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Old Mar 16, 2013, 01:22 PM
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United States, PA, Butler
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What is DSM2?

I'm considering buying a very inexpensive radio that is DSM2. I don't know much about the terminology so can someone enlighten me as to what the difference is between DSM2 and spektrum and wether or not its a bad idea or not? The radio I'm considering is the OrangeRx T-SIX 2.4GHz DSM2 6CH Programmable Transmitter (Mode 2 version)
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Old Mar 16, 2013, 01:32 PM
Air, Ground & Water
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DMS/DMS2/DSMX is Spektrum Protocol used with their radios and receivers.

What you are considering is a brand that is compatible with Spektrum's DSM2 protocol.

It stands for Digital Spread Modulation. DSM2 is the second generation of Digital Spread Modulation, it offers significantly reduced latency and a faster response time than any brand of 27, 75, or 72MHz PCM system.
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Last edited by freechip; Mar 16, 2013 at 02:59 PM. Reason: spelling
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Old Mar 16, 2013, 02:17 PM
Proud to eat Kraut ;-)
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Spektrum/JR DSM2 test (Part 1) (8 min 45 sec)



Spektrum/JR DSM2 test (Part 2) (4 min 20 sec)
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Old Mar 17, 2013, 04:36 AM
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Romania, Dolj, Craiova
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A thing of the past.
The way how some irresponsible manufacturers thought to enter in RC like Russians with tanks in Eastern Europe, violating all the regulations that exist that times in 2.4Ghz band usage.
The origin of curiously very unknown and ignored crisis from 2007-2008 that brought RC to the limit to be baned from 2.4Ghz, at Cisco and other network equipment manufacturers request.
The reason of the biggest known number of plane crashes due to a RC system.
Not the last, a system whose usage is limited now at 10mW in the whole civilized world, except US.
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Old Mar 17, 2013, 01:21 PM
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Quote:
Not the last, a system whose usage is limited now at 10mW in the whole civilized world, except US.
Not so, EIRP of 100mW in Europe due to relaxation of the true interpretation of the regulations.
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Old Mar 17, 2013, 02:01 PM
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Romania, Dolj, Craiova
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100mW if FH, DSM2 is not

"2.4GHz Band
2400-2483,5 MHz, max 100mW e.i.r.p. and power spectral density max 100
mW/100 kHz e.i.r.p., if FHSS modulation or other appropriate mitigation techniques are used (otherwise 10 mW e.i.r.p.)" from FAI CIAM frequencies page.
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Old Mar 17, 2013, 03:26 PM
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Illinois
Joined Sep 2001
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DSM2 is still legal, Renato. There is no problem with owners using their equipment.

We all know you like to say this to try to help your dealership, but really, please try to be honest. Instead of running down your competition by claiming it's bad, why not show why the brand you sell is better than all the others?

Andy
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Old Mar 17, 2013, 05:29 PM
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DSM2 is a good system. The Orange TX is an awesome value.
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Old Mar 18, 2013, 01:30 AM
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Quote:
Originally Posted by AndyKunz View Post
DSM2 is still legal, Renato. There is no problem with owners using their equipment.

We all know you like to say this to try to help your dealership, but really, please try to be honest. Instead of running down your competition by claiming it's bad, why not show why the brand you sell is better than all the others?

Andy
I didn't say it's illegal, just limited to 10 mW to almost all world.

What has to do my small watches business with bashing this system ?
So, once again, for the last time: I don't sell anything in this field. Try explain otherwise my attitude.
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Old Mar 18, 2013, 08:44 AM
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Eva Liu, Sales Manager at Frsky Electronic Co., Ltd. said, "Mr. Renato Aranghelovici is FrSky authorized Romania dealer" <snip>.

You say that it must be 10mW when in fact it is perfectly legal at 100mW in Europe.

Oh wait, when you said "limited now at 10mW in the whole civilized world, except US" I guess you mean that EU is not civilized.

I think you might find that statement offends many in EU who think they are more civilized that us "American Cowboys."

Andy
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Old Mar 18, 2013, 09:33 AM
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Other manufacturers, probably less civilized, don't forget to specify in their radio manuals:

"Ausgangsleistung ... ≤ 100 mW *innerhalb Deutschland dürfen nur 10mW eingestellt werden"

They might know legal regulations better than you probably... may I see such paragraph in a DSM2 radio manual, printed for an EU country ?

The discussion has no sense, if the regulation is now known to FAI and, as an effect, it is forbidden to compete with a non hopping system set on 100mW , don't you think you are debating with the wrong person ?
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Old Mar 18, 2013, 09:56 AM
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If the other person didn't have a vested interest in spreading disinformation, perhaps, but since we know you are a Frsky dealer and try to put down your competition instead of trying to find something good about your own products, I think you are a perfect person not only to debate, but also to call out.

Not everybody competes, in fact, a miniscule fraction of hobbyists do, so the fact that DSM2 is still legal to use in Europe as well as in civilized countries is of no consequence to them.

Andy
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Old Mar 18, 2013, 10:11 AM
Radio? Screwdriver!
United Kingdom, England, Bristol
Joined Aug 2011
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Hmm, I seem to remember this sort of conversation before...

Are we talking about v1.8.1 of ETSI 300 328 again? For those that are just reading along and don't know what that document is, it is one of the standards that 2.4GHz equipment has to pass to get CE certification in the EU.

Quote:
4.2.1 Modulation types
The present document defines two categories of Wide Band Data Transmission equipment:
• Equipment using Frequency Hopping Spread Spectrum (FHSS) modulation.
• Equipment using other types of wide band modulation (e.g. DSSS, OFDM, etc.).
All forms of wide band modulations,
So, in Section 4.3.2 it refers to the standards required for equipment that uses DSSS modulation.

In particular of interest to this conversation:
Quote:
4.3.2.1 RF output power
This requirement applies to all types of equipment using wide band modulations other than FHSS.
4.3.2.1.1 Definition
The RF output power is defined as the mean equivalent isotropic radiated power (e.i.r.p.) of the equipment during a
transmission burst.
4.3.2.1.2 Limit
For adaptive equipment using wide band modulations other than FHSS, the maximum RF output power shall be
20 dBm.

The maximum RF output power for non-adaptive equipment shall be declared by the supplier and shall not exceed
20 dBm. See clause 5.3.1 m). For non-adaptive equipment using wide band modulations other than FHSS, the
maximum RF output power shall be equal to or less than the value declared by the supplier.
This limit shall apply for any combination of power level and intended antenna assembly.
I can't see why any newly design DSM2 equipment won't still be legal...

No?

Someone correct me if I've missed something in that document. Of course, there may be other requirements that may be a problem - such as spectral density requirements, etc but iirc, these are the same as rev 1.7.1 anyway. The big other change is Listen-Before-Talk, which I if its not already implemented in DSM2 transmitters, its pretty straight forward to implement. E.g. IF (RSSI < -x dBm) THEN TransmitPacket

Si.
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Old Mar 18, 2013, 10:14 AM
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Illinois
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Quote:
Originally Posted by renatoa View Post
So, once again, for the last time: I don't sell anything in this field. Try explain otherwise my attitude.
"In this moment I offer the whole Frsky ACCST range, not Futaba TF line, at Asian prices, with full warranty and EU shipping." - see here: http://www.rcgroups.com/forums/showp...&postcount=155

So, which one is the truth, and which is a lie?

Andy
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Last edited by AndyKunz; Mar 18, 2013 at 10:29 AM. Reason: Correct link.
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Old Mar 18, 2013, 10:38 AM
KC
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United States, FL, Orlando
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Andy, the link you posted does not go to the statements in quotes.

edit. Ahh, corrected now.
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