FCC Part 15.209 vs. Part 15.219 for Unlicensed AM Systems, 510-1705 kHz

[rfry]

(From another board)
Poster 1:
>> While the rules may give you the ability to run up to a specific
>> amount of power, that does not imply that you can exceed the field
>> intensity limits of an intentional radiator and its ground
>> lead.
Poster 2:
>I know for a fact that the FCC will decide on Part-15 compliance
>based on Field Intensity Measurements.

- - - - - - - - - -

A few observations about all of this...

The FCC has issued Part 15 AM NOUOs based on excess field intensity AND excess radiating length of the antenna system (see the link below).

While the very low field intensities permitted under 15.209(a) in the band 490-1705 kHz cannot be measured accurately outside of a screen room, the FCC action is based on a field intensity so high that it -can- be measured accurately at an open site, and can prove that the operation does not meet 15.209(a), IF 15.209(a) applies (see text below).

Functional compliance with 15.219(b) about the total radiating length of the antenna system can be determined by physical/electrical inspection.

Here are the details from the rules:

+++
Sec. 15.209 Radiated emission limits; general requirements.

(a) EXCEPT AS PROVIDED ELSEWHERE IN THIS SUBPART, the emissions from
an intentional radiator shall not exceed the field strength levels specified
in the following table:

------------------------------------------------------------------------
Measurement
Frequency (MHz) Field strength distance
(microvolts/meter) (meters)
------------------------------------------------------------------------
0.009-0.490...................... 2400/F(kHz) 300
0.490-1.705...................... 24000/F(kHz) 30
1.705-30.0....................... 30 30
30-88............................ 100 ** 3
88-216........................... 150 ** 3
216-960.......................... 200 ** 3
Above 960........................ 500 3
/
/
/
Sec. 15.219 Operation in the band 510-1705 kHz.

(a) The total input power to the final radio frequency stage
(exclusive of filament or heater power) shall not exceed 100 milliwatts.
(b) The total length of the transmission line, antenna and ground
lead (if used) shall not exceed 3 meters.
(c) All emissions below 510 kHz or above 1705 kHz shall be
attenuated at least 20 dB below the level of the unmodulated carrier.
Determination of compliance with the 20 dB attenuation specification may
be based on measurements at the intentional radiator's antenna output
terminal unless the intentional radiator uses a permanently attached
antenna, in which case compliance shall be deomonstrated by measuring
the radiated emissions.
+++

The opening phrase in Sec. 15.209(a) above, which I emphasised, shows that Sec. 15.219 -exclusively- applies to unlicensed systems within the band 510 kHz to 1705 kHz, because Sec. 15.219 is included in the same subpart (Part 15) of 47 CFR as Sec. 15.209. Part 15.219 is the exception provided for at the beginning of 15.209(a), for unlicensed systems operating in the band 510-1705 kHz.

So a strict observance based on the English language in both 15.209 and 15.219 removes the need to meet the field intensity limit given in 15.209(a) for unlicensed systems operating in the band 510 kHz to 1705 kHz.

Really, the FCC wouldn't need to (and maybe shouldn't) refer to excess field intensity at the carrier frequency based on 15.209(a) in their actions against unlicensed systems in the 510-1705 kHz band, because 15.209(a) does not apply in that band. The rest of 15.209 does apply, however FCC actions for unlicensed AM systems in that band rarely, if ever, refer to those paragraphs.

Of course, the FCC alone determines the methods by which it interprets and enforces Part 15.

http://www.fcc.gov/eb/FieldNotices/2003/DOC-294572A1.html

RF

 

[WCWalker]

KENC is back on the air. It was finally determined the Field Strength limit mentioned in rule 15.209 did not apply. The unit has been grounded properly and now the station is fully compliant with Part 15 rules.

 

[druidhillsradio]

15.209 is the General Emission Requirements. Other rules like 15.219 may apply and supercede. There are those who often quote and misquote the Bible by ingnoring the verses simply to advance a personnal agenda. Please see the below from FCC Part 15. No stop beating this horse to death and deal with the fact that a transmitter certified to 15.219 is not subject to 15.209.

TITLE 47--TELECOMMUNICATION
CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION
PART 15_RADIO FREQUENCY DEVICES--Table of Contents
Subpart C_Intentional Radiators
Sec. 15.215 Additional provisions to the general radiated emission limitations. (a) The regulations in Sec. Sec. 15.217 through 15.257 provide
alternatives to the general radiated emission limits for intentional
radiators operating in specified frequency bands. Unless otherwise
stated, there are no restrictions as to the types of operation permitted
under these sections.
(b) In most cases, unwanted emissions outside of the frequency bands
shown in these alternative provisions must be attenuated to the emission
limits shown in Sec. 15.209. In no case shall the level of the unwanted
emissions from an intentional radiator operating under these additional
provisions exceed the field strength of the fundamental emission.
(c) Intentional radiators operating under the alternative provisions
to the general emission limits, as contained in Sec. Sec. 15.217
through 15.257 and in Subpart E of this part, must be designed to ensure
that the 20 dB bandwidth of the emission, or whatever bandwidth may
otherwise be specified in the specific rule section under which the
equipment operates, is contained within the frequency band designated in
the rule section under which the equipment is operated. The requirement
to contain the designated bandwidth of the emission within the specified
frequency band includes the effects from frequency sweeping, frequency
hopping and other modulation techniques that may be employed as well as
the frequency stability of the transmitter over expected variations in
temperature and supply voltage. If a frequency stability is not
specified in the regulations, it is recommended that the fundamental
emission be kept within at least the central 80% of the permitted band
in order to minimize the possibility of out-of-band operation.[54 FR 17714, Apr. 25, 1989, as amended at 62 FR 45333, Aug. 27, 1997;
67 FR 34855, May 16, 2002; 69 FR 3265, Jan. 23, 2004; 70 FR 6774, Feb.
9, 2005]

 

[rfry]

... a transmitter certified to 15.219 is not subject to 15.209.

That is part of what I stated in my post, from which I quote, "Really, the FCC wouldn't need to (and maybe shouldn't) refer to excess field intensity at the carrier frequency based on 15.209(a) in their actions against unlicensed systems in the 510-1705 kHz band, because 15.209(a) does not apply in that band."

However this isn't limited just to FCC-certified transmitters. A home-made transmitter for Part 15 AM is just as "legal"1 as a certified one as long as it meets the requirements for unlicensed operation given in FCC Part 15, per the following:

Sec. 15.23 Home-built devices.

(a) Equipment authorization is not required for devices that are not
marketed, are not constructed from a kit, and are built in quantities of
five or less for personal use.
(b) It is recognized that the individual builder of home-built
equipment may not possess the means to perform the measurements for
determining compliance with the regulations. In this case, the builder
is expected to employ good engineering practices to meet the specified
technical standards to the greatest extent practicable. The provisions
of Sec. 15.5 apply to this equipment.

1 Certified transmitters can be used in ways that
are functionally non-compliant with Part 15.219 just
as easily as uncertified, home-built transmitters.

RF

 

[RPowers]

15.209 is the General Emission Requirements. ........ the fact that a transmitter certified to 15.219 is not subject to 15.209.
Subpart C_Intentional Radiators
Sec. 15.215 Additional provisions to the general radiated emission limitations. (a) The regulations in Sec. Sec. 15.217 through 15.257 provide
alternatives to the general radiated emission limits for intentional
radiators operating in specified frequency bands. Unless otherwise
stated, there are no restrictions as to the types of operation permitted
under these sections......

Excuse the revival of this old topic, and what I think you are saying has become my understanding.
But just to clarify, --
15.219 supersedes 15.209...in that, either one or the other, and not BOTH requirements are expected to be met.-??
These are two entirely separate options of being compliant --Correct?

 

[LibertyNT]

Correct.
If you fail to comply with one of the methods the Agents will automatically switch to the other for compliance.

 

[pianoplayer88key]

About that home-brew allowance... Does that "quantities of five or less" mean you are only allowed to build a maximumum total of five kits in your entire LIFETIME? Or would the FCC make allowance for building more than that, just as long as no more than 5 are capable of operation simultaneously? (Meaning you could dismantle one kit and build another to try a different design or operate in a different band, for example.)

So let's say I was to build a home-brew 15.219 kit. I mount a 2.98-meter diameter air-core tuned loop antenna (basically a larger version of the Select-A-Tenna, but with a wire connection and using it for transmission instead of reception). with a 10-cm or less lead-in to the output of the homebrew transmitter. I then ground the transmitter to maybe utility ground or to a metal fence (making the connection at earth ground).
Now let's assume the transmitter is 80% efficient. (I've heard that number hinted at for some transmitters in discussions here.) The transmitter is designed to be battery operated, using 8 D-size cells. In our example we will use slow-discharge 1.2V 10,000 mAh NiMH cells. (If we wanted a smaller transmitter I suppose we could use 4 AA-size 2,000 mAh cells.) With the antenna and ground indicated and assuming 80% efficiency and starting with freshly charged/conditioned batteries (8 D's), if the batteries are completely depleted after, say, 4 hours (so that they won't even make the filament in a flashlight glow), is it possible for that setup to be compliant with 15.219?

 

[rfry]

...is it possible for that setup to be compliant with 15.219?

It will comply as long as the input power to the final r-f stage does not exceed 100 mW and the total, radiating length of the antenna system including the length of any "ground" conductor leading to a functional r-f ground does not exceed 3 meters.

BTW, you may wish to research the difference in the performance of a MW transmitting loop and a MW receiving loop of that size before posing such questions.

 

[druidhillsradio]

About that home-brew allowance... Does that "quantities of five or less" mean you are only allowed to build a maximumum total of five kits in your entire LIFETIME? Or would the FCC make allowance for building more than that, just as long as no more than 5 are capable of operation simultaneously? (Meaning you could dismantle one kit and build another to try a different design or operate in a different band, for example.)

That is an unenforceable rule.