设备通过usb连接电脑后，发射时电脑端口离线，目前看大家都在套磁环解决，我自己设备是一台qrp电台，功率5-10w，干扰这么大吗？

1.换平衡天线 2.加磁环 3.空气链接这种磁环就行，不过我这个是整活，找个类似的买就行，或者联系@"BG2EWI"#1206 ，我这个就是刘老师的 [upl-image-preview url=https://storage.hamcq.cn/2024-07-01/1719802035-319120-img-20240608-080112.jpg]

假定楼主的天线是端馈、地网不好的 GP、等等不平衡天线：解决方法：馈线套磁环，USB 线也套磁环，一个不行就两个，两个不行就三个如果不套，等功率上去了，甚至会出现（不限于）： - 显示器在发射时黑屏（或绿屏尿屏等，小米显示器受害者） - 键盘或鼠标失灵（需要重新插拔） - ……

@"BG2ELG"#p21972 目前使用的是MA-01，那看来只能套磁环了吧，天线接口、电源接口、usb连接接口都需要是吗？

@"Yuluoxk"#p21970 我昨天随便找了一个大磁环套进去线饶了3圈没什么变化，可能是磁环不行

@"BI1RRE"#p21973 地网情况如何

@"BI1RRE"#p21973 我之前也是用MA-01，一发射就掉，usb线加小磁环没用，得在馈线加上扼流圈就可以了（BG2FFJ上图中的绿色部分，不过我买现成的，不会绕😂）

【闲鱼】https://m.tb.cn/h.gh1AXFz?tk=FDbm3aDhZbB CZ0000 「我在闲鱼发布了【短波电台扼流圈，1：1巴伦，FT8抗干扰，玩FT8等必备配件】」点击链接直接打开巴适得很

就这个玩意如果自己有磁环也可以绕制可以有效抑制共模电流带来的干扰 [upl-image-preview url=https://storage.hamcq.cn/2024-07-01/1719809491-954153-img-20240120-235540-edit-27005603925045.jpg] [upl-image-preview url=https://storage.hamcq.cn/2024-07-01/1719809481-906763-img-20231102-152740.jpg]

@"BH8AVW"#p21994 这个不能说百分百有效，但是换一根好的usb线是可以百分百解决的，亲历！

@"BI1RRE"#p21968 首先最好是在天线上下功夫，尝试给天线增加地网，可以一定程度上缓解这种情况，当然加一个扼流圈也是可行的办法，我的端馈天线就是在加了地网和扼流圈之后对电脑的干扰大大降低。

First post for beginners: How to connect FT8 to a PC and troubleshoot port issues?

BI1RRE

After connecting the device to a computer via USB, the computer port becomes offline during transmission. Currently, it seems that everyone is using an external antenna loop to solve this problem. My own device is a QRP radio with a power output of 5-10W. Is the interference so severe?

BG2EWI

BI1RRE First, it's best to start by addressing the antenna itself. Try adding a ground wire to the antenna; this can help mitigate the problem somewhat. Adding a ferrite bead is also a viable option. In my case, after adding both a ground wire and a ferrite bead, I significantly reduced the interference with my computer.

Yuluoxk

1. Replace the balanced antenna
2. Add magnetic ring
3. Air Link

This magnetic ring works fine, but I'm going for something more elaborate, so I'll find a similar one to buy, or contact...@BG2EWI , this one belongs to Mr. Liu.

BI1RRE

Yuluoxk Yesterday, I tried putting a large magnetic ring around the wire and winding it three times, but there was no change. It's possible that the magnetic ring is not working properly.

BG2ELG

Assuming that the user's antenna is a simple feed-point, poorly grounded GP (or other unbalanced antenna):

Solution: Use magnetic rings to wrap around both the power cable and the USB cable. If one doesn't work, use two; if two don't work, use three.

If not properly configured, once the power increases, it may result in (but not limited to):

The display shows a black screen (or a green/blank screen, as experienced by some Xiaomi users) when turned on.
Keyboard or mouse malfunction (requires re-insertion)
……

BI1RRE

BG2ELG Currently, we are using MA-01. So, it seems that all the connectors – the magnetic ring connector, antenna interface, power interface, and USB connection interface – need to be compatible with it?

BH7HQT

BI1RRE What is the status of the ground network?

Jason

BI1RRE Previously, I used the MA-01, but it would immediately lose signal. Adding a USB cable and a small magnetic ring didn't help. I needed to add an inductor to the feed line (the green part in BG2FFJ's image), but I bought a pre-made one instead of trying to make one myself.😂）

BG2EWI

BI1RRE At the base of the antenna connection, use a stainless steel tube to secure several wires around the outside of the connector. The other end will naturally hang down, and the length of the wire should be approximately one-quarter wavelength.

BG2EWI

BI1RRE It seems a bit short; try going around a few more times.

BH8AVW

[Xianyu]https://m.tb.cn/h.gh1AXFz?tk=FDbm3aDhZbB CZ0000 "I posted on Xianyu: [Shortwave radio choke, 1:1 ratio, FT8 anti-interference, essential accessories for playing FT8]"
Click the link to open it directly.

Great!

BH8AVW

Regarding this device: If you have a magnetic ring, you can also wind it yourself. This can effectively suppress interference caused by common-mode current.

BH1AYY

BH8AVW While this might not be a guaranteed solution, replacing the USB cable with a good one should definitely resolve the issue. I've personally experienced this!

BH8AVW

BH1AYY The interference is caused by common-mode current generated by an unbalanced feed system, which in turn creates common-mode noise. Using a common-mode inductor can effectively suppress the common-mode current in the feed system, thereby achieving suppression or even elimination of common-mode current! This is also why almost all switching power supplies and precision equipment power supplies use either common-mode or differential-mode inductors.
If using a choke (provided that the appropriate magnetic core, turns ratio, and coil are used – not just any random magnetic core with arbitrary turns) still doesn't suppress common-mode interference, then it is definitely time to inspect the feed system.
As for using a USB data line sleeve with a magnetic ring, this will definitely have some effect, but it is only a passive solution that addresses the symptoms rather than the root cause. The interference still exists!

BH1AYY

BH8AVW Anyway, I tried it and it didn't work. It was the one you bought, haha. As I told you before, it didn't work, and now you're blaming this and that. Replacing the cable solved the problem.

BH8AVW

If you are winding it yourself, we recommend using a nickel-zinc magnetic core with a diameter of at least 50 mm, with a permeability of around 800. Wind 6-10 turns (depending on the desired inductance value).

BG2EFX

In reality, just buying a magnetic clamp would suffice.
The thing upstairs is also sold by RSJ.

BI1RRE

Thank you all for your technical suggestions. I tested using both the JTDX app on my Windows computer and the FT8CN app on Android, connecting via data cable each time, and observed the same phenomenon. My antenna is indeed an unbalanced one, and my current ground system consists of two copper wires fixed to the protective fence. The grounding environment is not ideal, so I am considering adding a magnetic loop to see if that helps. Thank you all!

dxs660

I'm experiencing the same issue with my UV K5, which is connected to a computer for control and transmission. Specifically, when transmitting in the V-band, the antenna immediately disconnects from the COM port. However, this doesn't happen in the U-band. When I use an external antenna, the V-band completely fails. It seems like this is the root of the problem.

BH8AVW

BH1AYY
This is perfectly normal. The choke coil can only suppress interference caused by the current flowing through the inductor, but in real-world scenarios, there are also beneficial radiated electromagnetic waves from the antenna, or excessive common-mode currents in the feed system that prevent complete suppression. This type of interference will still affect the device, but it cannot be said that it has no effect! As for replacing the USB data cable to solve the problem, this can only be said to exist as a source of interference and also due to quality issues with the data cable itself. After continuing to use the choke coil after replacing the data cable, you will achieve both symptom relief and root cause correction!

BH8AVW

BH1AYY
👏

BG2ELG

BH8AVW

同意，有时候 USB 线也会成为天线，接收电磁波转化成电流😂

闽ICP备2021006864号-7

闽公网安备35020602002794号互联网举报中心

用户协议隐私政策社区规范积分规则中继规则转载须知
更新日志联系我们常见问题友情链接运营报告赞助

浩奇科技（厦门）有限公司

是无线电，把我们联系在一起