I agree with you that this testing method cannot be applied.




The reason for using this test method is that when the B205mini and B210 use 
the same antenna, the B205mini signal is unstable and will be subject to 
irregular signal loss due to the tightness of the antenna SMA interface, so 
this extreme visual method is used to find problems.




From the current test results, no matter how the B210 shakes or tightens the 
SMA connector, even if it is slightly contacted by one of my probes, there will 
be no signal loss problem. However, this problem will occur when the other two 
B205mini are tested.













At 2022-10-27 20:16:39, "Marcus D. Leech" <[email protected]> wrote:

On 27/10/2022 00:37, luteo wrote:


Thank you very much for your reply!




I have two B205minis in my hand. Both of them have the phenomenon described 
previously, but the same antenna does not have this phenomenon on the B210.




Refer to the two videos of B205mini operating under GQRX ("B205 DuPont line. 
mp4"&"B205 DuPont line Acrylic. mp4") , I use the probe to insert it into the 
SMA interface, and the signal will be lost after changing different directions. 
My understanding is that the inner hole of the SMA interface should be the same 
as the metal probe on any surface. However, in the actual test, the two 
B205minis all show that the signal will be lost at the same position, which is 
also my confusion.




If you can, you can also test it in my way.







I just watched your videos.    That's not the way SMA connectors are intended 
to be used.   The internet construction of
  different SMA connectors will behave somewhat differently under these 
circumstances (with a random piece of wire
  jammed into the SMA socket).   Furthermore, the internal spring socket can 
get permanently deformed by doing that.
  Please don't.    Ettus/NI cannot guarantee performance if you aren't using 
the SMA connector the way SMA connectors
  were intended to be used.













At 2022-10-26 20:15:51, "Marcus D. Leech" <[email protected]> wrote:

On 2022-10-26 01:37, luteo wrote:


When testing the B205mini, we found that the SMA connector was tightened to the 
most tight, but there may be no signal or the signal is weak.




Of course not always. Sometimes it is better to loosen the SMA connector a 
little.




In short, the reception effect requires repeated adjustment of the sma 
connector. Even after the sma is tightened, applying an external force on the 
plug position may change the quality of the received signal.




There is no similar problem on other types of USRP boards. It is determined 
that it is not an antenna problem.




We used B210 and B205mini for comparison. See the attachment for video results. 
“B205-antenna.mp4” & “B210-antenna.mp4”




We used another B205mini for comparison. The phenomenon is the same. See the 
attachment for video results. “B205-DuPont line.mp4” & “B205-DuPont 
line-Acrylic.mp4”




We are not sure whether this phenomenon is caused by the absence of a shielded 
enclosure. But we don't think it will have such a big impact.




I want to ask if there is any way to solve this problem.

I haven't seen this problem with the several B205-mini that I have.

Check your cables.

Make sure that you aren't *over* tightening the SMA connector and breaking it 
at the shield.

Make sure that your source is well matched to 50 ohms.  Impedance mismatches 
(significant ones can cause high shield
  currents, making the performance inconsistent, and even subject to placement 
of the input cable.



从网易163邮箱发来的超大附件
B205-antenna.mp4 (3.61M, 2022年11月25日 13:35 到期)
在线预览 | 下载
B205-DuPont line.mp4 (2.75M, 2022年11月25日 13:35 到期)
在线预览 | 下载
B205-DuPont line-Acrylic.mp4 (17.49M, 2022年11月25日 13:35 到期)
在线预览 | 下载
B210-antenna.mp4 (4.56M, 2022年11月25日 13:35 到期)
在线预览 | 下载


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