Joe Roper Posted January 8, 2008 Share Posted January 8, 2008 I have just received a new Netto leaflet and I see they are selling "wireless colour CCTV kits" which operate on 2.4GHz if this band is now being used for commercial purposes are we now back with the old 27 MHs problems ? Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted January 8, 2008 Share Posted January 8, 2008 Joe I was thinking the same thing. Why is every thing 2.4 What we obviously don't know is about channels /band widths/frequency exact selection/other interference (like you said 27 !) I will keep a close eye on what the experts will hopefully tell us on this forum & if it comes to it at the end of the day I'll use my French gear on 40 'cos I'm P d off with this nanny state .Sorry but it seems you always have to be one step ahead of the next problem to survive these days & enoy even a hobby !I'm known for being Grumpy Guess why ?j Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted January 8, 2008 Share Posted January 8, 2008 2.4 GHz is NOT an exclusive model control band. It never had been, and it never will be! It is an ISM band (Industrial, Scientific and Medical) - ie a dustbin, where they put all the things they can't think of anything else to do with! In that sense its the same as 27 MHz and 459 MHz. However, mostly its used for wireless networks on computers - which is where the technology for 2.4 GHz RC comes from. Most (but not all) of this equipment is meant to be sensitive to other users, and most of it is used in towns - not out in the sticks, where the bulk of modellers operate.So there shouldn't be a problem!35 MHz is exclusively for RC aircraft. 40 MHz is exclusively for surface models. These bands have been allocated to us and we don't share them (well, there are some maritime buoys and flea-powered alarms for the elderly, but they shouldn't concern us). 2.4 GHz is shared with other users, but most of them are in urban locations and shouldn't cause us any issues. That is unless someone fits a 2.4 GHz TV camera in a model and tries to control it with a 2.4 GHz RC system. And if he's that dumb, he deserves everything that will be coming to him! (Probably a Darwin Award!) --Pete Quote Link to comment Share on other sites More sharing options...
Ian Posted January 17, 2008 Share Posted January 17, 2008 Surely you are all missing the point with 2.4ghz systems! that is the tx and model are digitally locked together once they are switched on correctly, and this link should not be affected however busy the frequency is. This is the same technology used in bluetooth technology ie mobile phones and headsets. I have never had my conversation interupted by anyone else in a nearby car, have you ? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 17, 2008 Share Posted January 17, 2008 Err....have you guys been sleeping today ? BAD NEWS Quote Link to comment Share on other sites More sharing options...
the unmagnificent man Posted January 17, 2008 Share Posted January 17, 2008 There are three FASST owners at my local club and we have done the checks with each other.We will have to do the checks again every time a new member joins with FASST until our transmitters have been checked at the model shop checking system and cleared.Luckily there have been no incidents to date. Al Quote Link to comment Share on other sites More sharing options...
Flanker . Posted January 18, 2008 Share Posted January 18, 2008 I never had a problem with 35 meg! Ian is correct in that although many systems use 2.4 gig the tech is not the same as good old amplitude modulation, and if all works as designed there will be no problem, that is the whole point of 2.4 gigs, it is like talking to your mate in a busy canteen, there are many voices but you listen to your mate. As with any new tech there will be teething problems but in the long term it is the way to go. Viz the Futaba issue, so far no trouble and they are fixing it. I remember well when the Pentium chip first came out - "its flawed, its flawed !" came the cry from the tech heads, and it was, but no one who just used their computer had any trouble , and it was soon superseded by pent 2, 4 etc.Personally I could never afford to replace the 7, 8 ? 35meg receivers that I have, so as usual by the time that most of us do go gigging it 'twill all be sorted and the tech heads will be wringing their hands over the glitches that their new telepathic control systems have when their wife has a headache!The lesson is that when one has a guided missile to play with it pays to check one's down link before flying it. RC should NEVER be fit and forget even if it's control line !Go well F Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 19, 2008 Share Posted January 19, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Flanker . Posted January 19, 2008 Share Posted January 19, 2008 I ALWAYS fly RC control line with the plane on the ground and me in the air. You mean there is ANOTHER way? What is U suspect ? I suspect you mean I suspect! Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 19, 2008 Share Posted January 19, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted December 14, 2008 Share Posted December 14, 2008 I'm sure Timbo will confirm this but what attracted me to 2.4 GHz was that there is a protocol on this frequency which requires any transmitter to find an unused frequency - I belive that there are 80 channels to choose from. If no channel is free then the transmitter does not go into transmit mode and you will not achieve any sort of link to your receiver. As someone has already pointed out the link between the Tx and Rx is unique and relies on a Global User Identiy (GUID) being established between the two which, again I look for someone to confirm, is unique. As far as I know, on the JR/Spectrum DSM2 systems, there is also a model match which means that even if the required 2 channels are free, if you have not selected the correct model memory, then the system will not connect. A great safety feature in my opinion. Mind you, that does not absolve preflight checks being carried out for correct sense of operation of controls but you may find the set up not as you expected! This is also the band used for Bluetooth devices - that includes those robo cop earpieces that are used with mobile phones for hands-free operation. However, you need to remember that none of these bits of equipment have particularly large transmitting powers and may not be anywhere near your chosen flying field. Put another way - again someone please confirm - my understanding is that there could be 78 other 2.4 GHz channel users but a JR/Spectrum/Futaba system would still work without interference. I hope I've got that right! Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 14, 2008 Share Posted December 14, 2008 Pretty much, yes Peter. On a slightly pedantic note of order, GUID = Globally Unique Identifier, Spektrum system uses 2 of the available 80 channels not just 1 - and model match only works with purpose made 2.4Ghz sets not modules. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted December 14, 2008 Share Posted December 14, 2008 TimboHow does that relate to Futaba's FAAST 's system (if it does ? )As I asked long time ago -Why 2.4 for everything ? Bet you dont know !!? But I rather suspect you do / I myself have had no problems what so ever BUT - Will they come along eventually ? I think I'll hang on to my 35 mg stuff a while longer Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 14, 2008 Share Posted December 14, 2008 All applicable to either Fuby or Spekky Myron, except of course Fuby uses frequency hopping rather than 2 x fixed frequencies. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted December 14, 2008 Share Posted December 14, 2008 Timbo Yep Understood GUT will 2.4 eventually get saturated by high power emissions .I still dont know why 2.4 GHz is the "magic" frequency for all & sundry & of course we are all at the bottom of the priority list Quote Link to comment Share on other sites More sharing options...
260 Flyer Posted December 14, 2008 Share Posted December 14, 2008 If the 2.4 GHz band does become swamped I for one would not tolerate a poor connection from my PC to the interweb and would quickly move to something more reliable. A mass exodus from 2.4GHz by one set of users would free up bandwidth for other users and some form of equilibrium would be achieved.I bet you are safe to fly on 27 MHz these days after everyone but the toy makers deserted the band. Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted December 14, 2008 Share Posted December 14, 2008 RobI never had a problem with 27 - Then again I was in the far west of Cornwall ! St.Just In Penwith Better than Newcastle ! Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted December 15, 2008 Share Posted December 15, 2008 The protocol that dictates that systems should co-exist harmoniously only applies to *digital* technology! There's quite a lot of gear out there - especially video cameras - that are analogue! A PAL colour TV signal (analogue) needs about 5.5 MHz of bandwidth - and will fully occupy that bandwidth! It will also transmit continuously - not in bursts like a digital signal. This will have the effect of "deafening" any nearby receiver, digital or not! It would be a little bit like trying to hold a conversation with someone on the other side of the street, whilst standing next to a pneumatic drill! Of course, analogue equipment is slowly being phased out as digital is generally cheaper to mass-produce. But there's still quite a bit out there, and because it is obsolescent, it is quite often sold at very tempting rock bottom prices!So I repeat my original advice - be very wary of installing 2.4 GHz video equipment in a model controlled by a 2.4 GHz link! Timbo - the reason that 2.4 GHz is the "magic" frequency is that it is useless for serious communications work! Because 2.4 GHz is the resonant frequency of a water molecule, signals tend to get absorbed very quickly by our damp atmosphere. Also the noise generated by microwave ovens raises the background noise level substantially. That means that about the only thing it can be used for is short range communications. Ideal for us, and computer networks, but totally useless for anything requiring long range!--Pete Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 15, 2008 Share Posted December 15, 2008 Errrr thanks Pete, but I didnt ask the question! Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted December 15, 2008 Share Posted December 15, 2008 Ooops! Sorry! Replied in a hurry before I left for work this morning! I should have addressed that to Myron of course......! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted December 15, 2008 Share Posted December 15, 2008 Peter Now - that I didnt know and is reasurring . Makes me think - Is it important to keep your gear & the short aerial very dry ? By the way We've been warned about bad language and you mentioned w--k Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted December 15, 2008 Share Posted December 15, 2008 Hi Myron,No, we don't need to worry too much. The path "budget" for 2.4 GHz is so high that for our purposes, we don't need to worry. The British Waterplane Association have done extensive tests with flying boats and seaplanes, and not had any issues. Avoid totally enclosed carbon fibre fuselages though, as these can work as a "Faraday Cage" and effectively screen the signal.However, I have suggested to the BMFA that tying a (potentially) wet pennant to the end of a highly tuned 2.4 GHz antenna is probably NOT a good idea. If they haven't dropped that recommendation already, they soon will!Sorry about the use of the dreaded four-letter word! I've been doing a lot of long/late shifts lately and my mind must have been slightly fuddled this morning.........8( --Pete Quote Link to comment Share on other sites More sharing options...
Phil Claridge Posted December 15, 2008 Share Posted December 15, 2008 myron w--k may be a dirty word but it makes you filthy rich so you can buy more models Quote Link to comment Share on other sites More sharing options...
Phil_G Posted December 15, 2008 Share Posted December 15, 2008 Peter Christy wrote:...Is that THE Peter Christy of Christy Mixer fame or am I just showing my age again?Phil Quote Link to comment Share on other sites More sharing options...
260 Flyer Posted December 15, 2008 Share Posted December 15, 2008 Ah! The Crispy Mixture! Quote Link to comment Share on other sites More sharing options...
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