[WISPA] FCC Regulations Clarification

2007-05-02 Thread Ryan Morgan

I have a few questions about part 15.247 ..


(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.



For one AP using 20db bandwidth of hopping channel   250 kHz , hopping 
on at least 50 channels.


How about 20 units in the same location, all hopping on at least 50 
frequencies.
The regulation mentions that the average time on any frequency shall not 
be greater than 400 ms within a 20 second period.
With all those AP hopping on those 50 hopping frequencies, you would 
think that the occupancy on any particular

frequency would be greater than 400 ms within a 20 second period?

If those particular units were trying to get away from interference, can 
they select certain frequencies to hop around and still be within 
regulations?


If somebody could clear this up for me then that would be great.

Thanks,
Ryan


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Re: [WISPA] FCC Regulations Clarification

2007-05-02 Thread Marlon K. Schafer (509) 982-2181

The rules apply on a per transmitter basis.

I know that some systems are able to hop around some known channels.  I'm 
not sure if that extends to 900mhz or not.


Marlon
(509) 982-2181
(408) 907-6910 (Vonage)Consulting services
42846865 (icq)WISP Operator since 1999!
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- Original Message - 
From: Ryan Morgan [EMAIL PROTECTED]

To: wireless@wispa.org
Sent: Wednesday, May 02, 2007 2:19 PM
Subject: [WISPA] FCC Regulations Clarification



I have a few questions about part 15.247 ..


(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.



For one AP using 20db bandwidth of hopping channel   250 kHz , hopping on 
at least 50 channels.


How about 20 units in the same location, all hopping on at least 50 
frequencies.
The regulation mentions that the average time on any frequency shall not 
be greater than 400 ms within a 20 second period.
With all those AP hopping on those 50 hopping frequencies, you would think 
that the occupancy on any particular

frequency would be greater than 400 ms within a 20 second period?

If those particular units were trying to get away from interference, can 
they select certain frequencies to hop around and still be within 
regulations?


If somebody could clear this up for me then that would be great.

Thanks,
Ryan


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