FAQ: Modulators


FAQ D.1
How can I combine the modulated signal with signals already distributed into the TV system?

The modulated signal have to be combined with the signals received by antennas upstream of distribution. This can be done by connecting the modulator output to one of the TV multiband amplifier inputs (if the modulated signal needs to be amplified), or by using a dedicated mixer to be placed between the multiband amplifier output and the first splitter or tap present in the TV system (if the modulated signal level is already sufficient to compensate for insertion losses along the distribution).

Digital modulators
Examples of application of digital modulators

FAQ D.2
Why am not I able to see the modulated signal anymore, after combining the modulated signal with signals received by antennas?

When you select the channel modulator output, it is advisable to check previously that on the same frequency there is not another signal in the TV system. Otherwise, both signals (the one modulated and the one already distributed in the TV system) will disturb each other, preventing their proper tuning.
Digital modulators

FAQ D.3
I connected the output of the digital modulator I purchased to a TV outlet, but the signal isn't received on the other outlets, due to a too low level. How can I solve this problem?

To be correctly received on all the TV outlets, the modulated signal have to be combined with the signals received by antennas upstream of distribution (see FAQ D.1).
Instead, connecting the modulator output on a TV outlet, the reverse attenuation of the various devices (sockets, splitters, taps) of the TV system prevents the proper distribution of the modulated signal.
Digital modulators

FAQ D.4
If two or more digital modulators are installed in the same TV system, can I have any problems?

If in the same system two or more digital modulators are installed, in order that the TV is able to tune all the signals, it is necessary to assign to each modulator:
1. an output frequency that is not already occupied by a signal received in antenna and different from the output frequency of the other modulators;
2. a different TS ID (Transport Stream ID) for each modulator;
3. a different LCN (Logic Channel Number, which is the number that you type on the remote control to watch on TV a specific program) from LCNs of all other signals.

FAQ D.5
I bought a digital modulator and I would like to program it using a PC. Is it possible?

Programming via pc is possible only on some models: 07-890, 07-894 / A, 07-897, 07-900, 07-901, 07-902, 07-903, 07-904 and 07-905.
You need to download the dedicated software for free at the link http://www.offel.it/ita/Download/Software.
After installing it, connect modulator and PC via USB cable and start the software.

FAQ D.6
I selected a band 3 frequency as digital modulator output channel. Why isn't my TV able to tune it?

Since channel E21 (first UHF band channel) is the default output channel of digital modulators, if you want a band 3 output channel, the bandwidth of the channel has to be modified from 8 MHz to 7 MHz.

FAQ D.7
What is the difference between the different types of Offel HD digital modulators?

Let's see what are the main differences between the available models:

Offel offers a wide range of HD digital modulators. Let's see what are the main differences between the different models:
● cod. 07-900 MD HD-USB is equipped with an HDMI input and the "Rec & Play" function, which allows you to record and play video content in .ts format on USB 3.0 devices. It is fully programmable even by the modulator itself;
● cod. 07-901 DM-S HD is equipped with an HDMI input. For complete programming it is necessary to use a PC;
● cod. 07-902 DM-L HD is equipped with a pass-through HDMI input (Loop), which can be connected directly to the TV without adding an HDMI splitter. It is fully programmable even by the modulator itself;
● cod. 07-903 DM-E HD is equipped with a pass-through HDMI input (Loop), which can be connected directly to the TV. It is equipped with a simplified menu and a complete menu which also allows programming from the modulator itself;
● cod. 07-904 MD4 HD has four HDMI inputs. Requires a PC to be programmed;
● cod. 07-905 MD2 HD has two HDMI inputs, whose signals are re-modulated on a single output mux, and the "Rec & Play" function, which allows you to record and play video content in .ts format on USB 3.0 devices. It has a simplified menu and a complete menu that allows programming even from the modulator itself.
● cod. 07-910 DM HD is equipped with a pass-through RCA/HDMI input (Loop), which can be connected directly to the TV. Programming via integrated LCD display and keyboard;
● cod. 07-915 DM HD-4K is equipped with a pass-through RCA/HDMI input (Loop) with 4K scaler function, which can be connected directly to the TV. The Scaler function allows the passage of 4K signals and, if the TV is not 4K, it resizes the resolution of the signal. Programming via integrated LCD display and keyboard.

FAQ D.8
I connected a DVR (Digital Video Recording) to the digital modulator HDMI input, but the TV shows the writing "No video". Why?

If the TV shows the writing "No video" and the modulator display shows the writing "Video ?", make sure of select a video resolution from menu of the source (DVR, NVR - Network Video Recorder -, etc.) connected to the HDMI input of the modulator which is compatible with resolutions allowed by modulator itself.
Digital modulators

FAQ D.9
I purchased a modulator with a HDMI input. Why there is no video on TV, but I can only hear audio?

Being a digital modulator with HDMI input, the output signal is encoded in H.264 / AVC (MPEG-4) and modulated in DVB-T HD. If the TV can only tune the audio track, but not the video signal, it means that the television is not Full HD, but only HD Ready, and therefore it is not enabled to receive these signals.

FAQ D.10
I purchased a digital modulator with HDMI input. Why does the audio of modulated signal on TV is delayed compared to the images?

Digital modulators with HDMI input are programmed by default with MPEG1-L2 standard as audio compression format. Some TV tuners, however, do not interface perfectly with this standard. The result is an audio delay compared to video. To avoid this, simply set AAC-LC standard as audio compression format in the corresponding menu.

FAQ D.11
I purchased a modulator with a HDMI input, cod. 07-905 MD2 HD-USB. What is  "Rec&Play" feature?

The MD2 HD-USB digital modulator is equipped with a USB port to which connect USB 3.0 devices.
Thanks to the "Record" feature, video contents in .TS format with H.264 compression, received from the source connected to the HDMI input of the modulator, can be recorded on these devices.
Using the "Play" feature, you can play back previously stored files on USB 3.0 device on the output of the RF modulator.

FAQ D.12
What kind of USB device you need to use to record/play contents with the "Rec&Play" feature (cod. 07-905 MD2 HD-USB)?

To record/play contents with the "Rec&Play" feature (cod. 07-905 MD2 HD-USB) you need to use USB 3.0 devices and the format needs to be FAT32 (vedi FAQ. K.11) or NTFS. The minimum capacity recommended for these devices is 32 GB.
The absolute compatibility with every USB device on the market is not guaranteed. It is recommended to use high quality USB devices with high read/write speeds.

FAQ D.13
Although a storage device is connected to the USB input of the modulator cod. 07-905 MD2 HD-USB, the "Rec&Play" feature stops after a few seconds. Why?

When the modulator seems start recording, but on the storage device there is no .TS file, it means the device used does not meet the minimum requirements. To find out which are minimum requirements see FAQ. D.12
07-905 MD2 HD-USB

FAQ D.14
I'm using a hard disk for the "Rec&Play" feature (cod. 07-905 MD2 HD-USB), but it doesn't work. Why?

If a hard disk is used to record/play content with the "Rec&Play" feature (cod. 07-905 MD2 HD-USB), the format must be FAT32 (vedi FAQ. K.11) or NTFS with USB 3.0 interface.
It is also recommended to power supply the hard disk separately, since the modulator can deliver up to 500 mA.
You have also to verify that in your hard disk there is space enough for the recording.

FAQ D.15
Recording a file on digital modulator cod. 07-905 MD2 HD-USB using the "Rec&Play" feature, the recording was interrupted. Why?

If there is no more free space on the storage device, the modulator stops recording.
The same happens when the stored file reaches 4 GB of memory, when the format of storage device is FAT32. To store files larger than 4 GB is recommended to use the NTFS format.
07-905 MD2 HD-USB

FAQ D.16
How can I play on PC files recorded by the modulator?

To play on PC .TS files recorded on USB storage device using the "Rec&Play" feature (cod. 07-905 MD2 HD-USB) it is necessary that software for playing videos (e.g. VLC)  is installed on the computer.

FAQ D.17
How do I play a video file or a multimedia presentation via modulator?

If you want to play a file with the modulator cod. 07-905 MD2 HD-USB, it is necessary to convert beforehand the video or multimedia presentation (e.g. Powerpoint) in .TS format with H.264 video compression.
To do this you have to use a dedicated software, such as OJOsoft Video Converter, Video To Video Converter or similar.

FAQ D.18
Why I can't play the file video of the USB Pen Drive using the "Rec&Play" feature?

The digital modulator can't recognize the file that You want to reproduce because the file name contains characters not accepted by the device. To make sure that the modulator art. 07-905 MD2 HD-USB is able to recognize the video file to be played with the Play function it's necessary that the file name of the video to be reproduced doesn't contain special characters such as spaces, asterisks *, hashtags #, brackets, etc.
The file name of the video to be played must not exceed 32 characters.
The file must be converted to .ts format (see also FAQ D.17) and the maximum file size is 32 GB.