Does anyone know how frequently a DSSS system may change channels? At
some point it has to resemble a frequency hopping system enough that it
falls under the rules reguarding hybrid DSSS/FHSS systems.

47 CFR Part 15 section 15.247(g) does say that "a [hybrid]system
employing short transmission bursts must comply with the definition
of a frequency hopping system and must distribute its transmissions
over the minimum number of hopping channels
specified in this section. "

This seems to suggest at least that a bursty DSSS system that changes
channels must follow the rules for FH.

Can anyone out there clarify things?

wrote in message
ups.com...
Does anyone know how frequently a DSSS system may change channels?

A dozen or more times per hour.


At
some point it has to resemble a frequency hopping system enough that it
falls under the rules reguarding hybrid DSSS/FHSS systems.
47 CFR Part 15 section 15.247(g) does say that "a [hybrid]system
employing short transmission bursts must comply with the definition
of a frequency hopping system and must distribute its transmissions
over the minimum number of hopping channels
specified in this section. "


Those rules are outdated and no longer apply in this situation.



This seems to suggest at least that a bursty DSSS system that changes
channels must follow the rules for FH.

Can anyone out there clarify things?



Just continue using your channel changing DSSS and don't worry.
Technology is growing too quickly for the FCC bureaucrats to
keep up.


73,

Henry

[Code of Federal Regulations]
[Title 47, Volume 1]
[Revised as of October 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR15.247]

[Page 740-742]

TITLE 47--TELECOMMUNICATION

CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION

PART 15--RADIO FREQUENCY DEVICES--Table of Contents

Subpart C--Intentional Radiators

Sec. 15.247 Operation within the bands 902-928 MHz, 2400-2483.5 MHz,
and 5725-5850 MHz.

(a) Operation under the provisions of this section is limited to
frequency hopping and digitally modulated intentional radiators that
comply with the following provisions:
(1) Frequency hopping systems shall have hopping channel carrier
frequencies separated by a minimum of 25 kHz or the 20 dB bandwidth of
the hopping channel, whichever is greater. The system shall hop to
channel frequencies that are selected at the system hopping rate from a

pseudorandomly ordered list of hopping frequencies. Each frequency must

be used equally on the average by each transmitter. The system
receivers
shall have input bandwidths that match the hopping channel bandwidths
of
their corresponding transmitters and shall shift frequencies in
synchronization with the transmitted signals.
(i) For frequency hopping systems operating in the 902-928 MHz
band:
if the 20 dB bandwidth of the hopping channel is less than 250 kHz, the

system shall use at least 50 hopping frequencies and the average time
of
occupancy on any frequency shall not be greater than 0.4 seconds within

a 20 second period; if the 20 dB bandwidth of the hopping channel is
250
kHz or greater, the system shall use at least 25 hopping frequencies
and
the average time of occupancy on any frequency shall not be greater
than
0.4 seconds within a 10 second period. The maximum allowed 20 dB
bandwidth of the hopping channel is 500 kHz.
(ii) Frequency hopping systems operating in the 5725-5850 MHz band
shall use at least 75 hopping frequencies. The maximum 20 dB bandwidth
of the hopping channel is 1 MHz. The average time of occupancy on any
frequency shall not be greater than 0.4 seconds within a 30 second
period.
(iii) Frequency hopping systems in the 2400-2483.5 MHz band shall
use at

[[Page 741]]

least 15 non-overlapping channels. The average time of occupancy on any

channel shall not be greater than 0.4 seconds within a period of 0.4
seconds multiplied by the number of hopping channels employed.
Frequency
hopping systems which use fewer than 75 hopping frequencies may employ
intelligent hopping techniques to avoid interference to other
transmissions. Frequency hopping systems may avoid or suppress
transmissions on a particular hopping frequency provided that a minimum

of 15 non-overlapping channels are used.
(2) Systems using digital modulation techniques may operate in the
902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz bands. The minimum 6 dB

bandwidth shall be at least 500 kHz.
(b) The maximum peak output power of the intentional radiator shall

not exceed the following:
(1) For frequency hopping systems in the 2400-2483.5 MHz band
employing at least 75 hopping channels, and all frequency hopping
systems in the 5725-5850 MHz band: 1 Watt. For all other frequency
hopping systems in the 2400-2483.5 band: 0.125 Watt.
(2) For frequency hopping systems operating in the 902-928 MHz
band:
1 watt for systems employing at least 50 hopping channels; and, 0.25
watts for systems employing less than 50 hopping channels, but at least

25 hopping channels, as permitted under paragraph (a)(1)(i) of this
section.
(3) For systems using digital modulation in the 902-928 MHz, 2400-
2483.5 MHz, and 5725-5850 MHz bands: 1 Watt.
(4) Except as shown in paragraphs (b)(3) (i), (ii) and (iii) of
this
section, if transmitting antennas of directional gain greater than 6
dBi
are used the peak output power from the intentional radiator shall be
reduced below the stated values in paragraphs (b)(1) or (b)(2) of this
section, as appropriate, by the amount in dB that the directional gain
of the antenna exceeds 6 dBi.
(i) Systems operating in the 2400-2483.5 MHz band that are used
exclusively for fixed, point-to-point operations may employ
transmitting
antennas with directional gain greater than 6 dBi provided the maximum
peak output power of the intentional radiator is reduced by 1 dB for
every 3 dB that the directional gain of the antenna exceeds 6 dBi.
(ii) Systems operating in the 5725-5850 MHz band that are used
exclusively for fixed, point-to-point operations may employ
transmitting
antennas with directional gain greater than 6 dBi without any
corresponding reduction in transmitter peak output power.
(iii) Fixed, point-to-point operation, as used in paragraphs
(b)(3)(i) and (b)(3)(ii) of this section, excludes the use of point-to-
multipoint systems, omnidirectional applications, and multiple co-
located intentional radiators transmitting the same information. The
operator of the spread spectrum intentional radiator or, if the
equipment is professionally installed, the installer is responsible for

ensuring that the system is used exclusively for fixed, point-to-point
operations. The instruction manual furnished with the intentional
radiator shall contain language in the installation instructions
informing the operator and the installer of this responsibility.
(5) Systems operating under the provisions of this section shall be

operated in a manner that ensures that the public is not exposed to
radio frequency energy levels in excess of the Commission's guidelines.

See Sec. 1.1307(b)(1) of this chapter.
(c) In any 100 kHz bandwidth outside the frequency band in which
the
spread spectrum or digitally modulated intentional radiator is
operating, the radio frequency power that is produced by the
intentional
radiator shall be at least 20 dB below that in the 100 kHz bandwidth
within the band that contains the highest level of the desired power,
based on either an RF conducted or a radiated measurement. Attenuation
below the general limits specified in Sec. 15.209(a) is not required.
In addition, radiated emissions which fall in the restricted bands, as
defined in Sec. 15.205(a), must also comply with the radiated emission

limits specified in Sec. 15.209(a) (see Sec. 15.205(c)).
(d) For digitally modulated systems, the peak power spectral
density
conducted from the intentional radiator to the antenna shall not be
greater than 8

[[Page 742]]

dBm in any 3 kHz band during any time interval of continuous
transmission.
(e) [Reserved]
(f) For the purposes of this section, hybrid systems are those that

employ a combination of both frequency hopping and digital modulation
techniques. The frequency hopping operation of the hybrid system, with
the direct sequence or digital modulation operation turned off, shall
have an average time of occupancy on any frequency not to exceed 0.4
seconds within a time period in seconds equal to the number of hopping
frequencies employed multiplied by 0.4. The digital modulation
operation
of the hybrid system, with the frequency hopping operation turned off,
shall comply with the power density requirements of paragraph (d) of
this section.
(g) Frequency hopping spread spectrum systems are not required to
employ all available hopping channels during each transmission.
However,
the system, consisting of both the transmitter and the receiver, must
be
designed to comply with all of the regulations in this section should
the transmitter be presented with a continuous data (or information)
stream. In addition, a system employing short transmission bursts must
comply with the definition of a frequency hopping system and must
distribute its transmissions over the minimum number of hopping
channels
specified in this section.
(h) The incorporation of intelligence within a frequency hopping
spread spectrum system that permits the system to recognize other users

within the spectrum band so that it individually and independently
chooses and adapts its hopsets to avoid hopping on occupied channels is

permitted. The coordination of frequency hopping systems in any other
manner for the express purpose of avoiding the simultaneous occupancy
of
individual hopping frequencies by multiple transmitters is not
permitted.

Note: Spread spectrum systems are sharing these bands on a
noninterference basis with systems supporting critical Government
requirements that have been allocated the usage of these bands,
secondary only to ISM equipment operated under the provisions of part
18
of this chapter. Many of these Government systems are airborne
radiolocation systems that emit a high EIRP which can cause
interference
to other users. Also, investigations of the effect of spread spectrum
interference to U. S. Government operations in the 902-928 MHz band may

require a future decrease in the power limits allowed for spread
spectrum operation.

[54 FR 17714, Apr. 25, 1989, as amended at 55 FR 28762, July 13, 1990;
62 FR 26242, May 13, 1997; 65 FR 57561, Sept. 25, 2000; 67 FR 42734,
June 25, 2002]

N9OGL wrote:
[Code of Federal Regulations]
[Title 47, Volume 1]
[Revised as of October 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR15.247]

[Page 740-742]

TITLE 47--TELECOMMUNICATION


is all pile of dung. fcc cant change law of physics like gravity or
electron mass.

electron mass in f=ma give force to big to be physical. to make wi-fi
radio signal electron supposed to vibrate at 2,400,000,000 times each
second. that nonsense becaues of f=ma make hop force so big no one have
enough power to do it in first place. forget regulations. do what I do
and do whatever you want on radio becaues fcc dont know crap anyways.

It should be noted by all that the rules below only apply to Part 15
operation - not to operation under the Part 97 Amateur Radio Service rules
....

73,
Carl - wk3c

"N9OGL" wrote in message
roups.com...
[Code of Federal Regulations]
[Title 47, Volume 1]
[Revised as of October 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR15.247]

[Page 740-742]

TITLE 47--TELECOMMUNICATION

CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION

PART 15--RADIO FREQUENCY DEVICES--Table of Contents

Subpart C--Intentional Radiators

Sec. 15.247 Operation within the bands 902-928 MHz, 2400-2483.5 MHz,
and 5725-5850 MHz.

(a) Operation under the provisions of this section is limited to
frequency hopping and digitally modulated intentional radiators that
comply with the following provisions:
(1) Frequency hopping systems shall have hopping channel carrier
frequencies separated by a minimum of 25 kHz or the 20 dB bandwidth of
the hopping channel, whichever is greater. The system shall hop to
channel frequencies that are selected at the system hopping rate from a

pseudorandomly ordered list of hopping frequencies. Each frequency must

be used equally on the average by each transmitter. The system
receivers
shall have input bandwidths that match the hopping channel bandwidths
of
their corresponding transmitters and shall shift frequencies in
synchronization with the transmitted signals.
(i) For frequency hopping systems operating in the 902-928 MHz
band:
if the 20 dB bandwidth of the hopping channel is less than 250 kHz, the

system shall use at least 50 hopping frequencies and the average time
of
occupancy on any frequency shall not be greater than 0.4 seconds within

a 20 second period; if the 20 dB bandwidth of the hopping channel is
250
kHz or greater, the system shall use at least 25 hopping frequencies
and
the average time of occupancy on any frequency shall not be greater
than
0.4 seconds within a 10 second period. The maximum allowed 20 dB
bandwidth of the hopping channel is 500 kHz.
(ii) Frequency hopping systems operating in the 5725-5850 MHz band
shall use at least 75 hopping frequencies. The maximum 20 dB bandwidth
of the hopping channel is 1 MHz. The average time of occupancy on any
frequency shall not be greater than 0.4 seconds within a 30 second
period.
(iii) Frequency hopping systems in the 2400-2483.5 MHz band shall
use at

[[Page 741]]

least 15 non-overlapping channels. The average time of occupancy on any

channel shall not be greater than 0.4 seconds within a period of 0.4
seconds multiplied by the number of hopping channels employed.
Frequency
hopping systems which use fewer than 75 hopping frequencies may employ
intelligent hopping techniques to avoid interference to other
transmissions. Frequency hopping systems may avoid or suppress
transmissions on a particular hopping frequency provided that a minimum

of 15 non-overlapping channels are used.
(2) Systems using digital modulation techniques may operate in the
902-928 MHz, 2400-2483.5 MHz, and 5725-5850 MHz bands. The minimum 6 dB

bandwidth shall be at least 500 kHz.
(b) The maximum peak output power of the intentional radiator shall

not exceed the following:
(1) For frequency hopping systems in the 2400-2483.5 MHz band
employing at least 75 hopping channels, and all frequency hopping
systems in the 5725-5850 MHz band: 1 Watt. For all other frequency
hopping systems in the 2400-2483.5 band: 0.125 Watt.
(2) For frequency hopping systems operating in the 902-928 MHz
band:
1 watt for systems employing at least 50 hopping channels; and, 0.25
watts for systems employing less than 50 hopping channels, but at least

25 hopping channels, as permitted under paragraph (a)(1)(i) of this
section.
(3) For systems using digital modulation in the 902-928 MHz, 2400-
2483.5 MHz, and 5725-5850 MHz bands: 1 Watt.
(4) Except as shown in paragraphs (b)(3) (i), (ii) and (iii) of
this
section, if transmitting antennas of directional gain greater than 6
dBi
are used the peak output power from the intentional radiator shall be
reduced below the stated values in paragraphs (b)(1) or (b)(2) of this
section, as appropriate, by the amount in dB that the directional gain
of the antenna exceeds 6 dBi.
(i) Systems operating in the 2400-2483.5 MHz band that are used
exclusively for fixed, point-to-point operations may employ
transmitting
antennas with directional gain greater than 6 dBi provided the maximum
peak output power of the intentional radiator is reduced by 1 dB for
every 3 dB that the directional gain of the antenna exceeds 6 dBi.
(ii) Systems operating in the 5725-5850 MHz band that are used
exclusively for fixed, point-to-point operations may employ
transmitting
antennas with directional gain greater than 6 dBi without any
corresponding reduction in transmitter peak output power.
(iii) Fixed, point-to-point operation, as used in paragraphs
(b)(3)(i) and (b)(3)(ii) of this section, excludes the use of point-to-
multipoint systems, omnidirectional applications, and multiple co-
located intentional radiators transmitting the same information. The
operator of the spread spectrum intentional radiator or, if the
equipment is professionally installed, the installer is responsible for

ensuring that the system is used exclusively for fixed, point-to-point
operations. The instruction manual furnished with the intentional
radiator shall contain language in the installation instructions
informing the operator and the installer of this responsibility.
(5) Systems operating under the provisions of this section shall be

operated in a manner that ensures that the public is not exposed to
radio frequency energy levels in excess of the Commission's guidelines.

See Sec. 1.1307(b)(1) of this chapter.
(c) In any 100 kHz bandwidth outside the frequency band in which
the
spread spectrum or digitally modulated intentional radiator is
operating, the radio frequency power that is produced by the
intentional
radiator shall be at least 20 dB below that in the 100 kHz bandwidth
within the band that contains the highest level of the desired power,
based on either an RF conducted or a radiated measurement. Attenuation
below the general limits specified in Sec. 15.209(a) is not required.
In addition, radiated emissions which fall in the restricted bands, as
defined in Sec. 15.205(a), must also comply with the radiated emission

limits specified in Sec. 15.209(a) (see Sec. 15.205(c)).
(d) For digitally modulated systems, the peak power spectral
density
conducted from the intentional radiator to the antenna shall not be
greater than 8

[[Page 742]]

dBm in any 3 kHz band during any time interval of continuous
transmission.
(e) [Reserved]
(f) For the purposes of this section, hybrid systems are those that

employ a combination of both frequency hopping and digital modulation
techniques. The frequency hopping operation of the hybrid system, with
the direct sequence or digital modulation operation turned off, shall
have an average time of occupancy on any frequency not to exceed 0.4
seconds within a time period in seconds equal to the number of hopping
frequencies employed multiplied by 0.4. The digital modulation
operation
of the hybrid system, with the frequency hopping operation turned off,
shall comply with the power density requirements of paragraph (d) of
this section.
(g) Frequency hopping spread spectrum systems are not required to
employ all available hopping channels during each transmission.
However,
the system, consisting of both the transmitter and the receiver, must
be
designed to comply with all of the regulations in this section should
the transmitter be presented with a continuous data (or information)
stream. In addition, a system employing short transmission bursts must
comply with the definition of a frequency hopping system and must
distribute its transmissions over the minimum number of hopping
channels
specified in this section.
(h) The incorporation of intelligence within a frequency hopping
spread spectrum system that permits the system to recognize other users

within the spectrum band so that it individually and independently
chooses and adapts its hopsets to avoid hopping on occupied channels is

permitted. The coordination of frequency hopping systems in any other
manner for the express purpose of avoiding the simultaneous occupancy
of
individual hopping frequencies by multiple transmitters is not
permitted.

Note: Spread spectrum systems are sharing these bands on a
noninterference basis with systems supporting critical Government
requirements that have been allocated the usage of these bands,
secondary only to ISM equipment operated under the provisions of part
18
of this chapter. Many of these Government systems are airborne
radiolocation systems that emit a high EIRP which can cause
interference
to other users. Also, investigations of the effect of spread spectrum
interference to U. S. Government operations in the 902-928 MHz band may

require a future decrease in the power limits allowed for spread
spectrum operation.

[54 FR 17714, Apr. 25, 1989, as amended at 55 FR 28762, July 13, 1990;
62 FR 26242, May 13, 1997; 65 FR 57561, Sept. 25, 2000; 67 FR 42734,
June 25, 2002]