Radios
 

Hello What is the best frequency for submarine use? also what is better FM or AM? I am needing a radio for my PVC sub. I need a three channel. Anyone have a spare for sale or a really used one??? I also need a coupld of speed controls. Thanks Tom.

RE: Radios
 

use FM and any surface frequency will do. you're not supposed to use aircraft frequencies

RE: Radios
 

I see people in the Wally sub topic have said lower frequencies--say, 27 MHz versus 49 MHz--theoretically should
have better range.

I don't have one sub of each frequency to compare side-by-side, but I remember talking with an ex-submariner
friend.

I guess he may have been transitioning off the boats--about to get out of the Navy after 12 years--when
he worked at a radio facility for talking to the submarines.

I remember he said storms around the power lines had eerie effects because of the really low
frequencies used to reach the subs. I don't remember whether he said ULF or ELF. In "Hunt For Red October"
I seem to remember a line about a transmission coming over the ELF. Maybe ULF was long-range and
the ELF was short-range?


Anyway, that the Navy uses super-low frequencies for subs kinda suggests 27 MHz might have a bit more penetration
power than 49MHz.

RE: Radios
 

Lower frequencies penerate water better. Transmitters which pump out more RF power give better range. FM ususally sufferes less interferance than AM.

RE: Radios
 

Fascinating...I've been reading how the Navy uses low frequencies to communicate with subs.

I don't think we can get a portable ULF controller box for our RC subs: The length an antenna needs to be reasonably efficient relates inversely to the wavelength it must send.

That's why one submarine communication facility in the US has an antenna over 200 km long.

(Plus, if someone started controlling RC boats with a ULF box, I'm sure the FCC would not be amused).

ULF/ELF signal bands have such penetrating power that antennae are buried in the ground; in fact, if the receiver antenna is aboveground, it picks up every little signal around, so they have to bury it to cut the noise.



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ULF can penetrate several hundred meters of seawater.

But the reach comes with definite considerations: A rate of--let's say one Herz--is one wave per second...meaning you can only communicate one bit per second ! If it your character set took eight bits to form each letter, you'd have to listen a minute and a half to receive "SURFACE NOW"

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ELF has less saltwater-penetrating reach than ULF: a few hundred feet, rather than a few hundred meters. But the signal rate is faster. ELF is used to beckon a sub to a shallower depth where it can receive a faster (shorter-wavelength) rate.