SharkRF openSPOT 3 Multimode Digital Hotspot
Building on the previous model, the openSPOT 3 multimode digital hotspot offers improved transcode performance for seamlessly allowing operators using different digital modes to talk with each other.
OpenSPOT 3 review. In the past few years, the digital voice modes have rapidly grown to be popular on the VHF/UHF bands. It would be nice if radio manufacturers had all chosen the same digital voice mode, but that is not the case.
On the other hand, for many hams, this is part of the fun because it gives them the opportunity to experiment with different approaches, and to meet the challenge of bridging together certain modes with virtual repeaters (called reflectors) that are accessed via the internet.
This brought the introduction of multimode digital hotpots, and the openSPOT3 is one of the latest models. Basically, the openSPOT3 is a digital radio internet gateway with a low-power (20 mW) 70-centimeter transceiver to communicate with an amateur radio digital-mode transceiver.
There are several general concepts that are important to understanding the key differences between the openSPOT3 and other hotspots. When choosing a digital mode to invest in, there are three simple things to consider:
1) Who do you want to talk with? (In other words, which mode is used by your friends?)
2) What types of digital repeaters are available in your region?
3) What is your budget? Can you afford a radio and a hotspot, or many radios plus a hotspot?
For new hams, the available choices can be overwhelming because this represents the unknown. It’s a critical choice, as their experience with the new radio and new mode may impact their first impressions of the hobby.
Many hams choose DMR as their first digital radio because these radios are usually less expensive. DMR can be the most complicated mode to program and operate, but fortunately setting up a DMR radio for a hotspot is easy.
I often suggest buying three radios, one DMR, one D-STAR, and one C4FM (Yaesu System Fusion, YSF), but the cost adds up very quickly. The openSPOT3 from SharkRF may help hams in their decision making and save some money at the same time.
There are two previous hotspot versions from SharkRF, the openSPOT and the openSPOT2.1 reviewed the original openSPOT in the October 2017 issue of QST, and the openSPOT2 in the June 2019 issue.
SharkRF has added features and improvements with each version, and in the openSPOT3, they achieved a serious milestone: the newest SharkRF hotspot has the ability to do hardware transcode between all digital modes without losing any quality. (For example, the hotspot hardware allows a ham using a DMR radio to talk to one using D-STAR.) See the sidebar, “Supported Digital Modes.”
The first thing I noticed is the quality of the packaging and the hardware. The openSPOT3 still has no eth-ernet RJ-45 jack and no external antenna port — features that were on the first version but were removed in version 2. Physically, the new version looks like the openSPOT2, but it’s bigger and heavier because of new hardware additions. The power connector is a USB-C which, in my opinion, is the best solution.
There are now two buttons on top. One is for Wi-Fi, and when you hold it for more than 3 seconds, the openSPOT3 switches into Wi-Fi AP (access point) mode. If you hold the Wi-Fi button for more than 30 seconds, it will do a full factory reset of all the settings and configuration profiles.
The second button turns the power on and off, because this version has an internal rechargeable Li-ion battery. The glowing LED indicator near the power button shows the battery and power status with different colors and blinking speed indications, fully described in the manual. As an example, when the power cable is connected, a green light means the battery is fully charged and red mean it’s charging. If you hold the power button more than 7 seconds, the device reboots.
Like the openSPOT2, there are five profiles you can save with mode and reflector preferences. If you press the power button three times quickly, it will transmit Morse code for the letter P, followed by the current active profile number and name.
Just like the previous version, you won’t see any obvious operating status LED indicators, as they are hidden inside the white plastic enclosure. When you turn on the unit, the status LED glows through the case. Many colors are used to indicate the current status, and it’s very intuitive.
For example, when the openSPOT3 receives a signal, the LED turns green. When it transmits, the LED turns red. Other status indications are described in the well-illustrated, online manual.
Setting Up the Device
To set up the openSPOT3, you can use any PC, tablet, smartphone, or other device with an internet browser and Wi-Fi capability. When you first receive the openSPOT3, by default it will be in Wi-Fi AP mode. Turn on the hotspot and scan for a new Wi-Fi network called openSPOT3 AP with your device, just like you would when you want to connect to any new Wi-Fi network.
Once connected to the openSPOT3, you can do the initial setup via its web interface and then connect the device to your home Wi-Fi network and the internet. (Remember, without internet access, the openSPOT3 is useless.)
After the initial setup, if you move out of range of your initial Wi-Fi network, simply press the Wi-Fi button for more than 3 seconds to switch the openSPOT3 back into its AP mode. Then again, connect into the web interface directly, and select a new Wi-Fi network. Doing this does not affect your hotspot configurations, and you won’t lose the other Wi-Fi setup as long as you do not hold the button more than 30 seconds and trigger a factory reset.
Once the Wi-Fi setup is complete, use the very intuitive web interface to enter your call sign, IDs, digital ham radio mode, and reflector you want to operate.
The web interface is almost identical to the one used with the previous openSPOT model. We have the same top tabs: status, connectors, modem, SETTINGS, and NETWORK. The left menu is for quick setup, a link to the online manual, and for SHARKRF link setup. On the right menu, you have pocsag/dapnet setup, the DMR ID database lookup, and the UPGRADE button. Upgrading this device is easy — just click upgrade and the rest is automatic.
There is an advanced mode option that you can select to add advanced settings in almost every tab. This device can be amazingly easy to operate, but you can still do complex configurations if you’re an advanced user, an important advantage that SharkRF implemented in all their devices. At the upper left, they added a battery indicator.
The center of the screen shows the reflector in use, the modem mode, and other information. In Figure 4, you can see that the modem mode is D-STAR, but the active connector is System Fusion/FCS. With the openSPOT3, you can communicate with a System Fusion reflector using a D-STAR radio, and the other way around is also possible.
The openSPOT3 offers a good solution for those wondering which mode to choose. This new third generation of the openSPOT hotspot benefits from all the improvements made in the previous devices. To that, they have added new hardware components, such as an AMBE vocoder, which is the same chip that digital radio manufacturers use to encode digital communications.
The AMBE vocoder allows the openSPOT3 to transcode perfectly (no glitches) between modes. This means that you only need one digital radio to access most of the digital mode reflectors. In advanced MODE, you can adjust the gain used during transcoding to correct the volume difference between systems. This ensures top-quality audio in every mode.
With the previous model, it was possible to transcode between certain modes, but this was achieved with software, and it was not perfect. Cross mode with D-STAR was not possible, as it uses a different protocol that needs to be re-encoded.
Now you can operate cross mode with all modes, including D-STAR because the openSPOT3 can decode and re-encode into another mode using the AMBE chip. This is a major improvement. Note that to operate cross mode with C4FM, you need to be in DN (digital narrow,6.25 kHz), as it will not work when you used VW (voice wide, 12.5 kHz).
Just like the openSPOT2, the new model boots very quickly, and it’s ready for operation in less than 10 seconds. You can also program multiple Wi-Fi networks, and it will connect automatically to the first one available. I programmed my home network and my iPhone Wi-Fi hotspot (tethering). If I ever want to take the unit mobile, I just have to share my cellular connection, and I’m ready to go.
They also added a 1,200 mAh Li-ion battery, allowing the hotspot to be autonomous up to 10 hours without any external power. The new version also has a built-in beeper for audio status tone and CW profile announcement.
Operation on the Air
The openSPOT3 operates exactly like the openSPOT2. It is easy to configure, and it’s very stable.
The big improvement in the openSPOT3 is the hardware transcoding capability. Figure 6 shows simultaneous reception on two radios from the same C4FM reflector (FCS003/90), but from two different hotspots.
The Yaesu radio on the left is set to the openSPOT2 frequency in C4FM. On the right, the Kenwood D-STAR radio is set to the frequency of the openSPOT3, which is connected to the same C4FM reflector, but with the modem in D-STAR mode for transcoding. The call sign of the received station (2E0SEI) is shown on both radios.
In this simultaneous receive test, I noticed that the signal from the openSPOT3 was slightly delayed before reception in the D-STAR receiver. This is due to the manipulation of the data in the transcode process, because the source is a C4FM signal.
On a busy reflector where people come back very quickly, you may have to call a few times before you can be heard in between transmissions. This is also true if you are far away (in the IP world) as the number of internet hops can also add some delay. This phenomenon is not new in digital modes and is the reason operators are asked to leave a pause after each transmission.
OpenSPOT3 Supported Digital Modes
The openSPOT3 supports multiple digital modes and reflectors (a reflector is the equivalent of a digital voice mode repeater and is accessed via the internet).
DMR (digital mobile radio) — Originally a commercial protocol, adapted for ham radio. The popular DMRplus, DMR-MARC, and BrandMeister reflector networks are all supported by the openSPOT3, along with Phoenix, XLX, and TGIF.
Yaesu System Fusion (YSF, C4FM) — Developed for ham radio by Yaesu, there are three different reflec-tors/networks. YSFReflector and FCS are both supported by the openSPOT3. Yaesu’s Wires-X network is not supported by hotspots like the openSPOT.
D-STAR — Developed by the Japan Amateur Radio League and supported by Icom and Kenwood transceivers. There are many networks, including DCS, REF/DPIus, XRF/DExtra, and XLX, all supported by the openSPOT3.
NXDN — Kenwood’s commercial digital mode. Only one ham network exists, NXDNReflector, which is supported by the openSPOT3.
P25 — Another commercial digital mode. Only one ham network exists, P25Reflector, supported by the openSPOT3.
POCSAG (DAPNET) — An amateur radio paging system used in Europe and supported by the openSPOT3.
APRS (Amateur Packet Reporting System) — APRS messaging and location data forwarding (APRS-IS) are supported.
The openSPOT3 is an excellent portable/mobile hotspot. It is more expensive than some other hotspots, but you can use it to operate the most popular digital modes with just one transceiver. The Visit https://youtu.be/GJ to see our review of the SharkRF openSPOT3 Multimode Digital Hotspot on YouTube.
openSPOT3 software and hardware is robust and very stable. It’s also very easy to use, it boots up very quickly, and it’s completely standalone.
The SharkRF website offers extensive documentation for setting up and using this device with the various digital modes and reflectors. Additional support is available from the online SharkRF Community Forum, accessed via their website. Check out my companion video overview to hear the openSPOT3 in operation.
Manufacturer. SharkRF, Tallinn, Estonia; www.sharkrf. com.
Price: about $300 depending on exchange rate.
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