DV4mini review in the QST Magazine

DV4mini review in the QST Magazine

The DV4mini digital hotspot offers the opportunity to interface your digital handheld via the Internet with users worldwide. It works with many popular digital modes, including C4FM, DMR, and D-STAR.

Reviewed by Pascal Villeneuve, VA2PV

In 2016, all aspects of our daily life are going digital — and Amateur Radio is no exception. More and more modulation protocols from different vendors are now available for the ham community, including D-STAR, DMR, and C4FM (Yaesu’s System Fusion). This variety of new technologies is an opportunity for operators eager to learn something new.

The two main advantages of digital voice modes over conventional analog FM are their tolerance to noise and interference, and their ability to transport the signal over the Internet without modification. Sure, we can transport an analog signal over Internet Protocol (IP), but it will not be as good quality as a digital signal. Digital voice modes also add the ability to transport data such as GPS information.

In the ham digital world, a reflector is a server connected to the Internet that acts as a virtual repeater. Digital hotspots provide the ability for amateurs to connect to those Internet reflectors from their digital transceivers. Hotspots contain a low-power transmitter and receiver for amateur frequencies, and plug into a computer connected to the Internet.

A year ago, the only hotspots available on the market were for D-STAR. The DV4mini hotspot is a real game-changer because it works with D-STAR, DMR, System Fusion (C4FM), APCO25, DPMR, NXDN, and other digital modes that are based on GMSK, 2FSK, or 4FSK.

The DV4mini enables amateurs to reach all reflectors using any of these modes through the Internet. This technology is very flexible and the possibilities are endless, only limited to a certain degree by the operator’s creativity.

Overview

Physically, the DV4mini looks like a simple USB storage drive with an antenna connector at the end. The red model shown in the lead photo is the US version, while the model available in Europe is blue. As far as I know, they are the same except for the color. The unboxing experience will be short, as the impressive part resides under the hood — in the software.

There are three versions of the DV4mini available at the moment:

The AMBE version contains an AMBE vocoder chip that allows the use of a PC microphone and speaker to talk simultaneously to reflectors through the DV4mini, while also allowing the use of any digital radios in range.

Prerequisites

You cannot just enter your call sign in the DV4mini software. You must first enter a DMR unique ID, and this will give you access to all the reflectors on all modes. So, in order to use the DV4mini, you must obtain a DMR-MARC digital ID, which is coordinated worldwide, even if your intention is to use the DV4mini exclusively in a mode other than DMR. This registration process is free, and the DMR-MARC team is very quick to respond. For details, see dmr-marc.net.

You also need to make sure you are registered to the D-STAR trust server in order to use this mode. For more information, please contact your local D-STAR repeater club, or visit dstargateway.org.

The Software

You can download the latest firmware and the Windows version of the software from:

Microsoft Visual C Runtime Environment:

Visual C redistributable can be found here

DV4mini Driver click here

Firmware:
The latest Firmware for all DV4mini versions 1.73 is here

If you don’t already have it, you also need to install Microsoft Visual C Runtime. A link for that is provided on the Wireless Holdings website. The firmware upgrade is simple and risk-free.

On the European website (dv4m.ham-dmr.ch) you can find versions of the software for Linux and for the Raspberry Pi. There is no Mac version. One Raspberry Pi version, called DV4mini Compact, is optimized for running the software with a small 3.5-inch touchscreen. Using the DV4mini with a Raspberry Pi allows hams to set up a very compact, low-power-consumption standalone hotspot.

Getting on the Air

First, install a correct antenna onto the DV4mini’s SMA connector and insert the device into a USB port on your PC. Wireless Holdings offers small 2-meter and 70-centimeter antennas and adapters. There is no driver to configure and no port forwarding to set up into your home router. It’s plug-and-play wherever you are — that makes the DV4mini the perfect companion for those on the move.

Every time you launch the DV4mini software, it will automatically search for the stick. Once you do the initial setup, the next time you open the software it will load the latest configurations that were used in the previous session. If you change anything, it will be saved automatically, and the next time you open the software, it will be set on the same mode/frequency, ready to use.

The DV4mini Control Panel (see Figure 2) is exactly the same in the Linux and Raspberry Pi versions. Before doing anything else, in the Control Panel’s PERSONAL SETTINGS area, you need to insert your DMR-MARC ID in the DMR/CCS7 ID field. Your call sign will be automatically inserted into the field HOTSPOT CALLSIGN. The letters beside that field are used to differentiate hotspots if you have more than one. If you only have one DV4mini, just choose any one. Then enter your LOCATION (CITY) and QTH LOCATOR (grid square).

Next, go to DV4MINI SETTINGS. From here, you can select the digital mode you want to use. You need a radio that is able to transmit using the selected mode at the desired frequency, unless you have a DV4mini AMBE that can use a microphone and speaker directly from your PC. The DV4mini hotspots are multimode, but you can only use one mode at a time.

For the POWER settings, you can adjust the transmitter from 0 to 12 mW, depending on how far you want your hotspot to cover. In my tests, I used a small flexible antenna from a handheld transceiver. At 12 mW, with the hotspot indoors on the first floor, I covered a radius of about 500 to 600 feet. It is not recommended to use a high-gain outdoor antenna or any RF amplifier, because this device is designed to be a low-power unit only.

The RX-QRG and TX-QRG fields are used to set the DV4mini’s receive and transmit frequencies. In the Figure 2 example, I used a simplex frequency, but you could set up an offset using different frequencies for RX-QRG and TX-QRG. Please note that the software will memorize the frequencies for all modes, even if they are different.

You will also need to specify the reflector to use. Figure 3 shows the reflector choices available to me, using the various supported modes (DPMR and NXDN are not shown; they look similar to P25). In D-STAR there are three different types of reflectors: DCS, REF, and XRF. Each one is like a different mode, soDownload DV4mini review in the QST Magazine December 2016, by VA2PV you need to select the desired type, but your radio setup will be the same configuration for all. In C4FM (Yaesu System Fusion), P25, DPMR, and NXDN there’s only one type of reflector. You can find all the reflector dashboard links on the website xreflector.net, which shows the activities and the connected stations. See Figure 4 for a C4FM dashboard example showing connected stations.

After configuring the items on the DV CONTROL tab, the EXPERT SETTINGS tab is the only other section you need to set up. In this tab (see Figure 5), you can set the local or network mode (this is for IP networks only). Local is preferable if you run the software on the same PC as the DV4mini stick. If you are running the DV4mini on another computer within your network, you can control it remotely by using the IP address of the remote PC. This is great if you have multiple DV4mini hotspots.

Download DV4mini review in the QST Magazine December 2016, by VA2PV

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