2.4GHz radio

[jean deschamps]

Hi need imformation on radio.Being new on rc sub, would like to know if
the new 2.4 GHz radio are ok for rc submarine
thank you Jean Deschamps

[toppack]

No, Short-wavelength high-frequencies, in the GigaHurtz bands, do Not have much range under water. The old AM 75.Megahurtz band is probably the best to use.
That's why Whales talk to each other in very low frequencies, much more range. :)

[toppack]

I got to wondering about the 'Speed' of Radio signals Under water ???
I've heard that Sound travels about 3.5 times Faster in Water than it does in Air, so I assume that radio waves would Also.
If so, then the response times of our Subs controls would be Faster when submerged, correct? :confused:
Maybe a few milliseconds faster. :D LOL :D

[jean deschamps]

:confused:
No, Short-wavelength high-frequencies, in the GigaHurtz bands, do Not have much range under water. The old AM 75.Megahurtz band is probably the best to use.
That's why Whales talk to each other in very low frequencies, much more range. :)

thanks, Toppack, but i am still a little bit confused:.First are Polks radio still availlable, they seem to be popular at sub regata. Secondo i already have 3 FM surface radio ,how bad are they compare to AM surface radio and finaly
what about 27MHz surface radio compared to (75MHz AM .That you sugest) You see i already have 3 FM surface radio and unless they are no good for rc sub would like to use them

[toppack]

I think Any radio systems in the Megahertz bands will work okay, it's just the Gigahertz bands that are very limited under water. Only slight differences in range of Megahertz bands.
For the AM versus FM question, I've been told that AM is better for Subs but I have no experience with FM. I've just always used AM for my surface RC ships, so that's what I have.
When I started using AM there were Not any FM radios. Does that make feel Old? Yep, it sure Does! :)

[toppack]

Sorry, I'm not familiar with Polks RC system. I've always used Futaba or Ace equipment. But Ace no longer makes the kits I liked so much. :(

[toppack]

I did an Internet search on Polk's system. I found some guys that really liked them but also some that were having a lot of trouble with them.
They seem to be Overkill for RC ships, since they are complicated, with a lot of trim adjustments, programming and calibrations (for aircraft) not usually needed for ships and boats. I like to keep it simple, since I have No need to 'Impress the Neighbors',with extra knobs, buttons and LCD displays. :)

[Kazzer]

I did an Internet search on Polk's system. I found some guys that really liked them but also some that were having a lot of trouble with them.
They seem to be Overkill for RC ships, since they are complicated, with a lot of trim adjustments, programming and calibrations (for aircraft) not usually needed for ships and boats. I like to keep it simple, since I have No need to 'Impress the Neighbors',with extra knobs, buttons and LCD displays. :)

BINGO! Merriman simply loves our WFLY 6 channel radio, its nice and simple and it works well with its own receiver AND with the SOMBRA LABS one. The Polk receiver has caused us some problems with this radio.
The WFLY uses Futaba crystals in the transmitter, so you can change the frequency quite easily. It comes set on ch 69.

http://support.caswellplating.com/index.php?_m=downloads&_a=viewdownload&downloaditemid=84&nav=0,5

http://support.caswellplating.com/index.php?_m=downloads&_a=viewdownload&downloaditemid=86&nav=0,5

[toppack]

Mike or David,
The W-FLY system is the new PPM-FM or PCM-FM , correct?
Do you know which it is?
Have you ever used an AM system for your subs?

[toppack]

I found an interesting website , with Info about PPM versus PCM FM.
Most of website is in German but this page has been translated:

http://www.aerodesign.de/peter/2000/PCM/PCM_PPM_eng.html#Anker143893

[toppack]

Mike or David,
The W-FLY system is the new PPM-FM or PCM-FM , correct?
Do you know which it is?
Have you ever used an AM system for your subs?

Looks like my questions have been Ignored here also. :rolleyes:
Oh well, I guess they can't have all the answers. :D LOL :D
Or maybe I just have too many questions, ya reckon?

[Kazzer]

Looks like my questions have been Ignored here also. :rolleyes:
Oh well, I guess they can't have all the answers. :D LOL :D
Or maybe I just have too many questions, ya reckon?

I'm not an expert on radio, but I do know where the 'on' switch is. Maybe someone could explain what PPM-FM or PCM-FM means? :confused:

[toppack]

I'm not an expert on radio, but I do know where the 'on' switch is. Maybe someone could explain what PPM-FM or PCM-FM means? :confused:

Mike, the link I posted explains it pretty well.
You need to be an Electronics Engineer to Really understand it, tho.
PPM - Pulse Position Modulation
PCM - Pulse Code Modulation
both are types of, FM - Frequency Modulation
The main thing is that PCM is an improvment over the older FM systems. I was just curious which the WFLY used, since everyone seems to be keeping it a Secret, as to what it is. ;)
http://www.aerodesign.de/peter/2000/PCM/PCM_PPM_eng.html#Anker143893

But I mainly wanted to know if anyone has experience with AM system, in a sub, like I'll be using???

[He Who Shall Not Be Named]

Mike, the link I posted explains it pretty well.
Altho there are slight differences in the 2, the main thing is that they are both improvments over the original FM systems. I was just curious which the WFLY used, since everyone seems to be keeping it a Secret, as to what it is. ;)
http://www.aerodesign.de/peter/2000/PCM/PCM_PPM_eng.html#Anker143893

But I mainly wanted to know if anyone has experience with AM system, in a sub, like I'll be using???

Yes ... ****** .... AM works fine punching through the water as long as its on or near the 40-75mHz bands. It's not the modulation mode that matters, it's the carrier frequency!

You trying to make e-bay stuff work for you? No one makes AM gear anymore.

David,

[toppack]

Thanks,..................******............:D LOL :D
I have enough AM equipment to last 3 lifetimes. ;)
Some I built myself, but most I've collected over 40 years in the RC hobby.
I know AM is not blocked by hills, buidings, etc. like FM is,
so I assumed water would not also, but I wanted to ask the experts to make sure, before sinking my boat.
The main reason for the big switch from AM to FM, was that the FM components, in development at that time, were Cheaper to make and assemble, not that it is a better system than AM.
Profit Rules, but Not always correct.

[He Who Shall Not Be Named]

Thanks,..................******............:D LOL :D
I have enough Am equipment to last 3 lifetimes. ;)
Some I built myself, but most I've collected over 40 years in the RC hobby.
I know AM is not blocked by hills, buidings, etc. like FM is,
so I assumed water would not also, but I wanted to ask the experts to make sure, before sinking my boat.
The main reason for the big switch from AM to FM, was that the FM components, in development at that time, were Cheaper to make and assemble, not that it is a better system than AM.
Profit Rules, but Not always correct.

What, You have old ControlAir and Heathkit stuff in the shop? I think Babcock also offered 'kits' of r/c systems 'in the day'. And Ace offered kits I think. Remember the old analog proportional gear that made the transition between reed and digital proportional? AirTrol (spelling) comes to mind.

My first r/c was rudder only, escapement types. Then I graduated to 'galloping-ghost'.

David,

[toppack]

Ah yes, the 'Good ol' days'. :D LOL :D
RC meant 'Real Challenge' back then.
I nearly cried when Ace stopped making kits. :D LOL :D

[Kazzer]

Thankfully, I'm not an electronics engineer, so that means I don't have to read that stuff, right?

Phew! I felt a migraine coming on!

[toppack]

Yep, No need to 'Confuse the Situation'! :D