UHF radio control for submarines (openLRS, LoRa, FSK etc. on 458Mhz and 433Mhz )

Yes indeed!

What is the implication of the French equipment at 41Mhz, Nigel?

HI Hermann
Don't no about having leaks in submarines all i ended up with was leaks in the bathroom needed a trip to the local hard ware shop to buy new fittings, but have sorted bathroom out now now to more interesting stuff. I see you did a test in your lab when you did your test i take it you used tap water, point i am coming to if you where in a pond the range would be even less like the losses you said 1DB at per CM is a lot and if you looked at a standard 2.4GHZ transmitter knocking out 20DBM of RF you will not get very far under water, you said that some lad had done a test to see how far they could get under water with 2.4 GHZ and he had said 12M my thoughts was there is no way you can get that far under water on 2.4GHZ, like you said Hermann there had to be something acting as a wave guide for it to travel down to that depth, one thing that would be interesting to do in the test that you did would be to put TX Ariel in the water as well and see if losses change in water but dipole would have to be smaller because it is under water. You are Lucky that you have this test gear that you can use Hermann at work i used to be able to use test gear like that where i worked but am no longer there, have got a fair bit of test gear at home but not like that. Thanks for trying test
John

I just wondered how people are getting on, now that 2.4Ghz has "swept the market."

My observations are:

- I don't have any problems now operating on 40Mhz at my local club now that everyone has moved on to   2.4 Ghz. (Norwich sub weekend was a bit of a special case but it worked out quite well.)

- I have been able to buy a "lifetime supply" on eBay of transmitters, receivers and crystals. (I can also modify 35Mhz  equipment if I need to.)

- But this approach is not really very suitable for someone just entering the r/c submarine hobby.

- Some discussion on Subcommittee of US legal use of 433Mhz equipment. But how well does it propagate in water (it can't be any better) and is equipment available?

- No sign of any niche commercial providers of 40Mhz equipment setting up.

The prospects of using 433MHz is a light in the otherwise dismal supply of manufacturers who are jumping away from the frequencies we use. I saw Tim Senecal in Keystone Colorado at the SubCommittee Regatta.

His sub ran great it went out about ~18 meters and he ran it down a meter or more (how is that for speaking in metric language!). In a heavily chlorinated pool he had no problems at 8', oops about 2.4 meters. The benefit of the 433MHz is getting feedback, like angle of boat, temp of motors, battery power remaining, and magnetic direction. These are future features Tim wants to implement and does not see a problem getting that to work. He even ran it from a tablet.

Here is a photo of the interface on a tablet:

I suppose I am rather disappointed that no niche-producer is producing equipment at "sub friendly" frequencies of a few tens of Mhz.

433Mhz shows promise but it is still dictated by model flyers whose frequencies head ever upwards.
By the way Salmon I'm impressed by your ability to go seamlessly from metric to imperial - we are still struggling with that one on our island nation!

On a slightly more serious note, in the UK we have a stereotype that all you US modellers only operate subs in your pools!? Has Tim tried 433Mhz in a large pond, say? With all the problems of signal loss caused by reflection off the water surface etc.?

I mentioned 433MHz to John Robinson recently and he felt that there would be propagation problems. (Mind you John still has not come up with any working alternatives.)

So yes, you are right, Salmon the interest  shown in 433MHz is the only light in a dismal world for us!

And what is the problem with pools? LOL I cannot verify whether that is a justifiable portrayal or not. I do run in pools and also in ponds.
Tim has run his sub in lakes. At Keystone Colorado the lake is a 5 acre lake or about 20,000 square meters. with a depth of 4 meters. He is currently testing how small both in power output and antenna size. He has gotten the antenna down to about a 4 cm and output power on the TX is down to 6mw. With that (you can turn on beeping when packets are dropped) he gets dropped packets, but never loses control or have failsafe kick in.

Thought this may be of interest.....



http://www.modelairplanenews.com/blog/2011/05/30/2-4ghz-is-it-all-its-cracked-up-to-be-join-the-discussion/





Cheers



John

Very interesting article and very good review of all the factors affecting aircraft radio propagation.

But typically no mention of the inability of 2.4 GHz to penetrate more than a few cm of water.

Just a reminder that we submariners are a tiny minority of radio users.

What is helpful to us is that aircraft users want to hang on to their lower frequencies also. (Governments selling off say 35 and 40Mhz would be a real blow to us.)

David

Good news for model submariners!

When Tom (salmon) mentioned Tim's (tsenecal) experiences with 433Mhz equipment over on SubCommittee, I was initially sceptical. (Look back on this thread for my embarrassment!)

Well I tried the 433Mhz equipment over at Barrow in Furness, yesterday, and it works sublimely well with none of the glitches we get on 40Mhz on our pond.

Some video "proof" using my Charlie class as test-bed:

UHF (400Mhz) trials for radio controlled submarine at Barrow on 8th March.

https://www.youtube.com/watch?v=4TB4v65oE5A

https://www.youtube.com/watch?v=CdV6hcb7e9w

https://www.youtube.com/watch?v=J8kz5Zxo0vo

https://www.youtube.com/watch?v=J8kz5Zxo0vo

https://www.youtube.com/watch?v=OFtqfbHfupE

I thought that increasing the frequency tenfold from 40Mhz could only mean no water penetration but those "data packets" just get through! It is also frequency hopping so model submariners will also enjoy operating without the dreaded (and argument provoking!) frequency peg board.

The photos show the equipment I used the HobbyKing Orange openLRS available for less than £50 (which also includes an RS232 "dongle" which you WILL need for re-programming.)

For this initial trial I deliberately used it without any re-programming and it worked "straight out of the box".







The 8 channel receiver is nice and small (rather dwarfed by my proportional piston tank control board!)

The aerials are all "rubber ducky" and could be improved, particularly when we consider that we will have to increase the frequency, here in the UK.

Which brings me on to the topic of legal frequencies in the UK.

Inspecting RA60 from OFCOM:
www.ofcom.org.uk/static/archive/ra/publication/ra_info/ra60.htm

This shows that 433Mhz is not available to us modellers in the UK but 458-459Mhz is. (Is this just for flying rather than surface models?) The modules can be reprogrammed to different frequencies  but this needs to be checked. Open LRS is open software so can be developed by us. (Open LRS stands for Opensource Long Range System)

It is not all good news:

- We are again having to rely on equipment being used primarily for model aviation. (In this case "Drones" which do not have a good "Press".)

-These systems are not fully established and you need to be able to do a lot of reconfiguring on a computer.

In conclusion, I suggest that you hold-off putting your order into HobbyKing until we have better confirmation that the systems works and can be used in the UK on 458-459MHz.

The next thing I am going to try is getting my "dongle" going to change frequency. I will let you know how I get on.

My thanks again to Tim and the SubCommittee for publishing a very full account on:

http://www.subcommittee.com/phpBB3/viewtopic.php?f=21&t=12146

David

David,
Very good, the system worked very well yesterday, could be the break through away from the peg board. Well done.
Dave J

Thanks Dave - always good to have a witness!

(I'm just posting those videos of your superb Type IX also taken yesterday.)

David

If you must use 2.4gHz gear for your r/c submarine, here's a method for running the receiver antenna up high into the sail, it's the frist post there:

http://forum.sub-driver.com/showthread.php?2836-How-To-Adapt-The-New-2-4gHz-Gear-To-R-C-Submarines/page2&highlight=2.4gHz

Hi Dave

Of the 4 videos you posted this morning, the three that have been edited pass me through to Google which is asking for an account ?!

Is it me???

The 433Mhz gear sounds great although the thought of putting it together and programming it will probably deter many people...

I've just checked hobbyking and the Tx's are on back order already

John

No it's not just you John,don't quite know what he has done there.
Nigel.

No John it is not only you, three of the four vidoes also ask for Google when I also tried unsuccessfully to view?

With the 433mhz system will you be able to stop interaction between two seperate users?

Dave J

Previous I have done also a little researched from my side:

In Belgium the 433MHz is used for all kinds of remotes (cars locks, alarm systems, Garage doors,....).
A continuous broadcast of the signal is not allowed...... only data "burst" technology is allowed, so that all these systems do not interfere with each other.

Also the frequency is part of the frequencies used by the Belgian Amateur Radio Society, if you want to transmit within there allocated range you have to possess a license issued by the Belgian authorities. Everybody can obtain it after passing an exam about 25 Eur, and a practicum with a recognized Radio Society.

The more I read about I become convinced that the interference will be huge en it will be illegal in Belgium to use it.
So for the moment I will keep way clear from the 433 MHz stuff.

Please note that the a.m. is only valid for Belgium other EU members may have other regulations......still some work ahead for Europe I guess.

Another option for me is to migrate to the US or UK when the 40Mhz will extinct.

grtz,
Bart

Sorry guys, Youtube was "waiting for improvements" for some reason!

I hope that has fixed it.

Yes, Dave it should be able to enable a number of simultaneous users. It uses random frequency hopping like 2.4 Ghz systems.

Yes, Bart , 433 seems less than ideal but 459 IS a legitimate r/c channel in the UK. (Increasingly used by quadcopters etc. for flying ranges of several miles - hence the availabilty of the hardware.) And yes, a bit of European "harmonisation" would help manufacturers (and modellers!)

Hope the videos prove something (and they are now working!)

David

If you look at the 4 links. One says "watch" in the URL and the others say "edit".

Thanks Tom. I have re-posted the links in the original post and I hope that has fixed it.

I would like to say that you have missed a lot, but strange to say, videos of technology working very well is slightly boring! (Disasters make for more exciting viewing!)

David

Well a further update on UHF (400Mhz).

You can perhaps say that my inability to post a Youtube video correctly means that I am the perfect candidate to test this technology i.e if I can do it, you certainly can!

After a couple of hours work I have successfully "burned" the openLRS software in the TX module and the receiver and set it to the more legal 458/459Mhz frequency for the UK. The Charlie class is now working again "on the bench". (It  will have to wait for another 2 weeks for a pond test.)

So I can't see any reason why those interested don't think about ordering some gear and having a go - the stuff is relatively cheap so low risk. I bought the gear too and my second receiver is now on order so that you can see I'm also sharing the risk, with no "freebies"!

My shopping list was: (I've added more detail in the latest edit following an enquiry by Davidf J)

1x #9171000147/27096 OrangeRx Open LRS 433MHz 9Ch Receiver = $19.95
1x #9171000270-0/40032 OrangeRX Open LRS 433MHz Transmitter 100mW (compatible with Futaba radio) = $19.99

http://www.hobbyking.co.uk/hobbyking/store/__40032__OrangeRX_Open_LRS_433MHz_Transmitter_100mW_compatible_with_Futaba_radio_.html

1 x FTDI Basic Breakout Board 3.3v (DEV-09873) (From Sparkfun)         $14.95

The last item is the RS232 "Dongle" which plugs into the 6 pins on both the TX and RX. The other end goes into the USB port on a PC. I believe this is a standard board used with Arduino devices but do get the 3.3 volt version. The 5v version can burn out the RF (radio frequency) chip in the modules.

I am now just going to give my own experiences based on the video on Tim's excellent thread on SubCommittee. Look at the whole video first.

A couple of health warnings first:

- Always leave the aerials/antennae in place on both TX and RX. They BOTH transmit and you can damage the RF chip if you don't.

- Probably best to get the 3.3 v board as above. The video covers using a 5v version but it makes the process more complicated (and risky).

The outline of the whole process is:

- On your PC install the Chrome Browser and the openLRS app. (This was a new method of installing software to me but it worked faultlessly and I am using Vista on my PC (Don't laugh!)

- You will only get the basic menu screen up at this point. (You need to plug in the devices to get the detailed menus.)

- You need to have access to the 6 pins for the Dongle and you need to identify the dtr pin of these 6. You will find dtr printed on the printed circuit boards. On the RX board you need to peel back the plastic sheathing a little to see it. On the TX module you need to take it out of its plastic box. I cut a small slot in the plastic case so I could plug the Dongle in with the module in the case. By the way dtr stands for Data Terminal Ready which perhaps gives you a clue to how long the rs232 standard has been with us!

- Flash the RX first  (as per the video). Plug the Dongle in with the dtr pins coinciding. Select the button on the menu. The loading only take  a few seconds and the menu tells you what is happening.

- Again as per the video, Flash the TX module. (You will find it simpler with the 3.3 volt Dongle than the video - just plug it in (dtr to dtr)

- Now you get onto the more interesting part. Setting up the devices. I got into a slight wrangle with the instructions for binding the TX and RX but just remember that you are not doing any damage and that it will all work out in the end.

- You are then presented with quite a detailed menu screen for TX setup. On the left column, type in a new frequency between 458.5 and 459.5 (UK surface users are recommended to use frequencies below 459.1) This link has useful info on UK frequencies:  

http://www.ukrcc.org/  

-Turn Telemetry off (more on this in a moment).

On the right column you can select the number of frequency hops and how they are selected. (I chose 6 and random.)

- I didn't change anything on the RX menu.

- As a hint of how clever this system is you will see that there is a button which carries out a frequency scan. Another button displays your frequency hops.

- A bit more binding and unplugging and you should have the system working.

However, I was faced with a whole lot of jittering servos and limited response to controls. Half an hour of anguish followed before I realised that Telemetry was ON and this was creating interference. I later re-checked the video advice and I had missed that point!

My thanks again to Tim S and the SubCommittee for spotting and developing this technology.

This COULD be the answer to the equipment problems facing the r/c subs fraternity. The more openLRS equipment you all buy the more likely they are to continue manufacturing it. Continuity of supply is probaby the key issue in the ultimate success of this technology.

It would seem to have significant advantages over 40 Mhz technology and so maybe more second hand 40Mhz gear will also re-enter the market.

All good news for folks wanting to enter the r/c subs hobby!

If you use and like the software (and I do) please consider making a donation to the open source enthusiasts who created it. (You will see a PayPal button on the menu.)

David

P.S The next thing I need to look at is improving the aerials for use in subs at this frequency. I have just put an order for a better TX aerial into one UK based supplier of openLRS equipment:

http://www.flytron.com/

I will let you know how I get on.

Well the first photo tells the story. A sub in the far distance just beyond the mooring buoy.That is the Charlie sub using the Orange receiver on the legal, in the UK, band of 458/459Mhz band using openLRS.

So very good control even at long range.

I then moved onto doing some dives. All was fine until I tried some rapid dives (all out on the piston tank!) I overpressured the hull and the two hull halves parted company at the O ring seal!

Oh well, s*** happens with model subs!

We have a good set of waders at Barrow but the expression on my face seems to indicate that the pond level is good and high (cold water and above my waders!) My thanks to Dave J for the photo.



But the important thing is that there were no problems with the openLRS equipment and so we have seem to have a new, legal band for r/c subs in the UK. (We have also been in touch with the radio regulatory bodies in the UK, to confirm this, and we will report that separately.)

So I can't see any reason for people not to have a go with this technology.

Some more information, I ordered some better aerials from Flytron and the order worked very well. So if you want a UK based supplier of this equipment (I think that they have developed a lot of it.) then order away. (They seem to have an order backlog just at the moment.)

The next thing to test out is the "lost model" feature of the openLRS software. (It will transmit a beacon signal on the "walkie talkie " frequency of 446 Mhz.) I have some on order - the idea is that if a 458 Mhz signal can get down to the sub then a 446Mhz signal MAY get back up from the sub.

Particularly when  used in combination with Pinger and hydrophone, a short range system with directionality would be very useful for model location and recovery.

Finally the aftermath of the sinking does not seem to be too serious. Everything except my "waterproof" Mtroniks ESC has been dried and coaxed back to life. (Later edit: The Mtroniks is fine actually!) The Orange receiver is as good as new. Modern receivers like this one, don't have things like inductors and trimmers which are tricky to dry out. It is just chips and other surface mount devices.

Nigel has just been in touch about this technology (he is planning to have a go with it) and he suggested that I make it  clear that you use standard transmitters with plug in modules (I just plug in the Orange TX module in the back of my Futaba transmitter.) So it is really that simple.

Tim Senecal in his original article on the SubCommittee Forum takes you through other transmitter options.

Bring and Buy at Heywood this Sunday.

So what makes of transmitter should I be looking for that take these modules ??

david f wrote:
...I thought that increasing the frequency tenfold from 40Mhz could only mean no water penetration but those "data packets" just get through! It is also frequency hopping so model submariners will also enjoy operating without the dreaded (and argument provoking!) frequency peg board....


David

Hi David,
it is interesting to read about your successful experiments on 433MHz.
Of course there is no doubt that a 433MHz Signal suffers more attenuation in water than a Signal on 40MHz but as the wavelength on 433MHz is only about a tenth (approx. 70cm in air) your antennas are more effective and this can partly compensate the higher attenuation.
So this frequency band may offer an alternative in the UK if the 40MHz should be cancelled sometimes...
In Germany 433MHz had been used in the past but today it is no more legal for RC. I know that some submarine modellers have had 433MHz RC sets used in those days.

Kind regards
Klaus-Dieter