FCC part 15.247(i) rule for Class B Digital Devices

[ZombieKnot]

Treasure_Hunter stated there is no FCC regulation for metal detector electric field gradient. There is a rule for Radio Frequency energy emitted for Class B digital devices-FCC part 15.247(i): The power transmitted by the transmitter(coil) can only have a maximum power level of 1 watt or 30dBm.
This chart is from Dan Blankenship;
EXp Deux ll: 3.9-135.7Khz | <-12.77dBm | <-72dBuA/m at 10 meters.
Minelab CTX: 1.3-141Khz | <-30dBm | <56.92dBuA/m at 10m.
Minelab Equinox 600-900: 2.5-143Khz | <-30dBm | <56.92dBuA/m at 10m.
Minelab Manticore: 2.5-143Khz | <-30dBm | <56.92dBuA/m at 10m.
Nokta Macro Legend: 3 and 15Khz | <-30dBm | <56.92dBuA/m at 10m. (Plural Frequency Transmission.)

So the Minelab machines are more powerful transmitting than the Deux ll ; a suspicion of mine confirmed.
The EU Declaration of conformity Directive 2014/53/EU is much the same for sales overseas.
www.minelab.com/compliance has these figures too.
When you open your Manticore box there will be a booklet inside: Instruction and Safety Information which has a chart of ALL Minelab detector's power and frequency specifications.
"Sometimes your corrections ain't so correct."
Source: YouTube video {Minelab's Full Response: Is the Manticore 50% more powerful?} by Metal Detecting NYC.
Happy Trails.

 

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[Ed144]

Treasure_Hunter stated there is no FCC regulation for metal detector electric field gradient. There is a rule for Radio Frequency energy emitted for Class B digital devices-FCC part 15.247(i): The power transmitted by the transmitter(coil) can only have a maximum power level of 1 watt or 30dBm.
This chart is from Dan Blankenship;
EXp Deux ll: 3.9-135.7Khz | <-12.77dBm | <-72dBuA/m at 10 meters.
Minelab CTX: 1.3-141Khz | <-30dBm | <56.92dBuA/m at 10m.
Minelab Equinox 600-900: 2.5-143Khz | <-30dBm | <56.92dBuA/m at 10m.
Minelab Manticore: 2.5-143Khz | <-30dBm | <56.92dBuA/m at 10m.
Nokta Macro Legend: 3 and 15Khz | <-30dBm | <56.92dBuA/m at 10m. (Plural Frequency Transmission.)

So the Minelab machines are more powerful transmitting than the Deux ll ; a suspicion of mine confirmed.
The EU Declaration of conformity Directive 2014/53/EU is much the same for sales overseas.
www.minelab.com/compliance has these figures too.
When you open your Manticore box there will be a booklet inside: Instruction and Safety Information which has a chart of ALL Minelab detector's power and frequency specifications.
"Sometimes your corrections ain't so correct."
Source: YouTube video {Minelab's Full Response: Is the Manticore 50% more powerful?} by Metal Detecting NYC.
Happy Trails.

Your post peaked my curiosity. I guess metal detector radiated emissions fall under FCC CFR Title 47, Part 15 Radio Frequency Devices, Subpart C Intentional Radiators. Reference to Part 15.247 doesn't make sense since it is for "Operation within the bands 902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz." I looked at the Minelab compliance data and it is sort of meaningless. It shows Detector Power as -30dBm, but the power reference or conditions of test are not defined. I'm guessing that this small power level of 0.001 milliWatt (mW) is the output power from the detector transmitter to the search coil. This seems like a very small power level to me, but I don't know much about detector transmitter design. If you are referencing dBm power levels to the detector search coil then the -12.77 dBm power spec of the XP Deus 2 is more than 53 times greater than the -30dBm rating of the Minelab. The dBuA is a value I'm not familiar with in field strength. Perhaps dB with respect to 1 microvolt (dBuV) is what was meant? Does anyone know what specific FCC rule metal detector radiated emissions must comply? Is it as simple as Subpart C, Cable Locating Equipment? Thanks. Az_Ed, Tucson.

 

[Ed144]

This is from the FCC spec regarding cable locating equipment. The power levels referenced are reasonably high. If this rule applies to general purpose metal detectors then equipment operating in the 9-45 kHz range could run ten times the power of 45-490 kHz detectors. Anyone out there have experience with detectors and FCC rules?

• Title 47 , Chapter I , Subchapter A , Part 15 , Subpart C

§ 15.213 Cable locating equipment.​

An intentional radiator used as cable locating equipment, as defined in § 15.3(d), may be operated on any frequency within the band 9-490 kHz, subject to the following limits: Within the frequency band 9 kHz, up to, but not including, 45 kHz, the peak output power from the cable locating equipment shall not exceed 10 watts; and, within the frequency band 45 kHz to 490 kHz, the peak output power from the cable locating equipment shall not exceed one watt. If provisions are made for connection of the cable locating equipment to the AC power lines, the conducted limits in § 15.207 also apply to this equipment.

 

[ZombieKnot]

This is from the FCC spec regarding cable locating equipment. The power levels referenced are reasonably high. If this rule applies to general purpose metal detectors then equipment operating in the 9-45 kHz range could run ten times the power of 45-490 kHz detectors. Anyone out there have experience with detectors and FCC rules?

• Title 47 , Chapter I , Subchapter A , Part 15 , Subpart C

§ 15.213 Cable locating equipment.​

An intentional radiator used as cable locating equipment, as defined in § 15.3(d), may be operated on any frequency within the band 9-490 kHz, subject to the following limits: Within the frequency band 9 kHz, up to, but not including, 45 kHz, the peak output power from the cable locating equipment shall not exceed 10 watts; and, within the frequency band 45 kHz to 490 kHz, the peak output power from the cable locating equipment shall not exceed one watt. If provisions are made for connection of the cable locating equipment to the AC power lines, the conducted limits in § 15.207 also apply to this equipment.

That is for a generated signal transmitted ALONG a ground cable as described in the text15.3(d) and then detected externally. Does not apply to radio frequency generated by a portable metal detector. As for 247(i) was quoting the video from [metal detecting nyc] and am sure the paragraph is wrong due to your reading. Now curious which RULE applies to transmitter coil frequency from a sweeping metal detector. Will ask NYC where he got this reference. Thanx. Hunting paper as hard as hunting ground.