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JR stops the sales of 2.4 as of last night for upgrade

Old 02-17-2011, 04:07 PM
  #176  
tyrick69
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: blighty

just been on the JR MacGregor website and found this about the DMSS and DMSX, sorry if posted before.

When can I buy a new MacGregor/JR DSMX set?

We are waiting for information on whether JR will incorporate DSMX into their European specification sets. But such product development is sure to take some time, plus any additional CE testing that may be required.
In addition, all the shipments that JR have planned for the UK are either DSM2 or JR’s own 2.4 DMSS sets.
The combined effect is that CE approved JR DSMX sets are unlikely to be available for a considerable time. If you need a ‘frequency agile’ radio in the near future then it would be well worth considering JR’s new series of XG radios, which use JR DMSS. The XG7 will be available very soon, with the XG8 being released shortly later this year. For more information on JR DMSS radios, please click here:
MacGregor/JR XG7 DMSS Transmitter



no upgrade, but why not bin your over priced Tx and buy a new over priced Tx.


Will I be able to use DSMX receivers with my MacGregor/JR DSM2 transmitter?

Yes, JR DSM2 transmitters are forward compatible with DSMX receivers.
But DSM2 and DSMX Remote receivers are not interchangeable. So please use DSM2 remotes with a DSM2 receiver, and only use DSMX remotes with a DSMX receiver.
In summary, please continue to enjoy using your JR DSM2 set.


unless i read that wrong, that's not what it said on the Horizon link posted earlier. they said DSMX Tx will work with DSM2 Rx's.

quote from Horizon's web site

Should I purchase the DSMX add-on?

Before investing in the DSMX transmitter add-on, there are several important facts about DSMX you need to know:

* To realize the full benefits of DSMX technology you must have both a DSMX Transmitter and a DSMX Receiver
* DSM2 transmitters are compatible with DSMX receivers. Likewise, should you add-on to a DSMX transmitter, the DSM2 receivers you have now will be compatible with it.
* Because DSM2 and DSMX share the same wide-band DSSS foundation, all Spektrum users will enjoy superior range, speed and precision whether theyre using DSM2 equipment, DSMX equipment or a combination of both.
* The difference a DSMX system makes is only apparent when hundreds of 2.4GHz systems are in use at once.* DSM2 users who rarely, if ever, fly in big events or other exceptionally ''noisy'' 2.4GHz environments may find the DSM2 equipment they have now is all they will ever need.


They're referring to the satellite receivers. A DSM2 satellite receiver cannot be used with a DSMX main receiver and vice versa.
Old 02-17-2011, 04:59 PM
  #177  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

thx, my bad, should learn to read.

U.S upgrade 79 bucks, hate to think what the U.K one will be.
Old 02-17-2011, 06:27 PM
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Mitchell-RCU
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

With the 3 year warranty that JR is so proud of you would think that they would at least update at no charge any radio bought in the last year. I sent my Futaba 14MZ in back in september. At that time it was five years old. They updated the software, updated several of the parts internal to the transmitter, and sent it back with a new battery. They charged me nothing.

Mitchell
Old 02-17-2011, 06:41 PM
  #179  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

FOR SALE ONE SEASON OLD JR9303 2.4 ghz transmitter dsm2  i paid near $600.00 with a reciever then they came out with the 9503 a month after i bought my system, cheaper than the 9303, now this!!!!! i'm just about to go get my no code technician and go ham freq.
Old 02-17-2011, 07:56 PM
  #180  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: ram3500-RCU


ORIGINAL: ira d

I am not confused about Horizon and JR at all. If JR really wanted to make their entire line available to the
U.S. im sure they could find a way to do so. The fact is if DMSS suddely became available a lot of the
current JR customers would be reluctant to purchase because their current gear wouldn't work with it.
I don't agree. Futaba already has 2.4 systems that won't work with each other. Nothing new here. I really don't think DMSS is necessary. How many guys do any of you actually know, who use DSM2, that have had problems. I know none. I have heard of cases, just as with any other system, but we are not talking about massive problems her. I think the percentages would be far less than with narrow band users, if the numbers could be compiled and made public. They will never be, but the fact it, time after time, I go and come from fields with no issues, as do the vast majority of us. What is the big deal?
You are correct about Futaba and the same is true for Airtronics as well in the sense that their lower end 2.4 sytems use a different protocol than their higher end systems,
however the the upper end systems are backwards compatible in both cases. OTOH I suppose JR could make a DMSS system that would also work with DSM2.

I do know and know of some guys that have had problems with DSM2, At my field the DX7 was very popular 2-3 years ago while a few still use it most have went to Airtronics
and Futaba.
Old 02-17-2011, 08:22 PM
  #181  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

ORIGINAL: ram3500-RCU


That is fine Bob, but why does that bother you? As far as it being a 'requirement', it is not. All of the JR receivers only have two antennas. And you don't need to use three or four to make the system work.

Many guys set up there expensive planes with more than one RX for redundancy. What is the problem? And if you do that with your system, you will be paying much more than 30 bucks for that redundancy.

I do monitor the reception of each RX, as well as battery health, servo health, engine performance, airframe integrity, mechanical devices, and more. No big deal to me. I want me planes to last, and be as safe as I can make them.
OK, so you would fly a DSM2/DSMX system with only one receiver? I don't think that would be a good idea...

Redundancy only increases reliability *if the system can operate with only one of the multiple components* That is, if your system *requires* two or more of a certain component, then your system is not as reliable as a system that requires only one. Its a basic tenant of reliability analysis. If the Spek DSM2/DSMX system would work perfectly well with one RX and they *then* gave you the opportunity to increase that by spending only $30 to double the reliability, I'd be all over it. The fact is though, you *have* to have multiple RXs (and fiddle with their placement, etc.) to get a reliable link and that means that their system is inherently less reliable than a system that can work with only one RX.

The perfect aviation example is the "light twins" that Cessna and Piper made in the 70s-80s. They had two engines, but the problem was, they were extremely marginal on one engine. Two engines means twice the engine failure rate as a single, but in this case, when one of the two engines quit, the airplane crashed. The end result was that their safety record (and reliability) was much worse than single engine aircraft and they eventually went the way of the Edsel...

The manufacturers did try a lot of stuff to try and save them, advertising, tweaking this and that, but the fundamental issue never went away and so, after awhile, when better singles came out, those models went away...

If DMSS ever comes to the entire market and it works as well as the other major brand 1 RX system out there (and as well as the other JR stuff works), then Spek DSMX, Y, Z etc. is headed down the same path...

Bob
Old 02-17-2011, 10:50 PM
  #182  
karl hibbs
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

it all comes down to DSM2 being compatible with anything new, HH does not want to leave anybody hanging. the crazy thing is JR has a proven rock solid system,DSMJ, but HH didn't go for it. it sounds like the DSMX system is rock solid and time will tell.
Old 02-17-2011, 11:48 PM
  #183  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

I look at it like this.

No matter what system you have If it works well and DSM2 certainly does for me who cares what it is called just use it and enjoy

Dennis
Old 02-18-2011, 02:35 AM
  #184  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


[/quote]

OK, so you would fly a DSM2/DSMX system with only one receiver? I don't think that would be a good idea...

Bob
[/quote]
Bob,
I have 5 planes and 4 helis (admittedly all smaller electrics) all using the ar6100 which is only one receiver. I've never had an issue with any of these aircraft that was related to the rf link. I do use the ar6200 which uses one satellite on my Raptor 30 and GP Revolver but there are thousands of people using the ar6100 which is only one receiver.
Rick
Old 02-18-2011, 02:58 AM
  #185  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

First let me say i do not own any JR/Spectrum radios but i have friends that do and i have seen them lose there bind with the DSM 2 radios and so far most have been on the ground before a flight but there has been a few in the air while flying foammies which they fell to the ground with little or no damage. I was at my local hobby shop yesterday and they where talking about it and they showed me a flier from JR/Spectrum telling about the upgrade and how it address the issues of brown outs or better known as losing your bind. this said that DSMX address this issue but only if you update both the transmitter and rec. I hope for everyone that owns JR/Spectrum that they get the right information out to everyone so they can make a informed choice that works for them.

Allen
Old 02-18-2011, 02:59 AM
  #186  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

Yes but thats for a parkflyer. and like u said your flying smaller elec. so thats fine, but try putting one in a gas or nitro plane and fly some nice big cycle's at your flying field and see what will happen.[&:]
Old 02-18-2011, 03:08 AM
  #187  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

You missed my point yes the the ones that fell where foammies but the others where full size rec and 120 size planes or larger so what i am reporting is for both and what i was trying to get accross is that they are admitting that they have a problem and they only way to fix it is to update both your transmitter and rec.

Allen
Old 02-18-2011, 03:10 AM
  #188  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: ka9fax

Yes but thats for a parkflyer. and like u said your flying smaller elec. so thats fine, but try putting one in a gas or nitro plane and fly some nice big cycle's at your flying field and see what will happen.[&:]
Your right, I would not and that's why I stated that I only use them in smaller electrics. As far as the need for satellites with DSM2, the explanation that I was given a few years ago is that because of the very short wavelength of the 2.4GHz signal, 2.4GHz systems are much more susceptible to shadowing than 72MHz systems. With a DSSS systems, if the receiver is shadowed behind an engine, battery, carbon fuselage, etc.. it can actually mistake a reflected signal as the actual signal which would appear as a glitch, unintended input, or delayed input. FHSS systems are not really susceptible to reflected signals because by the time the reflected signal reaches the receiver, the transmitter and receiver have already hopped to a new frequency, thus the reflected signal is ignored. With the Spektrum system, the main and satellite receiver are always talking to one another and use the strongest signal that's being received by either the main or satellite thus reducing the potential for reflected signals to cause glitching because any direct signal will have more strength than a reflected signal.
Old 02-18-2011, 03:42 AM
  #189  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

I think I will wait for Mikey to buy and try it. A public demo by Horizon Hobby at a place like Joe Nall with 100 transmitters turned on with a mix of JR, Futaba, Airtronics and Hitec to properly replicate a busy crowded event.
Old 02-18-2011, 05:17 AM
  #190  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: tyrick69

With a DSSS systems, if the receiver is shadowed behind an engine, battery, carbon fuselage, etc.. it can actually mistake a reflected signal as the actual signal which would appear as a glitch, unintended input, or delayed input. FHSS systems are not really susceptible to reflected signals because by the time the reflected signal reaches the receiver, the transmitter and receiver have already hopped to a new frequency, thus the reflected signal is ignored. With the Spektrum system, the main and satellite receiver are always talking to one another and use the strongest signal that's being received by either the main or satellite thus reducing the potential for reflected signals to cause glitching because any direct signal will have more strength than a reflected signal.
Sorry, but that's wrong - on a number of different issues. The main one being that multipath (which is what its called) does not result in "glitches" although if its bad enough, it can result in a packet being lost. Frequency hopping systems experience multipath as well (its a function of the frequency), its just that if multipath is bad enough to block the transmission, then when the system moves to another frequency, it changes the signal path enough (usually) that the transmission will get through.

Since DSMX is now "frequency agile" does that eliminate the need for the satellite RXs? Again, its not a function of what transmission mechanism you use, its a function of how good your receiver is... The chipset used in the Spektrum RX's (at least according to the info. that is out there - I haven't taken a Spektrum RX apart) was designed for short-range communication is USB-type devices, not long range radio control.

Bob
Old 02-18-2011, 05:19 AM
  #191  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: Kometfreak

I think I will wait for Mikey to buy and try it. A public demo by Horizon Hobby at a place like Joe Nall with 100 transmitters turned on with a mix of JR, Futaba, Airtronics and Hitec to properly replicate a busy crowded event.
However, as has been discussed before, if you turn on enough transmitters in the 2.4 GHz band, *all* of the above systems will have problems. Nobody knows for sure right now, what that number is, but I'd bet that with anything around 100 or more, and things are going to get dicey...

Bob
Old 02-18-2011, 06:08 AM
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

ORIGINAL: rhklenke


ORIGINAL: tyrick69

With a DSSS systems, if the receiver is shadowed behind an engine, battery, carbon fuselage, etc.. it can actually mistake a reflected signal as the actual signal which would appear as a glitch, unintended input, or delayed input. FHSS systems are not really susceptible to reflected signals because by the time the reflected signal reaches the receiver, the transmitter and receiver have already hopped to a new frequency, thus the reflected signal is ignored. With the Spektrum system, the main and satellite receiver are always talking to one another and use the strongest signal that's being received by either the main or satellite thus reducing the potential for reflected signals to cause glitching because any direct signal will have more strength than a reflected signal.
Sorry, but that's wrong - on a number of different issues. The main one being that multipath (which is what its called) does not result in ''glitches'' although if its bad enough, it can result in a packet being lost. Frequency hopping systems experience multipath as well (its a function of the frequency), its just that if multipath is bad enough to block the transmission, then when the system moves to another frequency, it changes the signal path enough (usually) that the transmission will get through.

Since DSMX is now ''frequency agile'' does that eliminate the need for the satellite RXs? Again, its not a function of what transmission mechanism you use, its a function of how good your receiver is... The chipset used in the Spektrum RX's (at least according to the info. that is out there - I haven't taken a Spektrum RX apart) was designed for short-range communication is USB-type devices, not long range radio control.

Bob
"Multipath propagation occurs when an RF signal takes different paths when propagating from a source (e.g., a radio NIC) to a destination node (e.g., access point). While the signal is en route, walls, chairs, desks, and other items get in the way and cause the signal to bounce in different directions. A portion of the signal may go directly to the destination, and another part may bounce from a chair to the ceiling, and then to the destination. As a result, some of the signal will encounter delay and travel longer paths to the receiver.

Multipath delay causes the information symbols represented in an 802.11 signal to overlap, which confuses the receiver. This is often referred to as intersymbol interference (ISI). Because the shape of the signal conveys the information being transmitted, the receiver will make mistakes when demodulating the signal's information. If the delays are great enough, bit errors in the packet will occur. The receiver won't be able to distinguish the symbols and interpret the corresponding bits correctly.

When multipath strikes in this way, the receiving station will detect the errors through 802.11's error checking process. The CRC (cyclic redundancy check) checksum will not compute correctly, indicating that there are errors in the packet. In response to bit errors, the receiving station will not send an 802.11 acknowledgement to the source. The source will then eventually retransmit the signal after regaining access to the medium.

Because of retransmissions, users will encounter lower throughput when multipath is significant.
The reduction in throughput depends on the environment. As examples, 802.11 signals in homes and offices may encounter 50 nanoseconds multipath delay while a manufacturing plant could be as high as 300 nanoseconds. Based on these values, multipath isn't too much of a problem in homes and offices. Metal machinery and racks in a plant, however, provide a lot of reflective surfaces for RF signals to bounce from and take erratic paths. As a result, be wary of multipath problems in warehouses, processing plants, and other areas full of irregular, metal obstacles.

802.11b suffers the most

When comparing FHSS (frequency hopping spread spectrum), DSSS (direct sequence spread spectrum) and OFDM (orthogonal frequency division multiplexing), DSSS used by 802.11b networks is the most susceptible to multipath propagation. The frequency elements of a wider band signal will vary greatly in terms of reflectivity as they encounter obstacles in the facility. FHSS uses relatively narrow channels (1 MHz) and changes transmit frequency often, making it difficult for multipath to occur. OFDM (used by 802.11a and 802.11g) transmits information on many narrow subchannels, which also reduces the impacts of multipath.

DSSS, however, transmits information continuously over a relatively wide channel, nearly 30MHz. This leaves enough room for lower frequency elements of the DSSS signal to reflect off obstacles much differently than the higher frequency elements of the signal. The differences in reflectivity will cause a wider range of signal paths. Thus, 802.11b systems are more susceptible to multipath delays."

Source: http://www.wi-fiplanet.com/tutorials...AN-Problem.htm

Maybe glitch wasn't the right word to use but if the error correction and subsequent retransmission of the data results in a delay, this could be viewed as a glitch by some, certainly latency by others. The fact that I may have had some of the terminology wrong, doesn't negate the explanation for the use of satellite receivers. I also understand that this article is in reference to WLAN networks but the theory is the same.
Old 02-18-2011, 07:06 AM
  #193  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

Of course you are using a discussion of 802.11 to bolster your defense of DSMX and the two are very different. In fact, with the new "frequency hopping," DSMX is now *very* close to the transmission mechanisms used by other 2.4GHz units. You didn't answer the question, if the reason for the satellite RXs is because of multipath, why does DSMX still need them? The answer has more to do with the gain and selectivity of the receivers rather than multipath..

If course, my bottom-line question still remains, why can't US customers get DMSS?

Bob
Old 02-18-2011, 07:15 AM
  #194  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

ORIGINAL: rhklenke

Of course you are using a discussion of 802.11 to bolster your defense of DSMX and the two are very different. In fact, with the new ''frequency hopping,'' DSMX is now *very* close to the transmission mechanisms used by other 2.4GHz units. You didn't answer the question, if the reason for the satellite RXs is because of multipath, why does DSMX still need them? The answer has more to do with the gain and selectivity of the receivers rather than multipath..

If course, my bottom-line question still remains, why can't US customers get DMSS?

Bob
Bob,
I am not defending DSMX. The question was asked earlier in the forum why the Spektrum system needs satellite receivers at all when these other systems did not. I was comparing DSSS to FHSS in an attempt to answer that question. I don't know the answer to your question regarding DSMX nor do I really care. Ask John Redman or someone with more knowledge of the system. I don't know why some (most of whom don't even use the system) spend so much time and energy trying to disprove it's validity. If you don't use it, why do you care? I don't care if you fly Futaba, Hitec, Spektrum, Airtronics, WHATEVER. If it works for you, that's great, I'm happy for you. Just let it go and have fun flying for Pete's sake.
Old 02-18-2011, 07:24 AM
  #195  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

Holy crap. There's way too much information in this thread. I'm outta here on this one. I wish someone would start a thread labeled "For Techies Only" and post all this technical stuff there and leave us morons something we can understand in the original thread.
Old 02-18-2011, 07:30 AM
  #196  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: tyrick69

Bob,
I am not defending DSMX. The question was asked earlier in the forum why the Spektrum system needs satellite receivers at all when these other systems did not.
Again, that's my point, you didn't answer the question - you put some information out there that does (or does not) apply to all systems.

Yes, I have used DSM2 and its too cold to do much flying yet, still in building mode for next season...

Bob
Old 02-18-2011, 07:33 AM
  #197  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: rhklenke


ORIGINAL: tyrick69

Bob,
I am not defending DSMX. The question was asked earlier in the forum why the Spektrum system needs satellite receivers at all when these other systems did not.
Again, that's my point, you didn't answer the question - you put some information out there that does (or does not) apply to all systems.

Yes, I have used DSM2 and its too cold to do much flying yet, still in building mode for next season...

Bob
Bob,
The question about the satellite receivers was in reference to DSSS vs FHSS. If your looking for someone to say that DSSS is inferior to FHSS, in my opinion, it is definitely inferior in terms of it's resistance to multi-path. From the information I gathered from watching the video on Horizon's site, DSMX appears to be more of a hybrid of DSSS and FHSS and not a true FHSS system, thus I would suppose that's why DSMX receivers still employ a satellite.
Old 02-18-2011, 08:19 AM
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: tyrick69


Bob,
The question about the satellite receivers was in reference to DSSS vs FHSS. If your looking for someone to say that DSSS is inferior to FHSS, in my opinion, it is definitely inferior in terms of it's resistance to multi-path. From the information I gathered from watching the video on Horizon's site, DSMX appears to be more of a hybrid of DSSS and FHSS and not a true FHSS system, thus I would suppose that's why DSMX receivers still employ a satellite.
FASST is a DSSS/FHSS hybrid approach too - as are probably many of the other 2.4 systems out there - no satellites... DSSS is *not* the reason for the satellites!

Bob
Old 02-18-2011, 08:48 AM
  #199  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade


ORIGINAL: rhklenke

. If the Spek DSM2/DSMX system would work perfectly well with one RX and they *then* gave you the opportunity to increase that by spending only $30 to double the reliability, I'd be all over it. The fact is though, you *have* to have multiple RXs (and fiddle with their placement, etc.) to get a reliable link and that means that their system is inherently less reliable than a system that can work with only one RX.
You obviously never flew the original AR6000 reeiver. It worked like an absolute champ and no satelltites. The satelite receivers were added to reduce the chances of shadowing by batteries, motors etc.

Old 02-18-2011, 08:59 AM
  #200  
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Default RE: JR stops the sales of 2.4 as of last night for upgrade

Bob , you cant get DMSS because it is not compatible with DMS2.

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