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Old Sep 17, 2008, 02:01 AM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
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The ZigBee module is perfectly capable of hopping in between frames.
Both ends just need to know exactly where they're going to do it.
The only slow part is if it has to search all the available channels.
Presumably they chose 5 channels because it's capable of scanning
through 5 channels inside the time of a PPM frame or two.

It sounds to me like they just pre-select a small number of channels out
of the larger set available, hop between two of them actively
and keep another 3 in reserve so that if it stops getting acks
on one or both of the two active, it tries the 3 in reserve
immediately. If communication is re-established on a reserve channel,
then it immediately negotiates a brand new reserve channel #.

Means its active hopping is more like Spektrum's two channels, but
has fallbacks elsewhere on the band.

The real question is, how did they manage to do antenna diversity
on a module that is a transmitter. Generally if you transmit the same
thing on two antennas at the same time, you basically create
multipath interference right at the source. Can guess only that
they're switching between the antennas on the fly.

ian
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Old Sep 17, 2008, 08:47 AM
Inciting Riots
village_idiot's Avatar
Joined Dec 2006
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So this looks to be "intelligent" adaptive DSSS. Whatever you call it, I hope it performs so that we don't have to rip it apart!
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Old Sep 17, 2008, 09:56 AM
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Sunnyvale, CA, USA
Joined Apr 2000
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"The ZigBee module is perfectly capable of hopping in between frames."

Probably between frames but the description seemed to imply every 1 msec.

Do you know for a fact that this particular hardware can settle fast enough, is that based on something in the Zigbee spec. or is it an intelligent guess? I ask because I haven't had time to dig through the specs on what is my guess and only a guess as to what they are using.

I really hope they are not trying negotiate on the fly in the presence of noise. They might get away with it if one of the two active channels sticks and the negotiation is only performed on the one which is suspect or..........it will work until it doesn't.
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Last edited by teamdavey; Sep 17, 2008 at 10:10 AM.
Old Sep 17, 2008, 01:32 PM
Flying Fatboy
Gordito Volador's Avatar
Tampa, FL
Joined Apr 2003
1,295 Posts
[QUOTE=teamdavey
I really hope they are not trying negotiate on the fly in the presence of noise. They might get away with it if one of the two active channels sticks and the negotiation is only performed on the one which is suspect or..........it will work until it doesn't.[/QUOTE]

I agree with your take on this. I am hoping that Jeti will deliver per their own specs and promises. They have so far with their speed controls. I own at least a dozen or more and they have all worked flawlessly.

Regards, Bill
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Old Sep 17, 2008, 01:40 PM
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The Netherlands, Utrecht, Amersfoort
Joined Oct 2004
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Jeti is a well established company. They will bring quality and quality is what they are known for. I can't imagine they come out with something that doesn't work as advertised.
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Old Sep 17, 2008, 03:50 PM
X-Era Motors
DavidB.'s Avatar
Newport, NC
Joined Jan 2002
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So the receiver itself can do mixing, and this supports telemetry...I'm sold
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Old Sep 17, 2008, 04:11 PM
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ricoalonso's Avatar
USA, KS, Derby
Joined Mar 2003
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plus the Jeti Box which is used to program their ESC can be used to program the Tx/Rx and display telemetry data. looks promising.
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Old Sep 18, 2008, 03:09 PM
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Joined Nov 2002
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Haven't seen this system posted yet:
http://www.weatronic.com/cms/index.p...d=67&Itemid=97
Seems very interesting as well. But couldn't find any pricing info.
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Old Sep 18, 2008, 03:34 PM
supreme being of leisure
ZAGNUT's Avatar
Tel Aviv, Israel
Joined Jul 2004
2,306 Posts
Quote:
Originally Posted by Luap
Haven't seen this system posted yet:
http://www.weatronic.com/cms/index.p...d=67&Itemid=97
Seems very interesting as well. But couldn't find any pricing info.
the narrowband receivers they are known for are around the $500 range...
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Old Sep 18, 2008, 03:45 PM
Registered User
UK
Joined Nov 2002
1,652 Posts
Quote:
Originally Posted by Luap
Haven't seen this system posted yet:
http://www.weatronic.com/cms/index.p...d=67&Itemid=97
Seems very interesting as well. But couldn't find any pricing info.
Its public debut is this coming weekend at the Jetpower show, it's so new that's why you haven't seen anything about it yet.
H
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Old Sep 18, 2008, 03:49 PM
X-Era Motors
DavidB.'s Avatar
Newport, NC
Joined Jan 2002
2,225 Posts
I didn't see anything about telemetry for the weatronics, I'm really tired of having to time my flights. I want a buzzer to go off at a certain battery voltage.
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Old Sep 18, 2008, 03:52 PM
Registered User
Joined Nov 2002
615 Posts
Actually there is
Quote:
The weatronicŪ module transmits and receives through two patch aerials on 12 channels. It logs all the transmitted and received data on a micro SD card which can be read out with the weatronicŪ GIGA control software. An acoustic signal (earplug) warns the pilot when the battery of the receiver has low voltage or the range is reaching the boundaries. The weatronicŪ system works as a frequency hopping spread spectrum with 79 channels (frequencies).The transmitting power is 100 mW EIRP*. The system complies with ETSI and FCC regulations.
But reading last posts seems this system is aimed for high end planes. too bad
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Old Sep 18, 2008, 04:12 PM
X-Era Motors
DavidB.'s Avatar
Newport, NC
Joined Jan 2002
2,225 Posts
So will it have the option to add sensors, etc? The versatility of all past systems is pathetic (including spektrum). So I hope that we'll get something fully configurable in the near future. Sort of like a flying PLC, if you know what I mean.
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Old Oct 04, 2008, 08:41 AM
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Slovakia
Joined Apr 2005
3,386 Posts
So, I have one up and running, (Jeti Duplex universal module and 6-channel receiver), but just tested it at home due to weather. So far, no problems.. receiver is light and nice.. All I have tested for now, was the low voltage, used poor old discharged nimh pack the is unable to support servo load. Receiver survived onine with no sign of troubles, even if blocked servo stopped pushing - well done.. And startup time after power cycle, either receiver either tx - link is restored in a flash, seems instant - amazing..
I have fitted TX module in very old analog radio with NE5044N 7-channel coder, pure analog PPM case good for PC simulator (graupner FM314), no settings there at all, but the receiver itself can configure variable settings, for example variable weight mixing of pairs of channels, adjustment of servo travel hi/lo endpoints, reverse, add exponential or logarithmic travel or delay servo movement. Failsafe can be configured as none/hold/defined position after variable pause.
Unfortunately, MUI sensors were not available for purchase yet, even if they had some - I was holding it in my hand, but i had to let it be.. grrr.. So the only values sent back to TX is the voltage at receiver (minimum, actual, maximum) and perhaps some link info.
Looking forward first flights.
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Old Oct 04, 2008, 10:25 AM
Registered User
Berlin, Germany
Joined Mar 2002
316 Posts
The first parts are available:

http://www.rc-easy.com/shop/index.ph...hz-Duplex.html

Prices are in EURO
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