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Post by Deleted on May 28, 2018 2:24:06 GMT
Why Haven't We Been Told That Artificial Ground is a Possibility?The artificial ground described for this product could do wonders for part 15 medium wave. Artificial Ground DeviceHere's more on this puzzling topic: Follow the Ground
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Post by mark on May 28, 2018 3:05:20 GMT
Why Haven't We Been Told That Artificial Ground is a Possibility?The artificial ground described for this product could do wonders for part 15 medium wave. Artificial Ground DeviceHere's more on this puzzling topic: Follow the Ground Problem is this unit is for 1.8 MHZ and up. the AM band stops at 1.7 MHZ
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Post by Deleted on May 28, 2018 3:30:19 GMT
Why It Still Matters
Mark is right: "Problem is this unit is for 1.8 MHZ and up. the AM band stops at 1.7 MHZ."
There is a slim possibility that the topmost frequencies of the medium wave band are within the tolerance range of this device, but even if it isn't, the fact that artificial ground is possible is the big news and the new hope for many stations, including those with transmitters on upper floors or indoors.
Perhaps the manufacturer could provide suggestions for a small modification to tune this unit down to 1.6 MHz.
ALPB wants to be the clearing house for new developments in artificial ground.
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Post by Admin on May 28, 2018 3:50:31 GMT
Why It Still MattersMark is right: " Problem is this unit is for 1.8 MHZ and up. the AM band stops at 1.7 MHZ." There is a slim possibility that the topmost frequencies of the medium wave band are within the tolerance range of this device, but even if it isn't, the fact that artificial ground is possible is the big news and the new hope for many stations, including those with transmitters on upper floors or indoors. Perhaps the manufacturer could provide suggestions for a small modification to tune this unit down to 1.6 MHz. ALPB wants to be the clearing house for new developments in artificial ground. This just might offer great possibilities for us Carl. Will you pursue this with MFJ for us? It could be a wonderful thing!
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Rich
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Post by Rich on May 28, 2018 11:58:07 GMT
Why Haven't We Been Told That Artificial Ground is a Possibility?The artificial ground described for this product could do wonders for part 15 medium wave. Artificial Ground DeviceHere's more on this puzzling topic: Follow the Ground
Another thought, to those it may concern:
The FCC might, and probably would consider such added wires/devices as described in the links quoted above to be non-compliant with ยง15.219(b).
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Post by Deleted on May 28, 2018 13:16:37 GMT
Artificiality
Rich believes: "The FCC might, and probably would consider such added wires/devices as described in the links quoted above to be non-compliant."
Still, we wonder. We know that the artificial is not real, and it's difficult to imagine the FCC would not know the difference.
What I would do is try it and wait for the FCC to arrive to render their judgement.
In any case we need an equitable process for indoor and upper-story transmitters to achieve equal footing with outdoor setups, so you might submit a recommendation how that could be realized.
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Rich
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Post by Rich on May 28, 2018 14:07:32 GMT
...We know that the artificial is not real, and it's difficult to imagine the FCC would not know the difference. ... Probably the FCC is most concerned about the EFFECTS of such added wires as they apply to meeting Part 15.219 (b). In fact, such wires add radiating length to the approximately 3-meter whip often used as, and considered by some to be "the antenna" of a Part 15 AM station. And... such added wires don't need to be connected to Earth in order to radiate effectively.
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Post by Deleted on May 28, 2018 14:15:20 GMT
Probably Leaves Wiggle Room
Rich stops shy of absolutism: "Probably the FCC is most concerned about the EFFECTS."
The word "probably" is used when certainty isn't definite.
I will also use an indefinite word: You may be right.
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Rich
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Post by Rich on May 28, 2018 14:23:37 GMT
Probably Leaves Wiggle Room ... However the last two paragraphs of that post have no wiggle room at all.
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Post by Deleted on May 28, 2018 14:41:16 GMT
It Depends
Rich: "However the last two paragraphs of that post have no wiggle room at all."
I half agree with you.
Suspended radials would be the exception.
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Rich
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Post by Rich on May 28, 2018 15:36:54 GMT
It Depends.. Suspended radials would be the exception. 1) Any time r-f current flows along a conductor, e-m radiation is produced. 2) If that wasn't provably and experientially true, then there would be no point in using one or more of them as an "artificial ground." Anyone wishing to investigate this accurately might consider studying antenna engineering textbooks, and/or accurately modeling such antenna systems with MoM software such as NEC (Numerical Electromagnetics Code). EZNEC is free to download and use, just Google for it.
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Post by Deleted on May 28, 2018 15:55:46 GMT
Classic Rich
To jog your memory, it was you Rich who posted on part15us awhile back about suspended radials, located above the ground, and how they phase-out any radiation from the radial wires while providing an elevated ground-plane.
In this regard you were the teacher and I remember the lesson well.
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Rich
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Post by Rich on May 28, 2018 16:41:53 GMT
Classic RichTo jog your memory, it was you Rich who posted on part15us awhile back about suspended radials, located above the ground, and how they phase-out any radiation from the radial wires while providing an elevated ground-plane. ... That is true, and is not negated by my post here today about the radiation produced by r-f current flowing along an elevated conductor. My memory is fine, thanks.
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Post by Deleted on May 29, 2018 12:44:21 GMT
Continued Inquiry
Whether the MFJ-931 Device is useful for part15 depends on whether it can be slightly modified to cover the 1.6 to 1.7 kHz range. At a convenient time I'll contact the manufacturer and discuss this point.
The MFJ-931 does not violate 15.219 because it does not extend the length of the ground lead, but is an artificial ground.
Part 15.219 does not mention ground whatsoever. One must recognize the difference between ground lead and ground.
To be thorough, but only if the MFJ-931 can be modified to cover the X-band, we will ask for an opinion about the part 15 aspect, knowing that the non-standard requirements of 15.219 may or may not be familiar to engineers at MFJ Enterprises, Inc.
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Post by Admin on May 29, 2018 13:15:17 GMT
Continued InquiryWhether the MFJ-931 Device is useful for part15 depends on whether it can be slightly modified to cover the 1.6 to 1.7 kHz range. At a convenient time I'll contact the manufacturer and discuss this point. The MFJ-931 does not violate 15.219 because it does not extend the length of the ground lead, but is an artificial ground. Part 15.219 does not mention ground whatsoever. One must recognize the difference between ground lead and ground. To be thorough, but only if the MFJ-931 can be modified to cover the X-band, we will ask for an opinion about the part 15 aspect, knowing that the non-standard requirements of 15.219 may or may not be familiar to engineers at MFJ Enterprises, Inc. I'm betting that you will find MFJ very helpful in responding to your query.
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