# Relation between frequency and power

Discussion in 'Electrical | Electronics | Communications' started by qaisarpk1, Aug 13, 2010.

1. ### qaisarpk1 Apprentice

Engineering Discipline:
Electronics
what is relation between frequency and power ...
which frequency travel long distance... low frequency or high frequency?

#1
2. ### mohit007kumar00 Apprentice

Engineering Discipline:
Computer Science
I think you know that power is directly proportional to energy.
E=h*(new);
where new represent frequency of the signals.
so you can say that power is directly proportional to frequency.
.
frequency is inversely proportional to time so and time is directly proportional to distance.
So with low frequency you can travel more distance.
low frequency->more time->>more distance.

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3. ### Voltaire Apprentice

Engineering Discipline:
Chemical
In terms of electricity there is no relationship. Electrical power is simply the product of the current and the voltage.
The lower the current is the less resistance there is to the current flowing through the conductor. That is why electrical power is transformed to high voltage (low current) when it is transmitted over long distances. This is a property of an electromagnetic wave i.e. wave particle duality.

The frequency of light does however affect the energy of the light wave viz. E = hf where h is Planck's constant and f is the frequency. Since c = fl, f = c/l. This simply implies that the frequency is a way to describe the rate of wave formation i.e. so may times per second and so we can say that the energy of a light packet is equal to some number multiplied by how many times per second the wave regenerates.

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4. ### qaisarpk1 Apprentice

Engineering Discipline:
Electronics
its fine mohit .....
as u said that the lower frequncy travel more distance then why we modulate low freq signal on higher frequencies ....
kindly explain one more thing that why we use higher freq in satellite comm instead of lower freq as lower freq travel more distance....
thanx....

#4
5. ### Voltaire Apprentice

Engineering Discipline:
Chemical
Could someone please formulate a mathematical relationship and provide an answer to the following question:

A nano-car travels on the edge of a light wave i.e. in a sinusoidal pattern. Remember that the speed of light is constant and hence our little car has to travel at some theoretical speed greater than c[/c]. The little car first travels on a wave with wave lenth l and then on a second light wave with a frequency double that of the first wave.

Q: on which wave does the little car travel the furthest distance in one time period.

#5
6. ### reachrkata Apprentice

Engineering Discipline:
Electronics
Ah !!! Unfortunately, lower the frequency greater is the antenna size required to radiate that frequency. It follows the lambda/4 relationship.

- Karthik

#6

Engineering Discipline:
Electrical
#7
8. ### silverscorpion Ace

Engineering Discipline:
Electronics & Telecommunications
Ah, how did I miss this??

Actually, lower the frequency, LESSER is the distance it can travel before it gets attenuated too much, or get corrupted by noise.

Higher the frequency, lesser is the attenuation. Which means, higher the frequency, greater is the distance which the wave can reach with reasonable attenuation levels.

This is the reason we modulate baseband signals to high frequencies in radio communication, It's also the reason for very high frequencies in case of satellite communications.

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9. ### lord_slayer Newbie

silverscorpion you got the concepts reversed there.. Lower the frequency LARGER is the distance it can travel.. and vice versa.. The reason for high frequency communication in satellites is that we can't have large antennas hanging around in space..

#9
10. ### vikash_pandey Newbie

Engineering Discipline:
Electronics & Communications
well mr. silver i have a question,
if signal attenuation is more in low frequency signal then why there is more attenuation in 30/20 GHz band in satellite communication as compared to 6/4 GHz band.
Thank You

#10
11. ### Jeffrey Samuel Knight

Engineering Discipline:
Electronics
Satellite are not very close to earth and air media travelled by these waves have ions(ionosphere) and so there is no ideally unity permittivity

That tells us the actual reason

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12. ### SATINATH DEBNATH Newbie

Engineering Discipline:
Electronics & Communications
One persons say attenuation is independent of frequency in free space ,.... then says lower frequency higher distance, again challenged by someone please we get confused.
It seems everybody is correct in their own explanation. But totally confused

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13. ### SATINATH DEBNATH Newbie

Engineering Discipline:
Electronics & Communications

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14. ### SATINATH DEBNATH Newbie

Engineering Discipline:
Electronics & Communications
I am working in GPS. we receive satellite signals at 1575.42MHz from thousand of miles distance . So my question is that whether there is no attenuation in signal between receiver and satellite.

#14
15. ### Jeffrey Samuel Knight

Engineering Discipline:
Electronics
Hey buddy 1575.42MHz=(approx) 1.5 GHz.

In the GHz region there are certain bands of frequencies that are affected very less by Atmosphere and water particles in air. You can refer any microwave books for more details on this.

And I am not clear of what you say here

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16. ### Ankita Katdare Moderator

Engineering Discipline:
Computer Science
@A.V.Ramani Sir could you share your thoughts on this?
Do low frequencies carry farther than high frequencies?

#16
17. ### A.V.Ramani Guru

Engineering Discipline:
Biomedical
This sound from the time of big bang is of extremely low frequency and more than 10
billion years old . It was recorded just a few years back. Electromagnetic radiation in free space is forever and distance is irrelevant unless some thing absorbs it. Frequency has no role. The situation is different on earth as there are many factors that can modify radiation. There are many videos on this page.

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