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FCC's John Reed Comments on Part 15 AM Rules and Interpretations

Hamilton said:
Really the issue that is important to me here (the point) is practicality, not the extra radiation as you may think. .... I don't care about radiation from the ground, I just want to get the unit installed in a practical manner. I would install a ferrite on both the control and ground wires if the ground was otherwise unshielded.
Click to expand...

Those are interesting statements, Keith.

According to FCC 15.219, the elevation above the earth that a "Part 15" AM transmitter and antenna system is installed is unimportant. What IS important is that the effective radiating length of the antenna system does not exceed 3 meters.

You are now implying that you are unconcerned if elevated systems use r-f filters in the conducting paths to an r-f / lightning ground (to a grounded, "massive" ground wire, flagpole, mast, billboard steel, building frame etc), and in the program, power and control lines -- all of which, without filters, will radiate even if not connected to a good "ground."

Users of such filtered configurations should understand that when the only radiation from an elevated Part 15 AM system occurs from the ~3-m whip attached to its antenna output connector, then the field strength that can be produced by such configurations will be considerably less than if the system was installed at / near ground level, and used very short, unfiltered conductors (apart from the 3-m whip).

Elevated and "filtered" Part 15 AM systems are not capable of the same performance as unfiltered systems mounted at / near the surface of the earth, using a very short path to a good r-f ground.

But such elevated / filtered systems may be the only viable choice for users wanting to observe the legal technicalities of 15.219, while needing to meet the physical restrictions imposed by their installation conditions.

//
 
One thing though, I THINK that getting the Part 15 (leaving any ground radiation out of the equation) above surrounding obstructions makes a difference, I have no real data to back that up, just field experience, so I would not defend that to the death or anything, it is just my opinion.
 
Shoo Fry Don't Bother Me...

There's a person like Fry in every forum.
I joined this forum just to add a comment about Fry's actions.

What is your major malfunction ? Did you get turned down for a CP or something.
Don't you have anything better to do than to run around the net stirring up trouble?

What next? Are you going to run around America and point out every p15 station out there?
How about this, what if you pull up next to young kid in a Eclipse rockin' out to rap and you get bent out of shape because he is using a p15 device to feed his mp3's to his stereo. What ?? You mean you can hear it on your stereo and it's jamming NPR?? OMG!! Please Fry, get a grip on yourself. Quit being so bitter and let others enjoy their hobby, wich is what p15 is a hobby!
Cant you take a hint? Can you see the anger and discontent your causing all across the boards?

Is that your hobby? Your like a playground bully. Shame on you.

To others on this board, i am deeply sorry for posting my thoughts like this, but i have seen stuff like this before and no good came from it, i believe he..(richard fry) would not be happy until the FCC decides to pull the plug on part15 radio. If that day comes, (shudders) is the day i go out and buy $1500 worth of chinese electronics and slaughter the fm/am dial with harmonics out the ying yang. i run my station as close to the standards as humanly possible, i could even bother my engineer friend and have him test it.

But the man has his hands full now as it is. Enjoy your hobby friends and ignore the playground bullies.
When in doubt ask questions and most important of all, have fun, learn and prosper.

AM 1630 Free Radio London
 
Follow-up

This thread is quite old, but still has some interesting discussion in it.

Since the time of my previous posts here, I have purchased engineering software that permits an accurate analysis of the performance of a "Part 15" AM transmit system for a given set of conditions.

Below is one such analysis, for the configuration and conditions shown there.

GW_F.I._vs_H-_Distance_from_Part_15_AM_Xmt_System.jpg

The pattern/field data resulting from accurate use of this software is accepted by the FCC for the filing/acceptance documentation they need for licensing even the directional antenna arrays used by some AM broadcast stations.
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


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