823669 Dog fence transmitters and pet containment systems operating at 10 kHz

Publication Number: 823669	Rule Parts: 15.209	Publication Date: 03/23/2007
Keyword: Dog fence transmitters and pet containment systems operating at 10 kHz

First Category:	Radio Service Rules
Second Category:	Part 15 Intentional Radiators

Question: Under what conditions will a 60 dB per decade extrapolation factor (roll-off) be acceptable for operations below 490 kHz for devices such as a dog fence transmitter or pet containment device?

Answer: Dog fence transmitters and pet containment systems operating on frequencies below 490 kHz are subject to the general radiated emission limits in 47 CFR 15.209. The procedures for measuring intentional radiators operating on frequencies below 30 MHz are given in 47 CFR 15.31(f). In the case of a dog fence transmitter or pet containment device operating at 10 kHz, a 40 dB per decade roll-off is acceptable. However a 60 dB per decade roll-off must be proven through multiple measurements at several distances, e.g. 3 meters, 10 meters and 30 meters. This higher roll-off is acceptable if it can be proven empirically. As an example, at 262 kHz, a maximum field strength (F/S) of 9.2 uV/m at 300 meters is permitted. A 40 dB per decade roll-off is acceptable and would convert the above stated 300 meter limited to about 8.3 millivolts/meter at the 10 meter distance. However, a 60 dB per decade (same as 18 dB/octave) must be proven through multiple measurements at several distances, e.g., 3 meters, 10 meters and 30 meters.

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