M6E-Nano Frequency Selection

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RadioKaKa
Posts: 2
Joined: Fri Nov 16, 2018 6:54 am

M6E-Nano Frequency Selection

Post by RadioKaKa » Fri Nov 16, 2018 7:08 am

Hello every one, I'm new here and didn't seem to find the answer of my question, so here it goes:

Unlike most users, I care more about the frequency that the reader reading the tags and the signal strength of the responses at different frequency. However, using the Arduino hook up and relevant library, only "Regions" can be chosen or a "custom" one which is basically sweep through all the frequency it's able to read, which is not so customisable. What I want is to read at same frequency for a little while (say 10 seconds), and then jump to the next frequency. However, after browsing the library I didn't find anywhere that I can make this modification.

So I'm wondering can I change this settings by just using the Arduino solution, or I need to hook it up to the PC and using SDK they provided? Or is this "Region" setting is embedded in the module that I cannot change, so that I can switch to another reader to save some time.

Thank you guys in advance

paulvha
Posts: 289
Joined: Sat Nov 11, 2017 2:39 am

Re: M6E-Nano Frequency Selection

Post by paulvha » Wed Nov 21, 2018 1:55 am

The region is a setting on the reader. Depending on where you are in the world, you MAY only use a specific frequency, which is made available for free, unlicensed use. The Nano, unlike some other readers that have fixed frequency set at ordering, has indeed a high flexibility in setting the frequency and perform automatic frequency hopping. It is clearly documented in the Nano Design guide book and the programmers manual. All that is possible to set and use with the full mercury -API /SDK, however the Sparkfun driver is supporting a sub-set (I assume due to memory limitations on an Arduino).

That said one should be careful using a frequency channel that is outside the free channel on your location. Often the other (licensed) channels are claimed / in use for military activities, and you do not want to get in trouble with them :-). A different frequency has hardly any impact on the read quality as all tags (maybe with a few exceptions that I have not seen yet) work within the different frequency bands

The bigger impact comes from the signal strength. You will have to balance that, not only for power consumption reasons. A higher signal strength will normally provide a better reading. Especially if you combine that with an external antenna. However.. radiation can be harmful as well: If you google, youĺl find many articles around that (like https://www.rfidjournal.com/blogs/experts/entry?5001). In my testing (the Nano on the desk). I will max 5dbm. Means I have to put the tag close by (nearly on top), but have the least impact from the radiation.

regards
Paul

RadioKaKa
Posts: 2
Joined: Fri Nov 16, 2018 6:54 am

Re: M6E-Nano Frequency Selection

Post by RadioKaKa » Mon Dec 03, 2018 3:45 am

Thanks, Paul. The answer is really useful. I'm new to programming, and Arduino is easier for me, that's why I'm bit reluctant to look into the API/SDK stuff.

Also in my case, I need to sweep through the frequency to read the tags' response and the change in response curve after the tags is elongated (the antenna is deformed, therefore function as a strain sensor). However here in Europe, the bandwidth is quite limited, only 3MHz from 865-868MHz, compared to the States that is 10MHz. And it means I have only at maximum response at 4 frequencies with 1MHz resolution. Do you have models that can read in higher resolution? Is this resolution in frequency hopping more related to the hardware or software? As far as I know there is some device can do the sweep in 0.1MHz resolution, but with 15X price of this one. So it will be a cheaper way for me the to do some modification of the hardware/software without changing the chip to increase the resolution.

Regards

paulvha
Posts: 289
Joined: Sat Nov 11, 2017 2:39 am

Re: M6E-Nano Frequency Selection

Post by paulvha » Mon Dec 03, 2018 5:03 am

The antenna work is more details than I have worked on so far.

The default hoptable for EU3 has indeed 4 entries by default:
/reader/region/hopTable: [865700,866300,866900,867500]
/reader/region/hopTime: 3975

The minimum quantization between the frequencies is 100Khz
Lowest limit allowed is 865,600 kHz
highest limit allowed is 867,600 kHz

It should be possible to use more frequencies than 4 ?

Code: Select all

	865600	Lowest	
		100	
	865700		default
		100	
	865800		
		100	
	865900		
		100	
	866000		
		100	
	866100		
		100	
	866200		
		100	
600	866300		default
		100	
	866400		
		100	
	866500		
		100	
	866600		
		100	
	866700		
		100	
	866800		
		100	
600	866900		default
		100	
	867000		
		100	
	867100		
		100	
	867200		
		100	
	867300		
		100	
	867400		
		100	
600	867500	highest

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