How should I choose between wideband and narrowband for my handheld radio?

BH4HOT

照理说如果选窄带，能量更集中，能传的更远，但我试了下如果设置窄带的话无法打开中继。
并且各大手台的默认模式是宽带，那应该大家都在用宽带吧？为什么手台不默认设置为窄带模式呢？
还有几个问题：一般什么时候会用到窄带？如果两个手台一个设置窄带一个设置宽带可以正常直频通联吗？设置窄带对扩大通联范围的作用有多大？音质会有损失吗（我知道用窄带音量会变小，但是不知道会不会降低音质）？

BG2GFC

Please refer to the A-license question bank.

For a given FM transmitter, the factors that determine the actual bandwidth occupied by its RF output signal are: [LK0786]
The higher the maximum frequency and amplitude of the transmitted signal, the wider the bandwidth occupied by the RF output.
Using a walkie-talkie configured for WFM (Wideband FM) reception to receive NFM (Narrowband FM) signals results in the following: [LK0789]
I can hear the signal normally, but the sound is quite faint.
Using a walkie-talkie configured for NFM mode to receive WFM signals results in the following effect: [LK0788]
It's possible to hear the signal, but a significant non-linear distortion occurs when the signal amplitude and frequency are high.
According to my understanding, it should be called a repeater. Is there something else I've set incorrectly?
The frequency spacing for NFM is 12.5 kHz, and the frequency spacing for WFM is 250 kHz.
Both the 25kHz and 12.5kHz settings on the handheld device are likely NFM, which means they should be used for stepped transmission.
Forget about using a Comtac; an FM radio is inherently unsuitable for DX (long-distance) communication. All the power is concentrated on the carrier wave.

BloodBlade

BG2GFC Wide and narrow are relative terms; some manufacturers may refer to 25 kHz as WFM and 12.5 kHz as NFM. Of course, both are considered narrowband compared to FM broadcasting.

BH9FPK

Therefore, using a narrowband signal allows for greater range and concentration, potentially increasing the communication distance between two devices compared to wideband communication. You can try testing the maximum communication distance between two devices in wideband mode, then switch both devices to narrowband mode and see if the communication distance increases significantly.

BloodBlade

Using a default bandwidth of 25 kHz is likely intended to ensure compatibility with other devices commonly available on the market.
Typically, narrowband usage is adopted by commercial users to conserve spectrum.
In an ideal scenario, a simulated signal would not experience any loss. However, the human ear has limited resolution, and volume cannot be perfectly amplified without distortion. Therefore, reducing the volume can be considered as a reduction in audio quality. Furthermore, if one person hears the audio at a lower volume, it will directly be cut off, resulting in distortion.
PressThis articleAccording to the statement, the narrowband mode has a worse signal-to-noise ratio, which actually results in a decrease (approximately 30%). Of course, a lower signal-to-noise ratio also means poorer audio quality, just as mentioned before. However, FM mode is not really suitable for DX.

BG2ELG

Always choose 25kHz / broadband / WFM. Choose whichever one you see.

Note: Only the broadcast version is the true WFM.

BH3PTS

It seems that only V-band APRS requires a specific frequency of 12.5 kHz, while other situations can use 25 kHz.

BG2KUJ

I've always wondered how this bandwidth is calculated. Does it include any amplitude on either side of the center frequency, or only those that reach a certain percentage of the maximum amplitude?

BH9FPK

Send bandwidth refers to the amount of frequency used when transmitting data. If you have an SDR, you can clearly see this.

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