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why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 10:09 am
by cutedrummerboy
hi all,

recently i have got an old dbii networks card and the problem is that it have no model number printed on it and i don't know what is the frequency band of that card. so i attached it in my one of rb411 and now it shows two different band of frequency. why it is displayed like this? can any one elucidate me?
DBii.PNG

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 10:52 am
by Neilson
Not all countries allow all frequencies to be used. This card seems to support the 5Ghz band frequencies.

If you don't set a country name I think it goes to American or similar to allow the most common ranges however it has a gap in the middle that they are considering allowing to be used but currently cannot in the US.

So this looks like a default wireless config for a 5Ghz card to my eyes

Regards
Alexander

EDIT: The above is absolute balls, sorry about this, didn't see the right hand side details at all, My apologies to everyone here.

I have no idea what is going on with this card.

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 11:12 am
by ohara
Take a closeup picture of the card and post it here, we can then identify it. You might be a lucky owner of a 3GHz card from DBii.
From balticnetworks description: "The card works by frequency shifting a standard 5Ghz Atheros Radio down to 3Ghz operation. Your operating system will see this card as a standard 5Ghz radio card but work within the 3Ghz spectrum."

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 11:19 am
by normis
Click "Advanced" and check if you have not entered anything in "Frequency Offset". Looks like you entered 2000 in there ;)

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 11:36 am
by cutedrummerboy
normis, i can not find any frequency offset in advance tab. here is the screen of advance tab.
dbii_2.PNG

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 11:47 am
by cutedrummerboy
here is the photo of the card, i just uncovered the rf shield before taking the picture. the cheapest labeled as atheros AR5414-001. and there is a marking on that board F28G.
IMG_20131120_165313.jpg

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 11:49 am
by normis
Frequency Offset is in the console only. You should ask the manufacturer or the seller, what should the correct offset be for this card.

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 12:15 pm
by ohara
The only reference is on a balticnetworks PDF, DBii F28-PRO with AR5414:
http://www.balticnetworks.com/docs/Dbii ... Matrix.pdf

seems to me that if you don't have a similar second card it won't be much of use to you?

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 12:20 pm
by cutedrummerboy
thank you all. as normis said, i checked frequency offset and got that it have a offset off -2200MHz. now my question is can i fix the offset to 0? if, then will it works at 5GHz?

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 12:39 pm
by normis
The offset only is for your viewing pleasure (to make it easier to understand at what frequency it operates), it doesn't affect card operation. You can set any number you want, card will operate at the same frequency.

This is made because the DBII card operates in 3GHz, but in RouterOS it's detected as 5GHz card. If you enter the offset correctly, it will show the actual operating frequency. This is optional. Even if you don't enter the offset, it will still operate in 3GHz.

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 1:39 pm
by cutedrummerboy
thank you normis,

now my question is who set that frequency offset?

i think the driver set that option after inserting the card. because i did not set it. that means atheros drivers (madwifi) are universal for all routerboard and my rb just sense the hardware and set the offset. so if driver set the frequency offset then there is should be a way to control the card through software. maybe it is like software defined radio aka SDR or maybe it is hardware modded thing, that you have to change the analog rf portion like filter etc. i don't know ar5414 works through serial or parallel data transfer.

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 3:39 pm
by ohara
I am not sure of the answer to your question. I would check how the card behaves in ROS 5.26 or 6.6 and contact support@dbii.com with further questions. Take care.

Re: why this frequency chart have 2 sets of frequency band

Posted: Thu Nov 21, 2013 3:41 pm
by normis
It's possible that RouterOS supports some other DBII card with 2200MHz offset, and this card was recognized as that one.

Like I said, this will not affect operation, just change the offset to the correct one.