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Old Sep 16, 2008, 02:04 PM
ricoalonso is offline
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any info on actual performance will be greatly appreciated.
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Old Sep 16, 2008, 02:36 PM
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OK..... I'm trying to understand how this system works.

- The TX/RX communicate and select 5 free channels
- If it finds a "bad" channel it then picks another for the 5
- The TX/RX then monitor signal strength, error rate, to pick 2 of the 5 channels
- The system then uses those 2 channels

now is where I have questions.

- Does it stay on 1 channel and go to the second only if it needs to?, or does it constantly "hop" between the 2?

- When 1 of the 2 selected has noise does it then substitute 1 of the other original 5 selected?

The website is not very clear on this.
Old Sep 16, 2008, 03:01 PM
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Seems from the JETI site that it uses 2 out of 5 free channels and hops to one of the previosly selected free channels if needed (if one of the two channels it started on is deemed "bad"?). I wonder if it now has 2 channels to backup to or if it "prebooks" another one so that there still is 3 backups. Seems like to work a bit like an improved spektrum with hopping

The esotop article mentioned that it constantly hops between the 5 selected "good" channels (ca 1 ms/each), and if one channel is "bad" another one is selected for the next round of data. (bit like FASST, but not as many channels, and feedback).

This is interesting, looking forward to a good test/article of it.
Old Sep 16, 2008, 04:35 PM
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Just a guess, but don't hold your breath for FCC certs in Jeti's name. That module looks very much like it has a commercial RF subassembly on it which means they will ride on the vendor cert (like XPS). IF this is true, it would also explain the somewhat convoluted theory of op because they have to work within the constraints of the vendor's code and certs.

Can anyone identify the source?

How many ways can you spell Zigbee
Old Sep 16, 2008, 04:45 PM
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I see CE markings, if that means anything...

I guess we have to wait until the Prauge hobby fair in october to find out much more..
Old Sep 16, 2008, 05:20 PM
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Quote:
Originally Posted by teamdavey
Just a guess, but don't hold your breath for FCC certs in Jeti's name. That module looks very much like it has a commercial RF subassembly on it which means they will ride on the vendor cert (like XPS). IF this is true, it would also explain the somewhat convoluted theory of op because they have to work within the constraints of the vendor's code and certs.

Can anyone identify the source?

How many ways can you spell Zigbee
If it turns out that Jeti actually uses a Zigbee module and it performs as they describe, then Jim D better hire some Czech programmers.....
Old Sep 16, 2008, 05:29 PM
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No comment.

Of course there are multiple vendors of Zigbee modules other than Maxstream (digi?). The specs on the Jeti site have certain clues in terms of the bandwidth, number of channels and theoretical maximum number of users. A quick trawl of the net pitched up a couple of candidates, but the FCC ident will tell for sure.
Old Sep 16, 2008, 05:32 PM
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Quote:
Originally Posted by bjpaul
If it turns out that Jeti actually uses a Zigbee module and it performs as they describe, then Jim D better hire some Czech programmers.....
Hehe

I'd really like to go to 2.4G, and this sollution looks promising so far.. Have a HET mig 29 on the building board right now and dont want any problems with that one. Had enough glitch/EMC problems with my small EDF, it's only flyable on a jeti rex jbc reciever (35MHz) with filtering set to 100% (graupner synth reciever was a big no-no).
Old Sep 16, 2008, 05:53 PM
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Well hopefully the do use a pre-certified module, makes time to market that much quicker.
Old Sep 16, 2008, 06:00 PM
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This would be my guess: http://www.meshnetics.com/zigbee-modules/amp/
Old Sep 16, 2008, 07:19 PM
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Quote:
Originally Posted by teamdavey
Looks like you are on to something.... and it does have according to the manufacturer a FCC id.

Brad
Old Sep 16, 2008, 07:39 PM
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Right. It looks like jeti have their own protocal overlay on top. I haven't the time to dig into the specs for the actual device, but would be surprised if it actually "hops" since Zigbee is not intended to be frequency agile on the fly as far as I know. However, that particular implementation may support rapid channel change which they could take adantage of. I can't even guess where the 5 channel stuff comes from but someone with the time to dig through the specs may find the clue.
Old Sep 16, 2008, 10:10 PM
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Whatever they use, I hope it lives up to the specs. And if it does then more power to them, looks like a nice system if it really works as claimed.
Old Sep 17, 2008, 01:53 AM
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I hope it doesn't start communicating with/confusing XPS systems or vice versa...
Old Sep 17, 2008, 02:04 AM
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Quote:
Originally Posted by bjpaul
OK..... I'm trying to understand how this system works.

- The TX/RX communicate and select 5 free channels
- If it finds a "bad" channel it then picks another for the 5
- The TX/RX then monitor signal strength, error rate, to pick 2 of the 5 channels
- The system then uses those 2 channels

now is where I have questions.

- Does it stay on 1 channel and go to the second only if it needs to?, or does it constantly "hop" between the 2?

- When 1 of the 2 selected has noise does it then substitute 1 of the other original 5 selected?

The website is not very clear on this.
Good point. So even if it "hops", does this mean that if you have two Jeti modules up at the same time, neither is hopping?


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