COFDM Wireless Video Transmitter and Receiver
Table of Contents
COFDM Wireless video transmitter and receiver Dimension
2-watt PA COFDM Wireless Video Transmitter
Size: 90x65x22mm
The most recent advancements in COFDM (Coded Orthogonal Frequency Division Multiplexing) wireless video transmitter and receiver technology have transformed how video is transmitted and received. COFDM is a modulation technique that allows digital data to be transmitted over a wide range of frequencies, resulting in a more reliable signal and improved data transmission.
We use COFDM technology in numerous applications, such as digital television, wireless video transmission, and digital radio. It’s also found in military and aerospace applications like satellite communications and unmanned aerial vehicles.
Finally, recent advancements in COFDM wireless video transmitter and receiver technology have transformed the way video is transmitted and received. This technology has enabled high-definition video transmission over wireless networks, as well as video transmission over a variety of networks and devices. The use of advanced coding techniques, such as forward error correction (FEC) and adaptive modulation, has enabled this.
5-watt PA COFDM Wireless Video Transmitter
5-Watt PA COFDM-912T Weight
Package for one full set of the COFDM Wireless Video Transmitter
FAQ of the COFDM Wireless Video Transmitter and Receiver
Hi, I am looking for a long-range hd video transmitter with hdmi input and a receiver with hdmi output.
Only transmit and receive in a surveillance center. The idea is to use the HDMI output of the remote control and retransmit it to the central. The drone has a system to transmit over the internet, but there is no internet in the desert, so we need to retransmit but not with the internet.
OK, our one-way long-range wireless video transmission solution is the base of COFDM technology (similar to DVB-T digital TV broadcasting). It is not on the base of the Internet.
Does this COFDM wireless video transmitter and receiver have AES 256 or 128 encryption? the output format is full hd?
Yes, COFDM-912T supports AES 128 encryption. Please notify us to plus a Parameter Configuration board for setting the AES128 password when you are placing the order. It is optional to buy.
The COFDM-912T transmitter only supports SD720P Video input. So even if the receiver has HDMI output, it cannot output real 1080P high-definition video, only 720P.
If you have very high requirements on the definition of picture output, I suggest you choose a model that both the transmitter and receiver support 1080P, COFDM-908T
Can it reach 30 km around?
In the introduction of the wireless video transmission system, all the transmission distances mentioned are based on the visible range (LOS). The 2WPA power amplifier supports 30 kilometers and is usually used on drones. The altitude is very high and the receiver is on the ground, so there is an obvious height difference between the transmitter and the receiver, and the wireless signal is transmitted in accordance with the waveform. The signal loss is small and other interference is very little clutter.
You mentioned that your usage scenario is that both the transmitter and receiver are on the ground, especially in desert areas, and there may be rolling sand dunes. Therefore, the signal transmitted wirelessly is easily interfered with. So here are the suggestions:
1. Try to use a high-power transmitter, such as 10 Watts or 20 Watts. Many of our ship customers use 20W transmitters.
2. Try to use a higher antenna or put the antenna on the roof or a nearby hill, and you can also increase the antenna tripod. Our clients always choose some 1.8-meter FRP omnidirectional fiberglass antennas.
3. If conditions permit, a repeater can also be added to enhance the signal strength and increase the transmission distance. The repeater can be fixed at a high place or on the roof of a moving car.
How to assemble the wireless video transmitter, camera, and battery?
Please check the below picture. 
There are two power connectors at the transmitter, the red connector is 12V output for the camera, and the black connector is 12V input.
What is the lag or delay in milliseconds of your COFDM-912T?
200-300ms with a regular camera and monitor.
Normal camera and screen have a delay of 200 milliseconds, right?
With our 100 milliseconds, it’s about 300 to 400.
We also have one with 30 milliseconds, but the price is 6 times that
300 milliseconds is acceptable if your plane has an automatic obstacle avoidance function.
I noted your transmitter can support up to 30 kilometers in LOS. How far will it support in the NLOS environment?
It’s hard to say the range of non-line-of-sight use, it depends on how many obstacles are in the middle. It is difficult to transmit if fully surrounded metal or mountains block it.
The test environment is unique, and the distance obtained from the test is also different. We can’t make any guarantees or promises about this.
We are a company that offers a solution to some rural areas here in the Philippines to monitor their rivers. If we purchased a 2W(30km) in the NLOS location, it could be reduced to 20km or more?
It is hard to say, it should depend on the obstacles between the transmitter and receiver. We don’t test it in your use environment, So I can’t tell you.
The same product will be interfered with differently in different environments, and the transmission distance is hard to say. Only the actual test will know.
Buyer: Actually, we have installed a radio transceiver that gathers a data sensor and transmits its data to an 18km distance center command. The operation is smooth and ok.
The same place we’re going to put up the device that we will buy from you.
As you have said, only an actual test will answer all of my questions.
Can the COFDM-912T TX device output separate serial data?
Data can only be transmitted in one direction from the transmitter to the receiver.
If you need to transmit data in both directions, you need to add a digital radio telemetry. (wireless data transceiver).
I would like to know if the transmitter can also output serial data on what the camera is capturing. Other than RF does it have a separate rs232 output for the transmitter?
Yes, COFDM-912T supports transferring the serial data for you. Please check the below picture. 
In this module where I can put up the camera? What type of camera is suited for this device?
The black one on the left shows a little bit of the above picture, which is connected to the camera.
It supports a 720p CVBS composite AV camera. or any HDMI camera by HDMI to AV converter box.
How can I let the transmission still work well if I remove the menu and panel board from the receiver?
Is there any way to disable the control panel so that the receiver can see the video from the transmitter?
If I remove the control panel on the receiver, the receiver does not see the signal from the transmitter.
Answer: Please check the FAQ in the below link.
https://ivcan.com/p/cofdm-video-transmitter-receiver-av-in-hdmi-out/#accordion-item-6._i_have_changed_the_parameter_on_the_configure_board_tool,_why_it_is_not_saving_when_i_restart?
I guess that you did not save the frequency, after you remove the menu on the receiver, the system will be back to the default frequency of 340Mhz. So you can not get the signal.
If GPS and TX are separated less than 1 meter – GPS is jammed. COFDM-912T has significant noise in GPS l1 and l2 freq. Do you have any low-pass filters to solve this problem?
Hi! We did extensive testing before ordering a bigger batch. And faced issues if combining the COFDM-912T transmitter with GPS.
Answer:
1. If you buy it again, I can add a low pass filter in the transmitter inside free. I can also provide an external low-pass filter for you for free.
2. “Do you know what insertion loss is in non-filtered frequency?”, Answer: max 0.6db
3. “Do you know what dBm loss is pass frequency?” 0.4dBm
COFDM-912T Customize Development
2 Watts default 595Mhz with 1.8-meter transmitter and receiver antenna
The client told us that his application details, the transmitter and receiver, are both used on the ground. In order to enhance the wireless transmission distance and avoid other signal interference, I recommend that both the transmitter and receiver antennas use 1.8-meter fiberglass antennas.
It was the first time the customer took the sample for testing, so he used the default two-watt amplifier and 595 MHz frequency.
The customer requires that the transmitter have an HDMI output so that he can transmit the received video to other devices. At the same time, in order to support HDMI input, I also matched an HDMI to CVBS RCA AV converter box.
The customer has added an optional parameter adjustment tool, the main function of which is to modify the transmitter’s transmission frequency and impedance. You can also add a password to the wirelessly transmitted video to encrypt the video of the transmitter. We must enter the same password on the receiver to decode the video to improve the security of the video.
Change COFDM Transmitter to 200 mW PA, with a power switch of the cooling fan for body wear
Customize a video on-off switch on the COFDM Transmitter for audio-only wireless transfer.
Here is the test video for this client’s requirement, added a video on-off switch at the 10-watt PA wireless video transmitter to transfer the audio only.
Here is a video to show you that we can add one video on-off switch on the COFDM wireless video audio transmitter.
Video on, then the transmitter will transfer the video and audio at the same time.
Video off, then the transmitter will transfer the audio only.
If you have any project or need to customize the function of the wireless video transmitter and receiver, please contact us.
The default power amplifier is 2-watt, we also make a 10-watt PA inside, to support long-range and transfer more extended distances.
2 Watts default 595Mhz with Yagi Directional Antenna and Omnidirectional antenna
300 Watts power amplifier modified 230Mhz COFDM wireless video transmitter and receiver
FAQs
- Yes, the frequency range can be changed from 170Mhz (better from 220Mhz) to 860Mhz. So it can work well at 260Mhz band.
- The frequency should be modified to the same on the transmitter and receiver. Of cause, the Power Amplifier and antenna frequency should modify the same frequency. (You need to buy a power amplifier and antenna for the transmitter and receiver to meet your changed frequency).
- In order to improve the sensitivity of transmitting and receiving, the frequency bandwidth is generally made very narrow (center frequency ±15Mhz, so bandwidth should be 30Mhz). The power amplifier of the transmitter and the frequency of the antenna are specially customized according to the frequency you need.
- It is best when you place an order, please tell me what kind of working frequency you need. Our engineers will modify the frequency of the transmitter and receiver, and also modify the PA and custom antenna according to this frequency range to ensure the best sensitivity and support the longest transmission distance.
- The default frequency is 590Mhz, With 30Mhz (+/-15Mhz), you can change it without modifying the Power Amplifier and antenna. For example, 578Mhz, 584Mhz, 590Mhz, 596Mhz, and 602Mhz.
- If you need to modify the transmitter frequency and bandwidth, you need a special tool of the parameter configure board, please see the below picture, it is not a default accessory, please buy it at an extra cost or contact us before ordering.
Yes, it supports to send the video and UART data from the transmitter and receiver.
As it is one-way transmission, so it can not send the control command from the receiver to the transmitter.
If you need to send control commands or other data from the receiver to control other devices such as cameras or drones at the transmitter, you can add a set of cheap digital transmission equipment, contact us, and we can customize it for you.
Please check the UART define on the transmitter and receiver at the below link. Please tell me if you want to have a lead cable. (default is no)
The transmitter default Power Amplifier is 2 Watts, so it can support 30 KM at line-of-sight.
The below picture is our tested distance from the mountain to the seaside.
If you want to transmit a longer range, you can increase the power amplifier. In addition to one watt and two watts, we can also make 5 watts, 10 watts, and 20 watts for your choice. Larger amplifiers also require larger batteries and current support.
For 20W PA, the power supply should be 24~28V. Only at 28 volts can the power amplifier achieve the best workability.
Our engineer can change the frequency to 300Mhz from the default 590Mhz, The antenna, and PA in the warehouse are 590Mhz, 300Mhz needs two weeks to customize, so the delivery time needs longer than our default 590Mhz.
Step 1: Please press OK and the right button at the same time, a menu of whether to save appears on the screen.
Step 2: Please press OK to choose Yes to save.
Remind, please use the bigger or longer antenna if your project allows, it can get better reception performance in the larger range.
The default full set
- SD Transmitter ( PA 0.5W, 1W, 2W, 5W, 10W, 20W, 50W optional according to your order demand)
- SD Transmitter antenna
- HDMI CVBS output receiver with parameter control menu and small screen
- 0.8-meter Receiver antenna 1 pcs. (There are two types of installing or fixing the antenna: 1. magnetic sucker base antenna, 2. Default U-type clamp FRP fiberglass antenna )
- Optional, parameter configuration board for the wireless video transmitter.
(If you need a magnetic sucker base antenna, the express or carrier thinks the magnetic products will interfere with their plane safety, so the shipping cost is higher than a U-type clamp antenna. )
The default full set package dimension
- 84*21*12CM
- Gross Weight 4.5KG
- If you choose over 100cm antenna and magnetic sucker base antenna, Some freight forwarders will charge extra fees, such as extra long fees and extra fees for strong magnetic items.
- The transmitter parameter configures board is different from the one on the receiver. The firmware on the parameter configure board was different from the transmitter and receiver, they cannot be used interchangeably.
- The transmitter parameter configures board can adjust the signal attenuation on the transmitter. Per 0.3db will reduce the 0.5W PA.
Question: Is it possible to change the outpout power (internal PA 0,5 w, 1 w, 2 w) via the configuration board?
- As answered above, you can adjust the output power by setting the parameters of ATTEN through the parameter configuration board tool on the transmitter. (This tool does not include the default package, you need to notify that you want to have this tool when you order)
- If you buy 2W PA, then you can set it 0.5W, 1W, but can not change it to 5W.
- We also can make it to 5W, 10W, 20W, and 50W if you need to support long-range.
No.
This wireless video transmitter only supports CVBS camera or video input, other type of video camera needs an extra converter box.
No. It is COFDM (DVB-T) technology.
So the COFDM frequency range is 170-860Mhz. It can support 477, 610, 675, 724, 816Mhz, but can not support 970, 1180, 1230 Mhz.
Our special model transmitter can support all the above ranges, but the receiver needs to use the downconverter block.
In order to allow our wireless transmitting system to support a wider range and better signal strength, we generally set the operating frequency to a certain point (170~860Mhz), and its supported range is only plus or minus 15Mhz. For example, the center frequency is 590Mhz, max support frequency range should be 575Mhz~605Mhz, The PA and antenna are specially customized according to this center frequency.
How to add a low-pass filter chip to the transmitter?
Some customers reported that when the distance between our transmitter and the GPS antenna is less than one meter, the transmitter will interfere with the work of the GPS through the transmitting antenna.
GPS satellite signals are divided into L1 and L2, with frequencies of 1575.42MHZ and 1228MHZ respectively. Our transmitter frequency is 595Mhz by default. If we encounter this situation, we can consider adding a low-pass filter, which means frequencies below 600Mhz. Frequencies above 600 MHz can be suppressed to avoid interference with other emitting electronic products.
There are two ways to add a filter. One is to add a filter IC to the COFDM-912T transmitter board, and the other is to add a filter box outside the transmitter. The down-pass filter can suppress frequencies below a certain frequency point, and the wave-pass filter can suppress the frequencies below a certain frequency point by allowing them to pass through.
