DFS Channel Disable

Installing and Using OpenWrt Network and Wireless Configuration
#1

Hello,
We are using doodlelabs radios (with ath9k driver) and a frequency shifter to remap the output frequency of a standart radio to another band.

The problem I am having is, while testing the radios, it seems I can not use any of the channels with marked (Radar Detection)

Normally, this channels will not be listening /tranmitting on that frequencies.. So I need to find a way to disable DFS channels.

This is the channel list I have
Frequencies:
* 5180 MHz [36] (23.0 dBm)
* 5200 MHz [40] (23.0 dBm)
* 5220 MHz [44] (23.0 dBm)
* 5240 MHz [48] (23.0 dBm)
* 5260 MHz [52] (23.0 dBm) (radar detection)
* 5280 MHz [56] (23.0 dBm) (radar detection)
* 5300 MHz [60] (23.0 dBm) (radar detection)
* 5320 MHz [64] (23.0 dBm) (radar detection)
* 5500 MHz [100] (23.0 dBm) (radar detection)
* 5520 MHz [104] (23.0 dBm) (radar detection)
* 5540 MHz [108] (23.0 dBm) (radar detection)
* 5560 MHz [112] (23.0 dBm) (radar detection)
* 5580 MHz [116] (23.0 dBm) (radar detection)
* 5600 MHz [120] (23.0 dBm) (radar detection)
* 5620 MHz [124] (23.0 dBm) (radar detection)
* 5640 MHz [128] (23.0 dBm) (radar detection)
* 5660 MHz [132] (23.0 dBm) (radar detection)
* 5680 MHz [136] (23.0 dBm) (radar detection)
* 5700 MHz [140] (23.0 dBm) (radar detection)
* 5745 MHz [149] (30.0 dBm)
* 5765 MHz [153] (30.0 dBm)
* 5785 MHz [157] (30.0 dBm)
* 5805 MHz [161] (30.0 dBm)
* 5825 MHz [165] (30.0 dBm)
and this is
iw reg get
global
country US: DFS-FCC
(2402 - 2472 @ 40), (N/A, 30), (N/A)
(5170 - 5250 @ 80), (N/A, 23), (N/A), AUTO-BW
(5250 - 5330 @ 80), (N/A, 23), (0 ms), DFS, AUTO-BW
(5490 - 5730 @ 160), (N/A, 23), (0 ms), DFS
(5735 - 5835 @ 80), (N/A, 30), (N/A)
(57240 - 63720 @ 2160), (N/A, 40), (N/A)

#2
  • Do you have a license (or Special Temporary Authority, or its equivalent in other nations) to do so - or is this an unlicensed (none needed/granted by regulation) setup?
  • I'm curious, what nation (or radio regulator jurisdiction) are you in?
  • What band have you shifted to?
  • How long did you upon setting the "DFS channel" - wait for the SSID to come up"?
  • Must you use the frequency, couldn't you shift the frequency more (if the equipment is variable, of course)? (I'm not sure this matters much anyway.)

Do you mean:

  • "disable [use of the] DFS CHANNELS"; or
  • "disable DFS [radar detection on THOSE] CHANNELS"?

All the questions are necessary to assist in this forum with your specific inquiry.

4 Likes
#3

Hello and thank you for reply..
I have two projects in mind..
First one is, I am a hamradio operator and I want to enable 5.7 ghz band on my device for ham-mesh networks..

Second one, I am in a project and we are using a downshift device to convert the 5 ghz frequency to C band with licence for sure.
So, the when I set the radio to 5.2 Ghz channels, it actually transmits at 4.4 ghz.
So, I am legally using this whole frequency range..

But to be able to use the DFS frequencies , I need to disable them..
As far as I search on the net, there is a way with wireless-regdb
Just I am not that much familiar with kernel compiling on wrt side..And what after installing wireless-regdb?

So, for the two projects I mentioned above, I have valid license to use the the band without limitation.

For ham bands, I need to modify the db.txt to allow the forbidden channels and next step to add the channels between 100-143
For the 4.4-5ghz tx, I need to use the whole band either..
So the concern is not only for DFS, for a whole frequency range

Best Regards

1 Like
#4

Yes...the DB is just the DB...so just look at it...and pick a nation that doesn't use DFS.

:wink:

Screenshot%20from%202019-10-04%2010-14-46

Screenshot%20from%202019-10-04%2010-16-40

Interesting...and from your PM, more so...!

I like the observation work and reports!

I read them regularly!

73 and best wishes!

#5

Arguably off topic or at least tangential, I'm curious about a 5 GHz transverter, especially with the input and output frequencies so close together and over a wide bandwidth. Wish I had the gear to tune filters like that at 5 GHz!

1 Like
#6

Using an unregulated country is not a solution actually.
Yes you may save some frequencies from blocking.. but for hambands you need to add some new channels.. And to do so, db.txt should be modified accordingly..(to give a wider range of channels which normally does not exist in db.txt file for any countries)

So, right now.. I am looking for way of modification wireless-regdb database on openwrt 18
I will update the topic when I find some solutions

#7

https://openwrt.org/docs/guide-developer/single.package

As the source is not part of the OpenWrt distribution, a patch would be required.

https://openwrt.org/docs/guide-developer/build-system/use-patches-with-buildsystem

(There are some issues with Python 2 vs. Python 3 on older source. Working with master would be my suggestion for a forward-looking project, in general.)

2 Likes
#8

Hello Jeff..
Actually modified the wireless-reg files according to my needs.
now had the whole channels....

2019-10-05_00-01-12
2019-10-05_00-01-12.png843×683 134 KB

So another question comes to my mind..
Anybody experienced to dial a direct frequency instead of channels?
I mean change the center frequency to something 5580 to 5585 or 5590..
So we can use 5/10 mhz channel spaces also with chanbw option..

#9

https://openwrt.org/docs/guide-user/network/wifi/basic

Screenshot%20from%202019-10-05%2023-40-33
Screenshot from 2019-10-05 23-40-33.png1060×31 5.42 KB

Should work on an ath9k chip.

Not sure on 5 Ghz. I've tester neither (due to regulations even when needed on 5 MHz bandwidth).

#10

No I mean channels.. If I set channnel 36 5 mhz i guess it will be in center of 5180 but I cant normally use 5190..

I need to set the channel frequency as 5180 5185 5190 etc..
And it iwill be added from
https://github.com/torvalds/linux/blob/master/drivers/net/wireless/ath/ath9k/
common-init.c
I need to try that also.

#11

Perhaps I'm missing why this is the wisest location...other than both sets of equipment are identical...which is likely.

That should work too.