Radio control

[Rickharris]

Hi,

I would like to pass this through the forum intelligence/experience filter -

I have come by a 6 channel Radio control unit - Esky 0406A - I can supply links to pictures/info if you need.

This is intended for light weight helicopter use and so mixes the channels in the transmitter.

the previous owner was under the impression (from the wonder web) that it has a set of dip switches inside to turn this channel mixing off.

It hasn't.

So it isn't any use to him to fly his foam plastic wonder aerobatic model.

I generously offered to take it off his hands and intend (bold statement there) to hack the circuit to replace the coding section which is a 20 pin SM pic micro of undetermined type (numbers removed by Chinese manufacture if it even had any)

I am no RC expert or even faintly familiar and so after some research I have come up with the following:

I understand to get 4 channels I need to produce 4 pulse between 1 and 2 milli seconds wide. Followed by a sync pulse of approx 8 milli sec

This needs to be sent at a frame rate of about 20 milli secs. i.e 5 times a second.

So as I am uncertain how servo out works as I need to make a pulse train of 4 pulses one for each channel depending on the position of the control pots I decided to use pulsout and have come up with the code below.

'picaxe 20
'gives pulse train between 1ms and 2.27ms
'200 micro sec inter channel break
'4 channels - 0 to 5v input to ADC.
'frame rate max 17ms
'min 13 ms



Start:


'ch1
readadc 1,b1
b1=b1/2        'divide 0 to 255 ADC reading to approx 100 steps (127)
b1=b1+100        'adds 100 to give correct pulsout time valuse for 10 micro sec units

'ch2
readadc 2,b2
b2=b2/2
b2=b2+100

'ch3
readadc 3,b3
b3=b3/2
b3=b3+100

'ch4
readadc 7,b4
b4=b4/2
b4=b4+100

'send pulse stream out
pulsout 1,b1
pulsout 1,20
pulsout 1,b2
pulsout 1,20
pulsout 1,b3
pulsout 1,20
pulsout 1,b4
pulsout 1,800  'sync pulse
goto start


'goes to FM  modulator

I think this produces the expected pulse train although have no Scope to see until I return to school in Sep. Actually as it stands if I calculate correctly the frame rate will be between 13 and 17 milli sec plus the overhead for the readadc and calculations but I would think still around the 20 ms per frame in total.

Has anyone done this as the solution seems very simple

And OR do you have any comments/ improvements to make - or am I totally off my trolly (it is the school holidays after all and I have put my serious brain to rest for 6 weeks!)

Comments welcome. - I can even tell you where to get the 6 channel 35 Mhz transmitter - Receiver 4 servos and a gyro for the grand total of £60.

Seemed like a bargain until he found out it didn't work for his application.

 

[goom]

It appears that some models of this transmitter come with DIP switches located underneath the batteries, some do not (but you can still see the holes where they should be). Two of the switched disable mixing. The switches probably connect directly into the microcontroller, so you may be able to add them if you find the wiring diagram (e.g. from someone with a unit with switches).
The 1-2 ms pulses at 100 ms intervals are what comes out of the receiver on each channel. Hobby servos and ESC's interpret these pulses (1 ms = servo fully in one direction, 2ms = servo fully in the other direction). Easy to read the pulses using "pulsin" on a Pcaxe. Can then be manipulated, and re-sent to a servo.

Hope that helps.

Kevin

 

[Andrew Cowan]

'1-2 ms pulses at 100 ms intervals'

It is standard for servos to run with 0.75 - 2.25ms pulses at 18ms intervals, although some servos can cope with up to 30ms between pulses.

Andrew

 

[Rickharris]

It appears that some models of this transmitter come with DIP switches located underneath the batteries, some do not (but you can still see the holes where they should be). Two of the switched disable mixing. The switches probably connect directly into the microcontroller, so you may be able to add them if you find the wiring diagram (e.g. from someone with a unit with switches).
The 1-2 ms pulses at 100 ms intervals are what comes out of the receiver on each channel. Hobby servos and ESC's interpret these pulses (1 ms = servo fully in one direction, 2ms = servo fully in the other direction). Easy to read the pulses using "pulsin" on a Pcaxe. Can then be manipulated, and re-sent to a servo.

Hope that helps.

Kevin

Nope I checked mine don't even have the holes other wise it wold be easy - In fact a bit of careful prodding suggests that the micro isn't programmed to cater for this option - ie I can't pull a pin up or down to disable the mixing function.

the problem is at the transmitter end where the mixing happens - the receiver is fine as it is.

i understand that the pulses that go into the transmitter modulator are the same as appear at the receiver demodulator to run the servoes.

that is you could in principle - wire the servos direct to the transmitter the FM RF bit is just to get the data from TX to rX.


All I want to do is replace the current micro and its mixed outputs with a picaxe that will feed a pulse stream into the FM modulator but with the correct action that I need/want

 

[Rickharris]

'1-2 ms pulses at 100 ms intervals'

It is standard for servos to run with 0.75 - 2.25ms pulses at 18ms intervals, although some servos can cope with up to 30ms between pulses.

Andrew

Thanks Andrew - I can alter the code to get the timing right assuming it works as I anticipate it should. BTW I did put 1-2 ms at a fram rate of 20 ms approx.

 

[goom]

Quite so, 20 ms frame rate (50 Hz), or is it 18 ms (60Hz). In any case, it's not that critical. Sorry for the misinformation. I usually try to avoid going below 1 ms or above 2 ms in order to make sure that sevos do not hit their end stops.
The transmitter presumably sends the 1-2 ms pulses sequentially for all 6 channels within the 20 ms frame. If this is what the microcontroller outputs, then you couldn't connect a servo directly. If the microcontroller puts out pulses for each channel separately, which then get combined before transmission, then I would suppose that a servo connected directly to the appropriate pin would move correctly. Worth a try? A 'scope would be really handy here.
I assume that the microcontroller gets its input as analog voltage from the joystick potentiometers. If so, you would need several ADC Picaxe inputs to read them.
Keep us informed on progress (or lack thereof).

 

[hippy]

These will probably be of interest ( especially the second one ) ...

www.omegaco.demon.co.uk/mectnpdf/mectn003.pdf
www.omegaco.demon.co.uk/mectnpdf/mectn004.pdf
www.omegaco.demon.co.uk/mectnpdf/mectn005.pdf

My understanding of PPM is as described; each channel occupies a time slot ( "Channel time" in Fig 18 ) so there's an on and off time for each channel which add up to the same period. I'm not sure about the timings stated in Fig 18 but have seen the same stated elsewhere, even though it doesn't match with what a servo needs for its control - But check Fig 30 in the third link as that could explain how the transmitted signal converts to what the servo expects; what's sent isn't exactly what a receiver puts out.

( Don't forget most people in this forum have dealt with reading / intercepting what a receiver puts out to a servo, not the stream which goes from transmitter to receiver ).

Also note in Fig 18 that transmission-on appears to be inverted to channel pulse.

This was all for the days where transmitters and receivers were hardware-based as described in those PDF's and micro-controller decoding is far more flexible so the original code ( PULSOUT, fixed-gap, repeat ) should work, although it's probably best to pad the frame for a constant(ish) 20mS rate ( frame padding = 800-b0-b1- ... ).

In the PULSOUT sequences, shouldn't you be pulsing the gaps beween pulses to a dummy pin ?

 

[hippy]

b1 = channel 1
b2 = channel 2
b3 = channel 3
b4 = channel 4

b5 = 200-b1
b6 = 200-b2
b7 = 200-b3
b8 = 200-b4

w6 = 2000-800-fudgeFactor

PulsOut TX, b1 : PulsOut DUMMY, b5
PulsOut TX, b2 : PulsOut DUMMY, b6
PulsOut TX, b3 : PulsOut DUMMY, b7
PulsOut TX, b4 : PulsOut DUMMY, b8

PulsOut DUMMY, w6

 

[Andrew Cowan]

Good point about inverted signal, hippy - I know that there are 'positive shift' and 'negative shift' (inverted) recievers and transmitters - check which you have. Some Hitech recievers are both - they automatically switch between the modes.

Andrew

 

[Rickharris]

Ah neat and tidy as every Hip. Thanks I take your point there.

Thanks guys - It looks like, (eyeball only), the micro puts out a pulse stream - I understand this wouldn't directly drive a servo. I guess I was trying to get my head round the transmitter actually produces the servo pulses that appear at the Rx. the complicated Rf bit is just a transmission medium - At least in my case the receiver does very little other than receive the signal and reassemble it for each servo.

I am a bit limited because of a lack of electronic instrumentation to actually see what is happening. - First time I ever wished I was at school or at least lived closer than 35 miles so i could get hold of a scope.

BUT I have a picaxe 20 by coincidence so will forge ahead and hack the circuit as carefully as I can and see what happens - Watch this space (assuming 'she who must be' doesn't find other jobs for me to do today!)

 

[hippy]

You should be able to get there without a scope though there may be some tweaking needed.

On the inversion of the TX line - PULSOUT takes the pin from what it was to opposite and back again and works that way regardless of initial pin state, so just issue a HIGH TX at the start of your program and all your TX pulses will be inverted.

 

[BeanieBots]

A lot of these "toy" RC transmitters shipped from china have digressed from the "standard" RC timings and mixings. That is why only THEIR Tx works with THEIR Rx. Walkera are particularly bad at doing it and so are some of the E-Sky products. I've never actually looked at the pulse stream of these 'odd-balls' but it may simply be that (as you say) the mixing is done in the transmitter. In which case, all you need to do is read the pots and produce the stream. Most PPM streams are spaced for 7 channels even if less than that are actually used. PCM streams are not so easy. Depends what your Rx is expecting but cheap usually means PPM.
Talking of cheap, have you tried your local hobby shop. You could probably pick up a second hand 4 channel Tx for £5.
Another approach would be to get an E-Sky Rx heli unit and use it's outputs to drive whatever it is you are controlling. Their "4 in 1" units used on co-ax helis have two motor outputs and include a gyro. Excellent for driving tank steer robots! However, the RF police will be on your back like a tonne of bricks if you get caught using 35Mhz for ground base control so make sure only to use 40Mhz for such work.

 

[Rickharris]

A lot of these "toy" RC transmitters shipped from china have digressed from the "standard" RC timings and mixings. That is why only THEIR Tx works with THEIR Rx. Walkera are particularly bad at doing it and so are some of the E-Sky products. I've never actually looked at the pulse stream of these 'odd-balls' but it may simply be that (as you say) the mixing is done in the transmitter. In which case, all you need to do is read the pots and produce the stream.

I gather from the web that sometimes they can be quirky and follow the "Chinese standards" - thats where the scope would help if only to give me confidence in what I am trying to do.

Most PPM streams are spaced for 7 channels even if less than that are actually used. PCM streams are not so easy. Depends what your Rx is expecting but cheap usually means PPM.
Talking of cheap, have you tried your local hobby shop. You could probably pick up a second hand 4 channel Tx for £5.

This set up can for free, more or less so I would like to make it dance to my tune if only to prove the point. I had been looking on ebay for a very low price set up for 35 Mhz but they seem to be rare (at present) £50 is about the going price and that will be a strange name manufacture.

Another approach would be to get an E-Sky Rx heli unit and use it's outputs to drive whatever it is you are controlling. Their "4 in 1" units used on co-ax helis have two motor outputs and include a gyro. Excellent for driving tank steer robots! However, the RF police will be on your back like a tonne of bricks if you get caught using 35Mhz for ground base control so make sure only to use 40Mhz for such work.

What I have is the full Esky Heli set - Actually that's the problem It was bought on the understanding that there were dip switches inside to turn off the channel mixing that the heli uses - unfortunately it seems these were not part of the older sets - No wonder it was cheap.

According to the Chinglish manual (not very informative!) it is PPM and as far as I can see the circuitry is very simple and straight forward - What seems to be a ATMel tiny micro is reading the pots as an analogue signal - then produces the relevant pulse stream which goes to a discrete transistor FM modulator and power stage.

The supply for the set is 12 V 8 x AA cells I guess for the power output stage this is regulated down to 5 V for the micro circuitry None of the components have markings on them you can see though - doesn't help much.

I will remove the existing micro and see if I can graft in a Picaxe 20 to do the same job but the way I want it to work . the intent is to put the kit into a light weight glider. Fly it up to height as a kite (its been made from rip stop nylon) and then drop the line to fly as an aeroplane - but one step at a time.

 

[hippy]

At the speeds we're talking, 50Hz frame rate, a standard PC soundcard is probably all you'll need.

 

[BeanieBots]

At the speeds we're talking, 50Hz frame rate, a standard PC soundcard is probably all you'll need.

Indeed, a PC 'scope would be more than capable.
Infact, there is a free application available (PPjoy) which will take a Tx buddy signal and convert it into a virtual joystick for use with RC simulators such as the free FMS simulator. It will also decode CCPM signals (including those from E-Sky) into the basic 4 channel signals.
I'll find links for you if you are interested. A simulator is a MUCH cheaper way to learn orientation before taking to the air for real. It's not as easy as it looks! The physics in FMS is not brilliant but it is free and PPjoy lets you connect your Tx via the microphone socket negating the need for a USB adapter.

I'm surprised you could not find a cheaper Tx. Even brand new from E-Sky they are only around £20. Be aware of power limits though. The cheapies are for "parkflying only" as they have limited range. A full range programmable Tx will set you back £300+ (you get what you pay for).

Back on topic. It should be possible to get a PICAXE to read the the pots and generate the required stream. Somewhere on this forum there are some very good links to documents which explain in full detail all the timings. Unfortunately, a quick search failed to find them but I know they are there. Try scanning all the "servo" related posts.

 

[Texy]

You might not even need a sound card with ppjoy. This link shows you how to use the parallel port, you just need to find the unmodulated tx signal :

http://www.heliguy.com/nexus/fmsinterface.html

FMS (a free RC flight sim that you can fly with a transmitter connected to the PC) has a calibration screen that graphically shows all the RC channels.

Texy

 

[Andrew Cowan]

A full range programmable Tx will set you back £300+ (you get what you pay for).

Huh?

I bought my full range Futaba 6 channel 6EXA-P (supports both PPM and PCM) for £59. Full range 6 channel reciever £29.99. High quality crystals £14.99. Total: £102.

 

[Rickharris]

Huh?

I bought my full range Futaba 6 channel 6EXA-P (supports both PPM and PCM) for £59. Full range 6 channel reciever £29.99. High quality crystals £14.99. Total: £102.

Ok guys I know the logic!

This has become a technical issue now - I hate to let the machines dominate!

Range is fine for what I need. Free is very cheap - even if not at this moment exactly working.

Just to bring up to now:

Picaxe 20 programmed and reading the pots ok. Producing an output stream.

I have found a PC scope-or two- and have found it invaluable (because I trained in radar I am very electrically visually oriented - I like to see what the circuit is doing.

I have also found it frustrating as it finds it hard to trigger from the composite signal no matter what conditioning and control combination I have tried (hence using 2 Pc scopes!)

The picture is fine when the output is a steady signal but when it changes it looses the plot (pardon the pun - dippy would be proud!) - I am not sure if this is the picaxe getting confused and needing several frames to settle or the scope picture.

I have isolated the feed to the modulator so tomorrow will separate the existing micro from the cct and try to drive the servos with the picaxe and see what happens. An interesting learning experience so far.

BB if you read this where did you see the tx for £20 from E sky - I can't see prices on their web site - This was bought from their UK distributor for £60 with RX and 4 servos and the heli gyro.

Servo say £8 x 4 £24 - gyro £12 ish = £36 so TX £24 at that rate.

 

[hippy]

The picture is fine when the output is a steady signal but when it changes it looses the plot (pardon the pun - dippy would be proud!) - I am not sure if this is the picaxe getting confused and needing several frames to settle or the scope picture.

One trick I've found ( and it applies to proper scopes too ) is to temporarily extend the frame so there's a long gap and add an extra pulse at the start of a frame. It probably depends on exactly how the scope software works internally.

 

[BeanieBots]

Further to Hippy's tip, try reversing the trigger polarity so that it triggers on the longer frame gap.
As for the E-Sky Tx, E-Sky don't (AFIK) sell direct. You need to search the hobby stores for a good bargain, particularly on seperates. I DO NOT recommend E-Bay for RC gear. Check any of the RC forums to get all the horror stories. Much arives DOA and/or second hand when advertised as new. The other common problem is getting stung for extorsionate P&P and import taxes.

A quick search found this:-
http://www.rc-spareparts.com/ek20406a-esky-6ch-radio-control-ccpm-transmitter-wo-rx-p-1476.html
£22.25 for Tx only.

 

[Rickharris]

Further to Hippy's tip, try reversing the trigger polarity so that it triggers on the longer frame gap.
As for the E-Sky Tx, E-Sky don't (AFIK) sell direct. You need to search the hobby stores for a good bargain, particularly on seperates. I DO NOT recommend E-Bay for RC gear. Check any of the RC forums to get all the horror stories. Much arives DOA and/or second hand when advertised as new. The other common problem is getting stung for extorsionate P&P and import taxes.

A quick search found this:-
http://www.rc-spareparts.com/ek20406a-esky-6ch-radio-control-ccpm-transmitter-wo-rx-p-1476.html
£22.25 for Tx only.

Good price!,

On the project front I have the system working on an 08M with internally generated pulse widths as the 08 only has 1 ADC channel.

The picaxe 20 is on hold until technical sort out the pulsout from a high start - at present it just stays high. - At least I have proven the principle - learned a LOT about radio control and PCM coding.

For the present I will have to use my 2 ch futaba radio Mmm wonder if I can extend it to 4 channels?

 

[BeanieBots]

For the present I will have to use my 2 ch futaba radio Mmm wonder if I can extend it to 4 channels?

Seriously, might be worth a try!
You know that it is possible to encode four pots and produce the correct stream, hence, it should be possible. I had an old Pro-Pilot 3 channel Tx once. When I opened it up to remove the throttle ratchet, low and behold, there was the fourth pot simply bolted down. Removed the screw and converted it to four channel. I've done the same with receivers. The Hitec 2,3,4 & 5 channel Rx's are all the same electronics board. The ONLY difference between them is the case and the price. Even the extra servo connectors are fitted

Glad you've made good progress. The hard part is learning how to fly
If you ever come across any details about the new 2.4Ghz RC protocol, please let me know.

 

[Rickharris]

On opening the Futaba I find a monolithic Futaba IC which appears to do everything - next up is to investigate as you say if it has extra inputs/outputs - at present it certainly outputs only 2 channels so this may be wrapped up in software.

On the other system front I may try running 4 08Ms in parallel to do the 4 adc inputs and produce the output stream perhaps speed would be difficult.

Shame the Pic20 has a fault and can't run pulsout from a high pin - sods law I guess - I though I was doing well when I found I had one spare.

On the flying front years ago I had a spate of flying slope soaring gliders But learning to fly cant be that hard I have been watching a young Blackbird undergoing tuition from it's parents in the back garden and he can't have a brain the size of a wall nut but picked it up quite quickly.






On the subject of 2.4 Ghz some basic info from a practical point here

 

[BeanieBots]

Gnats fly pretty well too. Guess that tells me all I need to know about my brain

I think 4 X 08M is a bit of overkill for generating a simple inversion!
How about a tranny + 2 resistors or 74C14?

 

[Dippy]

I didn't see any PICAXErs taking part in the recent MOD competition to make flying things. That would have been a great advert for the expertise of Rick and others.

 

[Rickharris]

Gnats fly pretty well too. Guess that tells me all I need to know about my brain

I think 4 X 08M is a bit of overkill for generating a simple inversion!
How about a tranny + 2 resistors or 74C14?

Reminds me of the guy who did everything the hard way - Swam the channel with weights on - ascended Everest backwards - in a TV interview a few of his fantastic feats were outlined and the interviewer asked him if he had children?

Yes he replied three and before you ask standing up in a hammock!.

Your right of course an option already in hand as soon as Rapidonline deliver.

I suspect the entrants had rather a bigger budget that I operate from. When Techno games was on (BBC robot contest) we entered \ couple of Robots & gt in to finals in both of our contests- In the swimming the chap next (who beat us) confessed he had spent almost £1000 on his 2 robots - one of which failed to start. We expended about £7

 

[BeanieBots]

Indeed, TG was a very good example of how throwing money at a project does not gaurantee a win. It does help though.
Robot wars started out the same way with robots made from what was lying around. Unfortunately, when it came to replacing "what was lying around", it all started to get very expensive with robots costing £10k and lasting all of 5 minutes.

Hopefully, TG (or something similar) will make another appearance. I have spoken with many ex-entrants and school reps about it. There is tremendous interest but no preduction company wants to take it on. Why that is, I have no idea. Some competitions continue but they get very little coverage.

 

[Rickharris]

Indeed, TG was a very good example of how throwing money at a project does not gaurantee a win. It does help though.
Robot wars started out the same way with robots made from what was lying around. Unfortunately, when it came to replacing "what was lying around", it all started to get very expensive with robots costing £10k and lasting all of 5 minutes.

Hopefully, TG (or something similar) will make another appearance. I have spoken with many ex-entrants and school reps about it. There is tremendous interest but no production company wants to take it on. Why that is, I have no idea. Some competitions continue but they get very little coverage.

Its a hard commercial world I guess but you would think that a public broadcasting service would do something to promote School kids interest in engineering - TCG was an ideal platform that hadn't the chance to establish it's self.

Greenpower cars seems to have established a foothold in schools but very little media coverage. W looked at other contests but nothing seemed to have the "glitter" of a televised show.

 

[Dippy]

Yes, TG and Robot Wars were great shows. Whilst it is true that throwing money at a project doesn't guarantee results - and I'm sure that too many experts spoil the broth - it does show that spending a few extra quid can give results.
Bring back Professor Heinz Wolfe! And an inter-school competition run by BBC (in UK) would be a great idea. They used to do it - "Young Scientist of the Year" in my era.

The MOD competition was different, there was money at the end of the tunnel. Some of the entrants (e.g. Reading University's) was a bigger-than-schoolboy budget, but there were some small devices that were superb. The UFO was excellent. Was the Competition Entry well publicised? Any invites to schools? I saw NO mention whatsoever on the Forum.

I'm all for these competitions. I wish I had the brains to enter.

Greenpower car projects are superb, but without a decent budget surely you're just covering ground that has been well-trodden by people years ago? No-one has the budget to design a new solar panel or new form of battery or light-weight materials and all the motors are 'traditional'. Don't get me wrong, I think its great (I'm being the Media Devil's Advocate). Its great from the education point of view , it promotes the competitive spirit, its good for team-building, it could encourage a few good engineers, but , without funding and big brains, where is the novelty and innovation? That is, I would hazard a guess, why it gets no media coverage.

A computer whizz-kid ain't the guy with the hgh score, he's the guy who wrote the game.

 

[Wrenow]

Good price!,

On the project front I have the system working on an 08M with internally generated pulse widths as the 08 only has 1 ADC channel.

The picaxe 20 is on hold until technical sort out the pulsout from a high start - at present it just stays high. - At least I have proven the principle - learned a LOT about radio control and PCM coding.

For the present I will have to use my 2 ch futaba radio Mmm wonder if I can extend it to 4 channels?

Ummm. The 08M has 3 ADC's does it not? This would allow you to run 3 proportional channels and a digital (on-off channel) for throttle, rudder, elevator, and gear. And the 14M can be configured for 4, I believe, and a few digitals. A 40X1 should be able to give you 8 proportional channels for your 4 channel box.

Of course, if you are wanting to do an encoder swap, you could save a lot of time and effort with the Microstar2000 - http://www.mstar2k.com/, which, indcidentally, is made for the home-brew market and has a forum on the Yahoo Groups at http://groups.yahoo.com/group/MP8K/.

Cheers,

Wreno

 

[BeanieBots]

I think the Microstar2000 is brilliant idea, but unfortunately, I'm quite sure it would be illegal in the UK. Firstly because of its frequency and secondly, because Tx equipment MUST carry a CE mark. It is possible to get it CE marked but the cost for an individual would be prohibative.

 

[Wrenow]

Hmmm. For the TX portion, I am sure that is true. Of course, modifying the TX with a picaxe would decertify it, too, right (would in the US)? The trick is to use the encoder with a TX that has stand-alone certification of the RF stage. Remember, the MS2K is the encoder, not the TX. If you are allowed to modify the encoder, and keep the RF stage, in the Esky that was being discussed, then you should be able to do a brain-swap with an MS2K encoder. If not, than going to a different RF system (like one of the 433mHz or 2.4gHz systems) that is individually CE certified might do the trick.

Or, in the UK, do you have something similar to the US HAM (ameture radio) band that allows you to build you own (a lot of the MS2K guys choos that option). By the way, I have an MS2K encoder that I am in the process of working up into a dedicated Model Warship Combat radio. It comes very close wo what I need/want in its current iteration, and is far less lucre than the Multiplex Profi 4000 that is the only other extant radio that is known to do the functions I want. And that is another one of the reasons I got into Picaxes....

Cheers,

Wreno

 

[BeanieBots]

Wrenow, I agree. A standalone certified module should keep it legal.
As for HAM, yes we have that in the UK but first off, the "HAM" must be certified and licensed which is not an easy exam (actually two) to pass. Secondly, there are vast restritions on the frequencies and also what type of data is transmitted. Between the BBC and the MOD, nearly all the usefull frequencies are totally locked down and very power limited. My favourite is 212Mhz which is reserved for air-to-air communication between Lancaster bombers. There is only one still in flying condition. One day the UK will catch up with the rest of the planet with respect to frequency allocation and useage

As for the Profi-4000. Quite simply, the best radio ever made.
I cried when I learned they had ceased production because I was saving up for one but just missed it I have the MC-3030 (with multinaut module)which is a minor consolation

P.S. There is a 2.4Ghz Tx module for MULTIPLEX available in the US but not the UK.