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

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?

Yes, it is possible. The programming mode and the connection mode between modulator and PC varies depending on the model.
In case of cod. 07-894/A MD4 SD, the modulator has to be connected to the PC via network cable and has to be programmed via web browser Internet Explorer 10.
In case of the other models, instead, the programming can be performed after installing on PC a dedicated free software (downloadable at the link http://www.offel.it/ita/Download/Software), connecting the modulator to the PC using USB cable.

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:
● art. 07-900 MD HD-USB is equipped with a HDMI input and with "Rec&Play" function, which lets you record and play back video contents in .ts format on USB 3.0 devices. It is also fully programmable using modulator buttons.

● art. 07-901 DM-S HD is equipped with a HDMI input;

● art. 07-902 DM-L HD is provided with a HDMI input with Loop, which can be directly connected to the TV;

● art. 07-904 MD4 HD is equipped with four HDMI inputs.

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. 07-900 MD HD-USB. What is  "Rec&Play" feature?

The MD 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. 07-900 MD HD-USB)?

To record/play contents with the "Rec&Play" feature (cod. 07-900 MD 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. 07-900 MD 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
07-900 MD HD-USB

FAQ D.14
I'm using a hard disk for the "Rec&Play" feature (cod. 07-900 MD HD-USB), but it doesn't work. Why?

If a hard disk is used to record/play content with the "Rec&Play" feature (cod. 07-900 MD 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. 07-900 MD 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.
07-900 MD 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. 07-900 MD 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. 07-900 MD 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. 07-900 MD 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.