. You can find all the specs, charts, etc. at: https://www.amidoncorp.com/ -- Jim Pennino Remove .spam.sux to reply. |
vertical antenna loading coil vs toroid
On Apr 3, 9:15*pm, Cecil Moore wrote:
wrote: Their red on the inner, outer, and top, the bottom is some color of a green or brown. Sorry, I once knew those color codes but I have forgotten them over the last 30 years. Perhaps someone else remembers. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com Thanks again I'll do a search on net for the color codes, I have some with some # on them but the spec on them are only good for 500khz or well below HF freq. Since some had numbers and are of different color i didn't know they had color code, I have some red , blue, yellow and 1 green, I'l look for the color code thanks. 73 brett |
vertical antenna loading coil vs toroid
On Apr 3, 10:30*pm, wrote:
wrote: On Apr 3, 8:22*am, Cecil Moore wrote: wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com I have the top portion of the antenna put togather, ready to go up in the next couple of days depending on wx, after I got it put together I realized that when I got the toroids I was only concerned about 40 & 80M, and then wanted 160M, should these be some what acceptable on 160M with 100watts *Their red on the inner, outer, and top, the bottom is some color of a green or brown. It measures very close to 26mm outside,15mm inside and 10mm high. No markings what soever. Any thoughts on if it should work or not. thanks 73, brett They aren't usually color coded on the "bottom". If they are iron-powder, red is material #2, which is good for .5 Mhz to 10 Mhz. The size seems closest to T-106, which in inches is 1.060 *X 0.570 X 0.437. You can find all the specs, charts, etc. at: https://www.amidoncorp.com/ -- Jim Pennino Remove .spam.sux to reply. Thanks for the link to the info on the color codes , I have the red one in the antenna right now ,I was going to test soon, According to the document on the link, the red toroid spec is 2-30mhz but blue toroid spec is .5-5mhz. The blue one I have is close to 25mmOD 11mmID 10mmHigh. I'll redo the blue toroid for the inductance I need before I waste my time with the red one Thanks again 73,brett |
vertical antenna loading coil vs toroid
wrote:
On Apr 3, 10:30Â*pm, wrote: wrote: On Apr 3, 8:22Â*am, Cecil Moore wrote: wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. -- 73, Cecil, IEEE, OOTC, Â*http://www.w5dxp.com I have the top portion of the antenna put togather, ready to go up in the next couple of days depending on wx, after I got it put together I realized that when I got the toroids I was only concerned about 40 & 80M, and then wanted 160M, should these be some what acceptable on 160M with 100watts Â*Their red on the inner, outer, and top, the bottom is some color of a green or brown. It measures very close to 26mm outside,15mm inside and 10mm high. No markings what soever. Any thoughts on if it should work or not. thanks 73, brett They aren't usually color coded on the "bottom". If they are iron-powder, red is material #2, which is good for .5 Mhz to 10 Mhz. The size seems closest to T-106, which in inches is 1.060 Â*X 0.570 X 0.437. You can find all the specs, charts, etc. at: https://www.amidoncorp.com/ -- Jim Pennino Remove .spam.sux to reply. Thanks for the link to the info on the color codes , I have the red one in the antenna right now ,I was going to test soon, According to the document on the link, the red toroid spec is 2-30mhz but blue toroid spec is .5-5mhz. The blue one I have is close to 25mmOD 11mmID 10mmHigh. I'll redo the blue toroid for the inductance I need before I waste my time with the red one Thanks again 73,brett Yeah, the numbers I quoted are from some old data sheets I have for some torroids I have. For whatever reason, some of the numbers are different on their web site. I have no clue if that's because the product changed over the years or the old sheets were wrong. YMMV. -- Jim Pennino Remove .spam.sux to reply. |
vertical antenna loading coil vs toroid
On Apr 4, 12:15*am, wrote:
wrote: On Apr 3, 10:30*pm, wrote: wrote: On Apr 3, 8:22*am, Cecil Moore wrote: wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com I have the top portion of the antenna put togather, ready to go up in the next couple of days depending on wx, after I got it put together I realized that when I got the toroids I was only concerned about 40 & 80M, and then wanted 160M, should these be some what acceptable on 160M with 100watts *Their red on the inner, outer, and top, the bottom is some color of a green or brown. It measures very close to 26mm outside,15mm inside and 10mm high. No markings what soever. Any thoughts on if it should work or not. thanks 73, brett They aren't usually color coded on the "bottom". If they are iron-powder, red is material #2, which is good for .5 Mhz to 10 Mhz. The size seems closest to T-106, which in inches is 1.060 *X 0.570 X 0.437. You can find all the specs, charts, etc. at: https://www.amidoncorp.com/ -- Jim Pennino Remove .spam.sux to reply. Thanks for the link to the info on the color codes , I have the red one in the antenna right now ,I was going to test soon, According to the document on the link, the red toroid spec is 2-30mhz but blue toroid spec is .5-5mhz. The blue one I have is close to 25mmOD * 11mmID * 10mmHigh. I'll redo the blue toroid for the inductance I need before I waste my time with the red one Thanks again 73,brett Yeah, the numbers I quoted are from some old data sheets I have for some torroids I have. For whatever reason, some of the numbers are different on their web site. I have no clue if that's because the product changed over the years or the old sheets were wrong. YMMV. -- Jim Pennino Remove .spam.sux to reply. I removed the red toroid from the vertical and replaced it with a blue one, I'm hoping to get this thing up today to see how it performs. I'll do some tests on it for a couple of weeks then maybe try the red toroid anyway to see if it too will work.From the specs I found red being 2-30mhz and blue 0.5-5mhz it seems obvious that the blue one is the better choice for 160 but not a good choice for 40M. And vice versa the red one better for 40 but a good choice for 160. I will to to find out more info on color code and material type, I also have a couple of type 43 binocular core very small black ones, that a fellow ham gave me, they measure about 15mm long X 11mm wide X 7mm thick the two holes are about 7mm center to center and 4mm in diameter. I used these on rx antennas, one wound 9:1 for an EWE and another 4:1 for loop, would these possibly work for tx with 100w or less on 160-40M They seem to work very well on rx for that freq range. Thanks again, 73, brett |
vertical antenna loading coil vs toroid
wrote:
On Apr 4, 12:15Â*am, wrote: wrote: On Apr 3, 10:30Â*pm, wrote: wrote: On Apr 3, 8:22Â*am, Cecil Moore wrote: wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. -- 73, Cecil, IEEE, OOTC, Â*http://www.w5dxp.com I have the top portion of the antenna put togather, ready to go up in the next couple of days depending on wx, after I got it put together I realized that when I got the toroids I was only concerned about 40 & 80M, and then wanted 160M, should these be some what acceptable on 160M with 100watts Â*Their red on the inner, outer, and top, the bottom is some color of a green or brown. It measures very close to 26mm outside,15mm inside and 10mm high. No markings what soever. Any thoughts on if it should work or not. thanks 73, brett They aren't usually color coded on the "bottom". If they are iron-powder, red is material #2, which is good for .5 Mhz to 10 Mhz. The size seems closest to T-106, which in inches is 1.060 Â*X 0.570 X 0.437. You can find all the specs, charts, etc. at: https://www.amidoncorp.com/ -- Jim Pennino Remove .spam.sux to reply. Thanks for the link to the info on the color codes , I have the red one in the antenna right now ,I was going to test soon, According to the document on the link, the red toroid spec is 2-30mhz but blue toroid spec is .5-5mhz. The blue one I have is close to 25mmOD Â* 11mmID Â* 10mmHigh. I'll redo the blue toroid for the inductance I need before I waste my time with the red one Thanks again 73,brett Yeah, the numbers I quoted are from some old data sheets I have for some torroids I have. For whatever reason, some of the numbers are different on their web site. I have no clue if that's because the product changed over the years or the old sheets were wrong. YMMV. -- Jim Pennino Remove .spam.sux to reply. I removed the red toroid from the vertical and replaced it with a blue one, I'm hoping to get this thing up today to see how it performs. I'll do some tests on it for a couple of weeks then maybe try the red toroid anyway to see if it too will work.From the specs I found red being 2-30mhz and blue 0.5-5mhz it seems obvious that the blue one is the better choice for 160 but not a good choice for 40M. And vice versa the red one better for 40 but a good choice for 160. I will to to find out more info on color code and material type, I also have a couple of type 43 binocular core very small black ones, that a fellow ham gave me, they measure about 15mm long X 11mm wide X 7mm thick the two holes are about 7mm center to center and 4mm in diameter. I used these on rx antennas, one wound 9:1 for an EWE and another 4:1 for loop, would these possibly work for tx with 100w or less on 160-40M They seem to work very well on rx for that freq range. Thanks again, 73, brett My gut feel is either core will "work" and that unless you have access to some lab grade equipment, you won't see any performance difference between the two. -- Jim Pennino Remove .spam.sux to reply. |
vertical antenna loading coil vs toroid
On Apr 4, 1:30*pm, wrote:
wrote: On Apr 4, 12:15*am, wrote: wrote: On Apr 3, 10:30*pm, wrote: wrote: On Apr 3, 8:22*am, Cecil Moore wrote: wrote: Did you ever try to model a resonator where the coil required is actually longer than the insulator, so that the vertical part of the resonator is actually inside the coil , ... Never modeled it but have seen its effects during 75m mobile shootouts. One fellow had a hamstick with the stinger bottom extending down into the hamstick loading coil. It was a very lossy condition which improved when he hack-sawed the excess stinger off. Do you have EZNEC? If so, I can modify a helical loading coil to extend the stinger into the middle of the coil and send the file to you. Conductors within the loading coil field lower the effective coil Q. However, I have had good luck with a 1.25" fiberglass pipe running through the center of the coil providing mechanical support. Perhaps you could consider swapping your insulator for a piece of fiberglass pipe or rod. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com I have the top portion of the antenna put togather, ready to go up in the next couple of days depending on wx, after I got it put together I realized that when I got the toroids I was only concerned about 40 & 80M, and then wanted 160M, should these be some what acceptable on 160M with 100watts *Their red on the inner, outer, and top, the bottom is some color of a green or brown. It measures very close to 26mm outside,15mm inside and 10mm high. No markings what soever. Any thoughts on if it should work or not. thanks 73, brett They aren't usually color coded on the "bottom". If they are iron-powder, red is material #2, which is good for .5 Mhz to 10 Mhz. The size seems closest to T-106, which in inches is 1.060 *X 0.570 X 0.437. You can find all the specs, charts, etc. at: https://www.amidoncorp.com/ -- Jim Pennino Remove .spam.sux to reply. Thanks for the link to the info on the color codes , I have the red one in the antenna right now ,I was going to test soon, According to the document on the link, the red toroid spec is 2-30mhz but blue toroid spec is .5-5mhz. The blue one I have is close to 25mmOD * 11mmID * 10mmHigh. I'll redo the blue toroid for the inductance I need before I waste my time with the red one Thanks again 73,brett Yeah, the numbers I quoted are from some old data sheets I have for some torroids I have. For whatever reason, some of the numbers are different on their web site. I have no clue if that's because the product changed over the years or the old sheets were wrong. YMMV. -- Jim Pennino Remove .spam.sux to reply. I removed the red toroid from the vertical and replaced it with a blue one, I'm hoping to get this thing up today to see how it performs. I'll do some tests on it for a couple of weeks then maybe try the red toroid anyway to see if it too will work.From the specs I found red being 2-30mhz *and blue 0.5-5mhz it seems obvious that the blue one is the better choice for 160 but not a good choice for 40M. And vice versa the red one better for 40 but a good choice for 160. I will to to find out more info on color code and material type, *I also have a couple of type 43 binocular core very small black ones, that a fellow ham gave me, they measure about 15mm long X 11mm wide X 7mm thick the two holes are about 7mm center to center and 4mm in diameter. I used these on rx antennas, one *wound 9:1 for an EWE and another 4:1 for loop, would these possibly work for tx with 100w or less on 160-40M They seem to work very well on rx for that freq range. *Thanks again, 73, brett My gut feel is either core will "work" and that unless you have access to some lab grade equipment, you won't see any performance difference between the two. -- Jim Pennino Remove .spam.sux to reply. I tried the blue toroid after being made aware of the color code.I seemed to be ok regards to swr and forward power levels, however I tried it in the SPDX contest and it was a flop , 0 contacts on vertical for 80M, where I made some contacts on a dipole at 25 feet. I will try it for another week or so as I am busy with work and not able to do much work on my antenna just yet.Maybe due to propagation, but dipole at 25 feet better than vertical for dx on 80M, boggles me. Thanks again, 73 brett |
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