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Comment by eisa01 | Hacker News Reader

Why do chips like these not have 5 GHz Wifi?

Living in a city, the 2.4 GHz band is crowded, and a lot of devices require you to play with your router settings to set them up [1] e.g., some Mill heaters must be set up on a 2.4 GHz network using a channel below 10 [2]

[1] https://millheat.zendesk.com/hc/en-us/articles/213305665-My-...

[2] https://millheat.zendesk.com/hc/en-us/articles/213310805-WiF...

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You can make 2.4ghz radio on more or less the same process as the logic.

With 5ghz, silicon cmos is still possible, but the power consumption will be very bad. The need for a specialty RF process is a big limiter.

What I mean is that you will have to go for 2 pieces of silicon, (one for radio on a specialty process, and another for regular CMOS logic) instead of one.

Even desktop wifi chips are still made in 2.4ghz only variants to save some cost in the lowest end, and for the chip priced in cents, it is completely not an option at the moment.

The setup issues aside, these devices need very little data, have small antennas and are often in hard to reach places.

2.4ghz with its better coverage is actually more appropriate.

There's probably also the issue that there is no _one_ 5GHz band. Suddenly you have to deal with DFS radar detection, and different regulatory compliance domains. It now matters which country you're selling to, or which firmware they're using.

You can get a RTL8720DN that has Dual-Band WiFi for $4

https://www.cnx-software.com/2020/01/17/realtek-rtl8720dn-du...

A lot of the problem is often not the band is crowded, but that often one too many send out DeAuth packages. This is fixed in WPA3.

Because everything else is on the 2.4GHz band and so adding 2.4GHz Wifi doesn't require any new HF circuitry.

That wouldn't apply to Espressif since they started with WiFi, right?

Probably because the target price point is at or below $1.

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