Simon Chambers Posted February 6, 2012 Share Posted February 6, 2012 Hi all, Over the last few months in between other commitments, I've been reverse engineering the Hitec 2.4GHz protocol with the aim of producing my own design receiver. I did this by monitoring the communications between the RF chip and the main microcontroller chip in both the Transmitter module and one of my Receivers, then using the assumptions from that and testing it out if it works in theory. Note, I should emphasize that I haven't looked at or seen any of the program code in any of the Hitec products - done on purpose so I don't infringe any copyrights (and hence so it wouldn't make my work illegal, immoral and useless). As its easier to explain over a video, here is a short demo video of the work: The next step will be to use one of the cheap Chinese receivers and reprogram them to be compatible. I'm currently waiting for the new FrSKY ultralight VD5M receiver which, from the pictures I've seen, should have the same IC I am using and hence only a tiny amount of work to get working. Its also a nice receiver to start with, as the aircraft it controls will be smaller and cheaper (less risk when testing) and also Hitec don't stock such small receivers yet either. Plus Hobbyking stock them for a really cheap, £8 each. For the future, I hope to also buy up some of the other transmitter systems that use the identical RF chip as the Hitec (Grapuner HoTT, Multiplex, Futaba S-FHSS, FrSKY and others) and make a multi-brand compatible receiver. Its one of my pet hates in the current RC market is the incompatibilities between equipment - even though they all use the same RF chip. It would be nice to go back to the days of 35MHz where you could choose any receiver off the shelf, plug it in and it works - rather than having to buy into one brand of manufacturer. So that being said, if anyone has a Futaba 6J or Futaba S-FHSS transmitter module and receiver unwanted and going cheap, I would be grateful to buy it from you!! I've also posted this to the other big bad RC forum, but this being the home of (my favourite magazine) Radio Control Models & Electronics I though there may be some interest and discussion here too! Also it should hopefully help dispel the myth that it isn't possible to produce your own receivers any more. In fact, if anything, I think once you know and understand the protocol, its easier than 35MHz! So if any mods feel offended by this being posted here, feel free to lock and close this thread. Even though I do hope to get a bit of cash from selling a couple of units (to cover some of the development costs - I can't imagine it'll make me a living), I've started this for the shear enjoyment of the challenge. Some people love building models, I love building electronics for models. Cheers, Si. Quote Link to comment Share on other sites More sharing options...
Pete B Posted February 6, 2012 Share Posted February 6, 2012 My knowledge of electronics doesn't extend beyond the on-off switch, Simon and your video left me behind after the opening credit but this seems to be a fascinating project and I shall watch your progress on both threads in blissful ignorance.......Being a Spekky user, I already have access to compatibles - I'm sure there will be interested Futaba/Hitec users out there, though!......... Good luck with it - just keep an eye out for faceless men sitting in cars on the corner of your road, though....... Pete Quote Link to comment Share on other sites More sharing options...
Martin Whybrow Posted February 6, 2012 Share Posted February 6, 2012 Interesting project Simon. I take it the TI development kit you're using has the RF front end incorporated; would you mind telling us what the dev kit / chip is? Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted February 6, 2012 Author Share Posted February 6, 2012 Posted by Martin Whybrow on 06/02/2012 17:59:06: Interesting project Simon. I take it the TI development kit you're using has the RF front end incorporated; would you mind telling us what the dev kit / chip is? Hi Martin, Yeah, the development board has the RF matching circuit on it. The development kit is the CC2510DK-MINI. It includes 2 dev boards and a debug tool and is around £70. Unfortunately the expensive bit is the IDE compiler tool for the chip which is over £2k a licence - I'm lucky in that I'm using the exact same compiler for a start-up I'm running (using a different IC - but in the same IC range), so I have a legitimate licence and know it well. There are free trial versions of the compiler available, however the code limit is quite small. However there is no reason why you couldn't use another IC. I only chose this IC (CC2510) as it has the RF Radio IC (Texas Instruments CC2500) and microcontroller (8051 core) all in one package - which makes it possible to have a one-chip receiver. Allowing the PCB design to be a lot smaller and simpler. The other way to do it, is to use a CC2500 and a Microcontroller of your choice - as what most of the Receiver manufacturers use. In terms of the RF front end, currently I am not intending to use a LNA (Low Noise Amplifier) as I am only interested in developing Park Flyer receivers right now - so only an Antenna matching circuit is needed. The FrSky V8R4 (and other ultralight receivers) use no LNA either, only the full range ones. So if I do go down the route of producing my own receiver design, I just need a matching circuit, which can be easily done with a chip balun filter - making the complex RF design smaller and a lot simpler. Slightly more expensive to buy, but as I would probably get the receiver manufactured in the UK, less components on the board, so less cost to manufacturer. As most of the manufacturing would be machine based, there wouldn't be much saved by producing it in China if I did decide to make my own design. The other option to get into production will be to use an off-the-shelf receiver. This is more attractive as there is no minimum build that I would have to do, thus making the risk less. Also the receivers from China are so cheap now, to match their price point and make a profit in the UK I would need to be producing at least around 200 off. Hence my interest in first converting an existing product out there first (hopefully the new FrSKY VD5M will be usable), and selling it on again for a small mark-up (and it still would make them very competitively price). Si. Edited By Simon Chambers on 06/02/2012 18:58:31 Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted February 6, 2012 Author Share Posted February 6, 2012 Posted by Pete B on 06/02/2012 17:33:06: My knowledge of electronics doesn't extend beyond the on-off switch, Simon and your video left me behind after the opening credit but this seems to be a fascinating project and I shall watch your progress on both threads in blissful ignorance....... Being a Spekky user, I already have access to compatibles - I'm sure there will be interested Futaba/Hitec users out there, though!......... Good luck with it - just keep an eye out for faceless men sitting in cars on the corner of your road, though....... Pete Haha, well the opening text is only there to prevent those faceless lawy... sorry, 'men' from arriving. I have deliberately gone down the route I have with reverse engineering to keep it all above board. Even down to using a Log book to keep all my notes on how I've done it - useful proof if there is any querying later. Interestingly with the Hitec Minima receiver, Hitec haven't enabled any code protection. So there is nothing to stop anyone taking that code off, knocking off the board design and making cheap knock offs (aka a clone). I would say this was very silly of Hitec, however as the Minima is their base receiver, I do wonder if this was deliberately done by Hitec. After all, I'm sure a large part of Spektrum's continued success is the cheap clones. A Cock-up or Conspiracy? I wouldn't like to say. Anyway Futaba, Hitec, Multiplex, Jeti and Graupner could all do with some low cost compatible receivers to tempt people to move to their platforms. According to my LMS (which is part of a chain of 3 other stores), Spektrum transmitters fly out the shop compared to other manufacturers - even to the point that they can't keep at least one DX6i on the shelf! I should expect its part in least to cheap receivers and their good range of Bind and Fly models... Si. Edited By Simon Chambers on 06/02/2012 19:11:23 Quote Link to comment Share on other sites More sharing options...
Pete B Posted February 6, 2012 Share Posted February 6, 2012 Posted by Simon Chambers on 06/02/2012 19:10:34:Interestingly with the Hitec Minima receiver, Hitec haven't enabled any code protection. So there is nothing to stop anyone taking that code off, knocking off the board design and making cheap knock offs (aka a clone)...... I do wonder if this was deliberately done by Hitec. After all, I'm sure a large part of Spektrum's continued success is the cheap clones. A Cock-up or Conspiracy? I wouldn't like to say. That's an interesting hypothesis, Simon. Their system remains attractive to many because of the availability of the low-cost option. Given that the demand for add-on components such as telemetry modules, etc, may not justify competitors' investment in cloning, the OE manufacturers tolerate a degree of cloning knowing that their core market is protected. Many will stay with OE anyway out of mistrust of cloned Rx's - as evidenced on this and other forums. They will always remain one step ahead in innovation, I'm sure, and will have the advantage of being first in the 'must-have' market, so it may be that the clone market isn't necessarily hurting them as much as one would suspect. Pete Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted February 6, 2012 Author Share Posted February 6, 2012 Posted by Pete B on 06/02/2012 20:39:21: Their system remains attractive to many because of the availability of the low-cost option. Given that the demand for add-on components such as telemetry modules, etc, may not justify competitors' investment in cloning, the OE manufacturers tolerate a degree of cloning knowing that their core market is protected. Many will stay with OE anyway out of mistrust of cloned Rx's - as evidenced on this and other forums. They will always remain one step ahead in innovation, I'm sure, and will have the advantage of being first in the 'must-have' market, so it may be that the clone market isn't necessarily hurting them as much as one would suspect. Pete Its the old principle of FUD in action I guess. We are told for years by manufacturers in all sorts of different markets that compatible products aren't as good quality as the original manufactures item. I would imagine many car dealerships would go broke if we all didn't believe that! Even though initially, I do intend to produce a cheaper Hitec receiver alternative - this is only to try and fund further development. Even though its a cheaper alternative, its also novel for the Hitec system, as there is no Ultralight receiver available in their range - nor one publicised in development (the Minima manual does mention the Micro range though - which currently hasn't been mentioned anywhere). The further development part would be producing a multi-brand compatible receiver. Being novel allows you to charge more, and thus make more margins (and be more viable). Racing to the bottom doesn't make good business sense - hence why none of the big manufacturers have really reduced their price at all. Even Futaba are charging big money for their FASST receivers still, when you can pick up FrSKY receivers for a lot less - and I bet FrSKY produce less receivers than Futaba and hence have to cut their margins slimmer compared to them. The irony would be however, that a multi-brand compatiable receiver would be marketable due to FUD! After all, the 2.4GHz market has been very volatile, with many big name brands changing protocols and dumping their old designs (Futaba FASST 7ch, Graupner iPS, Spektrum DSM/DSM2/DSMX, et al). Instead of buying one of their receivers and being locked in and stuffed if they drop the range again - why not buy a multi-brand receiver, so you can move to another platform if it happens? Not sure what transmitter system to buy, or worried about not liking it? Buy a multi-brand compatible receiver. As I am currently not in a job (was made unemployed) that is paying me (the start-up that I'm doing isn't generating any cash or orders yet), I'm hoping that this could make me a basic living. I certainly don't expect to be a millionaire out of it! If I was in full-time employment, I'd probably open-source it and allow others to produce it. It would be great if I could make a business out of the hobby I enjoy! I can hope... Saying that, didn't Hitec start off by making 35MHz compatible receivers that supported both JR (negative shift) and Futaba (positive shift systems)? Si. Edited By Simon Chambers on 06/02/2012 23:17:58 Quote Link to comment Share on other sites More sharing options...
Martyn K Posted February 7, 2012 Share Posted February 7, 2012 Hi Simon Very very interesting. At what point do you think you could offer compatible transmitter systems? That would open up the world to a home brew 2.4GHz system. I will watch this with interest. Good luck Martyn Quote Link to comment Share on other sites More sharing options...
Ben B Posted February 7, 2012 Share Posted February 7, 2012 Wow. Impressive stuff. I do agree the incompatibility of these systems is very annoying (especially if they all use the same basic chips etc).Why can't they just use a common dev kit and supply a CD with firmware for the various txs on? Grrrrrr. Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted February 7, 2012 Author Share Posted February 7, 2012 Posted by Martyn K on 07/02/2012 14:32:56: Hi Simon Very very interesting. At what point do you think you could offer compatible transmitter systems? That would open up the world to a home brew 2.4GHz system. I will watch this with interest. Good luck Martyn Probably not in the immediate future, as to transmit brings up a whole host of Type Approval issues (to get the CE mark and FCC ID) - not least the cost of going to a testing house. For 2.4GHz kit, it would be around the £10-12k range for each product. Hence initally I intend not to make a telementry version of the receiver - so only basic EMC (electromagnetic compliance - looking at the electromagnetic noise the product emits and can withstand being injected into it) testing is required. FrSKY would have done this for their receivers - hence if I reprogram them with my own firmware, along as I keep certain things the same (e.g. the oscillator and what speed the processor runs at) there is no reason why that CE result wouldn't still be valid. Remember CE approval is self-approved, so by putting the CE mark on a product, you would be saying that "I am certain that this product complies to all applicable standards". Of course if it doesn't really, but you still put the mark on, your in for a whole heap of trouble. Hence why you need to be really sure it does pass - and the need to get it documented. All what a testing house will do for you (for the obvious fee). The other potential problem with a multi-brand transmitter module and type approval is that usually you approve for certain standard channel bandwidths, hop channels, etc. So for a multi-standard transmitter, it'd have to be approved for each protocol. I may be wrong on this, it would be something I'd have to read up to be sure. I'm pretty certain the FCC report for the Futaba 18MZ, it details both S-FHSS mode and FASST. That being said, if I could make a living out of this, its certainly something I'd like to investigate. What there probably needs is a standards body with all the manufacturers coming together to produce a standard for all of them to implement. Is this likely to happen? No, I'd say, not at the moment. I'm sure if consumers complained enough it would happen, but even so, its too easy for the manufacturers to continue as they are. The only other option would be to produce a completely open standard. That way, the transmitters could operate in the manufacturer specific mode, and then have a magic mode switch to enter the open standard. For this open standard to have traction, it would have to have a significant market. With the amount of transmitters Spektrum/HH are selling purely due to their own parkflyer BnF/RTF/etc market, I'm sure the other manufacturers would like to get into it. Hence I feel if the smaller parkflyer manufacturers used an open standard, it could gain traction in the market place. Likely to happen in the near future? Probably not. Saying that, I was reading a post on RC-Groups that someone brought back from 2004 "2.4GHz for surface, aircraft next?" (quicker to post a link than re-explain it here). It just shows how far in just 6/7 years the market has changed - and how much Spektrum has got a foot hold into the market. Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted February 7, 2012 Author Share Posted February 7, 2012 I should also say that I shouldn't get too carried away about the idea of multi-brand receivers! As I've only reverse-engineered one system so far. Other systems may be more complex or not possible to reverse-engineer. According to the developer/company owner posts, the XPS 2.4GHz system encrypts the servo data - so that wouldn't be possible to be compatible without illegally disassembling the source code. With the Futaba S-FHSS system, they specify that the system "hops from frequency to frequency in a pseudorandom sequence". Is this sequence set when first initalised (as Hitec does), or is there a seed number (e.g. the transmitters serial number) that defines the hop sequence? If the former, it could be relatively tricky to reverse engineer. Of course, I can only find this out once I can get my hands on a Futaba 6J system. Finally, apologises to anyone reading my posts, I tend to be very verbose in them and typing everything that comes to mind! Si. Edited By Simon Chambers on 07/02/2012 16:50:54 Quote Link to comment Share on other sites More sharing options...
kc Posted February 8, 2012 Share Posted February 8, 2012 Isn't it symbolic of the despicable state of our country that someone with the knowledge, skill and enterprise to do all this stuff should not have a job? But at the same time bankers are paying themselves massive bonuses.One of the major RC manufacturers should be paying him a good salary NOT to do this! Or to research their competitors!Unfortunately I think there are many other talented people in the same boat. Quote Link to comment Share on other sites More sharing options...
Martyn K Posted February 8, 2012 Share Posted February 8, 2012 Posted by Simon Chambers on 07/02/2012 16:41:36: Probably not in the immediate future, as to transmit brings up a whole host of Type Approval issues (to get the CE mark and FCC ID) - not least the cost of going to a testing house. --- The type approval requirement would be interesting. I was not suggesting that the RF modules would be home built, these would be ex manufacturer and I think that this then excludes them from the necessity for further compliance testing (providing they meet the local national or international standard). The case for this has already been proven about 20 years ago with the introduction of CE. The issue was whether adding an extension card to a type approved PC would break the conformance (ie require the unit to be retested). This is a similar argument. It all depends whether Chinese modules have type approval at the assembly level and the circumstances that the approval has been granted. I have to admit that I don't know the answer, but I am tempted to try and find out I also think that the type approval requirement for kits is different - self certification can be used.The task then would be to develop your own protocol either directly from one that has been reverse engineered or extended with 'improvements'. Ultimately, it becomes a digital programmming issue, as you said the analogue days of 35MHz are in many ways more complex.Whether this could be done cost effectively with all the bells and whistles that modellers expect (rates, reverse, mixing, memories) is totally different question. Regards MartynEdited By Martyn K on 08/02/2012 17:08:11 Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted February 8, 2012 Author Share Posted February 8, 2012 Posted by kc on 08/02/2012 12:20:20: Isn't it symbolic of the despicable state of our country that someone with the knowledge, skill and enterprise to do all this stuff should not have a job? But at the same time bankers are paying themselves massive bonuses. One of the major RC manufacturers should be paying him a good salary NOT to do this! Or to research their competitors! Unfortunately I think there are many other talented people in the same boat. I wouldn't worry about me kc, I started this project as a relief from the intensity of running a start-up company (as my full-time job) at an early stage with no cash coming in, but still having cash coming out. Once the contract finished at my last job, I relised that I don't think I can handle another 9-5 desk job. There is plenty of good paid jobs for software + electronics development at the moment, so I'm not worried about that. However just the thought of going back to a job where you arrive, sit down, work and then go home, while following the corporate ethos and politics, scares (and bores) the hell out of me! As I'm relatively young (26), have no children and a stable relationship - now is the time to take the risks. Of course as I get older, etc, etc I'll probably change - just not yet! This project wasn't started to make money, it was more than I'm a cheapskate and don't like paying £35-£40 for a receiver, for which I can make cheaper. Its a nice fun project too with some good problem solving elements to it, a bit like solving crosswords. Like the great satisfaction of building a model from a plan or even a kit and giving it the first flight, I got great sanctification from working out how it all works, implementing it and then getting the first servo moving. Plus it is a good project to put onto my CV at a later date. Of course there is potential commercial aspects to this, which as they are there, I might as well investigate and give it ago. I'm just not expecting this to become terribly profitable. In fact if I can cover my development costs I'll be happy. Even more happy if I could fund my need for more planes to replace the ones I seem to keep breaking! Quote Link to comment Share on other sites More sharing options...
kc Posted February 8, 2012 Share Posted February 8, 2012 It was, of course, meant as a compliment and a reflection on British industry that a really competant technical person could be allowed to 'escape' The trouble is that on the one hand the money men wont invest in British industry and on the other that technical people are not keeping their knowhow completly confidential until they can exploit it commercially.( I have seen this for myself back in the 1970's when a top technical person at a major British motor component company explained all his firms know how to a deputation of Japanese who were there to 'buy' components but instead they just wrote every detail down and took it back to Japan. Now these components come from Japan) . I am afraid that whilst publishing the results of such experiments for all to see will help technology generally it mainly helps the far eastern companies who will just help themselves to your knowledge but wont pay for it. It's far worse than that because then there's no British jobs in manufacturing for the rest of the population who don't have technical expertise but want routine jobs to make a living. Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted February 8, 2012 Author Share Posted February 8, 2012 Posted by Martyn K on 08/02/2012 17:05:50: Posted by Simon Chambers on 07/02/2012 16:41:36: Probably not in the immediate future, as to transmit brings up a whole host of Type Approval issues (to get the CE mark and FCC ID) - not least the cost of going to a testing house. --- The type approval requirement would be interesting. I was not suggesting that the RF modules would be home built, these would be ex manufacturer and I think that this then excludes them from the necessity for further compliance testing (providing they meet the local national or international standard). The case for this has already been proven about 20 years ago with the introduction of CE. The issue was whether adding an extension card to a type approved PC would break the conformance (ie require the unit to be retested). This is a similar argument. It all depends whether Chinese modules have type approval at the assembly level and the circumstances that the approval has been granted. I have to admit that I don't know the answer, but I am tempted to try and find out I also think that the type approval requirement for kits is different - self certification can be used.The task then would be to develop your own protocol either directly from one that has been reverse engineered or extended with 'improvements'. Ultimately, it becomes a digital programmming issue, as you said the analogue days of 35MHz are in many ways more complex.Whether this could be done cost effectively with all the bells and whistles that modellers expect (rates, reverse, mixing, memories) is totally different question. Regards Martyn Edited By Martyn K on 08/02/2012 17:08:11 Are you aware of the Flysky/Turnigy/Eurgle/iMax 9x transmitter project? It sounds very close to what your describing. There are a number of open source projects that have, from the ground-up, produced working firmware for them. You can buy the Flysky 9x (for about £50 from GC, or ~$40 from HK), reflash it with one of these open firmware, and have a radio with capabilities equal (and in some cases, more) than equivalent big name brand radios. As its open source, there is no reason why you can't modify the firmware yourself and add new functionality - as some have done to support FrSky telemetry features. If you are even more adventurous, there are replacement main PCB's that offer more functionality that you can fit in. A bit of information here: Instructables How-To modifying guide er9x - One of the popular firmware builds around An enormous RC-Group thread about it Apologises if you know this already and I'm teaching egg-sucking! Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted April 12, 2012 Author Share Posted April 12, 2012 I thought I'd post a bit of an update on where I've got to on this project. Currently I've modified a FrSKY VD5M 5 Channel Micro receiver to work with the Hitec 2.4GHz system and been testing it out in my own planes. Seems to be a rock solid link and I have to say I'm rather chuffed with it! A short video demoing it in action: I plan to sell a couple of these on eBay today to gauge interest. But as I don't want to be advertising on here, I won't post links to them. I've also posted on the big ol' RCG as there appears to be more Hitec gear out in the US and hopefully more interest. I'm really hope there will be enough interest for me to be able to sell some more and bring enough money in to buy a Futaba 6J to work on next! They use the micro Molex 'PicoBlade' connectors which seems to be standard on Hobbyking stuff and I believe Futaba's micro stuff too. Spektrum use a different connector, the micro JST. I'm guessing that in the UK there will be a lot more interest in these types of receivers once (or if) Hobbyking open up in UK, as they stock a plentiful, popular range of micro parkflyers and indoor models. Cheers, Si. Edited By Simon Chambers on 12/04/2012 15:15:27 Quote Link to comment Share on other sites More sharing options...
Garbo Posted September 17, 2012 Share Posted September 17, 2012 Posted by Simon Chambers on 06/02/2012 19:10:34 Interestingly with the Hitec Minima receiver, Hitec haven't enabled any code protection. So there is nothing to stop anyone taking that code off, knocking off the board design and making cheap knock offs (aka a clone). I would say this was very silly of Hitec, however as the Minima is their base receiver, I do wonder if this was deliberately done by Hitec. After all, I'm sure a large part of Spektrum's continued success is the cheap clones. A Cock-up or Conspiracy? I wouldn't like to say. Anyway Futaba, Hitec, Multiplex, Jeti and Graupner could all do with some low cost compatible receivers to tempt people to move to their platforms. According to my LMS (which is part of a chain of 3 other stores), Spektrum transmitters fly out the shop compared to other manufacturers - even to the point that they can't keep at least one DX6i on the shelf! I should expect its part in least to cheap receivers and their good range of Bind and Fly models... Si. Edited By Simon Chambers on 06/02/2012 19:11:23 Wink. Sorry trying to post link and it's not going well Edited By Garbo on 17/09/2012 10:07:35 Edited By Garbo on 17/09/2012 10:16:20 Quote Link to comment Share on other sites More sharing options...
Garbo Posted September 17, 2012 Share Posted September 17, 2012 Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted September 17, 2012 Author Share Posted September 17, 2012 lol, you mean: **LINK** Look good don't they! Pretty good price after you get the logged-in discount. I couldn't possibly comment on where they came from and if I was involved or not.... Cheers, Si. Quote Link to comment Share on other sites More sharing options...
Pete B Posted September 17, 2012 Share Posted September 17, 2012 On balance, I would suspect that congratulations are in order, Simon As with Spekky, I believe this development will probably do Hitec more good than harm............ Pete Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted September 17, 2012 Share Posted September 17, 2012 here's a cheap way to build a motor for a bit of Fun..... ken anderson ne..1 .... basic motor dept....... Quote Link to comment Share on other sites More sharing options...
Simon Chambers Posted September 17, 2012 Author Share Posted September 17, 2012 Posted by Pete B on 17/09/2012 13:31:34: On balance, I would suspect that congratulations are in order, Simon As with Spekky, I believe this development will probably do Hitec more good than harm............ Pete Thank-you! Of course I don't want to harm Hitec in anyway, that's the last thing I want to do!! So what's the purpose? Well what I want to do is two things. First fill a void in the Hitec product range - i.e. a tiny receiver for indoor/etc fliers and also a 8 channel non-telementry receiver (with optional PPM and RSSI output) for a reasonable price. Secondly, I want to offer people choices. Yes you might want to use the 9-channel Optima 9 receiver for your ££££ jet, but for your IC hack model or a dirt cheap, HK special foamy, do you really need/want the same? I feel its like the same situation as when Hitec first brought out their compatible 35MHz receivers many years ago. When they came out, no longer did you have to spend £££ on a Futaba/JR receiver if you didn't want/need too. I frequently use a 8-channel version on my 46 sized Black Horse Travel Air - it's had a rock solid link. Another thing is that even though these are cheap (the price of two 8-channel's is the same price as one 6-channel Minima), they are by no means inferior quality - unlike some of the Spekky receivers floating around. It could be possible to make cheaper compatible receivers, however no-one wants crap flying around. As I think I said at the beginning of this thread, I started this project because I'm a cheap-skate. I like quality, but I don't see why I should pay over the odds for it. Just for note, the 5-channel is parkfly range (i.e. no more than ~300 metres - ~1000ft) and the 8-channel is full range (1.5km should be possible without much problem). I'd recommend the 5-channel for <500mm wingspan or something bigger like a shocky, etc that is flown close in. Next project is to finish my Hitec A-FHSS and Futaba S-FHSS combined compatible receiver. Then finish a Hitec A-FHSS compatible telemetry receiver. So many projects, so little time. Si. Quote Link to comment Share on other sites More sharing options...
Klippy Posted September 19, 2012 Share Posted September 19, 2012 Way to go Simon, I wish I had your brights! Quote Link to comment Share on other sites More sharing options...
TheFlyingCrust Posted September 19, 2012 Share Posted September 19, 2012 Cracking job, Simon! That'll save me a few pennies. Ian Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.