900mhz radios in subs

[RCSubGuy]

I have to admit... I had high hopes.

I think it was Bob Gaito that got my brain working in the direction of seeing if the high-powered transmitter option for the FRSKY radios might be a viable alternative to our traditional (and dying) 75mhz radios.

After much drama with getting a radio with a terribly outdated set of firmware that required sending to a repair facility, I finally got a functional 900mhz system here, ready to play with.

This video says it all...

Looking forward to comments from the peanut gallery!


Bob

[roedj]

There were comments on the video web page about the use of 433MHz radios, Others seem to make them work. All you have to do is to get a Technician class ham radio license. which is a true doddle here in the States. I'm not sure 433MHz is available outside of N. America.

Enough despair, Bob, there are workable solutions out there.

Dan

[Subculture]

Tim Senecal has done a lot of work with the 900 and 433mhz systems. So he would be a good person to consult.

Your results appear to be similar to what he got, you may get a bit more depth in a natural pond without a steel reinforced concrete liner and chlorinated water both of which can greatly diminish range.

433mhz can be used here in the UK, although the sets are typically pushed towards 458mhz, and we don't need a HAM license unless going past half a watt. In Europe that frequency cannot be used, so they're more restricted.

My thoughts on this? Most modellers are not going to be motivated to get a HAM license- 433mhz has been available for some years now, and it hasn't caught on with sub modellers beyond the very techy types that like to experiment and tinker. 900mhz (866mhz in UK and Europe) has some possibility but greatly diminished range compared with lower frequencies. So that leaves the old school sets, which are now getting very thin on the ground.

Has anyone considered designing a module in JR format to clip into transmitters like the Frsky Taranis, Turnigy sets and their clones etc. Combined with a receiver, ideally fully synthesized so the user isn't hampered by crystals and with some form of pcm or encoding to keep the glitches at bay.

Not a light undertaking I grant you, but the alternative is continued obsolescence, and the bigger manufacturers are unlikely to come to your aid. If the tuners could be designed to operate on alternative bands like 40mhz, 41mhz and 35mhz that would cover most parts of the world for surface (sub surface?).

[Subculture]

These guys did a lot of work on DIY transmitter and RF board adaptors.

http://mstar2k.com/microstar-2000/97-the-rf-deck

It's all become a bit less relevant in recent years with the advent of dirt cheap radio sets from China, and the explosion of higher frequency radios being spot on for anything but submarines.

The biggest obstacle I think, is simply that if something is built and sold commercially, it comes under a much tighter set of regulations than something that you might knock up yourself in a home workshop. Not that DIY RF is something where you can do as you please.

Sadly I think very modellers would be up to soldering up a board themselves.

Its too bad the big radio manufacturers didn't sell on the rights to their older designs. Hitec had a great synth module called the Spectra, which had a very simple method of switching the frequencies=- a pair of multiway switches on the side of the module. Therefore it could work with pretty much any radio. Many other synth rigs were specific to a manufacturer and the software in certain transmitters.

[Stephen Vick]

Has anyone asked the question: Will manufacturers continue to make 900 and 433 Mhz radios? Seems to me, we can go to a lot of trouble adapting to these frequencies, only to find that the manufacturers drop those freqs as well. Given they dropped the old surface frequencies as it wasn't financially feasible to continue. Because RC submarines are such a small portion of the market share, they had no incentive to cater to our needs.. How big is the market share for 433 or 900? I cant imagine its very big.
Observe , Adapt, Overcome.... I believe we will just need to face the fact that 2.4 will be all there is in the foreseeable future. I've recently read a couple of fine articles on adapting Coaxial cable for use as an extended antenna from a 2.4 Ghz receiver. Yes we will be restricted to "Periscope Depth" or a depth regulated by how long one makes the antenna (I intend a very unscale 12 inches above the sail)… As someone who, until recently, sailed in a salt water pond (San Diego). Running around at PD doesn't bother me. I sincerely hope I'm wrong about this, but, history has shown otherwise...

[Subculture]

This one has been thrashed around for the best part of a decade, once it became clear no new low frequency sets were likely to be coming to market. However no one has really come up with an answer, because there are a lot of obstacles in their path. It's also going to be a real tough one to even break even on any investment, let alone make a profit.

The facts are

1. Any solution is going to require some hard cash putting in to cover development and approval for sale. assuming the project was successful, recovering that cost may take years if it was returned at all.

2. Kits and DIY solutions are unlikely to appeal to all but a tiny minority who don't mind getting their hands dirty.

3. Uptake of any system which requires some form of certification or license e.g. ham is unlikely to gain widespread adoption.

433mhz and 900mhz are unlikely to disappear as they're largely based around units that are already in mass production, and their use is widespread beyond our hobby.

Although the lack of new equipment in the low frequency bands is an issue in the hobbies future, I do think it ranks lower on the list, with the most pressing situation being the advancing age of most active model submariners.

[Stephen Vick]

This one has been thrashed around for the best part of a decade, once it became clear no new low frequency sets were likely to be coming to market. However no one has really come up with an answer, because there are a lot of obstacles in their path. It's also going to be a real tough one to even break even on any investment, let alone make a profit.

The facts are

1. Any solution is going to require some hard cash putting in to cover development and approval for sale. assuming the project was successful, recovering that cost may take years if it was returned at all.

2. Kits and DIY solutions are unlikely to appeal to all but a tiny minority who don't mind getting their hands dirty.

3. Uptake of any system which requires some form of certification or license e.g. ham is unlikely to gain widespread adoption.

433mhz and 900mhz are unlikely to disappear as they're largely based around units that are already in mass production, and their use is widespread beyond our hobby.

Although the lack of new equipment in the low frequency bands is an issue in the hobbies future, I do think it ranks lower on the list, with the most pressing situation being the advancing age of most active model submariners.

I agree, and I would venture to say this; Adding yet another technical hurdle to our hobby does tend to keep it more exclusive. With the glut of RTR and ARTR boats, ships, planes etc... (hell they even have scale warships RTR) most facets of RC have gone to a "Shake the Box" level. It is hard to find builders anymore (although many do exist) I do a lot of RC Sailing which is overrun with Shake the Box.... Yet I find fellow builders, even in my small West Texas town. The RC submarine world is not nearly so overrun with "Shake the Box". Yes it is true that that so many are getting older, this is true throughout RC hobbyist. I'm afraid the newer generations get their thrills in the virtual world, with a plethora of games and simulators to keep them entertained. Still, I find a few young builders. from time to time. For my part, I'm swithching to 2.4 Ghz in my newer builds, iron out my problems now, before I have no other choice.

[QuarterMaster]

I agree, and I would venture to say this; Adding yet another technical hurdle to our hobby does tend to keep it more exclusive. With the glut of RTR and ARTR boats, ships, planes etc... (hell they even have scale warships RTR) most facets of RC have gone to a "Shake the Box" level. It is hard to find builders anymore (although many do exist) I do a lot of RC Sailing which is overrun with Shake the Box.... Yet I find fellow builders, even in my small West Texas town. The RC submarine world is not nearly so overrun with "Shake the Box". Yes it is true that that so many are getting older, this is true throughout RC hobbyist. I'm afraid the newer generations get their thrills in the virtual world, with a plethora of games and simulators to keep them entertained. Still, I find a few young builders. from time to time. For my part, I'm switching to 2.4 Ghz in my newer builds, iron out my problems now, before I have no other choice.

This is EXACTLY why I've been running and promoting 2.4Ghz for 4 seasons now.

To GET ahead of the curve, and accept that the world moves on.

As I told you in the other forum Stephen, I prefer this on MY terms, not the markets. My sub many not plunge deeper than PD, but I can run in ANYTHING.

CON:
Can't dive below periscope Depth.

PRO:
Inexpensive (12 Ch $105US TX and RX Spare RX for $20US)
Readily available
Digital/Programmable
Noise/Glitch FREE (ROCK SOLID performance proven at the North Lake in Groton, glitchiest pond on the planet) I circumnavigate that pond more times than I can count that day, hard to see a submerged scope at the far end!
Telemetry
No frequency flag begging at events.

For the 90% of us out there who's environment dictates PD running anyway, it's a boon, not a bust.

Any of ya'all tossing your boat's after the fall of 75Mhz, PM me with an selling price.

[Subculture]

How many have joined you in using 2.4ghz, Ed?

Seen one or two using it here in the UK, but it's rare. Mike Caswell spent a lot of time encouraging its use, as a new source of 75mhz sets was drying up. Don't think it was too popular with the punters.

[QuarterMaster]

I have 4, maybe 5 converts in various stages of setting up. Guy's in my area that run ponds and lakes. Water that is dark or not clear. Where one gets REAL nervous upon losing sight of a scope.

Those that have an existing large boat, plan on doing so in hopes are saving that 75Mhz radio for smaller boats (1:96 scale has a tighter PD tolerance than say my 1:48 SKIPJACK). The smaller boats also lend themselves to pool runners (my 1:15 Teskey PROTEUS vs my 1:48 Scale 688) and you see your boat running at depth. Also "littoral" running, watching their pride and joy skim the bottom between their legs in knee deep water. Granted Bob saw his boat at 20'(?) in a crystal clear lake in Canada where he first ran, but that's not the norm for any place I go. Finally, save the cherished 75Mhz for boats without scopes. NAUTILUS, PROTEUS, Military Mini subs, research subs etc.....

That is the among the best practices I have been learning these past four seasons.

Another thing to consider is the much needed fail safe. VERY important to know how they work in the newer radios in our line of work.

Remember, the industry is driven by millions of planes, drones, 'copters, cars, go fast boats that need INSTANTANEOUS Fail safes. Not the 5000 or so running RC Submarines on the planet. Which BTW Mr. Martin feels is an accurate number. 10k models may exist, but only 1/2 that running. EVEN if you double/quadruple that to 20K units running, NO way is that an investment for a Manufacturer when you can sell millions of 2.4Ghz. I feel I'm beating a dead horse now. Our community has to adapt, period.

The receiver now does ALL the "thinking" when LOS occurs, as programmed on the TX by you. NOT the device (IE a BLM) itself. For instance My Radio Link has two settings for each channel:
Adjustability: •Each channel may be set independently.
• The NOR (normal) setting holds the servo in its last commanded position.
• The F/S (Failsafe) function moves each servo to a predetermined position.

When I first installed it, I did not realize what was going on when I did my first functional test. She was up and running on the bench when I turned off the TX. The motor kept running as the ESC did NOT see the LOS, it was seeing the "NOR" setting of the receivers programmed fail safe. Same thing with the BLM! Had I been at "sea", the model losing signal would just keep going it's merry way!

So I set the throttle channel to F/S and go to 50% (0%= A/B Emergency, 100% is A/A FLANK!) That worked!!

However, while I can set my gas channel (I use channel 5, a 3 position Momentary switch for vent/Low Pressure Blower, and channel 8, a momentary switch for Gas Blow) to 100% on F/S, it would BLOW immediately upon LOS, so hitting a low buoyancy spot, or not watching yourself the model will immediately blow. Wasting gas!

So I took a spare channel (12) and added a mini servo, this was set to go "low" on F/S (0%) which swung the servo to hit a NC micro switch on the signal line of channel 8 between the RX and the F/S device (BLM, Old SubTech SES-2, newer-but still old SES 3/1 etc). Upon LOS it opens the signal to the F/S device, which appears to it as a LOS condition and it's inherent F/S programming takes over (IE 7 second countdown).

On my 1:48 591, I set that up along with throttle to 50%, Fairwaters (100%), and STERN planes (100%) which is full rise for boat.

Works perfectly!! If she drifts down and losses signal, both planes snap to rise and she usually coasts up and regains signal before she "safety's" with gas. Actually really cool seeing it in operation.

Granted the Servo/Microswitch setup is a tad cumbersome, but I'm currently investigating the use of an $11US ARDUINO "Beetle" to watchdog/pass-though channel 8 and give me a F/S countdown to blow. Learning the programming now. Kit comes tomorrow, plus I have enough Software Engineers at work to get help. I'm also hoping Bob's source in Canada (BLM, AD2 guy, name escapes me) will eventually supply a set that will spark at a specific setting (IE) so I can set the TX/RX to start the F/S at 50% on a 0-100% 2 position switch.

I understand some Radio's have a 3rd F/S setting, the third will actually pass through the LOS, allowing the F/S device(BLM), ESC, to fire their built in F/S programming
This is from a Frsky Xr8 manual.
Option-1: Set failsafe to a user-determined state on lost signal. (Set this for your dive planes)
Option-2: Set failsafe for no pulses on lost signal (What we’re used to, set this for F/S Devices)
Option-3: If failsafe is not set, failsafe default will hold last position before signal is lost. (Bad one, so set an option)

BTW, this is a perfect example of driving the market. Everyone reads this post and decides to by FRsky's Radio for thier sub's instead of Radiolinks, so Bob and Canada dude need not modify AD2, BLM for the Radiolink brand which he already has 5 receivers purchased for his boats. Eddie sad.

I did reach out to Radiolink and told them to up the game like Frysky. Many drones, planes have flight controllers now which have their OWN built in fail safe. Advantage...Frysky.

Speaking of "littoral" sailing, this is what I saw great many at Groton doing only that, they seem to fear deep water or crossing the lake submerged. I had 80% of the pond to myself where I sail with impunity. I patrolled it, I owned it lol. My only concern the surface craft not seeing me from shore. But avoiding Targets? That's what makes an RC Submariner! lol

Anyway, I do have Mr. Merriman and Mr. Caswell to thank for the initial push for me. Dave's article "How To Adapt The 'New' 2.4gHz Gear To R/C Submarines" really inspired me. I'm taking to it like a fish to water. Daves suggestion of full rise on the planes was obviously followed as well.

See I was SOOOO frustrated with glitchy running at Groton, or anywhere else, I had planned to start doing what Mike Dory, and Stephen Vick did, run my 75Mhz up the scope ANYWAY, since running at PD is my wheelhouse. That's when Dave's article inspired me. I also hated all the time wasted waiting for a frequency flag to clear. I ran for hours both days at this past Groton Fun Run!! Regarding Groton's know infamy for interference, I don't know how Rick Koelbrcher won "Bottom Gun" at the Groton regatta course 6 years in a row. Seemed like that USS TILEFISH SS-307 was immune to glitching! Some guys have all the luck.

But I'm sold on 2.4Ghz now, my boats sails rock steady, bring on any regatta course, any distance, any water quality. I will take reliability over diving beyond PD anytime. I sail with impunity.

[Subculture]

Frsky have been getting a bit of bad press of late. Quality control plus lack of backwards compatibility in their products.

For all the advantages of 2.4ghz kit, I've always felt the implementation of it was complete mess. It would have been far more beneficial to manufacturers and hobbyists if a common standard had been agreed on from the start and implemented across the board.

[RCSubGuy]

Progress, but painful options:

1). 72 and 40mhz radios, minimum order 300pcs of each. Negotiating prices and quantities now to see what this will end up like. 72mhz technically illegal to operate in the US for surface craft, but will work perfectly.

2.) 40mhz for Europe (300pcs) and 75mhz for NA (1000 minimum order).

Those quantities will carry this hobby for a decade at the current rate of consumption. If frequency regulations change, I could end up with tens of thousands of dollars in paperweights.

Like I said... progress, but not ideal...


Bob

[Stephen Vick]

I know most of us really do appreciate your efforts in this area Bob. I also know the overhead expense of having a stock of radios on hand. Crippling expense in this instance. I would not want that on my head. I'm coming around to Ed's point of view. I've got a newly finished type XXIII which is a perfect candidate for 2.4 conversion. Got an extra Frysky receiver which is getting a new longer antenna lead... Its gonna be Periscope depth for the foreseeable future! Oh well, my sailing venue is super murky anyway.

[QuarterMaster]

If frequency regulations change, I could end up with tens of thousands of dollars in paperweights.

Bob

I've always been a "Hope for the Best. Expect the worst." kinda guy.

My REAL fear through this whole mess has always been some yayo in DC is going to notice 72/75Mhz bands on the charts are pretty much free (except for 2500 or so numbskulls running RC Submarines which are a possible terrorist threat anyway), so why don't we assign it to something else?

After all, we can trust the US Government to not change things! Right?

Probably end up assigned to the "Submerged Freshwater Aquaculture Division" of the Undersecretary of the Interior!

Ed

[Subculture]

Don't think the lower frequencies are of great use, as their bandwidth is low.

Very few modellers use 27mhz these days, but the frequencies are still allotted to modelmakers same as they always were.

A bigger threat to R/C modelling in general is the tougher regulations being proposed for model flyers, with electronic tagging and/or restrictions to home built machines and where you can fly them. if that goes ahead, and it most likely will as there is a lot of very big money behind gaining control if the lower airspace, it will smash the model aviation hobby, and a lot of the development will follow.

As marine modellers we are just hand me down recipients of technology developed largely for the much more lucrative model aircraft sector it could greatly influence future availability of equipment.