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Thunder 8xb
- Thread starter freecell
- Start date
D
Devildog 985
Guest
Hey Steal Man,
Welcome aboard. This place here carries them Click here for SE I have never used one but have been in touch with them on a couple of there other antennas. Maybe you can get a hold of them and ask if you could contact someone who has purchased one from them.
Happy Holidays, Jim
</p>
Welcome aboard. This place here carries them Click here for SE I have never used one but have been in touch with them on a couple of there other antennas. Maybe you can get a hold of them and ask if you could contact someone who has purchased one from them.
Happy Holidays, Jim
</p>
T
Tumbleweed
Guest
Steal Man, I still have mine. I took it down and put up a four element MR4. I like the Thunder 8. It did very well for what it was designed to do. What I didn't like about it was that it doesn't have the rejection of unwanted signals. You were either north and south, or east and west on the direction of the antenna. It comes with a antenna switch, horizontal, verticle, both and horz/vert combined for an omnidirectional antenna. It worked well in that regard. The pattern of the antenna just didn't have very good rejection of the directions that you weren't using. But it is light, small footprint and easy to assemble.
You will need help putting it up after it's together due to the wires for the feed.and the fiberglass rods so you don't bend or break anything.
I hope this helps.
Jerry
CDX-350
2AK3350
RL39</p>
You will need help putting it up after it's together due to the wires for the feed.and the fiberglass rods so you don't bend or break anything.
I hope this helps.
Jerry
CDX-350
2AK3350
RL39</p>
I think that's just a bit optomistic.........
not at all. if you'll notice the 6.8 dbi gain figure is referencing the isotropic source for comparison. this translates to 4.65 dbd when referenced to the standard half-wave dipole. far from optimistic. i applaud signal engineering for their realistic gain figures and appreciate the fact that they haven't decided to inflate them much like the rest of the industry. when these gain figures are evaluated according to their indicated source references they are as real-world as i have seen from any manufacturer.
the real and obvious question after looking at the specs for the T8XB is this: does this (6.8 dbi) gain figure deal with the antenna when it is operating in the omni mode or the beam mode? i tend to think it applies to the latter rather than the former.
optimistic? hardly!
228
</p>Edited by: <A HREF=http://pub86.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=freecell>freecell</A> at: 1/4/04 2:22 pm
not at all. if you'll notice the 6.8 dbi gain figure is referencing the isotropic source for comparison. this translates to 4.65 dbd when referenced to the standard half-wave dipole. far from optimistic. i applaud signal engineering for their realistic gain figures and appreciate the fact that they haven't decided to inflate them much like the rest of the industry. when these gain figures are evaluated according to their indicated source references they are as real-world as i have seen from any manufacturer.
the real and obvious question after looking at the specs for the T8XB is this: does this (6.8 dbi) gain figure deal with the antenna when it is operating in the omni mode or the beam mode? i tend to think it applies to the latter rather than the former.
optimistic? hardly!
228
</p>Edited by: <A HREF=http://pub86.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=freecell>freecell</A> at: 1/4/04 2:22 pm
The gain figure has to apply to the directional mode.
that's already been said and we agree. and i don't know what your definition of "multiple" is but all 4 elements are active in the omni mode. even in the omni mode the 8XB ehibits gain when compared to a half wave dipole. you can disagree with that all you want. if you want to take a look at some "optimistic" ratings check out the ambiguous gain figures associated with the MS-119 Super Scanner Antenna. if i remember correctly they were 5.75 db in the omni mode and 8.75 db in the beam mode. i use the term ambiguous because Antenna Specialists never told us which reference they were using for the gain figures they came up with. without the dbd or dbi reference to clarify this the numbers are for the most part meaningless, merely attributed to sales hype rather than any attempt to offer the customer any useful information with which to make an informed decision. nonetheless, the 8XB WILL outperform a single halfwave dipole supported at the same height in ALL MODES.
and in addition to the normal operating modes, N/S and E/W Bi-Directional modes and Omni modes the 8XB is yet capable of two additional modes of operation never provided for in any other design to the present day. these modes were never even conceived of in the 8XBs design and development.
so the only question i have for steal is whether he wants the gain and multiplier figures as referenced to a theoretical "isotropic source" which can never actually be constructed, much less tested for comparison against the 8XB, (and some big numbers) or whether he wants the gain and multiplier figures as referenced against an antenna that can actually be constructed and compared to the 8XB in on-the-air testing.
unless someone here has figured out a way to connect the feedline to the center of the sphere without interrupting its surface, the only meaningful gain figures will have to be referenced against the 1/2 wave dipole. to date these are the only two standards recognized by the industry, one can be built and used in meaningful comparison tests and the other can't.
if we would all automatically subtract 2.15 db. from all the gain figures that we are constantly being exposed to we would have more realistic expectations, especially when the "i" is being referenced. if notation is absent to either the "i" or the "d", always assume "i".
228
P.S. if anyone has the numbers for the MS119 i would appreciate it if those figures could be corroborated.
</p>
that's already been said and we agree. and i don't know what your definition of "multiple" is but all 4 elements are active in the omni mode. even in the omni mode the 8XB ehibits gain when compared to a half wave dipole. you can disagree with that all you want. if you want to take a look at some "optimistic" ratings check out the ambiguous gain figures associated with the MS-119 Super Scanner Antenna. if i remember correctly they were 5.75 db in the omni mode and 8.75 db in the beam mode. i use the term ambiguous because Antenna Specialists never told us which reference they were using for the gain figures they came up with. without the dbd or dbi reference to clarify this the numbers are for the most part meaningless, merely attributed to sales hype rather than any attempt to offer the customer any useful information with which to make an informed decision. nonetheless, the 8XB WILL outperform a single halfwave dipole supported at the same height in ALL MODES.
and in addition to the normal operating modes, N/S and E/W Bi-Directional modes and Omni modes the 8XB is yet capable of two additional modes of operation never provided for in any other design to the present day. these modes were never even conceived of in the 8XBs design and development.
so the only question i have for steal is whether he wants the gain and multiplier figures as referenced to a theoretical "isotropic source" which can never actually be constructed, much less tested for comparison against the 8XB, (and some big numbers) or whether he wants the gain and multiplier figures as referenced against an antenna that can actually be constructed and compared to the 8XB in on-the-air testing.
unless someone here has figured out a way to connect the feedline to the center of the sphere without interrupting its surface, the only meaningful gain figures will have to be referenced against the 1/2 wave dipole. to date these are the only two standards recognized by the industry, one can be built and used in meaningful comparison tests and the other can't.
if we would all automatically subtract 2.15 db. from all the gain figures that we are constantly being exposed to we would have more realistic expectations, especially when the "i" is being referenced. if notation is absent to either the "i" or the "d", always assume "i".
228
P.S. if anyone has the numbers for the MS119 i would appreciate it if those figures could be corroborated.
</p>
S
steal man
Guest
No, i'm not. and all 4 of the elements ARE in the SAME PLANE. the vertical plane as a matter of fact. and the two active elements fed by each single feedline are not 90 deg. apart from each other, they're 180 deg. apart from each other. or to put it another way, the TWO ELEMENTS that are fed from each of the feedlines are directly opposite of one another. now explain to me again how the vertical planes containing each pair of elements don't cross or intersect at a 90 deg. (right) angle.
in any event, i NEVER said the 8XB would operate in these two novel modes right out-of-the-box. i thought i would throw that in here because it seems to me that some following this thread may have been operating under that assumption.
228
</p>Edited by: <A HREF=http://pub86.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=freecell>freecell</A> at: 1/8/04 4:24 am
in any event, i NEVER said the 8XB would operate in these two novel modes right out-of-the-box. i thought i would throw that in here because it seems to me that some following this thread may have been operating under that assumption.
228
</p>Edited by: <A HREF=http://pub86.ezboard.com/bworldwidecbradioclub.showUserPublicProfile?gid=freecell>freecell</A> at: 1/8/04 4:24 am
no we don't agree.
"Each element of the seperate antenna arrays are mounted parallel to each other and fed 180 degrees out of phase"
and just how is that being done? if the pair of elements per feedline were being fed 180 deg. out of phase then where is the phasing control box? where is the extra 180 deg. length of feedline going to one of the two elements? neither one of those conditions exist because both elements connected to each feedline are being fed in-phase, simultaneously, same signal amplitude at the same phase angle.
each pair of elements constitute "an antenna". there are two antennas. two, two element, bi-directional antennas (vertically polarized).
"To produce a circular or left or right hand circular radiation pattern (as stated in Fire Communication's responce) the elements of the antenna need to be 90 degrees from each other (at right angles)."
No. the two antennas need to be at right angles to each other.
the word "elements" is not used here and it would be meaningless even if it was. So, one more time....the ANTENNAS (two of them) need to be at right angles to each other.. and they are. quit changing the words.and attempt to understand it the way it was written, not the way you want it to read. as a matter of fact, after looking back over the previous posts, the only one talking about the elements being at right angles to one another is YOU! beginning with my very first post i stated that two linear ANTENNAS need to be at right angles to each other, AND THEY ARE.
One method of producing circular/elliptical polarization is to position two linear antennas at right angles to each other.
the north-south elements constitute one linear antenna.
the east-west elements constitute one linear antenna.
that's two linear antennas. 1 + 1 = 2
let's hit it again.
"The orientation of the E-field component of the TEM wave is called its polarization. If the direction remains constant with time at a fixed point in space, the field is said to be linearly polarized........"
and this is the case when the 8XB is operated in its normal modes
"If the direction of the E-field component at a fixed point varies with time, the electromagnetic field may be circularly or elliptically polarized. For circular polarization the E-field vector has a constant magnitude but its direction, in the plane perpendicular to the velocity of propagation, rotates smoothly through 360 degrees per wavelength of propagation........."
the trick is to force the direction of the E-field at fixed points to vary with time. if that can be accomplished then we will be able to rotate the normally stationary magnetic field which is already prevalent in the horizontal plane, which is btw perpendicular to the velocity of the propagated signal (E-field), to create the circularly polarized mode. the arrangement and the feeding of the two (antennas) and the E-fields shared by them (the two antennas) are at right angles to each other. the E-fields generated between the two antennas intersect at their midpoints and fulfill the requirement (1) mentioned previously in preparation for the next requirement to be implemented.
you keep talking about elements. when you're able to grasp the concept of two separate, discreet antennas let me know. because that's what you're looking at when you're talking about the 8XB.
this is as simple as i can make it. a yagi has two or more elements and is directional by design. and we still refer to it as an antenna. by the very definition it's still "an antenna". in a particular case a yagi antenna may be comprised of a driven element, a reflector element and a director element. but it's still an antenna.
" One method of producing circular/elliptical polarization is to position two linear antennas at right angles to each other...."
it's not about the elements.
228
</p>
"Each element of the seperate antenna arrays are mounted parallel to each other and fed 180 degrees out of phase"
and just how is that being done? if the pair of elements per feedline were being fed 180 deg. out of phase then where is the phasing control box? where is the extra 180 deg. length of feedline going to one of the two elements? neither one of those conditions exist because both elements connected to each feedline are being fed in-phase, simultaneously, same signal amplitude at the same phase angle.
each pair of elements constitute "an antenna". there are two antennas. two, two element, bi-directional antennas (vertically polarized).
"To produce a circular or left or right hand circular radiation pattern (as stated in Fire Communication's responce) the elements of the antenna need to be 90 degrees from each other (at right angles)."
No. the two antennas need to be at right angles to each other.
the word "elements" is not used here and it would be meaningless even if it was. So, one more time....the ANTENNAS (two of them) need to be at right angles to each other.. and they are. quit changing the words.and attempt to understand it the way it was written, not the way you want it to read. as a matter of fact, after looking back over the previous posts, the only one talking about the elements being at right angles to one another is YOU! beginning with my very first post i stated that two linear ANTENNAS need to be at right angles to each other, AND THEY ARE.
One method of producing circular/elliptical polarization is to position two linear antennas at right angles to each other.
the north-south elements constitute one linear antenna.
the east-west elements constitute one linear antenna.
that's two linear antennas. 1 + 1 = 2
let's hit it again.
"The orientation of the E-field component of the TEM wave is called its polarization. If the direction remains constant with time at a fixed point in space, the field is said to be linearly polarized........"
and this is the case when the 8XB is operated in its normal modes
"If the direction of the E-field component at a fixed point varies with time, the electromagnetic field may be circularly or elliptically polarized. For circular polarization the E-field vector has a constant magnitude but its direction, in the plane perpendicular to the velocity of propagation, rotates smoothly through 360 degrees per wavelength of propagation........."
the trick is to force the direction of the E-field at fixed points to vary with time. if that can be accomplished then we will be able to rotate the normally stationary magnetic field which is already prevalent in the horizontal plane, which is btw perpendicular to the velocity of the propagated signal (E-field), to create the circularly polarized mode. the arrangement and the feeding of the two (antennas) and the E-fields shared by them (the two antennas) are at right angles to each other. the E-fields generated between the two antennas intersect at their midpoints and fulfill the requirement (1) mentioned previously in preparation for the next requirement to be implemented.
you keep talking about elements. when you're able to grasp the concept of two separate, discreet antennas let me know. because that's what you're looking at when you're talking about the 8XB.
this is as simple as i can make it. a yagi has two or more elements and is directional by design. and we still refer to it as an antenna. by the very definition it's still "an antenna". in a particular case a yagi antenna may be comprised of a driven element, a reflector element and a director element. but it's still an antenna.
" One method of producing circular/elliptical polarization is to position two linear antennas at right angles to each other...."
it's not about the elements.
228
</p>
as well you should.
you play with the nice shapes and we'll continue testing the design. a small group of us have been studying and experimenting with CP antennas for several years now. your comment in regard to "simple geometry" is over simplistic given all of the varying dynamics involved in antenna design and i can't quite decide whether your "implication" that we haven't seen enough examples of CP antennas is more or less insulting than it is laughable. as far a seeing anything that you mean, all i can see is that you would have a hard time understanding anything you study given your clear-cut propensity to change the words and/or terms as you see fit during your discussion of the same.
a quick overview of this thread more than bears that out.
having said that and seeing that you have given up let me just add this. anyone who would like more information about CP operation for the 8XB can contact me via email. thinking back over the last couple of years i haven't seen anyone have such a tough time understanding what was presented here, not even in our little group of 8XB users. i will not attempt to present it again in this forum and have you put words into not only just my mouth but the mouths of accomplished authors on the subject as well.
all of the study and experimentation that i have been a part of recently tells me that it's much more than "simple geometry" as you claim. if you were to make that statement in one of the forums where this discussion is ongoing among some of the brightest and best educated in the field of physics you'd be quietly tolerated until you found somewhere else to go or you would come to the place that there's a lot more involved than merely "simple geometry". i still can't believe you said that. what's even scarier is the idea that you might even believe it.
my participation in this thread is finished, at least where you're concerned. maybe when you figure out the difference between an antenna and the "elements" that you're continually babbling about we can pick it up again. in the meantime several of us have 8XBs on the air and operating in all 5 modes, "elements" and all. LOL
228
</p>
you play with the nice shapes and we'll continue testing the design. a small group of us have been studying and experimenting with CP antennas for several years now. your comment in regard to "simple geometry" is over simplistic given all of the varying dynamics involved in antenna design and i can't quite decide whether your "implication" that we haven't seen enough examples of CP antennas is more or less insulting than it is laughable. as far a seeing anything that you mean, all i can see is that you would have a hard time understanding anything you study given your clear-cut propensity to change the words and/or terms as you see fit during your discussion of the same.
a quick overview of this thread more than bears that out.
having said that and seeing that you have given up let me just add this. anyone who would like more information about CP operation for the 8XB can contact me via email. thinking back over the last couple of years i haven't seen anyone have such a tough time understanding what was presented here, not even in our little group of 8XB users. i will not attempt to present it again in this forum and have you put words into not only just my mouth but the mouths of accomplished authors on the subject as well.
all of the study and experimentation that i have been a part of recently tells me that it's much more than "simple geometry" as you claim. if you were to make that statement in one of the forums where this discussion is ongoing among some of the brightest and best educated in the field of physics you'd be quietly tolerated until you found somewhere else to go or you would come to the place that there's a lot more involved than merely "simple geometry". i still can't believe you said that. what's even scarier is the idea that you might even believe it.
my participation in this thread is finished, at least where you're concerned. maybe when you figure out the difference between an antenna and the "elements" that you're continually babbling about we can pick it up again. in the meantime several of us have 8XBs on the air and operating in all 5 modes, "elements" and all. LOL
228
</p>
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