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-   -   RF (https://www.rcuniverse.com/forum/electric-general-discussion-106/5557530-rf.html)

Codeblack 03-13-2007 09:11 PM

RF
 
Hi, I have a myth that i want to turn into a fact, since i have been hearing a lot of commotion on this subject I would really like to know the real answer... The higher the radio frequency the wider the range? I know this is probably very controversial but please give me a common-sense answer, if you want to discuss then go nuts...thanks

GalenB 03-13-2007 09:23 PM

RE: RF
 
What do you mean by "the wider the range"? Do you mean the distance (range) between the Tx and Rx? Or are you asking about the spacing (range) between channels as the frequency increases?

jdetray 03-13-2007 10:13 PM

RE: RF
 
If the question is:

Do higher radio frequencies have a greater range than lower radio frequencies?

The answer is a no. In fact, if using equal transmitter power, the exact opposite is true for the frequencies we use in our R/C hobby.

For example, under the right circumstances, signals in the 27 MHz band (used by some R/C planes) can travel around the world. Signals is this band are readily refracted by the ionosphere, making the potential range very long, indeed.

Signals in the 72 MHz band (most popular band for R/C in the USA) will seldom travel so far but can travel up to 2,000 miles or so at relatively modest power levels.

Signals in the new 2.4 GHz band (used by the new Spektrum radios) are essentially line of sight and so do not usually travel beyond the horizon.

Higher transmitter power, more sensitive receivers, and better antennas can all increase range, no matter what the frequency.

- Jeff

Codeblack 03-13-2007 10:14 PM

RE: RF
 
Thank you so much for that clarification. Would you know where those worldwide radios are sold? I bet they are extremely expensive but I would like to check it out.

Dima

jdetray 03-13-2007 10:46 PM

RE: RF
 
Dima -

With an ordinary CB radio, which operates in the 27 MHz band, you can occasionally talk to other CBers thousands of miles away. You have to wait for the right conditions, but it happens. More powerful Amateur Radio (Ham) equipment can do this routinely, but an FCC license is required for using Ham equipment.

[link=http://www.hello-radio.org/whatis.html]Click here for more info about Ham Radio.[/link]

- Jeff

Codeblack 03-13-2007 11:10 PM

RE: RF
 
Seems to me that Ham radios for RC airplanes/cars would not work well worldwide because of all the interference, but is there a kind of a radio that's similar to Spektrum that's impervious to any other RF signal and that is able to reach worldwide?
Dima

jdetray 03-13-2007 11:58 PM

RE: RF
 
I wasn't suggesting the use of worldwide radio transmissions for R/C!! That would be ridiculous. You asked about the range of different frequencies, and I was providing some examples. For R/C use, we are restricted to relatively low-power transmissions, anyway.

Spread-spectrum technology (which is used in Spektrum R/C equipment) can also used for some Ham radio communications. The benefits are the same -- no intereference.

- Jeff

Time Pilot 03-14-2007 12:18 AM

RE: RF
 
If there was a radio that could effectively reach worldwide, the question might better be, would we want to let someone with the handle, New World Order, know about it? [&:]

jdetray 03-14-2007 12:31 AM

RE: RF
 
Now THAT is a good question!

- Jeff

Scar 03-14-2007 07:25 AM

RE: RF
 


ORIGINAL: New.World.Order

Seems to me that Ham radios for RC airplanes/cars would not work well worldwide because of all the interference, but is there a kind of a radio that's similar to Spektrum that's impervious to any other RF signal and that is able to reach worldwide?
Dima
No.

Dave Olson

Codeblack 03-14-2007 08:24 AM

RE: RF
 
hahaha, ill find out anyway...


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