Quectel BC28 NB module antenna debugging problem

QWE4562009

Quectel BC28 NB module antenna debugging problem [Copy link]

 

Quectel BC28 NB module antenna debugging problem--------Now I have a problem. A product must use NB module, which is BC28. The frequency band of NB is very wide, especially the low frequency. As a result, the antenna is very large. Since the structure cannot be changed, I don’t know which direction to go for antenna debugging? Please give me more advice if you have debugging experience in this area. In addition, does NB communication need to cover the entire frequency band? Only a small amount of data is transmitted, which is text and characters. This efficiency is also quite low. How much is qualified? The signal efficiency of NB

QWE4562009

Quectel BC28 NB module antenna debugging problem -------- Now I have a problem. A product must use NB module, which is BC28. The frequency band of NB is very wide, especially the low frequency. As a result, the antenna is very large. Since the structure cannot be changed, I don’t know which direction to go for antenna debugging? Please give me more advice if you have debugging experience in this area. In addition, does NB communication need to cover the entire frequency band? It is only a small amount of data transmission, which is text and characters.

QWE4562009

QWE4562009 posted on 2019-9-11 14:36 Quectel BC28 NB module antenna debugging problem -------- Now I have a problem. A product must use NB module, which is BC28. And NB's...

Quectel BC28 NB module antenna debugging problem -------- Now I have a problem. A product must use NB module, which is BC28. The frequency band of NB is very wide, especially the low frequency. As a result, the antenna is very large. Since the structure cannot be changed, I don’t know which direction to go for antenna debugging? Please give me more advice if you have debugging experience in this area. In addition, does NB communication need to cover the entire frequency band? It is only a small amount of data transmission, which is text and characters.

bobde163

Have you ever bought and tested the NB antenna sold on Taobao?

topwon

QWE4562009 posted on 2019-9-11 14:36 Quectel BC28 NB module antenna debugging problem -------- Now I have a problem. A product must use NB module, which is BC28. And NB ...

Do you make the antenna yourself with copper foil? The frequency band of NB is the same as that of mobile phones. It is easier to buy a ready-made mobile phone antenna according to the frequency band of the operator you choose. The FPC type is relatively small. After all, the size of mobile phones is now required to be thin and light. If it is really impossible, find an antenna manufacturer to make it for you. I have a NB technical group that makes antennas.

topwon

QWE4562009 posted on 2019-9-11 14:36 Quectel BC28 NB module antenna debugging problem -------- Now I have a problem. A product must use NB module, which is BC28. And NB ...

In addition, NB itself is a narrowband communication. The wide frequency band you mentioned is because the frequency points used by different operators are distributed in a relatively wide range, including 900M and 1800M.

Although the amount of data transmitted by NB is small, its installation location is generally hidden, resulting in large attenuation of the transmission path, so the requirement for antenna gain cannot be reduced.

chunyang

As the netizen above said, NB is not broadband. The frequency points seem to be very different, but there is a multiple relationship between them, similar to the situation of mobile phone antennas, and they can be wildly matched.

Note that the 900MHz and 1800MHz frequency bands are completely different from 900MHz-1800MHz. The former is a narrowband, and the signal frequency components are around those two values, while the latter includes all frequencies between the two values, with a huge difference in bandwidth and completely different properties.

QWE4562009

bobde163 posted on 2019-9-12 08:23 Have you ever bought and tested the NB antenna sold on Taobao?

That can't be used, right?! How can there be one that matches BC28 exactly?

QWE4562009

chunyang posted on 2019-9-12 11:51 As the netizen above said, NB is not broadband. The frequency points seem to be very different, but there is a multiple relationship between them, which is similar to the situation of mobile phone antennas. It can be connected through...

So does the NB frequency band belong to the range or is it near a certain frequency band?

topwon

QWE4562009 posted on 2019-9-16 08:28 That can't be used, right? ! How can it be matched with BC28?

Yes, people usually buy ordinary mobile phone antennas to adjust NB (nowadays, most mobile phone antennas support multiple frequency bands), there is no big problem. After you have the measurement, you can find the antenna factory to fine-tune the matching parameters and it will be almost the same.

chunyang

QWE4562009 posted on 2019-9-16 08:38 Does the NB frequency band belong to the range or is it near a certain frequency band?

There are several frequency bands, each of which is within a not-so-wide range. Please refer to the relevant standard documents for details.

topwon

First, you need to choose an antenna based on the frequency band used by the operator for NBIOT services (in fact, many mobile phone antennas support both 900 and 1800 frequency bands). In the NB frequency band of mainland China, China Telecom currently uses the B5 frequency band (850MHz), China Mobile mainly uses B8 (900MHz), and China Unicom seems to use B3 (1800MHz, said to be mainly in the south) and B8 (900MHz, mainly in the north). The actual frequency points used (each frequency band will be divided into multiple frequency points that can be allocated for different services, such as 2G, 3G, NB, etc., and even different adjacent base stations can use different frequency points to reduce co-frequency interference, that is, heterogeneous frequency networking) depends on the configuration of the local operator at the base station, and we generally don't need to care about it.

NB-IoT uses the frequency band numbers defined by LTE. Release 13 specifies 14 frequency bands for NB-IoT (B1, B2, B3...B66).

topwon

Because the higher the frequency of the wireless signal, the higher the path attenuation and the smaller the coverage radius, and NB is intended to serve a wide range of connections, so the high-quality low-frequency band 900MHz is the mainstream.

The signal bandwidth of NB is 180KHz. Therefore, after the center frequency is determined, the actual occupied frequency band is a very narrow range, which is truly a "narrow-band".

QWE4562009

topwon posted on 2019-9-16 14:15 First, you need to choose an antenna based on the frequency band used by the operator for NBIOT services (in fact, many mobile phone antennas support both 900 and 1800 ...

Each frequency band is divided into multiple frequency points. What does this mean?

QWE4562009

topwon posted on 2019-9-16 14:21 Because the higher the frequency of the wireless signal, the higher the path attenuation and the smaller the coverage radius, and NB is intended to serve a wide range of connections, so with high-quality low...

Currently, the telecom card is used. The efficiency is the lowest in the low frequency band, but the efficiency in other frequency bands is acceptable. Especially in the high frequency band, the antenna efficiency is acceptable. How can this be optimized?

topwon

QWE4562009 posted on 2019-9-17 09:32 Each frequency band will be divided into multiple frequency points. What does this mean?

Similar to this. You can use AT+NUESTATS command to send to the NB module, and then you can find out EARFCN, which is the number of the currently connected frequency point.

topwon

QWE4562009 Published on 2019-9-17 09:35 Currently, the telecom card is used. The efficiency is the lowest in the low frequency band,,,, the efficiency in other frequency bands is still good. Especially in high frequency, the antenna efficiency is...

I haven't actually adjusted this, I just used a ready-made mobile phone antenna. But I can find the QQ number of a group member who makes antennas, and send it to you privately later.

chunyang

QWE4562009 posted on 2019-9-17 09:32 Each frequency band will be divided into multiple frequency points. What does this mean?

You can understand it this way: the frequency band of FM broadcasting is 88-108MHz, but the specific radio station is a certain frequency point in 88-108MHz, such as 100MHz, and multiple radio stations can be distributed in the 88-108MHz FM frequency band. The situation of mobile phones and NBs is similar. The standard determines several frequency bands, but in actual use, only a certain frequency point in a certain frequency band is used.

QWE4562009

chunyang posted on 2019-9-17 18:25 You can understand it this way. The frequency band of FM radio is 88-108MHz, but the specific radio station is a certain frequency point in 88-108MHz, such as 100MHz, etc. In 88 ...

Then can't we just define it at the frequency point? Then what is the meaning of the frequency band?

QWE4562009

topwon posted on 2019-9-17 11:22 It's like this. You send the AT+NUESTATS command to the NB module, and you can find out the EARFCN, which is the frequency point number currently connected.

Thank you for your enthusiastic answer. Why is the NB frequency band so wide? And there are many frequency bands. Isn't NB a narrowband communication?