[RCSE] Breaking the 40 Spektrum Radio Barrier
Spektrum RC splits the 2.4 GHz band into 80 slices. When you turn on a Spektrum transmitter it takes two of these slices at its channels for talking to the receiver. It has long been expected that if you tried to turn on the 41st Spektrum system, it would not be able to lock with the receiver. Some people have been concerned about this at large contests. Well, in this month's month's FlyRC they ran a test. They turned on 44 Spektrum DX7s operated them all at once, in close proximity. They all seemed to work fine. Then they turned on a JR 9303 2.4 GHz, the 45th transmitter. Know what? They all worked, all at the same time, with no problems. The JR was being used to fly planes in a test pattern so any issues could be observed. No issues. They also were logging flight information on the Spektrum reporter. No problems. Seems the 40 radio limit is not a limit after all. Cool! -- aeajr aeajr's Profile: http://www.rcgroups.com/forums/member.php?u=16056 View this thread: http://www.rcgroups.com/forums/showthread.php?t=835893 RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Breaking the 40 Spektrum Radio Barrier
The German Open F3K contest scheduled for July is accepting and encouraging the use of 2.4Ghz. France simply has a lower allowable transmitter output and some 2.4Ghz sets have a France switch that cuts the output to the level allowable in France. Many of the things you've heard about 2.4Ghz systems that are sold in the US that are not legal in various parts of Europe are probably related to this power output level issue, but then you have to ask, who is running around with an output level meter to check on that. That is the extent of my knowledge on the issue but in general, I would think that that the Europeans are blessed with adequate common sense and any issues that might block or hinder 2.54Ghz RC usage will be dealt with. Phil - Original Message - From: Bill Bunny Kuhlman [EMAIL PROTECTED] To: soaring@airage.com Sent: Friday, March 21, 2008 3:39 PM Subject: Re: [RCSE] Breaking the 40 Spektrum Radio Barrier While 2.4 GHz virtually eliminates interference issues, it should be noted that using this frequency in nations other than the U.S. may be increasingly problematic. I understand Germany has just put out a notice that RC is not to use the 2.4 GHz band, stating it is a national security issue. Belgium seems to have banned RC use of 2.4 GHz a couple years ago. Additionally, I just read a notice that France has limited power output of 2.4 GHz systems to 10 MW, as opposed to the 100 MW standard elsewhere. (One of our South African correspondents has stated Horizon Hobbies put out a letter stating that Spektrum sets made for use in the US are illegal in South Africa and a number of European countries.) Late last year, CIAM, the FAI body, was discussing upcoming legislation in Europe as it applied to 2.4 GHz RC. Seems the EU is getting a lot of pressure from WiMax operators to ban RC use of the frequencies. We'd appreciate hearing from anyone who has accurate current information on this topic. -- Bill Bunny Kuhlman RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Breaking the 40 Spektrum Radio Barrier
This is likely to start an IT geeky discussion but its worth mentioning. This brings up my very first concern on this band. My concern was that there are literally hundreds of gain boosting products on the market for 2.4 Wimax technology. Many of these devices such as home routers and small to large business line of sigh WiMax shots get amped up by the IT department. I know I found a 10X gain booster for my home system. Now considering that most of these routers have their own range of channels and can switch between dedicated channels to a mode that basically hops channels until things hook up you can begin to see the challenge in this unregulated band in areas of high population. Luckily most of the units have a 150 foot range but with a major gain booster that could go up to 1000 feet. I improved mine enough to setup a WIDE area network between my house and my neighbors house about 900 feet away. I can get a small boost using a 2.4 aircard in a laptop and a pringles canthe technology is out there and the freq is unregulated. Consider the carnage potential at the next major event when some Frankenstein WIMAX WIFI solution fires up... not currently a challenge with multiple Chanel acquisition but without regulation how long will it be until something is created that flies through the channels in order to create better security for the ever increasing IT security threats? 900MhZ phones had that in the 90's and Sanyo is touting DSS at 2.4 as well. Its slightly different technology but my concern is that its simply not regulated. So while I will still move to 2.4 next year I will be paying close attention to this band. Let the bashing begin... http://ca.sanyo.com/en-CA/communications/cordless/special_features.cfm On Fri, Mar 21, 2008 at 12:39 PM, Bill Bunny Kuhlman [EMAIL PROTECTED] wrote: While 2.4 GHz virtually eliminates interference issues, it should be noted that using this frequency in nations other than the U.S. may be increasingly problematic. I understand Germany has just put out a notice that RC is not to use the 2.4 GHz band, stating it is a national security issue. Belgium seems to have banned RC use of 2.4 GHz a couple years ago. Additionally, I just read a notice that France has limited power output of 2.4 GHz systems to 10 MW, as opposed to the 100 MW standard elsewhere. (One of our South African correspondents has stated Horizon Hobbies put out a letter stating that Spektrum sets made for use in the US are illegal in South Africa and a number of European countries.) Late last year, CIAM, the FAI body, was discussing upcoming legislation in Europe as it applied to 2.4 GHz RC. Seems the EU is getting a lot of pressure from WiMax operators to ban RC use of the frequencies. We'd appreciate hearing from anyone who has accurate current information on this topic. -- Bill Bunny Kuhlman RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Breaking the 40 Spektrum Radio Barrier
Thank the wireless network guys for pushing for a ban on 2.4 for models. Burn your Cisco routers. Bill Bunny Kuhlman wrote: While 2.4 GHz virtually eliminates interference issues, it should be noted that using this frequency in nations other than the U.S. may be increasingly problematic. I understand Germany has just put out a notice that RC is not to use the 2.4 GHz band, stating it is a national security issue. Belgium seems to have banned RC use of 2.4 GHz a couple years ago. Additionally, I just read a notice that France has limited power output of 2.4 GHz systems to 10 MW, as opposed to the 100 MW standard elsewhere. (One of our South African correspondents has stated Horizon Hobbies put out a letter stating that Spektrum sets made for use in the US are illegal in South Africa and a number of European countries.) Late last year, CIAM, the FAI body, was discussing upcoming legislation in Europe as it applied to 2.4 GHz RC. Seems the EU is getting a lot of pressure from WiMax operators to ban RC use of the frequencies. We'd appreciate hearing from anyone who has accurate current information on this topic. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Breaking the 40 Spektrum Radio Barrier
WiMAX uses frequencies between 2 and 11GHz but as the 2.4 and 5.2 bands are unlicensed they're likely to get used for testing. Since spectrum is now something you buy, sell and hoard just like any other commodity its likely that everyone will be squeezing into what unlicensed space there is to save having to pay toll charges to whoever's got the license this month. I can't imagine what national security issues Germany has with this band. I know that the width of this band varies slightly by country which is why there's been a (relatively futile) attempt to configure the chipset drivers for use in one country or another. (Its required for stuff sold in a country but the whole thing falls flat on its face because people carry laptop computers around with them -- we have a conflict between a government desire to control stuff and what happens in real life.) There's also some conflict between the parts of 5GHz band and certain airport approach radars (a slight SNAFU by the FCC, I believe) that results in what could be called the mother of all kludges in the drivers for 802.11a interfaces in access points. But overall the whole reason why we're stuck in this band along with microwave ovens and industrial equipment is that it was supposed to be useless -- these frequencies are absorbed by water (which is why the signal won't go through you)(but it allows you to cook things provided they've got water in them). Google lost out on the recent spectrum auction which was a bit sad because what they were pushing for was blocks of spectrum that could be used for used for open access -- unregulated applications (like ours). They also wanted the FCC to impose a condition that the winning bidders were required to resell spectrum at wholesale prices, the intent being to prevent a handful of companies from grabbing the spectrum and sitting on it to maintain a monopoly. Unfortunately we went with the 'usual suspects' getting the spectrum so don't expect any rapid changes in spectrum use. Martin Usher PS -- It wasn't the wireless network guys. The real culprits are the mobile phone companies. Open spectrum threatens their market. Mike Lachowski wrote: Thank the wireless network guys for pushing for a ban on 2.4 for models. Burn your Cisco routers. RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Breaking the 40 Spektrum Radio Barrier
Actually, this was posted on the original 2.4Ghz thread, its just that nobody responded to the post. I too would be interested in any feedback on that point. I have no personal knowledge about the topic. Here is a link to the post: http://www.mail-archive.com/soaring@airage.com/msg105745.html And below is a cut and paste of the text of the post: I printed out the following post by Mike Lachowski. It specifically refers to JR 2.4Ghz systems. I can't remember where it was originally posted, maybe on RCSE, maybe on RCgroups: -- posted by Mike Lachowski: And on the 40 channel topic, the original DX-6 transmitted continuously on each of two channels in the band. The newer stuff only transmits for very short periods of time. You can see it on a wireless LAN sniffer if you know anyone who has one. So even if you have two pilots using the same two frequencies, they will each only be using a small part of the available bandwidth. end quote - Original Message - From: Ed Anderson [EMAIL PROTECTED] To: Soaring@airage.com Sent: Friday, March 21, 2008 1:21 PM Subject: [RCSE] Breaking the 40 Spektrum Radio Barrier Sorry if this is a repeat, but I did not see it come through the first time and I thought it was important. Breaking the 40 Spektrum Radio Barrier Spektrum RC splits the 2.4 GHz band into 80 slices. When you turn on a Spektrum transmitter it takes two of these slices as its channels for talking to the receiver. It has long been expected that if you tried to turn on the 41st Spektrum system, it would not be able to lock with the receiver. Some people have been concerned about this in terms of large contests. The earlier report about the International Heli competition where there were reported to be over 400 2.4 GHz radios had no problems but no one could verify how many were turned on at any time. There was no no impound for 2.4 GHz systems. Well, in this month's FlyRC they report on a test that was run. They turned on 40 Spektrum DX7s operated them all at once, in close proximity. They all seemed to work fine. Then they turned on a JR 9303 2.4 GHz, the 41st transmitter and had no problems. Then they took it up to 44 DX7s plust the JR and still no problems They flew test planes in predictable patterns to see if they saw any kinds of problems and there were none. I believe they did note a slight range check reduction but still within spec. They also were logging flight information on the Spektrum reporter. No problems. Seems the 40 radio limit is not a limit after all. Cool! I read elsewhere that the original DX6 transmits all the time, but the DX7 and the rest of the DSM2 systems transmit on about a 10% duty cycle. I can't say if that is an on demand thing and I can't verify that this is true, but this test seems to suggest some kind of time sharing/channel sharing going on. Ed Anderson RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Breaking the 40 Spektrum Radio Barrier
Its the same as a wireless network. In this network all the stations transmit short packets of data only when they need to. The actual bandwidth (amount of data) needed to control a model plane is very small compared to the amount you could get on one of those channels if it was running full time so there's no need to send data all the time. A bonus is that the transmitter will consume less power. The snag -- and its one we've not really addressed because this is one of the few outdoor applications in this band -- is that our R/C isn't the only user of the band. Wireless networks will probably suffer the most from interference (that is, they'll wait for the R/C transmitter to stop transmitting before transmitting themselves (assuming they're not an access point, that is)) but things like cordless phones may be a bit less discerning. One thing you should bear in mind is if this stuff behaves like wireless networks then the transition from Working Great to PoS will be quite abrupt. Martin Usher Ed Anderson wrote: Sorry if this is a repeat, but I did not see it come through the first time and I thought it was important. I read elsewhere that the original DX6 transmits all the time, but the DX7 and the rest of the DSM2 systems transmit on about a 10% duty cycle. I can't say if that is an on demand thing and I can't verify that this is true, but this test seems to suggest some kind of time sharing/channel sharing going on. Ed Anderson RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
Re: [RCSE] Breaking the 40 Spektrum Radio Barrier
While 2.4 GHz virtually eliminates interference issues, it should be noted that using this frequency in nations other than the U.S. may be increasingly problematic. I understand Germany has just put out a notice that RC is not to use the 2.4 GHz band, stating it is a national security issue. Belgium seems to have banned RC use of 2.4 GHz a couple years ago. Additionally, I just read a notice that France has limited power output of 2.4 GHz systems to 10 MW, as opposed to the 100 MW standard elsewhere. (One of our South African correspondents has stated Horizon Hobbies put out a letter stating that Spektrum sets made for use in the US are illegal in South Africa and a number of European countries.) Late last year, CIAM, the FAI body, was discussing upcoming legislation in Europe as it applied to 2.4 GHz RC. Seems the EU is getting a lot of pressure from WiMax operators to ban RC use of the frequencies. We'd appreciate hearing from anyone who has accurate current information on this topic. -- Bill Bunny Kuhlman RCSE-List facilities provided by Model Airplane News. Send subscribe and unsubscribe requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
