Wifi range of an average flagship?

[newby_investor]

Your hotspot's antennas will factor just as much into the equation as the phone's transmit power. Any given antenna can receive just as well as it sends, so a high-gain antenna on the hotspot will be able to pick up a weak signal from the phone. Your distance will depend more on that than on the phone specifically.

That being said, some phones' wifi antennas are better than others, and how you hold the phone (i.e. physical orientation) can affect it as well. And obstacles in the way. And obstacles not quite in the way that cause multi-path (the bane of any wireless system).

Another factor to consider is that the phone will adjust its transmit power according to how weak the wifi is, it assumes that weak wifi signal means the transmitter is far away. So you'll find that network traffic when you're far from the hotspot will drain your battery faster than if you were sitting in the same room.

I live in a 4th-floor flat and can often get signal from my B618 when I'm out in the garden. Distance of about 30m I guess? I have a Nokia 8. Granted not good signal, wouldn't watch YouTube on it, but WhatsApps get through just fine.

 

[Thor]

Still a bit baffled by this Hotspot antenna can make up for a weak transmitter. (awesome if that is the case).

Guess who just ordered a 13dBi omni for the house and then I'll use the 19dBi sector antenna for the garden.

 

[newby_investor]

Your cellphone's transmitter will be able to transmit at a certain power level, with a certain gain, and as you move further away the signal level attenuates with an inverse square law. So technically, the signals go everywhere in the universe (eventually, because light-speed isn't infinite). It's not as though, after say 20m, all of a sudden there's no signal. It doesn't just stop, it gets progressively more faint.

So if you go and measure that signal where your hotspot is, it'll have power level X. As long as your hotspot's sensitivity in the direction of your phone is >= X, then you're good. So your omnidirectional antennas will help. They trade off sensitivity in the upwards and downwards directions (which you don't need anyway) for increased sensitivity in the horizontal direction. The 19 dBi antenna will be more sensitive towards whichever direction you point it, it'll assume you don't need signal anywhere behind the antenna.

High-quality low-noise amplifiers on the hotspot will help as well, though you usually have less control over that.

You can of course extend this principle to extreme lengths. Crazy sensitive receivers can make up for weak, distant signals on the other end, it's how NASA still manages to communicate with Voyager 2 (albeit very slowly).

All that being said though, a better quality antenna / transmitter on the cellphone's side will help improve your useful range. They just don't normally publish that sort of technical info for handsets AFAIK.

 

[pancakes]

Your cellphone's transmitter will be able to transmit at a certain power level, with a certain gain, and as you move further away the signal level attenuates with an inverse square law. So technically, the signals go everywhere in the universe (eventually, because light-speed isn't infinite). It's not as though, after say 20m, all of a sudden there's no signal. It doesn't just stop, it gets progressively more faint.

So if you go and measure that signal where your hotspot is, it'll have power level X. As long as your hotspot's sensitivity in the direction of your phone is >= X, then you're good. So your omnidirectional antennas will help. They trade off sensitivity in the upwards and downwards directions (which you don't need anyway) for increased sensitivity in the horizontal direction. The 19 dBi antenna will be more sensitive towards whichever direction you point it, it'll assume you don't need signal anywhere behind the antenna.

High-quality low-noise amplifiers on the hotspot will help as well, though you usually have less control over that.

You can of course extend this principle to extreme lengths. Crazy sensitive receivers can make up for weak, distant signals on the other end, it's how NASA still manages to communicate with Voyager 2 (albeit very slowly).

All that being said though, a better quality antenna / transmitter on the cellphone's side will help improve your useful range. They just don't normally publish that sort of technical info for handsets AFAIK.

This. A directional good quality antenna and transmitter may help. Essentially you're still going to hit a brick wall with mobile devices as they simply don't have the ability to send data back to the station over such a range, even though they may 'see' the wireless network.

 

[Thor]

This. A directional good quality antenna and transmitter may help. Essentially you're still going to hit a brick wall with mobile devices as they simply don't have the ability to send data back to the station over such a range, even though they may 'see' the wireless network.

That's what I'm getting at, can the phone transmit back. Or is that what the guy is explain the phone transmit example upto 20meters from there a super antenna can do the rest 2Km away.

 

[genetic]

That's what I'm getting at, can the phone transmit back.

What phone?

 

[newby_investor]

the phone transmit example upto 20meters from there a super antenna can do the rest 2Km away.

The concept of "the phone can transmit up to 20 m" is the one you've misunderstood, perhaps I didn't make it clear enough. The phone transmits an infinite distance, theoretically. The further away you go though, the lower the signal power becomes.

Let me illustrate with a made-up example. I'm going to use unrealistic numbers but they'll hopefully make it clear.

Say your phone can transmit with a signal power of 10W, and 10m away you have your receiving antenna and it's measuring 5W. An inverse square law means, if we double the distance, the signal should decrease by a factor of 4. So if you move your antenna to 20m away (double the distance), then you'll measure 1.25W of signal (a quarter of the previous measurement). If you move the receiving antenna to 2km away, then it'll measure a really small amount of power. 125 microwatts (0.000125 W) in this example.

So here's the rub. If your antenna is sensitive enough to detect a signal only 0.000125W - then you're good to go. But if your antenna can only detect signals above 1.25W, then you're limited to 20m.

What you're doing by getting those improved antennas is improving the ability of your wifi router to detect the signals that your phone sends out.

If you were a radar engineer then of course then there would be slightly more advanced maths than this, but in a hand-wavy way, that's how it works. It's not really accurate to say that your phone can transmit X number of meters, because the max effective distance between transmitter and receiver depends on any number of things, on both the transmitter and the receiver end.

 

[genetic]

The concept of "the phone can transmit up to 20 m" is the one you've misunderstood, perhaps I didn't make it clear enough. The phone transmits an infinite distance, theoretically. The further away you go though, the lower the signal power becomes.

Let me illustrate with a made-up example. I'm going to use unrealistic numbers but they'll hopefully make it clear.

Say your phone can transmit with a signal power of 10W, and 10m away you have your receiving antenna and it's measuring 5W. An inverse square law means, if we double the distance, the signal should decrease by a factor of 4. So if you move your antenna to 20m away (double the distance), then you'll measure 1.25W of signal (a quarter of the previous measurement). If you move the receiving antenna to 2km away, then it'll measure a really small amount of power. 125 microwatts (0.000125 W) in this example.

So here's the rub. If your antenna is sensitive enough to detect a signal only 0.000125W - then you're good to go. But if your antenna can only detect signals above 1.25W, then you're limited to 20m.

What you're doing by getting those improved antennas is improving the ability of your wifi router to detect the signals that your phone sends out.

If you were a radar engineer then of course then there would be slightly more advanced maths than this, but in a hand-wavy way, that's how it works. It's not really accurate to say that your phone can transmit X number of meters, because the max effective distance between transmitter and receiver depends on any number of things, on both the transmitter and the receiver end.

Nicely explained!

The proliferation of cellular towers in a confined space means that the average cellphone only transmits a couple of hundred milliwatts at most.

Improving the antenna on a cellular base station means that it can detect weaker signals without the transmitter or cellphone having to be more powerful or larger.

A good analogy is NASA's Deep Space Network. A tiny 3 meter 20 watt dish on the Voyager space probe can transmit and receive data billions of KM away. That's due to the incredibly large and sensitive 34m dishes on Earth.

Your phone doesn't need to be more powerful to get a good signal - the cellular tower has to be.

 

[Dave]

The concept of "the phone can transmit up to 20 m" is the one you've misunderstood, perhaps I didn't make it clear enough. The phone transmits an infinite distance, theoretically. The further away you go though, the lower the signal power becomes.

Let me illustrate with a made-up example. I'm going to use unrealistic numbers but they'll hopefully make it clear.

Say your phone can transmit with a signal power of 10W, and 10m away you have your receiving antenna and it's measuring 5W. An inverse square law means, if we double the distance, the signal should decrease by a factor of 4. So if you move your antenna to 20m away (double the distance), then you'll measure 1.25W of signal (a quarter of the previous measurement). If you move the receiving antenna to 2km away, then it'll measure a really small amount of power. 125 microwatts (0.000125 W) in this example.

So here's the rub. If your antenna is sensitive enough to detect a signal only 0.000125W - then you're good to go. But if your antenna can only detect signals above 1.25W, then you're limited to 20m.

What you're doing by getting those improved antennas is improving the ability of your wifi router to detect the signals that your phone sends out.

If you were a radar engineer then of course then there would be slightly more advanced maths than this, but in a hand-wavy way, that's how it works. It's not really accurate to say that your phone can transmit X number of meters, because the max effective distance between transmitter and receiver depends on any number of things, on both the transmitter and the receiver end.

So one of these and @Thor is set

 

[Thor]

Finally makes a lot of sense to me now.

The plan is as follows:
Map of the house:


Corner of the yard I put up a 120 degree 15dBi sector antenna and inside the house I put down a 13 dBi omni antenna - omni powered by a Bullet and the sector uses my rocket prism.

Nicely explained!

The proliferation of cellular towers in a confined space means that the average cellphone only transmits a couple of hundred milliwatts at most.

Improving the antenna on a cellular base station means that it can detect weaker signals without the transmitter or cellphone having to be more powerful or larger.

A good analogy is NASA's Deep Space Network. A tiny 3 meter 20 watt dish on the Voyager space probe can transmit and receive data billions of KM away. That's due to the incredibly large and sensitive 34m dishes on Earth.

Your phone doesn't need to be more powerful to get a good signal - the cellular tower has to be.

The concept of "the phone can transmit up to 20 m" is the one you've misunderstood, perhaps I didn't make it clear enough. The phone transmits an infinite distance, theoretically. The further away you go though, the lower the signal power becomes.

Let me illustrate with a made-up example. I'm going to use unrealistic numbers but they'll hopefully make it clear.

Say your phone can transmit with a signal power of 10W, and 10m away you have your receiving antenna and it's measuring 5W. An inverse square law means, if we double the distance, the signal should decrease by a factor of 4. So if you move your antenna to 20m away (double the distance), then you'll measure 1.25W of signal (a quarter of the previous measurement). If you move the receiving antenna to 2km away, then it'll measure a really small amount of power. 125 microwatts (0.000125 W) in this example.

So here's the rub. If your antenna is sensitive enough to detect a signal only 0.000125W - then you're good to go. But if your antenna can only detect signals above 1.25W, then you're limited to 20m.

What you're doing by getting those improved antennas is improving the ability of your wifi router to detect the signals that your phone sends out.

If you were a radar engineer then of course then there would be slightly more advanced maths than this, but in a hand-wavy way, that's how it works. It's not really accurate to say that your phone can transmit X number of meters, because the max effective distance between transmitter and receiver depends on any number of things, on both the transmitter and the receiver end.

 

[Swa]

As has been said it's your assumption that the phone only transmits for say 20m that's wrong. The signal drops off but it never disappears. That means if the hotspot has sufficient gain it will still "see" the signal. In general if it can transmit for 1km it can receive over 1km as well provided your phone has sufficient power. It won't work if the hotspot is 1W but your phone only transmits at 1mW. But typically both your phone and hotspot will vary the signal as required up to the maximum allowed.

However you do get more distortion when amplifying a weak signal which affects the reliability and speed of your connection. This is how it works with cellular towers which will transmit at a few watts but the phone itself only transmits at a few hundred milliwatts so you can receive multiple megabits but can only send a few hundred kilobits per second.

 

[ThatOtherDude]

IMHO:

15-20 meters indoors.
30-40 meters outdoors
with stock equipment,

deduct 30% if you have lots of "noisy" neighbours (interference)
add 30% if you spend money on wifi "kit"