Assuming all other variables are the same (modulation type, transmit duty cycle, receive sensitivity, data rate, etc), what is the relationship of RF frequency, range, and power consumption? The dataset is any frequency between 300MHz and 5Ghz, and assume low data rate (<50kbps).

Is there a frequency range that is superior to other ranges in terms of range and power consumption?

I assume lower might be a little better.

What RF frequency is best for maximum range (assuming same transmit power is used)? I also assume lower might be better here to a degree (i.e. comparing 5 Ghz to 2.4 Ghz), but I am not certain.

Is there data available that shows how well certain frequencies propagate through different materials (trees, buildings, etc)?


closed as too broad by Andy aka, Voltage Spike, brhans, Dmitry Grigoryev, Daniel Grillo Jan 19 '17 at 10:31

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • \$\begingroup\$ Is this related to your earlier question of a few days ago: electronics.stackexchange.com/questions/279806/… ? \$\endgroup\$ – Andy aka Jan 17 '17 at 9:32
  • \$\begingroup\$ @Andyaka, it is related, but it is different question. This is more about determining the best frequency for various applications. \$\endgroup\$ – Adam B Jan 17 '17 at 16:33
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    \$\begingroup\$ Other variables are legislation permitting the bands you can use, legislation permitting the power you can use, legislation permitting the duty cycle of usage, the occupancy density of other users/interferers, the terrain effects versus frequency, the added complexity needed by higher frequency receivers to make best use of the signal bandwidth, the desired antenna size, the range required (desired range can affect frequency choice), and possibly other things that aren't springing to mind. All these factors make any reasonable answer "too broad" so I'm voting to close. \$\endgroup\$ – Andy aka Jan 17 '17 at 18:05
  • \$\begingroup\$ Legislation meaning within the USA? This question is applicable throughout the world. Certain areas around the globe are much less restrictive, if any at all. This is a question on the theory of RF signal propagation and power consumption. \$\endgroup\$ – Adam B Jan 18 '17 at 7:20
  • \$\begingroup\$ Your question mentions power consumption as a constraint yet there is nothing in your accepted answer that factors this in so, in reality, what is your question. Neither is there anything in the answer about RF propagation versus operating frequency. Your question and accepted answer are some distance apart. \$\endgroup\$ – Andy aka Jan 18 '17 at 8:11

It's called Friis Transmission Loss.

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You're trying to compare apples and oranges.

Making certain variables the same makes for an unfair comparison. At 1 MHz transmitting a signal with a bandwidth of 100 kHz takes up a lot of frequency space but does not allow for a high very datarate.

At 5 GHz the situation is quite different, the bandwidth can be a couple of MHz allowing for high many channels all with high datarates.

Also that 1 MHz will have a long range so you can only have very few transmitters.

For 1 MHz you need a very large antenna, this is impractical in a laptop for example.

There is no simple answer to your question because each frequency range has its own applications. There is no "best" in that respect.

Read here for an overview of usage of the radio spectrum.

  • \$\begingroup\$ I clarified the question to state between 300MHz and 5GHz, and also stated the same data rate. If 300MHz is limited by a certain data rate, then assume that data rate across the frequency spectrum for comparison. \$\endgroup\$ – Adam B Jan 17 '17 at 16:32
  • \$\begingroup\$ The only thing I'm going to assume after your remark is that you still do not seem to "get it". There is no "best". Forget about trying to find it. \$\endgroup\$ – Bimpelrekkie Jan 17 '17 at 16:39
  • \$\begingroup\$ I think I have the answer after the post about the Friis Transmission Loss equation. Basically, it shows that theoretically lower frequency is generally more efficient, but it comes at the cost of less bandwidth.The other impacts to this other variables which were not asked about such as the signal degradation going through materials, which may differ depending on frequency and material. \$\endgroup\$ – Adam B Jan 18 '17 at 7:27
  • \$\begingroup\$ wiley.com/WileyCDA/WileyTitle/productCd-EHEP002478.html This book discusses this in detail, including the description of the Friis equation and RF wave propagation across frequencies, and bandwidth considerations. \$\endgroup\$ – Adam B Jan 18 '17 at 7:38

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