Saturday, August 3, 2019

Radioditty RF 28 Portable Radio

Measuring 12 x 7 x 2 cm and weighing less than 200g, this palm sized pocket portable radio is the ideal travelling companion. The case is of good quality and does not look tacky or cheap. The buttons and switches are also of good quality. On Switch on, there is a clear backlit LCD display. By pressing the scan button, the radio will scan across the band (87.5 – 108 MHz) and memorise the stations received and store them in memory channels. It is also possible to make direct entry by keying in the actual frequency. The radio is sensitive and all stations were received without having to extend the antenna. Weaker stations would obviously benefit by doing so. The radio did not topple over when the antenna was extended and appeared quite stable.

The Audio from the speaker is striking in that it is crisp, clear and has a good dynamic range. It is not possible to drive the radio into distortion by turning up the volume too loud. The sound from this radio is impressive to say the least. 

It is possible to insert a mini SD card containing MP3 files and play these on the radio. One can scroll through the contents of the SD card and select a file using the arrow buttons on the keypad of the radio. There is also a play and pause facility. Provision is also there for playing files from a flash drive. Whilst the file is playing the file number and name of track will appear on the screen. There is also a frequency spectrum display which appears to give an accurate display of the audio being played.  

The Radio is powered by a rechargeable Li-ion 3.7v 800mAH battery which, when fully charged, will give a good 6 hours of operation. The battery may be charged with a mini USB to USB lead which may plug into any standard 5V mobile phone charger or into the USB socket on the computer. The charging light shows red for charging, green for fully charged and may be used as a mini torch by pressing the appropriate button in the keypad.

In conclusion this portable radio is excellent value at £19.99 purchased from The sound is very impressive indeed. I would recommend this radio without hesitation. 

Monday, November 20, 2017


Digital Hotspots

Two hotspots are in use in the EI5DD QTH. The Shark RF Openspot and the DVMega bluestack. They are both excellent Hotspots and result in an excellent signal through the Network to which they are connected. Other Hotspots include MMDVM and the DV4Mini.

A Digital Hotspot is a standalone digital radio IP gateway connected either directly to the Internet router via WiFi, Bluetooth or direct connection. Effectively, it is a small transceiver which transmits auudio derived from the internet connected to an appropriate Network such as Brandmeister, YSF or FCS.

The DVMega comes in two forms, either UHF only or dual band UHF and VHF.

The DVMega comes with a USB programming lead allowing the Firmware to be updated as required and the lead will double as a direct connection to a computer, Raspberry pi or windows,  or Android phone/tablet or is used to power the device. 

The initial set up of the device on a  windows system is simple by filling in the appropriate boxes with the reuired information and ensuring the correct frequency

A similar, but simple, screen is available on the Andriod tablet or Phone.

Using Pi-Star 

Pi-Star is a custom, pre-configured SD Card image for the Raspbperry Pi (and other ARM based single board computers). Pi-Star is the whole image, it is made up of a number of software components, but Pi-Star is the sum of its parts. The major components that make up Pi-Star include the excellent software stacks by Jonathan Naylor (G4KLX) & others - MMDVMHost / DStarRepeater and associated tools / programs. This software stack is fairly feature complete (it's not complete, until its complete....) and contains many innovations and tools that are usefull to hotspot operators and repeater keepers alike.

Pi-Star may be downloaded >>>> click HERE

Simply download the image to the laptop or desktop and use a program such "Etcher" to flash the image to a micro SD card. Insert the SD card into the Raspberry Pi and apply power and the Raspberry Pi will boot up straight into Pi-Star. Fill in the station details in the configuration page as shown. It should be noted that it does need a Raspberry Pi 3B  for best results. 

For the DV Mega configure each section as shown and click on "Apply Changes" before moving to next section.

Select the modes on which you wish to operated by clicking on the appropriate sliders. In this case both DMR and Fusion have been selected

Fill in the Callsign, DMR ID and other appropriate details in this section and apply changes. The frequency selected may be any of your own choice. By entering the LAT/LON details, the location of the station will appear on the Brandmeister Map.

For each Digital Mode, it is necessary to set up the default  server and in the DMR Configuration in this case the Default Server is the Ireland Call Talk Group 2722. Again do not forget to click on the Apply Changes button.

The Fusion also needs to be set up with default Server and APRS server. Apply changes.

Finally to Network Configuration. After setting the Firewall as shown, the WiFi can be set up as in the second panel. Once set up the dashboard will be accessible via the WiFi system. provided a password has been set up in the last panel. I generally set up the unit with an Ethernet connection but if portable or mobile the set-up can be used on the WiFi system with little noticeable difference in performance. 

If this system is to get constant use as a multimode Gateway, it is advisable to acquire a set of heatsinks for the main chips on the RPi motherboard, two on top and one on the underside. A cooling fan as also a good  finishing touch. This will keep the Raspberry Pi running cool if left running 24/7/365. As a home hotspot this would not be a priority.

Finally this is the activity Screen on the Dashboard. 

This is the set up as used on my holiday in the UK. The router is a 4G router with 4 ethernet ports as well as being WiFi. I was testing the router with a view to its use on a gateway and possibly a repeater in a remote location. To date it has worked well.

The system below shows the Raspberry Pi in a case with a Fan to keep the system cool in conjunction with heat sinks on the processor chips. Sitting on top of the Raspberry Pi, is the DVMega.

The system has been in use for approximately one month without any problems so I can recommend this set up.

When operating Yaesu Fusion, it is possible to press the Wires-X button on the transceiver and the Hotspot will transmit a list of reflectors allowing one to select the reflector of choice in much the same way as one can do on the Wires-X network using a Fusion Repeater or a Fusion Gateway.

Shark Openspot 

The Shark RF OpenSpot is a standalone Digital radio IP gateway / hotspot. It supports Brandmeister DMR, DMR+, D-Star(DCS, REF/DPlus, XRF/DExtra, XLX) and System Fusion (FCS, YSF Reflector) networks. More supported networks and features will be available with each Firmware release.

The OpenSpot supports cross modem modes e.g. TX C4FM to the DMR networks and with C4FM on DMR networks. A web interface allows configuration and monitoring. It is USB powered with a low energy consumption and 20nW output on single or separate Rx/Tx UHF frequencies.

The Openspot support page provides all resources for setting up the modem with regular Firmware upgrades available from the Openspot website. There is a video for all eventualities so it is possible to set this item with all possibilities covered. If the questions are not answered there is always the Facebook page with many enthusiastic users who will have a wealth of knowledge on this unit.              
The unit was developed by two hams who understood the need of other hams. The result of their knowledge produced features that are not found in other hotspots.

Whats in the Box?

The Shark RF Openspot, a 1A wall P.S.U., a small UHF antenna and an Ethernet Cable.

To start with, the openSPOT is a very solidly built unit.  Don’t let the size fool you.  The chassis size is only 2.5 x 2.75 x 1.0″, but the weight is 5oz.  This is due to the weighted base plate inside the enclosure to stabilize it when the cables are connected.  There is no heat build up inside, which allows it to run 24/7. The antenna jack is a standard SMA-F, with the antenna terminating with an SMA-Male. Four small rubber feet assist in keeping the chassis stable.

The power level of the openspot is variable up a max of 20mW but 1mW is more than adequate to operate around the house. Possibly placing the unit on the shack antenna will cover the neighbourhood.

To change the settings on the open spot it is a simple matter of logging into the internet using the IP address of the unit.

The OpenSpot has to be set to work on the desired digital mode and will not automatically toggle between modes on receipt of a transmission. One interesting and useful facility, is the ability to calibrate the unit. This will set up the demodulation mode for the transceiver in use thereby guaranteeing crystal clear modulation/demodulation at all times.

The ability to cross-connect between DMR and C4FM has made this hotspot very popular. Results are excellent and, to date, the YSF to DMR system on TG 2724 has been made possible via an OpenSpot connection located in Northern Ireland. The audio quality is excellent using both DMR and C4FM.

To change the settings on the open spot it is a simple matter of logging into the internet using the IP address of the unit.

The OpenSpot has to be set to work on the desired digital mode and will not automatically toggle between modes on receipt of a transmission. One interesting and useful facility, is the ability to calibrate the unit. This will set up the demodulation mode for the transceiver in use thereby guaranteeing crystal clear modulation/demodulation at all times.

                Using the TP-Link TL-MR3020, it is possible to connect a mobile 4g pebble and obtain the necessary ethernet connection from this unit. Powered by a 5v Li-Ion battery. This is a great way of going both portable or mobile.

The Mobile combination makes this a versatile setup and even if there are no Repeaters in the area one has constant connectivity. It is small enough to carry in the case if one is going on holiday. The beauty of this arrangement is that one can use the same frequency on the handheld to keep in touch or work around the world via the network of choice. This  combination will work well if the 4g connectivity is good in the area.