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    openLRS and 2.4 Ghz and Submarines

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    tsenecal
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    openLRS and 2.4 Ghz and Submarines - Page 7 Empty Re: openLRS and 2.4 Ghz and Submarines

    Post  tsenecal on Wed Jun 07, 2017 4:44 pm

    David,

    a few things to add to this...

    1)  FrSky has now announced that they will be selling an 868/915mhz transmitter module and receiver for LRS...  using the FrSky protocols, which allows for 16 channels, telemetry, and specific model ID.  (RX will refuse to do anything if you have the wrong model selected on your transmitter)  It has no ETA yet, but will be called the r9m (tx module) and r9 (receiver).

    this will be using 868mhz for europe, 915mhz for USA/Canada...   you will have to look and see if 868mhz is allowed in GB.

    2) the ChipLRS parts have an advantage for the europeans.. 1) it is made by a guy in russia, so shipping is quicker/cheaper than from china.  2) his prices are reasonably cheap, $20 for a receiver, $65 for a TX/RX combo, not as cheap as OrangeRX, but cheaper than hawkeye.  all of his equipment works with my ersky9x/openTX firmware based transmitters, so soldering a 3 pin connector to the receiver allows me to get full telemetry on the built in LCD display on the transmitter (and voice alerts based on telemetry triggers as well)  even ordering his stuff off ebay, it arrives within 10 days, which is faster than the chinese.

    3) you can order from the russian group with any of three frequency choices:  433/458mhz, 868mhz, or 915mhz...  so even if you stay with the 458mhz, ChipLRS might be an option for you.

    4) i have ordered a set of Nagoya 915mhz antennas for both the TX and the RX, these should show an improvement over the stock crappy antennas that all these things ship with off the shelf.
    david f
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    openLRS and 2.4 Ghz and Submarines - Page 7 Empty Re: openLRS and 2.4 Ghz and Submarines

    Post  david f on Thu Oct 05, 2017 2:02 pm

    A bit of an approaching winter "heads-up" on openLRS and my experiences.

    Well I have been operating only on openLRS 458 Mhz  since Spring 2015. My 40 Mhz gear has mostly been "raffled-off" at Club meetings!

    openLRS is still rather thin on the ground at the various national meetings I have been to (Bournville, Norwich etc.)  with a maximum of 2 people using it. So we haven't tested its ability to operate 30 sets on frequency-hopping all at once! But no need for crystals, peg-boards and the plaintive cry of "any one on Channel XX etc."

    I have only been using the Hobbyking receivers, still available at about $15 (That's about £75 of your English Pounds - feeble joke!)

    I have rationalised my use of Telemetry and I only use sensors for battery voltage and depth. I didn't find compass heading very useful or consistent - stray magnetic fields?? Battery voltage readout  is a real boon if you are using Lipo batteries. It is the only reliable system I know of for subs.

    This has reduced the "wiring loom" in the sub. The next photo shows the Arduino Nano used to handle the telemetry. Note only 5 wires.

    openLRS and 2.4 Ghz and Submarines - Page 7 20171010

    The next 2 photos show the inside of my standard WTC with the telemetry board above the Hobbyking receiver:

    openLRS and 2.4 Ghz and Submarines - Page 7 20171012

    openLRS and 2.4 Ghz and Submarines - Page 7 20171011

    I attach the Arduino sketch which works with this. ( I hope that Tim forgives my clumsy "hacksawing" of his software. The original software is on the SubPirates Forum https://www.subpirates.com/showthread.php?5271-Custom-Frsky-Telemetry-Hub/page4  )

    The TX option is rather limited for use by others because I am using the FrSky LCD display on my Futaba T9CP . (This LCD display is no longer available but Tim points out that many Tx's have LCD telemetry displays built in.)

    I am really pleased with this development thanks to Tim. It is not just a replacement for 40Mhz but it is a significant improvement. (BTW after my early experiments with different antennae I have gone back to the standard commercial ones - they are easily good enough.)

    David

    // FrSkyTelemetryLRS - Version: Latest
    #include <FrSkyTelemetryLRS.h>

    /*
     FrSky Telemetry library LRS test
     (c) Pawelsky 20150724
     Not for commercial use
     
     FrSkyTelemetry library modified to deal with LRS format (TTL level serial instead of FrSky format...
     renamed to FrSkyTelemetryLRS
     
     modifications by tim senecal

     Working for voltage input (/2?) on A3 by David Forrest
     A2 gives depth input from pressure sensor.Multiply reading by 3 to give mm of water approx,
     Software from Page 4 of Subpirates
     Improvements? - get actual battery voltage. Calibrate depth sensor. Aug 2017
     
    */

    #include "FrSkyTelemetryLRS.h"


    #define minraw  272.0
    #define maxraw  1015.0
    #define minreal  9.0
    #define maxreal  158.0
    //#define voltsdiv  84.81
    //#define voltsdiv  102.40
    #define voltsdiv  82.0 ;    // was 67 by RDF for Holland lipo
     
    FrSkyTelemetryLRS telemetry; // Create telemetry object

    const int analogTemp1 = A0;
    const int analogTemp2 = A1;
    const int analogAmp = A2;
    const int analogVolt = A3;

    int mVperAmp = 66;    // use 185 for 5A, 100 for 20A, and 66 for 30A
    int ACSoffset = 2500; // offset to remove negative side of range

    float amperes = 0;
    float voltage = 0;
    float actual_rpm = 0;
    float calc_speed = 0;
    float Temp1;
    float Temp2;
    float depth;

    void setup()
    {
     // Configure the telemetry serial port
     telemetry.begin(SERIAL_1);
     
     Serial.begin(9600);
    }

    void loop()
    {
     actual_rpm = 3000;
     calc_speed = 2.258;

     amperes = calc_amperage_val();
     voltage = calc_voltage_val();
       
     telemetry.setFasData(amperes,   // Current consumption in amps
                          voltage);  // Battery voltage in volts
       
     depth = amperes-180;    
     telemetry.setFgsData(depth);  // Fuel level in percent -  unsigned int16 - any value between 0 and 65535
       
     // Set LiPo voltage sensor (FLVS) data (we use two sensors to simulate 8S battery
     // (set Voltage source to Cells in menu to use this data for battery voltage)
     float v1 = voltage/2;
     //float v2 = voltage/2;
     telemetry.setFlvsData(v1, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0);  // Cell voltages in volts (cells 1-8). Cells 9-12 are not used in this example
       
     // Set variometer sensor (FVAS) data
     telemetry.setFvasData(depth);  // Altitude in m (can be nevative)
     
     // Set GPS data
     float heading = 125.22;
       
     telemetry.setGpsData(39.847993, -105.104269,  // Latitude and longitude in degrees decimal (positive for N/E, negative for S/W)
                          depth,                   // Altitude in m (can be negative)
                          calc_speed,              // Speed in m/s
                          heading,                 // Course over ground in degrees
                          15, 2, 19,               // Date (year - 2000, month, day)
                          12, 00, 00);             // Time (hour, minute, second) - will be affected by timezone setings in your radio
       
     float accel_angle_x =  2.35;
     float accel_angle_y =  4.25;
     float accel_angle_z =  3.15;
                         
     telemetry.setTasData(accel_angle_x,     // calculated x angle
                          accel_angle_y,     // calculated y angle
                          accel_angle_z);    // calculated z angle
     
     // Set temperature sensor (TEMS) data, two temperatures T1 & T2
       
       // Set temperature sensor (TEMS) data, two temperatures T1 & T2
     Temp1 = calc_temp_val(analogTemp1);
     Temp2 = calc_temp_val(analogTemp2);
     telemetry.setTemsData(Temp1,   // Temperature #1 in degrees Celsuis (can be negative)
                           Temp2);  // Temperature #2 in degrees Celsuis (can be negative)
     
     // Set RPM sensor (RPMS) data
     // (set number of blades to 2 in telemetry menu to get correct rpm value)
     telemetry.setRpmsData(actual_rpm);  // Rotations per minute
     
     // Send the telemetry data, note that the data will only be sent for sensors
     // that had their data set at least once. Also it will only be set in defined
     // time intervals, so not necessarily at every call to send() method.
     telemetry.send();
     
     delay(100);  //delay for 1/10 of a second
    }


    float fmap (float x, float in_min, float in_max, float out_min, float out_max) {
     return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
    }

    float calc_temp_val(int analog_pin){
     uint16_t raw_val;
     float temp, raw_float;
     
     temp = 0;
     raw_val = analogRead(analog_pin);
    //  raw_val = 1023 - raw_val;
     raw_float = raw_val;
     temp = fmap(raw_val, minraw, maxraw, minreal, maxreal);
     
    //  Serial.print("raw temp: ");
    //  Serial.print(analog_pin);
    //  Serial.print(" ");
    //  Serial.println(raw_val);
     
     return temp;
    }

    float calc_voltage_val(){
     int RawValue = analogRead(analogVolt);
     voltage = RawValue;
     
    //  Serial.print("raw volt: ");
    //  Serial.println(RawValue);
     voltage = voltage / voltsdiv; // Gets you adjusted Volts
     
     return voltage;
    }

    float calc_amperage_val(){
     int RawValue = analogRead(analogAmp);
     Serial.print("raw amps: ");
     Serial.println(RawValue);
     
     float mVoltage = RawValue;
     mVoltage = mVoltage / 1024.0;
     mVoltage = mVoltage * 5000; // Gets you mV 5000 is VCC for 5v arduino
     Serial.print("mVolts: ");
     Serial.println(mVoltage);
     //Next 2 lines by RDF to output raw amps
     //amperes = abs(((mVoltage - ACSoffset) / mVperAmp));
     amperes = RawValue;
     
     Serial.print("Input on A2: ");
     Serial.println(amperes);
     
     return amperes;
    }


    Last edited by david f on Mon Oct 09, 2017 9:00 am; edited 2 times in total
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    Post  tsenecal on Fri Oct 06, 2017 5:33 pm

    I too appear to be a lone wolf at the majority of meetings where submarines are around....  i have not yet met anyone actively using the 433mhz or 915mhz equipment besides myself here in the states.

    at the last fun run i traveled to (Golden Gate Park in San Francisco California, September 16 & 17)  I took 3 submarines, two running on 915mhz ChipLRS equipment (Delta and a Moebius Skipjack), 1 running on 433mhz, using a combo of DTF-UHF and Brotronics micro 4ch receiver (SWM blueback).

    i did get my hands on a thunder tiger pump, and rebuilt the delta's pump, so it now is working as expected.  I have also found that the 915mhz equipment works well enough that i will probably move over to that, unless something unexpected comes up, or the specific model works "better" on 433mhz

    like you, i find that the only real data i need to "help" me run my sub is voltage and signal strength.  the rest are purely luxury items.  i do like the pressure sensor, as well as the RPM, but they aren't necessary.

    I have not yet had the time to test the new FrSky brand 915mhz equipment, but it has arrived, and i have looked at it to make sure it binds, etc.   need to install it in the delta to test it.
    david f
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    openLRS and 2.4 Ghz and Submarines - Page 7 Empty Re: openLRS and 2.4 Ghz and Submarines

    Post  david f on Tue Oct 10, 2017 9:25 am

    Looking back at your post before last and the use of 868 Mhz in the UK. It doesn't seem to be available:

    http://www.ukrcc.org/40mhz.html

    So it is 458 or nothing for us here.

    You make the very good point about signal strength being an important part of telemetry. I use the TX module sounder all the time but muted with a bit of tape stuck on it to avoid annoying my fellows at the pond side!

    I realise that if we had been marketing this technology again we should have pitched it as an improvement rather than as a 40Mhz replacement.

    It would seem that most model submariners are a bit conservative and will cling on to 40Mhz until their crystals fracture!

    David

    PS Just made a mention of openLRS on the SubCommittee forum. It can only help.
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    Post  tsenecal on Mon Nov 20, 2017 4:11 pm

    due to demand, i made 3 videos on how to configure the ChipLRS brand of 433/458 mhz equipment. they have a few quirks of their own that don't seem to get covered by more generic OpenLRSng videos...

    how to bind and set failsafe: https://www.youtube.com/watch?v=50mAgYoCL7M
    how to set up and use the configurator, with specific details for ChipLRS: https://www.youtube.com/watch?v=lp3fm-oeQrU
    a quick video showing simple telemetry with OpenLRSng and ersky9x: https://www.youtube.com/watch?v=yw9wOFiG8zE

    if there are any questions, ask, and hopefully we can find an answer, maybe with a matching video.
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    Post  tsenecal on Mon Nov 20, 2017 10:24 pm

    david f wrote:....

    PS Just made a mention of openLRS on the SubCommittee forum. It can only help.


    i have been mentioning it there since 2014... doesn't seem to help...
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    Post  tsenecal on Mon Nov 20, 2017 10:29 pm

    david f wrote:Looking back at your post before last and the use of 868 Mhz in the UK. It doesn't seem to be available:

    http://www.ukrcc.org/40mhz.html

    So it is 458 or nothing for us here.


    did a quick and dirty google search, and found a pdf put out by "Ofcom"

    Ofcom UK Frequency Allocation:

    High band devices
    The high band (868–870 MHz) is primarily used by wireless alarm systems,
    including fire, intruder and social alarms which are each subject to different
    operational and technical requirements. The band is subdivided further into a
    number of sub-bands, based primarily on technical characteristics such as power
    and duty cycle. Parts of the band are specifically identified for alarm systems,
    although alarms may also operate in the part of the band identified for non-specific
    devices. One of the alarm sub-bands is identified specifically for social alarms.
    Underlay systems may utilise the whole 863–870 MHz band and typically deploy
    spread spectrum or other wideband RF technologies. Applications are non-specific
    and may include any of the applications associated specifically with the low, mid and
    high bands.
    Apart from the three types of alarm system already identified (i.e. fire, intruder and
    social alarms), a number of other applications take advantage of the non-specific aspect of the regulations. These applications include home/office automation, access control, remote controllers, medical, telecare, smart meters, telemetry
    and automotive."

    emphasis on content is mine.


    defining what "remote controllers" means in this context is unknown by me, but definitely needs to be clarified. I also have no idea what "Ofcom" is or what its purpose in life is.
    thegrimreaper
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    Post  thegrimreaper on Tue Nov 21, 2017 9:08 am

    Hi Tim,

    https://www.ofcom.org.uk/

    OfCom is the official office for our communications here in the U.K. they govern the airways and have far reaching powers through our courts over anything to do with cable or wireless transmitions within the borders of the U.K.

    Regards Mark.
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    Post  tsenecal on Tue Nov 21, 2017 9:03 pm

    Mark,

    i figured you guys would know who Ofcom is, and it appears i hit the right site by sheer accident.  they appear to be the equivalent to our FCC here in the states.   i would definitely see if they have a specific definition of "remote controller", and verify if the devices we/you use will fall under that definition. if the definition works, that would make 868mhz a viable alternative. I ran my 915mhz equipment at a recent model sub regatta, with as good a performance from the 3 915mhz subs as i did from the single 433mhz sub.
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    Post  tsenecal on Fri Nov 24, 2017 4:31 pm

    just so that you understand why i have gone to the effort for the research on the 868mhz equipment... there are several commercial products that are either available or will be available soon that are 868mhz, designed specifically "for the european market"... i also understand that "european market" doesn't necessarily mean "UK"... but it does bear researching to verify

    http://fpvlab.com/forums/showthread.php?51594-FrSky-R9-R9M-module-900Mhz-(868Mhz-EU)-Long-range-system
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    Post  david f on Fri May 17, 2019 12:14 pm

    I have just ordered and received another couple of Orange 433Mhz receivers from Hobbyking.
    So they are still available and took 17 days to arrive.

    David
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    Post  Nickj_UK on Mon May 27, 2019 9:55 pm

    Just out of interest I acquired a pair of Arduino nano's which have onboard 868mhz transceivers. I only picked these up as they are a known quantity and there is plenty of info and field tests on these specific units.
    I've also disemboweled an old 4 channel 2.4 transmitter purely because the trims are mechanical and simply advance/retard devices.
    At the moment the boards 'chirp' quite happily to each other over a reasonable line of sight (as far as I was happy to walk as extreme range isn't an issue) and the nominated transmitter continued to send a test signal and received confirmation of the signal with virtually no loss of signal strength.
    Next thing is to read and encode the tx components and add that to the tx signal with a decode at the receiver and conversion to a signal for servo's/switches and I'll have a working tx/rx combo.

    It's really the frequency that is at issue,as senecal noted OFCOM says 'These applications include home/office automation, access control, remote controllers, medical, telecare, smart meters, telemetry'.
    I think that by remote controllers they mean the small click on off devices, everything else in the inclusions is going to be more occasional signal pulses rather than what we would want, an almost continuous signal which is more the role envisaged for 915.
    So 868 is an experiment as 915 boards don't cost any more (I just couldn't find the ones I wanted at the time) and the code is all transferable between base arduino's.
    It's also possible to add a few more odds and ends like multiaxis gyros (levelling), pressure sensors (depth control) and custom OLED displays albeit very small.



    Last edited by Nickj_UK on Mon May 27, 2019 9:58 pm; edited 1 time in total (Reason for editing : added a bit)
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    Post  tsenecal on Tue May 28, 2019 9:19 pm

    Nickj_UK,

    what brand/model radio did you pick up? most traditional fm style radios will output a ppm signal to the RF deck, but a lot of the newer 2.4ghz systems are "digital" for the entire workflow, and much harder to find a signal that can be "hijacked"...
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    Post  Nickj_UK on Tue May 28, 2019 11:15 pm

    It's a generic 4 channel, E sky 2.4 ghz tx. There are the usual two twin axis sticks and there was a trainer switch.
    The encoder board and tx board where seperate discrete pcb's, as I am going to use the arduino to capture the stick positions and the digital inputs of on/off switches then the encoder board becomes redundant.
    The tx board is replaced by the tranceiver piggy backed on the arduino so again the original becomes redundant.
    I just (mostly simply) measure the volts out of the pots using the arduinos built in ADC's, put a that into a string of data that becomes the tx signal.
    The receiver arduino converts the numbers in the signal to an output to drive the servos, it'll also send back a signal reception strength (these LoRa's are all tranceivers so do 2 way) that the rx end can display it. That can also act as a 'panic' trigger to put planes to rise and blow tanks.

    I've added a further two rotary pots for two more analogue inputs and a pair of switches for simple digital on/off switches.
    I might swap a one of the rotary (or both) for a 3 way switch to give a hi/mid/low output from the tx which would be more useful for driving a piston tank controller.

    As this has cost me the grand sum of £40ish so far for arduino boards, pots switches tranceivers and the original transmitter I won't be too worried if it doesn't work as planned. I can reuse most everything in other projects.
    Mostly it's just being doing for the fun of it and the possibility that I'l get something at the end that works and works in the way I want it to.

    Otherwise I'll just use one of my 2.4 computer tx's with a hacked 40mhz module, my F14 (14 available channels but a limited number of crystals ) or the brand new old stock synthesised multiplex 40mhz tx I recently acquired (nice if an odd menu system).
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    Post  C-3PO on Mon Jun 03, 2019 11:09 pm

    Hi Nickj_UK,

    Interesting posts - what transceiver is it on the Arduino Nano boards that you recently aquired?

    Regards

    Jonathan
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    Post  Nickj_UK on Tue Jun 04, 2019 8:36 am

    The boards I have to experiment with are these Transceivers .
    Not the highest range units but for a sub it is really a bit arbitary, after all is it likely that you'll be running on the surface at something like 6km range!!


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    Post  C-3PO on Tue Jun 04, 2019 8:58 am

    Hi - Thanks for info - that looks like a HOPE RF device plonked on the board - probably - RFM92W-868S2

    It also looks like you can select the operating frequency by changing device registers.

    Do you know if there is a duty cycle restriction with the board you have tested?

    Regards
    Jonathan
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    Post  Nickj_UK on Tue Jun 04, 2019 2:57 pm

    All of these drop power output (so decrease range) you increase the frequency of transmissions, this is to prevent overheating I believe. Quite by how much is a very good question and I'll probably end up needing a higher output transceiver to account for this. These were after all designed for the Internet Of Things which would typically use a very brief and occasional signal, after all who needs to check (as an example) soil for moisture a few times a second to control an automatic irrigation system? I'm going to start with 4 chirps a second and ramp up from there. I've not got anything that will be physically very fast, depth keeping and levelling are to be managed by an AD2 & DC from Kevin McLeod so a 'slow' response is probably less of an issue than it might seem.
    To avoid too much of this throttling the sent message needs to be brief so there can be a sleep period between chirps. All I'm planning on sending are the control stick & switch positions with the receiver converting them to the servo output. I could as easily send the stick positions as servo positions though I'm not sure that would make any difference to the to signal content as they will be very similar length numbers.
    In any case one or other end of the Rx Tx combo will allow modifications to the values, I'm thinking along the lines of keeping the Tx end just stick positions and then tune the Rx output to the boat.

    Oh Yes the frequency seems to be selectable but the ariels need to be different lengths for each.
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    Post  C-3PO on Tue Jun 04, 2019 3:03 pm

    It's a fascinating topic - I will look out for your updates on progress

    I am on a similar path but on 459mhz

    Regards
    Jonathan
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    Post  david f on Sat May 02, 2020 8:42 am

    Just a note to say that I have uploaded two sample files for openLRS transmitter and receiver configuration on the "Files" section of our Facebook site. (My thanks to Tim G for showing the way on this. You will need to rename the .zipp files to .zip files to unzip them.)

    These will get you started and get you onto the recommended UK legal frequency of 458-459 Mhz.

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    Post  Uptona on Sat Jul 11, 2020 12:27 pm

    David, Tim,
    I’ve read with interest this post as somebody who is new to this hobby.
    I am finishing my first model submarine and need to acquire a suitable transmitter radio and receiver set for use in UK. I’ve quickly learnt 40Mhz devices are scarce and arguably prefer something future proof.
    Are the Orange OpenLrs modules I’ve read about the way to go and what new radio transmitter would you start with and will the said modules drop in ?

    If you could point me to where such devices are available for me to consider that would be really helpful.
    david f
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    Post  david f on Tue Jul 14, 2020 8:14 am

    I wish there was an easy "off the shelf" availability of openLRS equipment suitable for "beginners" but it is not that simple. Lack of commercial suppliers of equipment continues to be one of the major problems in our hobby.

    The frequency for r/c equipment is heading ever upwards and this creates problems for model submariners who need lower frequency signals that propagate in water.  2.4 Ghz is useless for us. We once had a good supply of drone equipment at 433 Mhz (which we could configure to the UK legal frequency of 458Mhz). But drone enthusiasts have moved up to about 800Mhz which is less good for us. Tim Senecal (who pioneered openLRS for subs) has shown that equipment at this frequency can be used for subs. (The UK is typically independent in that we are the only country using 458 MHz! In the US they can use 433 but have to pass on online exam first.)

    Some links from Tim regarding 800Mhz equipment:

    https://www.banggood.com/FrSky-Taranis-Q-X7-ACCESS-2_4GHz-24CH-Mode2-Transmitter-with-R9M-2019-Long-Range-Module-for-RC-Drone-p-1612732.html?rmmds=search&ID=2336279156&cur_warehouse=CN

    https://www.banggood.com/FrSky-R9-900MHz-16CH-Long-Range-RC-Receiver-R9M-Module-System-p-1152994.html?akmClientCountry=GB&p=6L1818635832201406F2&cur_warehouse=CZ

    The only supplier of 433 Mhz openLRS RXs and TX modules, that I know of, is Hobbyking and they are out of stock of RXs at the moment. Flytron in the UK no longer supply this equipment.

    https://hobbyking.com/en_us/orangerx-open-lrs-433mhz-transmitter-1w-jr-turnigy-compatible.html?queryID=5153abbff8c2c9fc2790af5d2da25b13&objectID=46651&indexName=hbk_live_magento_en_us_products

    It also used to be possible to drop an openLRS module into the back of Futaba and JR Txs but I don't think these are available other than secondhand.

    My, UK specific, advice to you would be to buy the Hobbyking TX and RX modules when they both come back into stock. (They are not expensive). Uploading the open source openLRS software would be easy for you if you have experience of (say) Arduinos. (To avoid frying the modules always  have an aerial connected and also check the continuity of the aerial coax. I have had reports and experienced one module where the earth screen was not connected. The TX module can transmit at 1 Watt but 100 mW is the maximum power in the UK. You can set the power output in the Chrome configurator setup.)

    You will need to connect the TX module to a transmitter via the trainer socket. It will be a little bit of a "Frankentransmitter" as a US colleague named it but you can easily add useful things like telemetry (see my thread on here.) so it would be worth the effort at not much cost.

    You could also try the 800Mhz option that Tim has tried. (See link above and I hope Tim updates us on this and the Russian supplier option. Fortunately nothing seems to be available from Huawei - joke!)

    Sorry that it involves a fair bit of research and DIY. It would help everyone in the hobby if you could report back on here on the availability of equipment.

    It seems to me that there is a commercial opportunity for somebody to provide specialised (and premium priced!) submarine radio control equipment running at 400 or 800 Mhz (or come to think about it - 40Mhz!).
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    Post  david f on Mon Jul 20, 2020 11:49 am

    I have had email conversation with Tim Senecal who pioneered the openLRS system for subs. I attach it in full below:

    Hi Tim,

    I am trying to give an answer to a UK guy on this over on the AMS forum but I don't know much about the above Russian supplier.

    Where can I track them down?

    (It does seem that these frequencies are legal in the UK (Ofcom report attached)  but I have no experience of operating subs at these frequencies.)

    Stay well!

    David

    Hi David,

    ChipLRS (in Russia - DF note) has left the market, he is no longer making OpenLRS items, he says the market has dried up, and he has moved onto other things...


    Tim

    Hi David,

    For people that want to move to 915/868 who have JR style equipment, i have moved over to the commercially available FrSky "R9" equipment.

    Tim

    Hi Tim,

    Thanks for the info.

    So it looks like 433 is fast disappearing and it really looks like newcomers would be best advised to go to FrSky on 915 Mhz. Can I quote you directly on the Forum?

    I have never tried  915Mz. Does it work as well as 433 in your experience?

    Stay well,

    David

    Hi David,

    due to the lack of anyone outside of hobbyking keeping 433/458 alive, i would have to say that the FrSky 868/915 is the only thing currently available.

    915/868 does not work as well as 433, you will be lucky to reach depths of 2 feet.

    915/868 also has as many faults as 433/458...  it is not as mature as 2.4ghz, so generally step number one when you get a new module or receiver is to update it to make sure it is running the newest version of the firmware, and if that is newer than the rest of your equipment, then all your old equipment then needs to be updated as well...   which can be a real pain in the ass if you have a ton of receivers.  updating them requires connection to the "s-port" on the receiver.

    Tim


    Based on Tim's reply, my conclusions are:

    - For someone new to submarines in the UK you have 3 equipment options:

    -- 40 Mhz (Works well at a good depth 2m+. Secondhand, older gear. May be available new from Germany.)

    -- 458 Mhz (Works well at 1m+. Telemetry available. Supply from Hobbyking may be drying up (RXs out of stock at time of writing. Needs DIY approach. Low cost.)

    -- 915 Mhz (Works down to about 0.5m. Good supply from FrSky. Works "out of the box." Telemetry. Not much user experience among model submariners. We need people to try this and let us know how they get on.

    So it is not a particular good situation for model submariners regarding supply of equipment. We have rather been boxed in to the use of high frequencies by flying enthusiasts.

    There are signs of  specialised suppliers for model submariners appearing. Matt Thor of Nautilus Drydocks has some news of promising developments over on the SubCommittee.

    David
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    Post  david f on Sat Aug 01, 2020 9:42 am

    Thanks to Uptona for asking the original and rather important question. I have tried to summarise my suggested answer to Uptona at the bottom of the post.

    I posted the question on various submarine sites and Model Boat Mayhem contributors came up with very useful contributions:

    https://www.modelboatmayhem.co.uk/forum/index.php/topic,65389.0.html

    I hope that Model Boat Mayhem and their contributors don't mind if I post some extracts but this AMS forum  thread represents most  of  the development of this topic (Going back to 2010 !) so it is worth making it complete.

    Extracts follow:

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


    Quote from: Subculture on July 30, 2020, 05:35:57 PM
    Bob tried it and didn't seem too impressed.
    https://www.youtube.com/watch?v=hGDxRDqIfdk

    tsenecal
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    I saw bob's video several months ago, and all i can say is is that i got better results than he did, i do not know what type of pool chemicals he uses, but i have run 433mhz and 915mhz equipment in swimming pools, and small ponds with performance as follows:

    433mhz:  best case scenario was at 100mw output and i was able to reach 5 foot depth in a swimming pool and similar depths in a city pond used as a city water source (clean with very little mineral content), i was able to achieve 2 to 3 foot depths at a spring fed city pond where there was an extremely high mineral content

    915mhz:  best case scenario was at 1000mw output at the same swimming pool used above, where i reached a depth of about 2 feet.  at the same city pond used as a city water source, this equipment regularly reached depths of less than 2 feet (perhaps 18 inches or so).

    In all situations, i judged "full use" as total control of the vehicle, and no invocation of failsafe systems., however, proper configuration of failsafe systems allowed for swift retrieval/resumption of service and some of the equipment allowed for missing data packets, and until total loss of system control, failsafe would not be invoked, allowing for the appearance of total control, even though the standard 50hz data path may have degraded to as low as 1hz before failsafe was invoked.


    in layman's terms, due to the protocol used by OpenLRSng, lost data packets were not immediately considered to be loss of control, and only when zero packets were transferred for a user selected period of time (i chose one second) did failsafe kick in.   this is very much in line with other stand-alone failsafe systems used by model submarines for the lower 27-75mhz classic setups which would allow for as much as a 5 second delay before the failsafe was invoked.


    I will also say that David F and I have spent considerable time testing many different antennas both on the transmitter and receiver, and i have also found that antenna placement on the model can alter perceived range drastically.


    My attempt at a summary:

    Thanks to everyone for their most helpful replies, from which some picture is emerging.


    The reason why I asked the question originally was just passing on a query from a newcomer to the hobby without any equipment. ( I have enough 433 and 40 Mhz  gear to last a lifetime!)


    Based on your replies, I think my reply to them would be:


    - Purchase the "900" Mhz gear if you can't obtain ANY OTHER r/c equipment and it's use will be legal in the country you are operating it in.


    - Be prepared for the fail safes to operate (Don't forget to set them!)


    David

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