Personally, I think it's best not to use amateur radio equipment on trains.

arwoon

刚刚看来《再谈铁路通信电磁环境》这篇微信上的文章https://mp.weixin.qq.com/s/vYuET2ItRGd1P3MAW58I4g
其中一段话作者提到“ 早期铁路的下一代无线是450MHz的LTE-R系统。专业研究机构不知如何开始研究，在诚心地恳求下加入了既有的研究团队，开始了下一代的研究。
2016年铁路集团公司在大西线进行了各个专业的试验，其中也有通信的LTE-R的试验。我参加了试验结束后的评审，发现研究院通信部门只进行了450MHz的覆盖测试，对此提出了意见。评审单位不同意把意见写入评审报告，说是参试单位已经知道了就可以了。但是他们真的知道了吗？！
那时根据450MHz在铁路电气化区段存在问题做了一些测试，在公众号中已说明了电磁环境情况。由于专家们多是关心系统的功能，对电磁环境情况不是很注意。基本没有做过试验研究。”
业余手台U段430MHz-440MHz距离450MHz很近，为公共安全起见，我觉得还是还是不要在列车上使用业余无线电台为好。这是我个人的第一感觉，不知道是否正确，也希望资深大佬能够给大家分析科普一下铁路通信电磁环境与干扰的内容

BI7LVX

arwoon 430 MHz - 440 MHz distance is very close to 450 MHz.

"Anything close enough is considered close, and all legal radio stations undergo spurious harmonic testing. The results must meet the required standards. Furthermore, amateur business on the U band is only a secondary activity. Therefore, it should be recommended that in areas within several hundred kilometers of railway lines, those using the 430-440 MHz frequency as their primary business should not use it."

arwoon

BI7LVX I thought of another scenario, as described in the article "超外差" (https://forum.hamcq.cn/d/3258). The comments below mention: "I just verified it again, and it's true. I set several frequencies in the U band, and the receive-to-transmit difference is 26 MHz, but the results are the same, and we can communicate with each other. However, due to limited conditions, we cannot perform long-distance testing. It's possible that the field strength is too strong, preventing effective suppression." In the 430-440 range, 430 + 26 = 456, which could potentially cause problems. I welcome everyone to discuss these points.

tudoubocai

BI7LVX Actually, I know that three provinces have already banned the use of U-segment: Shanghai, Chongqing, and Zhejiang. They can only use V-segment, and in Shanghai and Zhejiang, it's limited to 144-146.

BI7LVX

It's obviously not advisable to avoid drinking water altogether because of the risk of water intoxication. According to this reasoning, V-segment is also close to the airport segment, so shouldn't we stop using it if pilots can see aircraft with their head-up displays?

BI7LVX

arwoon So, what's the conclusion? If you want to prove that using a 430+26 frequency affects public safety, then you might be wondering what the Ministry of Industry and Information Technology does, and how manufacturers can get approval codes. My view is that as long as the equipment is set up legally and operated within the scope of the license, there's no problem. Moreover, the current environment for UV frequencies is already not very favorable, so there's no need to impose more restrictions or raise the bar to public safety. I haven't heard of any cases where legal amateur radio transmissions have affected aviation or railway safety. For example, if I feel that an airplane is unsafe, I would choose not to fly, rather than urging everyone to avoid flying for their own safety.

BI7LVX

I'm not going to name any specific manufacturer, because modifying their equipment can be quite fun. However, since we're talking about this, perhaps we should consider why only certain specific handheld radios, like Yaesu, and those from manufacturers such as ICOM, can operate on other people's noise-canceling systems, while others cannot. But let's not delve too deeply into it, because they have the necessary approvals, and even products approved by the Ministry of Industry and Information Technology (MIIT) are fine. If something does happen, at least I know that the MIIT will back me up.

BG5EGC

BI7LVX
When interference actually occurs, it should be stopped immediately. Otherwise, there is a legal risk for the operator, and the Ministry of Industry and Information Technology cannot provide any protection.
Specific handheld deviceInIn this scenarioIt's worth noting.

BH6AOV

Although, LTE-R private networks typically operate at around 1800 MHz.🤔

BG5ELQ

BH6AOV China's railway network doesn't need to use LTE-R; it can directly transition to 5G-R.

arwoon

BG5ELQ Currently, we are indeed discussing 5G-R. The excerpt I provided was from an article titled "Revisiting the Electromagnetic Environment of Railway Communication" on WeChat. https://mp.weixin.qq.com/s/vYuET2ItRGd1P3MAW58I4g中的一部分。
Regarding radio frequency regulation, it seems that the National Railway Bureau requires railway groups to provide electromagnetic environment reports along high-speed rail lines every year (and perhaps also requires鐵道 (PTE) to conduct electromagnetic environment testing). The report should focus on [details about what the report should cover], and how to address the issues raised in the report is unclear. However, based on the current situation, I haven't seen any specific requirements from the management department. The author shares their observations based on their understanding of the situation. One example mentioned is early LTE-R. Currently, it seems that the electromagnetic environment reports along high-speed rail lines (and PTE) are not yet sufficiently standardized. This leads to discussions about whether amateur radio should be used on trains, and I hope everyone can share their opinions.

BH6AOV

BG5ELQ As of now, I haven't heard anything specific about LTE-R; 5G-R is still in the whitepaper stage and hasn't been implemented practically.

BG5ELQ

It's possible that a very small number of lines support LTE-R.

yitsunc

BG5ELQ Currently, I only know that the Shanghai City Area Airport Line uses LTE-M (

BD8DLV

Regarding certain technical specifications of handheld devices, it would be virtually impossible to pass a comprehensive testing machine.

BH2VYJ

It's best not to use amateur radio equipment on trains, primarily to avoid causing confusion among staff. Issues like stray signals, radiation, and interference are secondary concerns.

BI2UL

Honestly, it depends on the individual.
If there's a risk, then it should be prohibited, which would prevent many things from happening, including amateur radio.
So, if you're concerned about legal risks, you don't necessarily need the best.
Regarding freedom of use, there's no need to worry excessively, as you can simply turn off the device if it's causing interference without posing a serious threat to safety. For typical, everyday use, devices that pass inspection will generally not cause fatal interference.

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