433mhz links and info (Tim's Regatta Seminar)

[cheapsub]

look like hobby king is dumping all the module for less then $10 for cheap and transmitter too $22

[David F]

Some useful developments in DIY openLRS equipment starting with the link below.

Reasonably easy to solder the wireless chip+logic level shifter+ Arduino nano + ppm decoder chips together and a lot of people have the time nowadays to have a go with this useful technology developed by Tim Senecal in the US. (And it is all very low cost.) (I'm from the UK where we have the benefit of a dedicated frequency for r/c at 459 MHz)

Hobbyking still have the TX modules in stock but it looks as if the receivers will not be re-ordered by them. You can program RX's as TX's in openLRS.

https://www.modelboatmayhem.co.uk/forum/index.php/topic,65683.0.html

[David F]

The last post was a long time ago but actually quite a bit has been happening with 433MHz technology and the new UHF chips with significant extra features such as telemetry.

Some experimental underwater range testing to compare various systems here:

https://www.theassociationofmodelsubmariners.com/t83p225-openlrs-on-458mhz-and-433mhz-and-submarines#11599

David

[coryhenry]

Interesting, so only 1.5ft deep but pretty far for being that deep. I didn't see any depth tests?

[crueby]

Interesting data. Do you know how that would compare to 75 mhz off the shelf radios?

[cheapsub]

Wolfbox TX module and RX , still can get them from china. Works with old orangerx.

433 MHz VS 75 MHz.
75 or lower MHz is a no brainer. just turn it on is working. Based on no Frankenstein stuff. But Always someone using the same channel!
433 MHz works better with opentx or er9x transmitter.
Did Frankenstein to some none module transmitter (no PCM)it works too.
The orangerx stuff was not out of the box working.
Software reprogram etc...
I did give some set out, all end up in the garage.

Crueby if you're a HAM, want to give it a try, PM me.

[David F]

Thanks for the interesting questions.

The aim of the trials was to screen out different approaches with different chips and I chose 1.5 feet as a "typical" depth. The LoRa system shows great promise.

i think that 75 MHz would probably have a better range but I have no plans to test this. I would have to brush the dust off my 40MHz (in the UK) gear!

And yes 433MHz is still a little bit Frankenstein - everything a bit new is. The problem is that we model submariners have been left out in the cold by large equipment manufacturers. What we really need is some small commercial enterprise to take the technology onboard and make it less Frankenstein.

[cheapsub]

What manufacturer find out they could sale everyone all new equipment, they drop the 72 MHz/35 MHz stuff like a rock. We are only a change of crystal away, we end up in the dumpster too.

In US you need a HAM to use 433MHz.
Just like the old days, The HAM guy is the happiest at the field, no one uses his frequency.

David, did you tryed the sander antenna?
Fly boys didn't like the antenna came with the orangerx.

[David F]

I have tried various 433Mhz antenna. The Sander looks like a whip antenna, I think.
The practical problem is fitting them into a narrow WTC in a sub. I tried some dipoles but the standard commercial one seemed to be the best compromise. The antenna behaves in quite a different way when positioned horizontally, underwater, anyway. The best reference on this (if you don't mind some math!) is a US writer in this old British AMS mag:
"A very informative article by John Elin about antenna. (Best article I've ever seen about underwater antennae. Conclusions are TX height important, water conductivity important, shortened aerials may be better in water.)"
AMS 1986 6OCR:
IN:

https://www.facebook.com/groups/AMSmembers/files

Yes, know about the HAM requirement in the US but I understand it is an online test which is not too tricky??!!

[DrScoles]

cheapsub, are there futaba modules out there now for 433?? I got HAM license in 8th grade, 39 yrs ago.... I heard you don't even need to know morse code anymore?? sad...

I have a Futaba 14MZ that I really want to use for subs. I speak futaba fluently and have the 18 and 32mz radios for planes... the old 14 is pretty close software wise.

I got a hold of a 72mhz module, paid $150 for something that most plane guys have in the back of their junk drawers! Fine for my pool at home, but I'd like to be "legal" if I ever attend an event.

[cheapsub]

Hobbyking stop making TX and RX, but I stocked up.
The RF module is for the older Futada, may not work with your high tech futaba.
BUT, I think there is a way by using the trainer port PPM signal.
Can let you have one set with programming unit, and some other goodies.
Pick "1" watt ( false advertisement ) or 100 mw module. Rx only 100mw.

Also thinking selling one of my Frankenstein TX, so it just use a synthesiz 75MHz module be done with.