Has anyone tested the range claims on their wi-fi extenders? 1/4mi club?

Has anyone actually tested the range claims on their wi-fi extenders?  What sort of experience have you had?

I am a little unsure of how to buy one of these.  For example, my <3 likes the AllPro RV Wi-fi Range Extender on Amazon, which is claiming a 15 mi range, but this seems like a bogus claim to me.  While I can believe it can *detect* a Wi-Fi signal 15mi away, it is something altogther different to reliably communicate with it.  Would I not have to point my antennae at a location analogous to the size of a quarter, a football field away?  We called the manufacturer and got an 'idk, I just make the parts', which was not unexpected I guess.

Has anyone ever experienced a good connection with anything as far as 1 mile away with any wi-fi extender?  1/4 mi?

Thanks!

Over calm water or empty desert in an otherwise RF-free area, maybe you can get a mile. Maybe. Anywhere there are trees, buildings, hills, other RVs, etc., all bets are off. Most any decent range extender or high power wifi transceiver will do a 1/4 mile, but again intervening obstacles usually makea that academic.

I use a Crane SuperUSB Wifi  transceiver plugged to a pair of USB ports on my PC (to get max power) and it does quite well. I've not measured distances in a lot of conditions, but have "seen" wifi sources that were about 1/4 mile distant. Rarely effective to use, though, but lab instruments are needed to determine why.  In many cases it's the source, not my end, that is a chunk of the problem. You can't fix everything from your end.

I have a RedPort wifi extender and I can get over 2 miles. If it's an open connection, I can connect to it within that range. I can pick up signals from nearly 4 miles.

I've had it for about a year now. The software that comes with it is a bit dated but the extender certainly works.

Now there is a great testimonial! RedPort Halo is reported to be an excellent system and popular in the marine world.

I built my own using the Bullet system and a 9db omni antenna and Netgear router. I built and used it on our boat and now it's mounted on the RV. I have only confirmed a 4 mile distant access point, but we may have connected to others farther away. Been using the system for almost 10 years. Chuck

Everything depends on line of sight between you and the access point versus what's actually there.  And how many other people are trying to share the channel.

The rated distance is based on free space propagation, with full Fresnel Zone clearance between two points.  For example, you're on a mountaintop and the access point is across the valley on another mountaintop.  There's nothing in between to block or diffuse the signal.

Fresnel Zone clearance is a cone that starts from each antenna and grows to it's largest point at the midpoint of the path.  In other words, it's not enough just see the other antenna, you need a minimum amount of clearance along the path.  You'll get a better signal from an antenna that's up in the air versus one at table height.

The second factor is how many other people are sharing the spectrum.  In this case, might makes right - a weak signal will get stomped on by a stronger signal so your distant, weak signal won't be heard over the other noise.  Since you're a distance away from the access point you're probably in a relatively quiet area so you can hear the access point but your packets are drowned out by the noise at the other end.

WiFi is supposed to be intelligent enough to only send packets when the channel is clear, but unless all of the systems sharing a channel are in close proximity and can hear transmissions from all of the other systems you develop a "hidden transmitter" problem.  This is where one or more systems can't hear all of the other signals so they think the channel is clear when it's not.  The simultaneous packets collide at the access point and depending on the relative signal strengths the collision either trashes both signals or the weaker signal is overridden and lost.