之前玩ft8一直开10w，感觉已经差不多了，能收到的dxcc都能通得到，但自从最近10米传播打开之后，下午玩ft8几乎打不出去，直到晚上6点之后才慢慢变好，难道真的遇到了传说中的单向传播？还是因为JA台都睡觉去了因此没被盖台？因此想在此问问大家为啥会遇到这种情况，以及大家平时玩ft8都开的多大功率？

我挂机轰15W，人工操作开25W，日本人太多开50W，追台开100W，追台受日本人干扰就开300W，再大开不了超过天线耐功率了

糟糕，投票时间设置错了

天馈太烂的话堆功率也很痛苦，特别是FT8

我都看图别人收我多少决定功率。当然，追台的时候，还是力大砖飞吧。

FT8开发作者建议是不超过50%,一般控制到30%以下各大短波机官方也是这么认为的 (因为短波机标称功率都是PEP,持续功率输出30%为宜,否则存在散热不及时,烧功放的风险)

@"BD3OOX"#p35063 这是说的白瓦机器？ QRP机器是否可以

@"BI4PMQ"#p35070 QRP可能连散热风扇都没有作为一件产品，其散热设计是和其使用方法相关联的 QRPP可能不需要散热 QRP被动散热百瓦就大散热片加风扇千瓦可能就服务器暴力扇了所以和是啥机器没关系，满功率用就是踩着设计极限

@"BD7PPD-xiaohei-lv"#p35081 理论上应该设计有余量，比如705，满功率10W，实际上功放管支持20。可能是散热，供电种种原因限制到10瓦

What's the ideal transmit power for FT8?

BG5VLI

I've been using FT8 with a power of 10W for quite some time, and it seems to be working well. I can receive DXCC stations easily, but since the 10-meter band has opened recently, my ability to transmit in the afternoons has significantly decreased. It wasn't until after 6 PM that things started to improve. Could this be due to a phenomenon like one-way propagation? Or is it because all the Japanese stations are asleep at that time, which allows me to get through? I'm curious to know why others experience similar situations, and what power levels they typically use when operating FT8.

BI1JNP

I use a dead-key to transmit at 15W, manually operate at 25W, Japanese users transmit at 50W, and those chasing specific channels transmit at 100W. When interference from other Japanese users is detected, the transmission power increases to 300W. However, this maximum power cannot exceed the antenna's rated power capacity.

BG5VLI

Oops, the voting time was set incorrectly.

BG5UWQ

BG5VLI It has been modified.

BH7HQT

If the antenna is too poor, it can also make transmitting power very difficult, especially with FT8.

BI4PMQ

I decide on the power level based on what I see in the diagrams of how others are charging me.
Of course, when chasing the signal, you still need to use a powerful antenna.

BD3OOX

The developers of FT8 recommend that it should not exceed 50%, and typically control it to be below 30%.
The official representatives of major shortwave radio manufacturers also share this view.
(Because the nominal power of shortwave transmitters is PEP, a continuous output of 30% is recommended; otherwise, there is a risk of overheating and burning out the amplifier.)

BI4PMQ

BD3OOX
Are you referring to the White Vase machine?
Can a QRP transmitter be used?

BD3OOX

I recommend that you shut down this survey because it contains misleading information. Some people may click on random options or use equipment with high power (such as amplifiers) or have good cooling, or the room temperature is very low...

In simpler terms, SSB (Single Sideband) transmits power based on the audio level, so the output is not continuously at full load but rather intermittent. However, FT8, with its 15-second continuous transmission, achieves full load output, resulting in maximum amplifier heat.

BD7PPD-xiaohei-lv

BI4PMQ QRP may even lack a cooling fan.
As a product, its heat dissipation design is related to its usage method.
QRPP may not require cooling.
Passive heat dissipation for QRP
A large heatsink with a fan is needed for 100 watts.
The server might have been overloaded with power consumption, possibly exceeding its capacity.

So, whether it's a specific machine or not, as long as you use it at its full power, you're essentially pushing the design limits.

BG5VLI

本投票具有较强的主观性：

有些人会乱点，或者他的机器可以大功率 (比如功放), 或者他的机器散热很好，或者他室温很低....
用个通俗点的话说，SSB 是根据音量大小输出功率的，所以功率输出是非持续满负载的，而是间歇性的，但是 FT8 这种 15 秒是持续满负载输出的，功放发热量达到最大值

（感谢BD3OOX的提醒）

如需参考，请根据所用电台实际情况选择合适的功率发射，并请做好散热工作！

BI4PMQ

BD7PPD-xiaohei-lv Theoretically, it should have a margin of safety, such as 705, with a maximum power output of 10W. However, the amplifier tube supports up to 20W. This is likely due to factors such as heat dissipation and power supply limitations.

BG4IDK

This also depends on the specific situation. FT8 is designed for low power, and I personally prefer to use less than 15 watts regularly. Of course, the actual power level is often adjusted based on feedback from the other station. When trying to decode rare call signs or CQ calls, you can increase the power slightly, but it's important to constantly monitor the radio, power supply, and antenna when using high power. I personally prefer to watch the SWR (Standing Wave Ratio) meter while transmitting to prevent any unexpected issues.

BG2GFC

The transmitting station should only radiate the power necessary to ensure satisfactory service (Abba).

BI4UMB

Normal operation at 40W

BI7LVX

In fact, by looking at the sale of the BAE, you can easily tell. When people generally say that SSB can tolerate 100W of FT8, they usually recommend around 40W. I have also seen people using the 891 at 40W continuously and then it breaks down. It mainly depends on the usage scenario. For example, since the weather is currently quite cold, chasing stations for a short period with 100W is not impossible. If it's for continuous operation (QSO), then I would recommend staying below 20W, because FT8 can decode weak signals, and the remaining time can be used to transmit good signals to North America.

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