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Post by Druid Hills Radio on Mar 16, 2017 18:08:41 GMT
Station8 mentioned: "the thickness of material being used..."
Mr. Know-It-All bemused: "I was educated to think that the thickness has no relevance since radio frequency currents travel on the surface of the conductor."
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Post by mighty1650 on Mar 16, 2017 18:15:57 GMT
I'm just going to say the obvious, it is illegal to have that coax running to your antenna on AM.
Edit: Boy it'd help if I read the whole thread first. LOL
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Post by mighty1650 on Mar 16, 2017 18:26:06 GMT
Station8 mentioned: "the thickness of material being used..." Mr. Know-It-All bemused: "I was educated to think that the thickness has no relevance since radio frequency currents travel on the surface of the conductor." The only thing I could think of is the ability to carry larger amounts of current but that's usually with coax. At part 15 levels it doesn't matter quite as much.
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Post by Deleted on Mar 16, 2017 18:36:08 GMT
Old School New School
Druid Hills recites rote from his education: "I was educated to think that the thickness has no relevance since radio frequency currents travel on the surface of the conductor."
The clue is in "currents traveling on the surface"...
I'm thinking that Station8 has discovered how to get those currents to travel an alternate way.
We must ask, "If they don't travel on the surface, what other way might they make the journey?"
Only then will we know what we know we don't.
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Post by End80 on Mar 16, 2017 21:29:09 GMT
Out of curiosity.. how do they know? How is it determined that current flows on the surface only and not all through it's guts?
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Post by Deleted on Mar 16, 2017 22:43:19 GMT
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Post by Deleted on Mar 16, 2017 22:56:32 GMT
I've often thought that a magnetic loop antenna perhaps offered the greatest promise for Part 15 AM broadcasting. Here is an interesting link for a helically wound loop - 6 feet in diameter - that operates efficiently in the 80 meter amateur band (3.5-4.0 Mhz). It takes advantage of the 'skin effect' that is being discussed. www.hlmagneticloopantennas.com/I wonder if this design could be used at or near 1700 Khz with a 10 meter diameter loop? Now, I don't know what the legal aspects are of running a loop for Part 15 broadcasting - it IS 10 meters in physical 'length' after all. It would be interesting to experiment with such an antenna.
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Post by Deleted on Mar 16, 2017 23:25:08 GMT
Loops and Hoops
DavidC believes: "I've often thought that a magnetic loop antenna perhaps offered the greatest promise for Part 15 AM broadcasting."
It's astonishing that we have never heard of anyone trying a loop antenna for part 15 either AM or FM (maybe they don't exist for FM).
It appeals to me that a loop antenna would be directional much like a figure-8 microphone.
It might be possible to rig two loops together to become omni-directional.
Maybe we should declare a project to build and test a 3-meter high loop antenna!
Challenge No. 1 -- What do we build the circular "hoop" out of that would be used to support the Litz wire?
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Post by End80 on Mar 17, 2017 0:15:03 GMT
Loops and HoopsDavidC believes: " I've often thought that a magnetic loop antenna perhaps offered the greatest promise for Part 15 AM broadcasting." It's astonishing that we have never.. Maybe we should declare a project to build and test a 3-meter high loop antenna! As David pointed out; diameter not height. - I'm sitting here with Big Bang Theory on the TV, a Banquet TV dinner sandwiched in the Forman grill, box and all, cigarette in hand, imaginary beer in the other, trying to figure out how high a diameter of three meters would be, and wondering if the crossbar like section needs to be factored in, which, if it did (and probably does), would mean the diameter would need to be that much smaller, making the antenna height even shorter, so I'm visualizing the antenna would be about 2 foot high (and round). But not sure how to figure it, so don't know if that's right and I wish my beer was real.
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Post by Deleted on Mar 17, 2017 1:20:42 GMT
Some Things Need To Exist
For several days I was undecided between getting real beer and staying in the warm room by avoiding the trip in cold weather.
A couple times I searched for beer videos on Youtube but they didn't help, they made the urge worse.
End80 hits it dead on: "I wish my beer was real."
It finally got to me yesterday and I went over to Save-So-Much where the beer is stocked waiting for me.
There are so many confused people on a life long quest to solve the meaning of life, but we know what it is!
The meaning of life is beer!
Notice how your station sounds better with beer?
That proves my point.
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Post by Admin on Mar 17, 2017 1:38:57 GMT
Actually, Jeff did give me some details on the original design. I just have not had time to do anything with it.
I hope my life slows down a bit soon...
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Post by jimhenry2000 on Mar 17, 2017 2:14:08 GMT
@staion 8: Are you a Jags fan? What is a jags?
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Post by Boomer on Mar 17, 2017 6:07:53 GMT
Jags, could it mean Jaguars, maybe a team. The 'Unfair Radio Transmitter' uses a loop antenna, a small one, and says the signal easily covers his home and bomb shelter, and the cave next door. Look down about 2/3s of the way on the page and see the copper pipe loop: www.techlib.com/electronics/amxmit.htmIt's part of the transmitter, but that's a loop. Carrier-Current radio also uses inductive loops, which might not be seen as such, but they're part of the wiring in the home and lines going from pole to pole. The signal goes out and returns through the ground from many different distant points on the line. With an AC powered radio plugged in, it's tapping into that large loop and taking a teeny bit of power from it, and that's part of the signal you hear, along with some signal on the radio's own loopstick antenna, received from the line nearby. Signal power not used up by the radio gets returned through the ground to the transmitter. Boomer
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Post by Druid Hills Radio on Mar 17, 2017 12:35:11 GMT
@staion 8: Are you a Jags fan? What is a jags? Station8 lives just outside Jacksonville, FL. I live just inside Dade City, FL.
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Post by station8 on Mar 17, 2017 13:25:04 GMT
Howdy y'all: Sorry I have replyed back been busy on project and making note for meeting at team speak !
Jim
The jags are short for jaguars the football team in Jacksonville Florida !
MEETING INFO:
I urge everyone to come please from part 15. Us, alpb site, hobby broadcaster and other site as well so I can share To you guys what I know,
I can't help you if you don't show up !
And I can't give you guys design techniques for your tx f you don't show up at meetings Do to I need to talk to you personally about what your running and if the antenna design I have Done will work with your tx.
Now the other reason I like to get maxiuam range with 1 tx setup is that its Easy maintained,if something goes wrong your there to fix it immediately!!
If you run several tx it cost more for up keep and if the tx breaks done you have to figure which one And load the car up and tools etc.and on top of that by FCC law you have to have full control of a remote Operate system.
This is why I try to build a better antenna system without breaking the law .
Another point to think about when building a efficent antenna is that the father range you get with very low power setting ( close to off power ) you wil get great range and now as you turn your power up to 100 mW now what kind of range your going to get outstanding range and you haven't broken the law as long as you built a very Efficient antenna .
Like I said before its easy to talk on team speak its up to you guys to show up And learn something new.
See ya station 8
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