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May 26, 2008, 04:39 AM
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Question

Frequency hopping version for Europe


In this thread Jim Drew stated:

Quote:
We will also have a full time frequency hopping version required for Europe in August that will also be just a firmware upgrade.
Jim, what do you mean by that? Are we talking about a system like FASST? Can you give more details please?
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May 26, 2008, 12:04 PM
In order to have 100mw output, you must have no fewer than 15 hopping channels that are used in a psuedo-random pattern. We had to create this for Europe's ETSI compliancy starting August 1st. It's just a simple firmware upgrade.
May 26, 2008, 02:53 PM
VE7FM
TheSteve's Avatar
Quote:
Originally Posted by JimDrew
In order to have 100mw output, you must have no fewer than 15 hopping channels that are used in a psuedo-random pattern. We had to create this for Europe's ETSI compliancy starting August 1st. It's just a simple firmware upgrade.
Sounds great - I thought the Xbee pro only had 12 channels though...
May 26, 2008, 03:23 PM
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Quote:
Originally Posted by TheSteve
Sounds great - I thought the Xbee pro only had 12 channels though...
I remember Jim saying that he would request MaxStream to change the firmware and use all 16 available channels.
May 26, 2008, 03:49 PM
Registered User
So this Euro-version will be just like FASST now?
May 26, 2008, 11:58 PM
No, it is a completely different configuration from the FASST. The Motorola (Freescale) chipset has the ability to use 16 channels, but at the time only 12 were certified for use in the U.S. We can access all 16 channels for receiving data, but only 12 of those can be used for transmitting in the U.S. (something that the normal XBEE firmware does not allow). This firmware will be certified for compliancy with EN 300-328 v1.71.
May 27, 2008, 12:46 AM
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Quote:
Originally Posted by JimDrew
We can access all 16 channels for receiving data, but only 12 of those can be used for transmitting in the U.S. (something that the normal XBEE firmware does not allow). This firmware will be certified for compliancy with EN 300-328 v1.71.
You don't have to transmit on 15+ channels: http://www.macgregor.co.uk/faq/Transmitters/DSM_FAQ.pdf
(https://www.rcgroups.com/forums/showthread.php?t=854217)
May 27, 2008, 07:34 AM
FHSS won Europe hitherto
You HAVE TO transmit on 15+ channels because of:

3.1 Definitions

For the purposes of the present document, the terms and definitions given in the R&TTE Directive [1] and the following apply:
.
.
frequency hopping spread spectrum modulation: spread spectrum technique in which the transmitter signal occupies a number of frequencies in time, each for some period of time, referred to as the dwell time
NOTE: Transmitter and receiver follow the same frequency hop pattern. The frequency range is determined by the lowest and highest hop positions and the bandwidth per hop position.

There will be an European decision to close this loophole between 3.1 and 4.x.x in mid of June, if the holy frequencyspirit is on duty.

Rudy
May 27, 2008, 07:52 AM
Registered User
300-328 is going to be re-written so that the difference between FHSS & DSSS becomes irrelevant. So anticipate v1.8.1 coming out sometime in the future.
May 27, 2008, 09:07 PM
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gregw's Avatar
So, XPS will have a "European only" version starting August 1 or will this be selectable in the firmware options like the "France" setting now that restricts the available frequency?
May 27, 2008, 10:20 PM
We are not sure yet. We just received our final FCC ruling today. We can actually use this same hopping technique with any number of channels that we choose (2 to 12) with our existing hardware and XBEE firmware, so we may make several different types of modulation schemes available and selectable much like you can set the country code now.
May 27, 2008, 11:01 PM
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Can you publish the FCC ruling?
May 28, 2008, 09:31 AM
Inciting Riots
village_idiot's Avatar
Since it is an official clarification, it would be nice if the FCC published it as a new sub part to the part 15 rules. Not sure if that will happen, but if it does it should be published in the rules in the next 2 to 3 months.
May 28, 2008, 10:57 AM
Quote:
Originally Posted by IPFlyer
Can you publish the FCC ruling?
The latest response on this subject is shown below:

---Reply from Customer on 05/20/2008---

Publication 453039 states that frequency hopping devices have to abide by FHSS rules and direct sequencing devices must abide by DSSS rules, and that it is possible to be both. However, we can not find anywhere in the FCC litterature that states the maximum amount of frequency changes that can occur with a direct sequencing device. We can only find information pertaining to the FHSS type devices. Can you point us to the proper direction to find information on this exact subject? The answer we are looking for really is how often can a FCC certified DSSS device change frequencies?

Response:
A devices operating under the rules for DTS systems in 15.247 does not have any prohibition on the number of channels it can hop to.
May 28, 2008, 11:03 AM
We have already confirmed that for ETSI compliancy the minimum number of channels that can be used is 15 and the maximum channel occupancy time is 400ms/number of channels (roughly 26ms). Since we occupy the channel for a maximum of 1.62ms (with all 16 channels of data being sent), we are well within the specifications for EN 300-328 v1.71 with the new European code.


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