Re: [PATCH] wireless-regdb: Update regulatory info including bandwidth for Trinidad and Tobago (TT) for 2025

Hi,

On Wed, Sep 24, 2025 at 10:22 AM Ping-Ke Shih <[email protected]> wrote:
>
> From: Ping-Ke Shih <[email protected]>
>
> The Telecommunications Authority of Trinidad and Tobago [1] provides
> Schedule of Devices Eligible for Use under a Class Licence [2]. The
> type 1 (End-user devices or customer premise equipment) with Schedule B.1
> and B.2 shows
>
>  - 2400 - 2483.5 MHz
>    * 30 dBm
>  - 5150 - 5250 MHz
>    * 24 dBm
>  - 5250 - 5350 MHz
>    * 24 dBm
>  - 5470 - 5725 MHz
>    * 24 dBm

For these bands, the rules specify ERP, or effective radiated power.
However it states "Maximum Effective Radiated Power ERP (from RF
transmitter)", so I think it is meant to "maximum conducted output
power" as seen in FCC rules?

This is not the same as EIRP, or effective isotropic radiated power.
AFAIK the latter is what is supposed to be used in the database. This
discrepancy is found in many rules originating from the FCC rules. The
FCC rules specify maximum conducted power (TX power) plus max antenna
gain in dBi.

So there is some conversion involved. I think the values should be
"max conducted power" + "max gain in dBi". This assumes no cable loss.

I think we would also need to revisit the US rules.

>    * extend 5 MHz to 5730 MHz for channel 144
>  - 5725 - 5850 MHz
>    * 30 dBm
>  - 5925 - 6425 MHz
>    * 24 dBm

These two bands have 0 dBi for max antenna gain, so max TX power ==
max EIRP.


ChenYu

> [1] https://tatt.org.tt/licensing/class-license/
> [2] https://tatt.org.tt/wp-content/uploads/2025/07/Schedule-B_Schedule-of-Devices-Eligible-for-Use-under-a-Class-Licence-25th-July-2025.pdf
>
> Signed-off-by: Ping-Ke Shih <[email protected]>
> ---
> Hints to find these entries: by searching "Wi-Fi" with type 1 in [2].
> ---
>  db.txt | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/db.txt b/db.txt
> index 6e1ad30222a4..90ffa4e0d5d7 100644
> --- a/db.txt
> +++ b/db.txt
> @@ -1946,12 +1946,15 @@ country TR: DFS-ETSI
>         # 60 GHz band channels 1-4, ref: Etsi En 302 567
>         (57000 - 66000 @ 2160), (40)
>
> +# Source:
> +# https://tatt.org.tt/wp-content/uploads/2025/07/Schedule-B_Schedule-of-Devices-Eligible-for-Use-under-a-Class-Licence-25th-July-2025.pdf
>  country TT: DFS-FCC
> -       (2402 - 2482 @ 40), (20)
> -       (5170 - 5250 @ 80), (17), AUTO-BW
> -       (5250 - 5330 @ 80), (24), DFS, AUTO-BW
> -       (5490 - 5730 @ 160), (24), DFS
> -       (5735 - 5835 @ 80), (30)
> +       (2400 - 2483.5 @ 40), (30)
> +       (5150 - 5250 @ 80), (24), AUTO-BW
> +       (5250 - 5350 @ 80), (24), DFS, AUTO-BW
> +       (5470 - 5730 @ 160), (24), DFS
> +       (5730 - 5850 @ 80), (30)
> +       (5925 - 6425 @ 320), (24)
>
>  # Source:
>  # Table of Frequency Allocations of Republic of China (Taiwan) / Feb 2017:
> --
> 2.25.1
>