890-900Mhz Frequency 6 7 8Mhz Bandwidth COFDM DVB-T Wireless Video Receiver customized special channel to avoid disturbance from local tv channel

I will buy COFDM-907T Video – Audio, Transmitter – Receiver HD 1080P. I will use it for FPV in the RC cars. But,
1.. Will the 1080p HD PTZ camera work?
2.. Can you set the operating frequency between 890 – 900MHz?
3.. Can you make the working bandwidth over 6MHz?
4.. How far (km.) does it go between buildings in the city?
5.. Is the microphone connected?

Some clients want to use our digital tv receiver as COFDM Wireless Video Receiver, normal DVB-T frequency is from 170 to 860Mhz. In order to avoid interference from local tv channels, they hope the frequency to work at 890Mhz and 900Mhz. In this video, we can show you that we modify two special frequencies at 6Mhz bandwidth. it is working well and gets the signal from the wireless video transmitter COFDM-907T. We also can modify up to 930Mhz at the transmitter and receiver.

Thanks

COFDM-907T Video–Audio Transmitter–Receiver (HD 1080P) – Customer Inquiry and Technical Clarification

A customer has expressed interest in purchasing the COFDM-907T Video–Audio Transmitter–Receiver HD 1080P system for use in FPV (First Person View) applications with RC cars. This type of system is commonly used in ground-based projects where stable, low-latency video transmission is required. Below are the customer’s key questions, followed by our detailed technical answers and additional clarifications regarding frequency range and bandwidth customization.

---

Customer Questions and Answers

1. Will the 1080p HD PTZ camera work?
Yes, the COFDM-907T supports full HD 1080P video input. The important detail we must confirm is the type of video connector used by the PTZ camera. Our transmitter currently supports both HDMI and CVBS (composite video) inputs, which cover the most common camera interfaces.

If the customer’s PTZ camera outputs via HDMI or CVBS, it can be connected directly. However, if the PTZ camera requires remote control of its pan, tilt, and zoom functions from the receiver side, then a bi-directional data link is necessary. This means the system must not only send video from the car to the ground station but also allow return control signals from the ground to the transmitter. Such a setup is possible but will increase cost and complexity. If the requirement is simply to view video without PTZ control, then the standard one-way COFDM-907T system is sufficient.

---

2. Can you set the operating frequency between 890–900 MHz?
Normally, COFDM wireless video systems, especially those compatible with DVB-T standards, are designed to operate in the 170–860 MHz range. However, we understand that in some regions, customers want to avoid interference from local digital TV channels or other devices operating in the lower bands.

For this reason, we can provide a custom modification to extend the supported frequency range. The COFDM-907T can be adjusted to work up to 930 MHz, meaning that 890–900 MHz is fully achievable. This provides a clean operating band outside of typical DVB-T usage, reducing the chance of interference and improving stability in urban environments.

---

3. Can you make the working bandwidth over 6 MHz?
Yes, our COFDM transmitters and receivers support multiple bandwidth options, typically including 6 MHz, 7 MHz, and 8 MHz. By default, many systems are configured at 6 MHz, but we can adjust the bandwidth to suit customer requirements.

Wider bandwidth (e.g., 7 or 8 MHz) allows for higher data rates, which can improve video quality and support higher resolution or frame rates. However, wider bandwidth also requires more available spectrum and may be more susceptible to interference. For professional applications like HD FPV video, a 6–8 MHz bandwidth is common and well-supported.

---

4. How far (km) does it go between buildings in the city?
In urban environments, wireless video transmission is much more challenging compared to open line-of-sight (LOS) conditions. Buildings, walls, and other obstacles create a non-line-of-sight (NLOS) environment, causing reflection, absorption, and interference.

While the COFDM-907T can reach 10–15 km under LOS conditions, the range is naturally reduced in a city setting. Based on our field tests, when operating between buildings, trees, and streets, the effective range is around 1 km in NLOS conditions. This is still stable enough for most FPV and RC car applications within a city. For improved range, using higher-gain antennas or selecting less congested frequency bands can help.

---

5. Is the microphone connected?
Yes. Both HDMI and CVBS inputs on the COFDM-907T support audio and video together. For HDMI, digital audio is embedded in the same signal as the video, while for CVBS, the system uses RCA connectors that carry composite video and audio. This means if the camera has a built-in microphone, the audio will be transmitted along with the video to the receiver.

---

Frequency Customization Example: 890–900 MHz Operation

Some clients have requested that our digital TV receiver be used as a COFDM wireless video receiver at frequencies outside the normal DVB-T allocation. By default, DVB-T operates from 170–860 MHz. However, to avoid interference with local TV broadcasting, some users prefer to operate at 890–900 MHz or even higher.

In response, we have successfully demonstrated that both the transmitter and receiver can be modified to work at 890 MHz and 900 MHz using 6 MHz bandwidth. In our test video, the system worked smoothly at these frequencies and successfully received video from the COFDM-907T transmitter. Furthermore, we can extend the supported frequency range up to 930 MHz, giving users more flexibility in selecting a clean operating channel.

---

Conclusion

The COFDM-907T is a versatile and reliable wireless video transmitter–receiver system suitable for HD 1080P applications in FPV RC cars and other mobile projects. It supports multiple video input formats, adjustable bandwidths, and customizable frequency ranges up to 930 MHz. While line-of-sight range is significantly greater, in urban environments it can still provide stable transmission up to 1 km, making it practical for city-based FPV projects. Additionally, both video and audio (microphone) signals are supported, ensuring a complete transmission solution.

By addressing the customer’s questions, we can confirm that the COFDM-907T is a strong match for the project, and frequency customization ensures that interference can be avoided even in complex environments.