如题，请教一下，我用手台可以打开U段中继台，有收到清晰回音，也能收到其他友台的通联（接收信号能到59），但是自己的语音信号上不去，其他友台反馈是信号微弱，完全无法听清，或者根本听不到，这种情况一般都有哪些原因，或者可以尝试从哪些方向去改善呢？（PS：我通联的QTH处于城市近郊，高度有海拔100左右，四周无遮挡，电磁环境应该还可以，与能够打开的中继台所在位置之间没有明显遮挡，但是直线距离有近100多公里了）

大概率还是和功率有关，手台功率太小，电磁波大气衰减后，中继台抄不清楚。100公里对于手台来讲，还是太远了。决绝方案： 1、手台外接车载天线 2、手台外接八木天线 3、手台换长天线，如771或者拉杆 4、加功率 5、加高度我的例子，同样的位置和天线，10瓦手台59，降到5瓦别人听不清语音。

太远了，功率不够，要么八木定向，要么加大大功率

手台功率小，距离远，没高度，

加大功率不太可能只能换天线提高增益。

手台天线增益小，且手台功率小。不改变功率，建议外接天线，接一个一米二的小棒杆试试。或者有条件就就架更长的天线，增益更高，接收和发射效率都高，条件不好就弄个车载天线扔空调室外机上。高度看海拔没用，你得和你周围的建筑物的高度差不多或者更高，效果才好。uv的通联，高度是第一因素，功率提高狠容易，现在手台十瓦很多，车台25wa 50瓦的也不少。没高度，110瓦效果也不会好。天线最好高增益的八木或者棒杆。棒杆有四米多的，五米多的甚至也有7米多的。北京通大连，3瓦，这是夏天有传播的情况下，用的八木。当然不是我通联，在500上听倒的他们通联。

@"tudoubocai"#p61320 那么可以使用功率放大器嘛

非常感谢各位的解答与建议，我会根据这些建议再去尝试的另外，补充一点哈，我是用的8W功率的手台，771的天线，我的位置与目标中继之间在我目视距离内是没有任何遮挡的，至于远处从地图上看基本也是平原地区，所以估计还是像各位友台所说需要从功率和天线上着手吧

@"BI7CKR"#p61354 虽然是平原，但地球曲率导致40km过后，就不存在“目视”了。除非你或者中继特别高。我这手台能打200km的中继，但那个中继海拔3500米，这才是“真目视”

@"mayiliuzhijiao"#p61352 先找到问题点，在确定解决方案。用八木和加功率，其实问题的原理是类似的。都是提升辐射能量密度。八木可以提升收发效果。功放只能提升发射效果，且降低接收效果（有损耗）。还有一点，功放似乎不合法…仅仅测试的话，提升高度是最简单的，跑到楼顶、山顶去试。但长期使用的话，换增益更高的天线，如玻璃钢棒子、八木，是在有性价比的方案。

I have a question about UV repeater connectivity.

BI7CKR

As the title indicates, I would like to ask for your advice. I can operate a U-band repeater using my handheld radio and receive clear echoes and other stations' communications (with signal strength up to 59). However, my own voice signals are not transmitting properly; other stations report very weak signals that are unintelligible or completely absent. What are the common causes of this situation, and what steps can I take to improve the situation? (PS: My operating location is in a suburban area near the city, with an elevation of approximately 100 meters, with no obstructions around it. The electromagnetic environment should be good, and there is no significant obstruction between my location and the repeater's location. However, the direct distance is over 100 kilometers.)

tudoubocai

It's likely related to power. If the handheld transceiver has too low a transmit power, the repeater won't be able to pick it up after atmospheric attenuation. For a handheld transceiver, 100 kilometers is still too far.
The definitive solution:
1、External vehicle antenna for handheld radio
2、External Yagi antenna for handheld radio
3. Replace the handheld radio with a long-range antenna, such as the 771 or a telescoping one.
4、 Increase power
5、 Increase height

For example, using the same location and antenna, a 10W handheld radio (model 59) becomes inaudible to others when reduced to 5W.

mayiliuzhijiao

tudoubocai Then, a power amplifier could be used.

BA4RGB

It's too far away, and the power isn't sufficient. Either use a directional Yagi antenna, or add a high-power amplifier.

BA7LOG

The handheld device has low power, long range, and no elevation.

BG5DUT

Increasing power is unlikely; the only viable option is to replace the antenna with one having a higher gain.

bd3qdg

The gain of the handheld antenna is small, and the handheld's power output is also low. Without changing the power, I recommend using an external antenna; try connecting a 1.2-meter short whip antenna. If possible, use a longer antenna to achieve higher gain, which will improve both reception and transmission efficiency. If conditions are poor, you can install a car antenna on the air conditioning unit's outdoor unit. The height is not important; it should be approximately the same as or higher than the surrounding buildings for optimal performance. For UV (Ultra Violet) communication, height is the most important factor. Increasing power is easy; handhelds with 10 watts are common, and car radios with 25 watts or 50 watts are also available. Without sufficient height, a 110-watt radio will not perform well. The best antennas are high-gain Yagi or whip antennas. Whip antennas can be up to 4 meters, 5 meters, or even 7 meters long.
Beijing to Dalian, 3 watts – this is a Yagi antenna used in the summer when propagation conditions are favorable. Of course, I'm not using my own Yagi; I'm listening to their transmissions on 500 kHz.

tudoubocai

mayiliuzhijiao First, identify the root cause of the problem and then determine a solution. Using a Yagi antenna and a power amplifier essentially addresses the same underlying issue: increasing radiated energy density. A Yagi antenna can improve both transmitting and receiving performance. A power amplifier only improves transmission performance and reduces receiving performance (due to losses). Also, it seems that using a power amplifier might be illegal… If you're just testing, increasing height is the simplest approach, such as going to the top of a building or mountain. However, for long-term use, replacing the antenna with one with higher gain, such as a glass fiber rod or Yagi antenna, offers better value.

BI7CKR

Thank you very much for your answers and suggestions. I will try again based on these recommendations.

Also, to add a note: I am using an 8W power transceiver and a 771 antenna. The distance between my location and the target repeater is clear line of sight with no obstructions, and from the map, the area appears to be mostly flat terrain. Therefore, it seems that addressing both power and antenna issues is likely necessary, as suggested by other users.

tudoubocai

BI7CKR Although it's a flat area, the curvature of the Earth means that "line-of-sight" is lost after about 40 km. Unless you or the repeater are exceptionally high. My handheld radio can reach repeaters at 200 km, but that repeater is at an altitude of 3500 meters – that's true line-of-sight.

BI7CKR

tudoubocai Learned

BG4LZP

tudoubocai Which repeater has such a high frequency?

mayiliuzhijiao

tudoubocai Learned

BG7MHN

Learned! Thank you for sharing your experience!

tudoubocai

BG4LZP For Ya'an Jiao Ding Shan, a directional antenna with a range of over 200 kilometers is required.

Bi4KKF

Receiving a signal labeled "59" does not mean that the signal was transmitted as "59".

Increasing height is a more practical approach than increasing power.

Also, pay attention to your posture. When calling, try to keep your body still, with the antenna vertical – even if you're sitting on top of a manhole cover, it should work well.

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