looking at that install he was at most 30ft above the ground. likely more like 20ft. we are talking a paved inner city so the ground conductivity is not as good as solid dirt ground. given riches calculations and the fact they may be a little more liberal then than stations actual installation and riches own calculations show an ERP of 165mW, this guy was very likely running that hamilton at it's limits for input power (or about 800mW) this is likely what first grabbed the inspectors attention rather than the long ground lead. if he had just a long ground lead but had the rangemaster set to 100mW the inspector would have likely called it a day and went home. the inspectors have access to NEC as well and likely ran the same calculations rich did and noticed this guy could not possibly be running the transmitter at 100mW input to the final. the same thing happened to my friend. it wasn't the long ground lead that got him in trouble it was the excessive power to the final that did initiially grabbed the FCC's attention. they had him at 1.xx millivolts about 2 miles away and his input was 800mW on a 20ft mast with a 102 inch steel whip. hell the FCC didn't even need to run NEC to know that this guys input was higher than 100mW it is obvious by a 30mV reading at 40m that it wasn't. in short this guy wasn't bending the rules he flat out was breaking them and in the end making us all look bad.
...riches own calculations show an ERP of 165mW, ...
In my NEC model the unmodulated r-f carrier output power of the final amplifier that was applied to the input of the loading coil was 165 mW.
The amount of that power that was radiated into space by the conductors of the antenna system (e.g., ERP) was less than 165 mW. Some of that power is dissipated in the a-c resistance of the loading coil, and in the r-f ground connection via the ground rod.
oh ok, i missed that point.
Given the fact that the station received an NUOU, I'd say that it's a pretty safe bet that it was 'bending the rules', rather than a mistake.
I'm also generally suspicious when any station purportedly running under Part 15 rules doesn't describe its installation. As has been reiterated here many times, you can be running a certified transmitter at 100mw and still not be complying with the Part 15 rules (how you install that transmitter does matter). Of course, my suspicions and $5.00 might buy you a cup of coffee.
My issue with all this is that Part 15 stations receiving NUOU's give everyone operating under Part 15 a bad name - perception is everything, both with the public and the FCC. The public doesn't see the dozens (or hundreds) that follow those rules - they just see the ones that don't. And why should the FCC even consider being more generous with the Part 15 rules (opening up the possibility of more interference) when there are those who seem unable to follow the existing ones? What assurances does the FCC have that if Part 15 stations start operating with more signal that even then, stations will attempt to push the boundaries even further?
Just saying...
I also find it interesting that the guys at that other site appear to take a hard line in complying with Part 15 rules with their transmitter reviews. And yet at least 2 of the Part 15 stations they have profiles for have received NUOU's. They probably should be a bit more diligent in vetting those station profiles before publishing them.
Since different soil conditions could lead to different measurements.
Here we go again.
"Here we go again."
Great! Where are we going?
"Why is it so difficult to stay at 100mw with a ground mounted install?"
Did you ever stop and think that maybe some folks do not have access to an area to 'ground mount' a transmitter?
Should people who live in a second floor apartment, or higher, be excluded from enjoying the Part 15 hobby?
Besides, it should be obvious that a Hamilton Rangemaster, by design, is not intended to be placed on the ground. It is sold with a mast mounting bracket. No information is included in the installation instructions for a 'ground mounted' installation, but several descriptions of elevated installs are.
Should people who live in a second floor apartment, or higher, be excluded from enjoying the Part 15 hobby?
Of Course not, but keep in mind that if the install is not complient, then it is not "Part 15", it becomes "pirate'. Whether or not a ground install is feasable for an individual is besides the point entirely.
I too suffer from an unfeasable ground install situation myself.. Presently it remains to be a major thorn to my station.. I just don't know what to do.
But I'll tell you a curious story.. My transmitter is located in the business district of this little city, I'm directly next to a bar and grill. Earlier this summer, several months ago, as soon as I stepped into the bar, about four people began telling me about two men in suites and holding what they described to be a large walky-talky looking unit, had spent about 5 minutes standing outside and knocking on the office door and trying to look through the window (the blinds were drawn). They all suspected them to be some kind of cops, but they never bothered to walk next door and question anybody about my whereabouts, nor had anyone spoke to them at all.
The two men had never returned, nor tried to contact me, or have been seen again by any of the locals. I don't know who they were, or what it was about, but I have always had a sneaking suspicion from the start that they were FCC inspectors. But the fact is, other than some sporadic and infrequent occassions, I haven't even had the transmitter turned on for most of the year.. But my website has been present, making it appear that it's active all along. My suspicion is, that based soley on my website, the FCC, being in the area, and previously noting my website, had decided to stop by.
Of course it's all just speculation, but I can reason no other possibilities on who these two mysterious gentleman may have been to have come looking for me. If it was something important, I'm certainly not hard to find.
At the time of the visit (as it still is) the transmitter is mounted, ungrounded on the peak on the roof of the bar, and can be seen from the street.
"...it should be obvious that a Hamilton Rangemaster, by design, is not intended to be placed on the ground..."
Depends on how far above the ground you place it. You're still bound by the Part 15 rule (if you're using 100mw) that the antenna plus ground wire cannot exceed 10 feet (3 meters).
If you mount that Rangemaster up 20 or 30 feet from the ground, as the discussed station did, and attach a ground wire of that length, then you are obviously not compliant with the rules, regardless of whether your transmitter is operating at 100mw or not.
If you live in an apartment on the 2nd floor or higher, there ARE alternatives for providing an RF ground other than running long wires, such as radials (which are the subject of many a thread here on this Forum). If the radials are perpendicular to your antenna, and 180 degrees from each other, then they will not radiate.
Of course, the final say on all installations (regardless of what is said here or in manufacturer documentation) is up to the FCC inspectors if/when they come calling.
Google is a wonderful thing!
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Maybe it wasn't actually the Rangemaster producing that feild stregnth.. Not that I see another antenna, but maybe he had bought the Rangemaster, then when it didn't have the range he wanted, he decided to utilize an entirely different and more powerful transmitter to do his broadcasting.
I ran the numbers on EZNEC and got essentially the same results as Rich.
The modeling results depend on the assumed ground resistance. This can vary all over the place depending on the ground connection (ground rod vs. ground radials) and the effect of the composite of the water pipes and electrical wires in the house under the antenna.
Suffice it to say that this particular user must have goosed up his AM1000 power a bit to somewhere in the 125mW to 200mW range. This additional power is well within the AM1000's adjustment range.
OK, so the installation produced a signal level of 30,000 uV/m at 40.7 m. That's many times stronger than a ground mounted 3 meter antenna can produce.
Looking at the pictures of the installation, it really seems unfair for him to get an NOUO. If he had complied to the letter, he would have ended up with a puny little ground mounted antenna with a few short radials. In the pictured environment, his little antenna would be surrounded by a bunch of nearby buildings. His range would have been zip.
So, maybe the FCC should amend the rules to allow maybe a 20 or 30 ft total length? This would get us to the second story level. Maybe the FCC power level would be reduced somewhat to compensate for the height increase, but it would allow a bunch of people in densely populated areas to have practical antenna.
How about a graduated system of rules where the power level is inversely proportional to the antenna height?