New FHSS from JR?

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Re: New FHSS from JR?

Postby ronw » Wed Sep 15, 2010 3:25 am

What do you make of the comments that JR may provide tools to upgrade DSM2 to DSMJ in the UK. Unless I completely misread the posts.
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Re: New FHSS from JR?

Postby RCModelReviews » Wed Sep 15, 2010 4:13 am

ronw wrote:What do you make of the comments that JR may provide tools to upgrade DSM2 to DSMJ in the UK. Unless I completely misread the posts.

Did they say that?

From what I've been told, the only difference between DSM2 and DSMJ is the software so it sounds feasible that they'd offer a reflash service to convert DSM2 to DSMJ in the event that it was to meet EU regulations -- if that's the reason.
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Re: New FHSS from JR?

Postby ronw » Wed Sep 15, 2010 6:07 am

Check through all of that thread when you get a moment as I would like your view on what he is hinting at about or just trying to put people at bay!
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Re: New FHSS from JR?

Postby Ameisenbaer » Thu Sep 16, 2010 7:34 am

RCModelReviews wrote:DSM2 is reliant on devices that don't work well at low voltages and have been "repurposed" from their original job of providing very short-range data-links for things like wireless mice, keyboards etc. To maintain backwards compatibility would effectively be like trying to build cars with iron wheels so they could still use the railway tracks as well as the roads. As we can easily see -- doing that would severely compromise their road-handling and effectively negate much of the benefits that were to be gained from the shift away from railway to freeway.


To the best of my knowledge, nobody else is using the Cypress chips that Spektrum/JR have been using -- they're certainly *not* the best tool for the job.


FASST use the ML2724 used in
-Digital Cordless Telephones
- Wireless PC Peripherals
- Wireless Game Controllers

The CC2500 (Hitec, Frysky.. ) is used for
- Wireless audio
- Wireless keyboard and mouse

so what?

So i suggest read the data sheet of the CYRF69103 the voltage range is 1.8V to 3.6V.

Multiplex, ACT, Nomadio use the Chypress chips too.
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Re: New FHSS from JR?

Postby RCModelReviews » Thu Sep 16, 2010 7:55 am

And check the specs/performances of the different devices -- gives more of a clue to their suitability.

The cypress device may have a minimum voltage of 1.8V but there's more than just the transceiver chip involved in producing a receiver solution. In fact, when you look at the LV performance of DSM2 receivers, you've got to wonder how on earth they could come up with such a high brownout voltage.
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Re: New FHSS from JR?

Postby Ameisenbaer » Thu Sep 16, 2010 8:25 am

The lack of a baseband make this both IC more usefull for RC?

What is the brownout voltage for a AR500?
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Re: New FHSS from JR?

Postby Engineer » Sat Oct 23, 2010 4:49 am

I read somewhere that Spectrum has released a statement that they were not abandoning DSSS.
I think the truth is they are developing a FHSS system to sell in those countries that prohibit DSSS.
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Re: New FHSS from JR?

Postby jeffie8696 » Sat Oct 23, 2010 6:51 am

So the US gets stuck with DSM2? :(
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Re: New FHSS from JR?

Postby Engineer » Sat Oct 23, 2010 7:46 pm

You may want to read this:

http://www.zytrax.com/tech/wireless/fh_ds.htm

I don't know if Spectrum uses OFDM but it seems there is more to it than is immediately apparent.
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Re: New FHSS from JR?

Postby RCModelReviews » Mon Oct 25, 2010 9:02 pm

Spektrum uses DSSS for its DSM2 syste, not ODFM. What's more, Spektrum's spread is not as wide as most of the other DSSS systems and its channel allocation algorithm is flawed.

I predict that very soon now, DSM2 will be restricted to the domain of parkfliers. The continuing rise in noise on the 2.4GHz band (due to increased use of 2.4GHz for RC and other uses) will see it become too unreliable for use on larger/faster models which may pose a danger to life or property.

One only has to browse the other forums on the internet to see the rapidly rising levels of discontent from DSM2 users who, sometimes after years of trouble-free use, have started experiencing issues.
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