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Old 09-18-2010, 08:48 AM   #1
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Spektrum DSM what is it?
What is DSM?
DSM or Digital Spectrum Modulation is a form of digital spread spectrum modulation that had been developed and optimized for R/C use.

What channel will I be on?
The DSM system scans the 2.4GHz band and finds a channel that is not being used. Once an open channel is found the transmitter begins transmitting on that unused channel. The DSM System has an available spectrum of 79 channels. In the unlikely event that the spectrum is full, the 80th system will not connect or cause any interference, going into "hold scan" until a channel is free.

Won't other 2.4Ghz devices like phones and wireless computers cause interference?
No, the FCC requires that all 2.4Ghz DSS devises be "smart"- incorporating collision avoidance such that when any DSS system is turned on, it scans the 2.4GHz band until a channel that is not being used is found then begins transmitting on that unused channel.

What is the range?
Typical range is about 3000ft. depending on conditions.

What kind of response time does Spread Spectrum have?
Spectrum's DSM system is optimized to give the fastest possible response time of 5.6ms. Typical FM systems offer a response time of 12 to 18ms.

Will the DSM system affect or be affected by other transmitters on 27 or 75mhz or lap counting systems?
No. The DSM system operates in the 2.4Ghz ISM band and is well above the range of any equipment including lap-counting systems presently in use.

So I can just turn on my radio any time with out worry of getting or causing interference?

Sounds like a lot of magic to me. How do we know it will work?
The system has been extensively tested for months by Horizon and Team Losi drivers, in some of the worst areas in the country. It worked flawlessly in all cases. What's more, at the recent 1/10th World's in Kissimmee, FL, we had about two dozen units in use by many pro-class drivers. No one had a glitch. In fact, we had some drivers who were being glitched, switched to DSM, and their troubles went away.

What type of telemetry will be available?
The first optional telemetry module will include the ability to monitor Real-time engine temperature, engine rpm, speed in mph or kph, battery voltage, signal strength and individual lap times. We hope have this telemetry module available in early spring.

When the temp reading device comes out where will this data be displayed and will there be an option for an audio alert if the temp maybe gets to high while racing? How much more expensive will the "telemetry modules" be?
That data will be displayed on a handheld reader. A programmable tone alerting a "max temp" is likely. Pricing of the plug-in telemetry module (that plugs into the receiver) sensors, and the handheld reader are in the works. Stay tuned for more info!

Why is it "surface only"?
Surface and air operations are very different in nature. The current system is designed to be used only with surface models. The module will not work with air transmitters. Do not operate on any aircraft - parameters are different for flight. We are looking at these matters, but right now, there is no telling if reliable aircraft operations can be attained.

Are you going to develop this for aircraft?
Well, applying Spread Spectrum to airplane use involves different challenges from surface. The unit we are presenting today was four years in development. We will try, but whether aircraft Spread Spectrum ever happens in production or not by us is unknown right now.

Will the KO Helios module also work with the KO EX-1 Mars, KO Esprit, KO Vantage Esprit 2, etc.?
The Spektrum KO module will only fit the Helios and Mars. The two-stick systems use a different module that we may eventually manufacture if there is enough demand.

Will this be available for the Multiplex 707 series radios?
Sorry, but the modules will be available only for JR, Airtronics, Futaba/Hitec and KO pistol grip radios.

Will this device work for the Futaba 3PJ?
The Futaba Module fits the 3PK and the 3PJ systems

Will this device work on an Airtronics Caliber or Airtronics 3PS transmitter?
Sorry, these radios use a different type of module than the M-8 and presently there are no plans to produce these modules.

Will the Spektrum system work on the Hitec Lynx and the new Hitec SRX?
Yes, it will work with both. The new SRX system should be a hot seller - it'll be perfectly matched with the Spektrum system.

Will the Spektrum system work with the JR 756?
Yes. You should purchase the Spektrum JR R-1 module.

Do you have plans to support the JR XS3/XS3 Pro?
These are non-module systems, so the current DSM modules won't work.

Does the receiver have an antenna? If so, how long is it?
Yes, the stock antenna is 8.5" long making mounting the antenna easy. What is more, if you prefer a shorter antenna, you can carefully cut the Spektrum receiver antenna to just 3.6" and not lose any performance. This way, you can keep the antenna inside the body.

Does the antenna have to be vertical?
The antenna can be either vertical, or start out vertical and then bend to horizontal. The only condition to be avoided is having a completely horizontal antenna.

Can the DSM system be certified for use worldwide?
Since the Spektrum DSM system operates on the 2.4 GHz world-wide ISM band (ISM stands for Industrial Science and Medical), your Spektrum system is legal to operate in virtually any country throughout the world.

Is it legal for surface RC with the FCC, ROAR, IFMAR, etc.?
The DSM system is currently FCC legal and by January it will be ROAR and IFMAR legal.

Can this TX be modified for more than three channels?
Our first release is designed for three channels only.

Can the 75MHz channels that we are currently using be used at the same time with the DSM system when it comes out?
The DSM is on 2.4GHz and has absolutely no effect on 27MHz or 75MHz frequencies.

A lot of high end radios alternate ways of transmitting, for example on a Futaba you run PCM, FM, or HRS depending on your receiver, when I plug this into my Futaba radio, what setting would I leave it on, or does it matter?
It is essential that all transmitters be operating on PPM modulation.

What type of servo is usable with the receiver? For example, Futaba digital or analog servo? Is there a recommended/approved servo list?
All brands and types of digital and analog servos are compatible. For best results, we'd recommend a digital servo. Digital servos will provide the best chance of putting DSM's amazing 4096 resolution to best advantage. The result? You'll feel connected with your model like never before.

How many Spektrum-equipped cars can be run at the same time?
Up to 79 cars can be run at one time. As we all know, it's highly unlikely that this number will ever be exceeded, so from a practical point, you can run as many cars as you like.
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Old 09-18-2010, 08:50 AM   #2
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Thumbs up Re: Spektrum DSM what is it?

Do I have to buy a separate module for each receiver?
No. An infinite number of receivers can be bound to a single module. It's very similar to the 75 MHz system you own today.

What is the battery consumption, both on the transmitter and receiver side, for this system compared to PPM or PCM systems?
The DSM receiver current draw is slightly higher, at 40ma vs. an average of 10ma for FM receivers. The difference is negligible for most applications. On the transmitter side, the DSM module current draw is around 120ma vs. 280ma for an FM module. This provides vastly extended transmitter battery life for most applications.

Will the standard receiver (without optional telemetry parts) transmit anything back to the transmitter? I am asking because the rules for the class I compete in specifically prohibit this.
The receiver is actually a transceiver and does transmit a signal, but without the telemetry module no meaningful information is being transmitted.

What kind of warranty / return policy will the DSM module and transceiver have?
The Spektrum DSM system has a 1 year warranty.

What are the pros and cons of your system vs. the Nomadio?
Ours is available now and uses your existing 3-channel module base radio. We haven't seen an operating Nomadio system, so any performance differences would be pure speculation. But in general, our system allows your current radio - a radio with familiar software, features, ergonomics.

How would water affect this unit? Is it watertight? Can the unit be treated with Corrosion-X?
Like other receivers the DSM receiver in not water proof. We've had issues with Corrosion-X soaking in on PC boards and expanding the boards causing the components to lift.

Has this system been tested in 1/8-scale buggies for durability?
John Adams did most of the DSM testing using an 1/8th scale buggy which included racing every weekend for over 9 months without a single problem.

Will the DSM receiver fit in a NTC3 receiver box?

When turning on the transmitter and with more than one person using this system will it take the risk of my transmitter locking with somebody receiver if someone is also turning on their transmitters?
No. Each module has it's on unique identifier. When a receiver is bound to a specific module it will only listen to that module.

I see you say the mode for Futuba will fit the 3PJ transmitter. Will it fit the 3PJS with FP-TJ-FM module?
Yes it will.

I see your receiver only has 4 slots. How will I be able to connect future devices such as your speed and cooling sensor and still plug in my personal transponder?
The telemetry module will plug into the battery port of the receiver. As you will see soon, the telemetry module will have a port for battery input and additional spot for all telemetry sensors.

How does the receiver know which transmitter it should match? Is there any possibility of confusion if two transmitters are turned on at exactly the same time? How long does it take for the tx/rx to find a channel?
Each module has it's own code # (GUID) with over 4.2 billion possible codes. The receiver is programmed to recognize the GUID during binding. The receiver will then only listen to it's specific GUID and nothing else. It doesn't matter if two transmitters are turned on simultaneously. Each will search for it's own GUID. It takes about a second for the connection to take place.

How will the timing systems know who is who?
The lap times will be sent back to a hand held unit so your car will be the only car sending lap time to your hand held unit.

Let's say the radio locked on a channel for example ch 78 and I'm playing with my car, what will happen if someone turn on my channel. Will the radio freeze to acquire new channel?
The FCC requires that all Spread Spectrum radios be smart. Upon turning on a system the radio scans for an open channel and when one is found it transmits.

Will the reciever affect battery performance or duration in a race?
No. The receiver draws a mere 40 ma.

Should I remove the antenna from my 3pk transmitter?
It's up to you. The antenna is disabled but some drivers prefer the feel and balance with the antenna in.

What receiver battery voltage can I use?
3.2 to 9.6volts.

Will the spectrum work with an older Futaba Tx, namely the Field Force 3 (3UCP)? I note that the module for the 3PK is of the same size, but not sure if the internals are different.
No. The module is a different size.

All my radios are 2-channel and AM. Can the DSM system be installed on a 2-channel radio? Will the system work on an AM radio?
The DSM system will only work with module-based radios.

Would you recommend the system for someone like me who is more into the hobby aspect of R/C, and does not compete?
If the idea of never having radio interference sounds good then the DSM system is for you.
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Old 09-18-2010, 08:53 AM   #3
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Thumbs up Re: Spektrum DSM what is it?

Is the receiver reverse voltage protected?
Like all receivers it's not.

Can I use my personal transponder with the Spektrum system by plugging the personal transponder into the Spektrum receiver along with my servo and ESC?

It is stated in the FAQ that the receiver battery drain is 40ma Vs. 10ma of a FM receiver. That means that the current drain is 4X higher. Why do you state that the difference is negligible? On the same accord you state the battery consumption of the Tx is 120ma Vs. 280ma of a FM module, and now you state that the consumption is significantly less and will extend the battery life (this is ~2.4X). If my math is correct, the 4X reduction in Rx would significantly affect driving time. If a 1000mah battery last about an hr, does it mean now, that the DSM Rx will last 25min on a single charge due to the 4X battery drain??? Does it mean then, it is not possible to use in a Nitro main since most mains are 30 min and longer?
Under load high torque servos can draw well over 1 amp each. That 1000mah x 2 servos or 2 amps. Under normal loads these servos draw about 300-500mah. The additional 30 mah that the receiver uses is miniscule in comparison. With my 1/8th scale buggy I typically get about 1 hour and 40 minutes runtime with an 1100 mah receiver pack.

I have 3PK and Ex-1 Mars. What is PPM modulation? Is it PCM or FM? I use HRS receiver. How much response time do I lose by using the DSM module?
KO radios only offer FM (PPM) modulation. The HRS mode is compatible with the Spektrum module and response time is 5.6ms.

3PK currently has built in fail-safe feature, and Ex-1 Mars does not have it. Is the DSM module fail-safe function compatible with the fail-safe feature of 3PK? (i.e. can I adjust the fail safe from the 3PK menu?) If equipped with DSM module, does the Ex-1 Mars still need an external fail safe for running nitro cars?
Failsafe is built into every DMS module system. The failsafe servo and throttle positions are stored during the binding process when the system is used for the first time. The 3PK must be operated in FM (not PCM) mode and the preset failsafe position is set during binding by holding the wheel and throttle in the desired positions.

Are there different tranceivers for 3PK and Ex-1 Mars?
No the transceivers (receivers) are the same for all versions.

How will the telemetry module measure the rpm? Where will we build in the sensor and the magnet or the optical device? How will the telemetry module measure speed?
On gas cars a magnet will be installed in the flywheel. On electrics a small magnet will attach to the axle. This allow the calculation of RPM or speed.

With the DSM system, will there still be a need to run a fail-safe unit such as the Venom VSF?
Absolutely not. A fail-safe is built in.

Will the Spektrum work on Futaba FP-T3PG?

PPM modulation, I don't understand that, I have a KO Propo Helios, and would like to know what I should do, I have the radio in its stock setting, and have not touched anything about PCM or HRS.
The KO radios are always in PPM mode. The system is compatible in all forms of frame rates for KO including HRS. You won't have to change anything!

I have heard that at Cleveland many of the drivers running it took it out because the response time was too slow. Will this have been corrected in the retail units?
The prototype units that the Losi team used in Cleveland are very different than the production units. The Losi team found an issue that we previously hadn't discovered in testing outdoors. This issue caused the response time to be inconsistent as some packet information was being lost. The following week through further testing we discovered the specific problem and it was simple to correct. All production units will have corrected programming and hardware changes that prevent this issue.

Will it work with the Airtronics MX-3?
No. This is not a module radio.

Will the Spektrum work with the Airtronics Super Exzes radio?

Have you tested in a graphite car? Will your system eliminate those kinds of glitches as well?
We've been running the system in several graphite sedans and molded graphite buggies. All RF noise is generated below 300mhz. The system operates at 2400mhz and doesn't recognize these RF noisemakers.

Can you use a 6volt RX pack or does it have a 4.8volt pack?
Actually the receiver can handle up to 9.6 volts. The problem is that most servos can only handle around 7 volts.
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Old 09-18-2010, 08:55 AM   #4
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If I have two receivers and one module do I have to go through the steps to bind the receiver to the module every time I switch cars?
It's only necessary to bind a receiver to a module once.

Can I use 7.4-volt Li-Po batteries with the transceiver? Will it regulate the voltage to roughly 6 volts to the servos? It states the operating voltage is up to 9 volts.
The receiver will easily handle a 2-cell Li-Po pack. The voltage to the servos is non-regulated and some servos won't handle this higher voltage.

How well does the receiver work with a 4cell pack at 4.8 volt? Also, how will it work at 4.8 volt with the antenna at 3.6"?
The receiver performance is unchanged from 3.4 to 9.6 volts. The servo speed and torque is what's affected by using the different voltage packs.

Can this be used with a Traxxas top qualifier radio system?

You said that you could cut the antenna down to 3.6 inches from the 8.5 inches, is range the only thing that is affected doing that?
The range will be unaffected.

Does this system offer any built in failsafe for battery failure?
No. The telemetry system, coming soon, will offer the ability to monitor battery voltage in real-time.

What frequency would I indicate when I sign up at races?
Most racers are listing SS for spread spectrum and the race director ignores the frequency.

802.11b (g and n also) are required not to interfere with each other...FHSS (Frequency Hopping Spread Spectrum) devices "Avoid" interference by hopping through all the 79 channels in predefined hopping patterns. When they encounter a DSS signal, which occupies typically 6-7 of the "Channels" with wireless WAN equipment, single channels with less bandwidth intensive applications like telephones and apparently the Spektrum units, it still transmits on those channels, but only for 128us, then hops to the next channel in its sequence (Not necessarily the next sequential channel).
Well, all new Bluetooth 1.1 systems employ AFH (Adaptive Frequency Hopping) to build a table of free channels before it acquires the media. But let's say it's an old system. In that case, our engineer Paul Beard has built in technology to assure that the link stays solid. How does he do it? Hey, we can't give away all the secrets now, can we? But rest assured, you'll breeze through this without ever knowing it was there.

I think the likelihood of any of this equipment actually being deployed close enough to a track to capture the receiver's is minimal, but it is a possibility. With 128us of "Interference", I would think that would kick on the failsafe on the units, and could cause issues.
The Spektrum system uses directing sequencing spread spectrum not frequency hopping. When a frequency hopping system lands on the channel that you are operating on the duration is so short that it totally ignores the signal.

Is the 10ma for a standard receiver and 40ma for the Spektrum receiver per minute, per pack, per input (throttle/steering movement)? Please explain this in more detail. In a micro with 1050mah cells it could be big as well as in 45-minute gas mains.
40 mili-amps is the current rate. If the receiver is used for 1 hour then 40 mili amps hours are used. In 2 hours the receiver would consume 80 mili-amp hours ands so on. A high torque servo under load typically uses 1000 mili-amp plus. The 30 mili-amp increase is negligible, as I've raced in several 1-hour long gas mains using the Spectrum system.

If I have a vehicle with all analog servos (T-Maxx/Revo), will this system still work, and if so, what advantages from the DSM system would I lose?
The DSM system works with both digital and analog servo. The advantage of digital servos is the same for both conventional radio systems as well as the DSM system. Digital servos offer improved accuracy; faster response and improved holding torque but consume more energy.

Have these systems been tested in a 5th scale vehicle that is powered by a two-stroke engine with a spark plug and an ignition system? I understand that they have been tested in nitro vehicles, but gas engines with spark plugs are a totally different breed. We commonly fight interference.
Yes. The system was tested in a Harm car as well as gas boats. The system works flawlessly is these applications and the failsafe function gives an added measure of security for these giant scale vehicles.

Will there be more channels added to the Spektrum system? 79 Channels is a lot but it seams like the demand for this system is going to be so high more will be needed. At a big race more than 79 Racers will potentially own a Spektrum requiring radio impound.
The 2.4GHz band only has room for 79 channels.

Is this "Telemetry Module" going to an add-in or replacement for the original Spektrum Module that you sell now? Will the read outs be displayed on your handheld radio or on the new telemetry module itself?
The telemetry module will plug into your current receiver. A hand held unit will have four line of info.

Will the future telemetry modules be 100% compatible with the radio modules and transceivers already in the market?

Will it make a 45min to 1hour main for sedan nitro or 1/8th scale racing? These cars normally run 900mah battery pack.
I've run several 1-hour mains with my 1/8th scale buggy with plenty of battery to spare. I use 1000mAh Dynamite packs and typically get around 90 minutes of run time using high torque digital servos.

I noticed that the input voltage can be run as high as 9.6 volts. My current receiver max is 6 volts. Will it harm my servos if I run a 7.2 volt battery on your receiver?
Some servos are capable of using the high voltages. You'll need to contact the manufacture to see if the servos your using can be run at the higher voltages.

If the battery input polarity input is accidentally reversed will this hurt the receiver?
As with all receivers if the plug is reversed no damage will occur however reversing the plug does not reverse the polarity because the center wire is positive. If you truly reverse the polarity which would require swapping the positive and negative wires in the plug all receivers would be damaged.

Will it work for RC boats?

I have a Futaba 3PK. Will all my radio functions such as ABS and failsafe still work?
Yes. The failsafe will be set differently however.

With a Futaba 3PK on PCM run as the PPM mode you require, will the transceiver pass through enough current to run two Hitec HSR-5995TG servos?

Is It true that the only connections to the transmitter will be battery + and -, and the PPM signal? If it is, it must be possible to connect the set to the JR-XR6? Or any PPM transmitter?
I wish it were that simple! The coding of each transmitter is unique and requires specific programming in each module. Unfortunately just hooking up a module to a transmitter won't work!

I currently have a KO EX1 Mars. Will I have to re-wire my servo and speed control receiver connectors to match the new receiver?
The DSM receiver uses the industry standard 3-wire connector with signal, positive and negative as the lead sequence. Any servos not using the sequence will need to be changed however KO's new servos and ESC's have been using this order for at least the last 5 years.

Will the KO version work with older models of the EX-1 Mars or just the EX-1 Mars R?
All the Mars systems will work.

Can the receiver be installed into an aluminum case with the antenna sticking out?

Will Spektrum work with my Hitec Flash Procar 4?
No this is not a 3 channel module radio.
rc hobby.
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Old 09-18-2010, 09:14 AM   #5
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Re: Spektrum DSM what is it?

Great stuff. Did you write up all this stuff on your own??
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Old 09-18-2010, 10:46 AM   #6
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Re: Spektrum DSM what is it?

Originally Posted by Max View Post
Great stuff. Did you write up all this stuff on your own??
Looks like a copy/paste


of a q&a from mfg website. He has several of those infoposts on here.

Last edited by voyager_663rd; 09-18-2010 at 10:48 AM.
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