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Based on the relation between frequency and wavelengths, the higher the frequency, the shorter the wavelengths and therefore the distance of travel is lower. Assuming two frequencies from the ISM band: 2.45 GHz and 5.8 GHz. With the same amplitude and antenna gain, the frequency of 2.45 GHz will travel further than the 5.8 GHz based on their wavelengths.

However, in this link under the subtopic of frequency, it is mentioned that

In general, the higher the frequency, the greater is the range. RF radiation has more energy at the higher frequencies.

In this case, the range does depend upon both the transmitter power and operating frequencies. Does it suggest that higher frequencies have naturally higher amplitudes which may cause them to travel further or higher frequencies needs to be supplied with sufficient transmitting power in order to improve its distance compared to lower frequencies?

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    $\begingroup$ Both statements are equally wrong. The difference in effective distance for these technologies is simply a function of the environment they are being used in. Lower frequencies get attenuated less by walls etc. and they suffer less from interference than higher frequencies. All else being equal (which means proportionally larger antennas for the 2.4GHz band), the free-space line of sight distance would be the same, but that's rarely how these systems are being used. $\endgroup$
    – CuriousOne
    May 29, 2015 at 4:29
  • $\begingroup$ Ok. So basically if two systems, one with operating frequency 2.45GHz and the other with operating frequency 5.8GHz, under the same parameters(antenna gain, transmitting power, environment, etc) theoretically, the lower frequency will travel further. Please correct me if I'm wrong. $\endgroup$
    – user3156387
    May 29, 2015 at 5:39
  • $\begingroup$ I believe that to be the case for these frequency bands and for the usual architectural materials in use (wooden frame/masonry/concrete construction), but that's a materials property, not a fundamental property of electromagnetic waves. $\endgroup$
    – CuriousOne
    May 29, 2015 at 6:05
  • $\begingroup$ In Conductors, lower frequencies travel further. $\endgroup$
    – jensen paull
    Jan 30, 2022 at 11:49
  • $\begingroup$ Why do you believe lower frequencies would have a greater range? $\endgroup$
    – Jagerber48
    Dec 18, 2022 at 14:24

2 Answers 2

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In general, the higher the frequency, the greater is the range. RF radiation has more energy at the higher frequencies

That's not correct as stated. Yes, higher frequency photons have more energy than low frequency photons. But your transmitter isn't counting photons. You can have a $1W$ transmitter at low or high frequencies. The high frequency transmitter will produce fewer photons per second, but radiate the same total energy.

The range of radio signals depends on many things including elements of the equipment (antenna, filters, etc.) and the environment (scattering, absorption). While the statement about higher frequency having greater range may be true in the context of normally-available RFID systems, it's not true in general.

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  • $\begingroup$ Ok. If I consider the fundamentals in terms of wavelengths, I understand that the range of higher frequencies are lower compared to lower frequencies. RFID systems which claims that higher frequencies produce greater range maybe referring to the inclusion of equipment. But if we compare two RFID systems(with the same parameters and environment) each with different frequencies, I believe the system with the lower frequency will have a greater range. Please correct me if I'm wrong. $\endgroup$
    – user3156387
    May 29, 2015 at 5:46
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I believe if you match your signal with the electro-magnitic field of the planet your signal would continue around the entire planet without ever having to be rebrocasted as a result of the power being transmited by the earth itself

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  • $\begingroup$ Hello Mijaco and welcome to Physics SE. Your answer doesn't seem to provide some information regarding the original question posted which seeks to relate the frequency and the distance traveled by electromagnetic waves in general. I suggest you edit your answer to provide some more relevant information. $\endgroup$
    – ZaellixA
    Jan 30, 2022 at 14:20

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