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Re: WiFi range ...

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>On Sun, 31 May 2026 21:19:08 -0700, Lars Poulsen <lars@beagle-ears.com> wrote:
>On 2026-05-25 22:27, c186282 wrote:
>> On 5/25/26 13:56, rbowman wrote:
>>> On Mon, 25 May 2026 01:46:15 -0400, c186282 wrote:
>>>
>>>> Anyway ... NOW I may have a use for RF "modems",
>>>> a link to a kind of far-off property site. Do not need video, MAYbe the
>>>> odd still image. The low speed isn't relevant, just the range. WiFi
>>>> isn't gonna cut it at all.
>>>
>>> How far off?
>>
>>
>>    About 1000 meters.
>
>My company's high reliability radios use essentially 20 year old WiFi
>technology, and we have customers than routinely run them over distances
>of 5-10 km. It is not the technology per se that limits distance; it is
>the cheap off-the-shelf gear that is crap.
>
>We use an 802.11b modulator, in 900 MHz or 2400 MHz bands, at speeds
>from 100 kbps effective data transfer rates to 8Mbps. We do NOT us the
>802.11 MAC layers, because we WANT to be guaranteed to be incompatible
>with WiFi. We pair this modem chipset with a very good front-end (low
>noise receive amplifier and very clean, very linear power amplifier. And
>then we put good directional antennas on them. We have one customer who
>runs a 100km radio link with a 27dBi antenna at 500mW (27 dBm) power
>output. For years.
>
>I bet many commercial WiFi radios if paired with a decent front-end and
>a good antenna, even an 18dBi panel antenna, would give you a reliable
>link over 5km/3miles, so long as you have a clean line of sight. Its not
>really that hard.

For a 1 km link, I would start with the boring purpose-built gear rather than
trying to make ordinary indoor WiFi stretch that far.  A pair of outdoor
CPE/bridge units with directional panels will usually be far less fiddly than
routers plus random antennas.

The practical checks are mostly RF geometry, not Linux-specific:

* clear line of sight, including some Fresnel-zone clearance;
* fixed mounting and careful alignment at both ends;
* outdoor-rated cable/enclosures and proper grounding/lightning protection;
* enough margin for rain, leaves, and future clutter in the path.

If only low-rate data and the occasional still image are needed, backing the
link down to a slower modulation/rate can buy a lot of reliability.  Once the
bridge is up, Linux just sees an Ethernet path, which is the nicest possible
outcome.

-- 
TheLastSysop <thelastsysop@dev.null>
"I survived the great rm -rf / rehearsal and all I got was this .signature."

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Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-05-25 01:46 -0400
  Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-05-25 17:56 +0000
    Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-05-26 01:27 -0400
      Re: Recent Experience With RF "Modem-ish" Data Links ? TheLastSysop <thelastsysop@dev.null> - 2026-05-26 22:11 +0000
        Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-05-26 23:04 -0400
          Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-05-27 03:21 +0000
            Re: Recent Experience With RF "Modem-ish" Data Links ? c186282 <c186282@nnada.net> - 2026-05-27 00:18 -0400
              Re: Recent Experience With RF "Modem-ish" Data Links ? rbowman <bowman@montana.com> - 2026-05-27 07:09 +0000
            Re: Recent Experience With RF "Modem-ish" Data Links ? The Natural Philosopher <tnp@invalid.invalid> - 2026-05-27 14:14 +0100
      WiFi range ... Lars Poulsen <lars@beagle-ears.com> - 2026-05-31 21:19 -0700
        Re: WiFi range ... TheLastSysop <thelastsysop@dev.null> - 2026-06-01 04:26 +0000
      Re: Recent Experience With RF "Modem-ish" Data Links ? Andy Burns <usenet@andyburns.uk> - 2026-06-01 08:10 +0100
        Re: Recent Experience With RF "Modem-ish" Data Links ? TheLastSysop <thelastsysop@dev.null> - 2026-06-01 07:33 +0000

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