20 channel radio setup - any interest?

[Subculture]

I would imagine easier said than done. I agree a custom module and receiver combo would be the way to go, as it allows the use of modern TX's which are readily available.

Manufacturers want orders in the hundreds or thousands to make a special line, otherwise it's not worth their time. This niche sector of the hobby is too small to support that, so it would reply on cottage industry professionals to make or adapt a device, hence the VEX tweaks.

Will there be the customers for this at all? Don't see many new starters in this hobby, and the well seasoned already are 'radioed up', guess Bob will have a better feel for sales volumes than I

[vital.spark]

Wyfly make reasonable priced receivers that use Synthesized RF Modules! Just produce modules in 75mhz! I have 2 Wfly WFT-08 Transmitters one from Caswell and the other I picked up on ebay. I damaged one and I contacted Candy at Wfly in Shenzhen. I was able to send it to them for repair with a quick turn around. They are a great group work with them on the Module side only if possible? This way no need to stock transmitters, only modules! This will keep us going for a long long time! To me, this makes common sense.

[Bob Gato]

One other question:
Since it was stated the 40Mhz cannot be used in the US, how are the small toy 40Mhz RC submarines sold in the US, does anyone have a simple answer?

I would think the same way 433MHZ is used for 4 channel relay activation and garage door openers without a Ham license

[Subculture]

Purchasing and using are two different things. Not legal to use 40mhz even for toys, but difficult to enforce. Toy radios also tend to be extremely weak compared with hobby grade.

[SSN687]

Afraid not. You can use 75mhz, 50mhz and 433mhz with a HAM technicians license and 900mhz.

One other question:
Since it was stated the 40Mhz cannot be used in the US, how are the small toy 40Mhz RC submarines sold in the US, does anyone have a simple answer?

[SSN687]

13 July 2019
I sorta think that we are looking at this problem the wrong way. I’m using Futaba is just as an example here. There are enough old pcm1020 Futaba T7 and T9 with 7 and 9 channel radios and receivers that can be recycled and modified from 72Mhz to 75Mhz to be used for our hobby to last for a very long time. I live in a rural area of South Carolina, the fly boys here have their own landing field, most use or have swapped to 2.4Ghz systems. The fly club has been very helpful explaining the capabilities and answering any programing questions with my Futaba T7CAP radio. A lot of the fly clubs are even buying the old 72Mhz systems just to teach the radio basics to the new and younger members and how to swap them to 2.4Ghz. The 2.4Ghz systems have made the 72Mhz systems are very inexpensive. The 72Mhz systems can be purchased for under a $100 and then have it converted from 72Mhz to 75Mhz if you have the crystal to send along with it to Tony Stillman.

The problem is that there is not enough 75Mhz crystals sets around to convert these 72Mhz systems to 75Mhz systems.

I think our solution is in the development or modification of crystal sets for the conversion of existing radio systems. I have no clue what it would cost or if possible to have crystals made or modified for this solution. I do know that Futaba still makes 75Mhz systems for car and trucks, but 2 to 4 channels.

We need a new crystal sets that will work for the conversion of the 72Mhz systems to 75Mhz systems.
or
Modification of the new 75Mhz crystals to work on the older systems with 7 to 9 channels.
or
If not specific crystals sets then maybe 75Mhz synthesized RF modules for radios, something like the Hitec Spectra Synthesized RF Module, that can be dialed into channel 61 to channel 90 and receivers that are synthesized RF also.

My $0.02 worth

[Bob Gato]

Bob, consider the possibilities of designing and marketing it as 8-10 channel and expandable to 20?

[Subculture]

Tim Senecal did some experimenting with the 900mhz Frsky kit. He was getting a foot or so of depth, perhaps a bit more when close to the bank. Not as good as 433mhz or the lower frequencies, but no Ham license needed, and it's an improvement on 2.4ghz. Cost is reasonable.

[RCSubGuy]

This is all great feedback, guys. Thanks a lot.

I think the consensus is that anything north of 8 channels is a waste. Having a couple of additional proportional channels would be good, along with a couple of latching 2 and 3-way switches. I think I'll see what we might come up with in regard to an expansion board that offers two proportional channels off the sticks, two two-way switches off the other stick, and one three way off the rear buttons. It would be a piece of cake to add up to two, giving 15 channels for a very reasonable price. In that way, you could even group functions such as torpedoes on an expansion board for easier operation in the field, and less chance of an inadvertent launch.

The bigger issue, as we all know, is radio availability in low frequency. WFLY in China said they could work with me on 35, 40 and 72mhz, but not 75mhz. Minimum order 300pcs. Ouch.

Ultimately, I think the writing may be on the wall in regard to full diving capability in our boats, or at least diving capability that retains submerged control. I could see developing a module that would assume control of a boat when in controlled dive mode, perhaps maintaining a set depth and keeping a locked center rudder for a period of time before automatically surfacing again, but submerged operation while retaining control and using high frequency radios will be off the table.

As Quartermaster said, 2.4GHz is not a tremendous limitation to the hobby, but it does limit our capabilities and flexibility.


Bob

[Subculture]

Is 40Mhz legal to use in the US?

Afraid not. You can use 75mhz, 50mhz and 433mhz with a HAM technicians license and 900mhz.

[SSN687]

12 July 2019

Riddle me this Batman,
Is 40Mhz legal to use in the US?
If so why no use the Futaba/Robbe F14 from UK?
If not how are the wireless RC submarine toys that use 40Mhz sold in the US?

Just curious

[QuarterMaster]

Okay we need 433, 40, 75MHZ to control our subs underwater.
What you might want to think about is a radio that converts those needed frequencies to 2.4ghz.
Why you ask? Then you could possibly use your phone, I-pad, game/drone controller to control your submarine.
The phone would send commands to the frequency converting radio then on to the submarine.
This would do away with your gimbals, switches, sliders if you wanted to.
Program your dive sequences, servo throws, and throttle levels in your submarine control app.
Add as many features as your receiver allows.
I can dream this stuff up all day. Just an idea for thought.

Not sure about the conversion part.....

I'm probably the only dude actually running with 2.4Ghz.

Since periscope depth is my wheel house, it meets's my needs and I'm actually pretty excited by it when I let go of the fact I can't submerge my scope, accounting for 99% of my dive time anyway.
I use it on any boat with Mast's and Antennas and is practical (Not the Harper Goff designs lol)
Blame Dave M. on his original article about it which drew me in.

Thanks to the Drone dudes, here I am receiving telemetry from my 1:48 Scale DeBoer SKIPJACK on the Test Bed.





RSSI of -55dBM indicates excellent signal strength
She's on a heading of 001 deg (Yaw +1.3, reads 0-359 deg)
Listing to PORT 1 deg (Roll +1 deg)
and a slight up bubble of 1.3 deg (Pitch +1.3)
Transmitter Voltage is 10.3V
Subs Main Power is at 12.3V
RCVR Power on the home screen had indicated 5.4V
Throttle indicates ALL STOP
Now what about this altitude?? .4m???
It's the on board Barometer...if that increases, YOU have a leak lol!!

Now if I can only get a small enough GPS antenna.....

This weekend I'll have real world trials in Queens.

So, a few questions:

1.) Is 15 to 20 channels something that you can see a need for, or is this overkill?
2.) What setup would be best for the expansion channels? IE: full proportional control, two-way, or three-way switches?

Bob,

With respect to your questions, I'd say with your database of customers, you should already have your answer.

I'd say 80-90% of your customers need only 6 channels. Or am I wrong?
1-Helm
2-F/W or Bow Planes
3-Throttle
4-Vent/Blow
5-Stern
6-Spare (Weaps, LPB etc)

More so with question 2, I think it's the choice of switch action and availability above channel 4 that drives my purchase.
IE is channel 5 a dial, 2 pos switch or 3 position switch??

That's a 12Ch Radiolink AT10II above and realistically, I'm using 7 because of the limitations of choice the RadioLink has w/loss of signal w/regards to FailSafe.
Nice thing is that I can program which switch for whatever channel I want it on. Like 5 is a dial now, and 4 is a 3 position operating my vent or LPB, 6 is a 2 pos spring return for my Gas Emergency blow which also has the fail-safe.

If you have more than 20% of your customer Database actually purchasing more than 6 channels I'd be surprised.

But that's me, the idiot loving 2.4Ghz guy.

[Subculture]

Touch screens okay for momentary controls, but don't think you can beat a tactile set of sticks for control of the proportional aspects of a model.

[Scott T]

Okay we need 433, 40, 75MHZ to control our subs underwater.
What you might want to think about is a radio that converts those needed frequencies to 2.4ghz.
Why you ask? Then you could possibly use your phone, I-pad, game/drone controller to control your submarine.
The phone would send commands to the frequency converting radio then on to the submarine.
This would do away with your gimbals, switches, sliders if you wanted to.
Program your dive sequences, servo throws, and throttle levels in your submarine control app.
Add as many features as your receiver allows.
I can dream this stuff up all day. Just an idea for thought.

Drone controller I found while looking for 2.4GHZ controllers.

https://www.dronenerds.com/products/drones/consumer-drones/tello/gamesir-t1d-remote-controller-for-tello-drone-cp-pt-00000220-01-dji.html?msclkid=e14312b9414c13f663514f9e2b4c5ea2

[Subculture]

I think the vast majority of model submariners look for a set that offers five or six fully proportional controls, and one or two switched functions. A much smaller number may wish for extra channels for auxiliary functions like torpedoes, missiles, lighting, opening hatches, sound functions. Four proportional channels can be a bit limiting if you're running boat with forward and aft hydroplanes or a sophisticated ballast system

The Futaba/Robbe F14 is the only new radio set still available in 40mhz here in the UK, it's an old design now dating back to the early nineties, but despite its age it does offer what the majority of model submariners require- eight channels completely flexible in assignment, so they can be switched or proportional controls.