Some trivial questions

ping

有几个问题想问问大佬们

我现在使用钻石771+威诺n76，想提升通联距离（打到中继），客观条件限制，不能提升高度
1.看到好多人说车苗好，使用车苗能提升通联效果吗？是否为玻璃钢材质，影响大吗？
2.虽然说增加功率效果不明显。但是还是想问，值得买个功放，上25W吗？

地理条件：家住四楼，离中继很远（四五十公里吧大概），学校教学楼最高5楼，周边六层小楼为主，少高楼（二三十层那种高楼），但有一电信大厦（很高，上不去，保安拦下了）

目前没有打到过中继，但是能抄到中继的信号，很清晰。同镇的友台可以打到中继（功率不详，不过他有高度）

BI3QAC

1.关于天线的增益和距离问题：
每增加 1 dBi，理论上发射/接收距离会增加约 12.2% 。这个结论对 433 MHz 和 144 MHz 都适用 —— dBi 的相对影响与频率无关，影响只是按同样比例放大或缩小距离。举个直观例子：如果你现在在某环境下 433 MHz 的有效通信距离是 5.0 km，天线增益提高 1 dBi 后，理论距离变成 5.0×1.122≈5.61 km。
会有一定效果，但效果达不到你的要求。

25W功放的价格，加点钱，够买一个25W的小车台了，没必要。
最优解是买一个八木天线试试了，如果八木也不行，那多数是要准备入手车台了。

ping

BI3QAC
I currently have a Lactobacillus Yagi antenna, and I've tried it, but I still can't connect to the repeater...
I saw that the Vino amplifier looks good, what do you think about it? Is that price reasonable for a car stereo?

Some concerns about the vehicle: I go to school outside and rent an apartment, so I need a vehicle that can be easily moved. The parking situation is a concern (mainly due to power supply issues). Buying another power source seems too expensive, but I have a 3000mAh Xiaomi power bank, and I'm not sure if it will work. Also, there are antenna issues; I'm not sure if I can use the hand-held antenna, and buying a new set of antennas is also too expensive, plus my environment isn't suitable for setting them up...

BI3QAC

ping The chassis and this amplifier both operate on a 12V power supply, although some chassis require a 13.8V supply. With a power rating of 25W at 12V, the rated current is 25/12 = 2.083A. Therefore, even when paired with a lead-acid or 18650 battery, it still needs to be 12V, and the output current can reach over 2.1A.
For the UV segment, you can temporarily use a power supply from a case, and Mingwei's are quite good.
It's clear that your Xiaomi power bank isn't working.
If your budget is limited, consider buying a used chassis from online forums or platforms like Xianyu. When purchasing, try to choose some popular domestic brands that are widely used, rather than imported brands, as imported brands tend to have more counterfeit products.

ping

BI3QAC Inspired by a comment from a fellow listener on a forum, I wondered if a power bank could be used as a "lure" to achieve the desired output power. Here's a diagram of the power bank specifications: [Diagram of power bank specifications]

BI3QAC

I've also used 12V power supplies like this one before, and they work well with small tables.

BI3QAC

ping I don't understand this.

BG7XSS

25 W transmission power ≠ 25 W power requirement. Due to an overall efficiency of only 30%–50%, the entire system requires approximately 2–3 times the transmission power in DC power from the power source; it is recommended to use a server-grade switch power supply with a capacity of 100 W or more, to ensure sufficient margin and long-term reliable operation.

BG7XSS

You can directly purchase the phosphate iron lithium battery pack from BG2FFJ to solve your problem.

ping

BG7XSS I don't usually stay in one place for long. Currently, I'm in Shanghai, but I return to Anhui during the holidays. In the future, I might also go elsewhere after university. The homemade batteries from "大佬" (which I assume refers to a specific individual or brand) are not 3C, and their capacity is too large, making them inconvenient to carry around with me (even in places where public transport like subways may not be accessible), and they're also difficult to ship. Therefore, for me, this option doesn't seem very practical...

BD3QCY

ping The CoolTech 100W power bank + lure cable might be suitable for you.
It's best to add a current meter. Start using with low power; a 25W amplifier likely needs more than 100 watts of power supply support.
My 10W shortwave radio transmits at 5W power, resulting in an output power of approximately 45W.

BG7XSS

ping Then use a server power supply.

ping

BD3QCY It sounds like a good product. Could you recommend specific models, or provide purchase links?

BD3QCY

ping When choosing a brand from SearchCoolTech, consider which one best suits your needs.
You can refer to this article. https://forum.hamcq.cn/d/2028/2

BA4QBK

Try using an antenna mounted in your car. It's likely to work. A domestic 770 antenna is also not expensive. Buy another suction cup mount. First, try it outdoors. If it doesn't work, return it. I used to have a similar setup, at about the same height as you (6th floor), with the original antenna. I could hear the repeater but couldn't transmit. Now, I'm using a new 770 antenna and mounting it on my balcony, with a 5.5-7 meter coaxial cable connected to a handheld radio. The QuanSheng UVK6 can clearly connect to the repeater, with a signal strength of 59.

ping

BA4QBK I checked, and New Min is selling them for 80+ yuan, with some available for 30 yuan. The appearance seems similar, so can I buy one? I want to connect an "m" head to a K6, what adapter do I need to buy?

BA4QBK

ping I need a connector, M female to SMA male. This is essential for connecting an external antenna with my handheld radio. The connectors cost 8 yuan each. I recommend buying a slightly better antenna. If you can make contact, keep it; otherwise, return it. A 30 yuan antenna isn't reliable. I bought a new one from a large store (likely "Xinmin"). Because of the standing wave issues, I even exchanged it once. Maybe with a good antenna, you'll be able to connect. However, I missed out because of a poor antenna. I am 70 kilometers away from the repeater. Currently, I have good connectivity. Of course, if possible, using a more powerful antenna would be better.

ping

BA4QBK I only have a multimeter, which can't measure standing wave (unfortunately). I also don't have much time, as I need to go to school and my phone is monitored at home, making returns difficult. Given this, I think it would be best to buy from a larger store; something around 80 yuan.

BA4QBK

ping 我又回头仔细看了一下您的情况，我感觉您应该好好研究一下手上的八木，乳酸菌八木是三单元莫克森八木，增益应该不会小于6db，90公分长的车载天线和1.2米的玻璃钢增益也就在5.5，所以先搞清楚您手上的八木是不是有问题，有没有正常工作，指向对不对，八木的指向很重要

BH7HCU

Build your own Yagi antenna using a small, approximately 1-meter long wooden block and an old, broken measuring tape. Use coaxial cable for the feedline; if you don't have a feedline, use copper wire, either twisted or arranged in parallel.

ping

BH7HCU This... it's too difficult. You overestimate my abilities.

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