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Sunday, July 16, 2017

Technology Updates:New DRM receiver GOSPELL GR-216

The latest Mediumwave / Shortwave / VHF-FM receiver GR-216 from Gospell can receive both digital and analogue mediumwave and shortwave signals as well as VHF FM broadcasts. The software-defined receiver is based on a NXP chipset. The firmware may easily be updated over the USB connector on the front. The size of the radio is 240 mm (w) x 120 mm (h) x 150 mm (d) (without the knobs). It is supplied with a 230 VAC power cord, a 230 VAC / 9 VDC power supply and a user's manual.

The radio has a pleasant design like your favorite kitchen radio but it is also fit for any living room. Unlike other products the GR-216 has a soft and clean design and all buttons and controls are easy to operate. It weighs about 2 kg and sits firmly on a table or a shelf. Much of the weight comes from its large loudspeaker (77 mm diameter) and the mains transformer. The two strips on the bottom of the cabinet prevents the GR-216 from slipping around when tuning or pressing the push buttons. The AF output power amplifier is 4 W.

There is also a 12 or 24 hour clock and a dual alarm clock (radio or buzzer) and a sleep timer. In addition to the built-in AC/DC power supply there is a DC jack on the rear panel for an external 9 Volt DC power supply if so required.

Two BNC connctors are provided to connect external antennas, one for medium- and shortwave and one for FM. There is a built-in ferrite antenna for the medium wave band and a telescopic antenna for FM and shortwave. A switch is provided to select either internal or external antennas. Both the ferrite antenna and the telescopic antenna (on shortwave) are active antennas. On FM the telescopic antenna is a whip antenna. On the rear panel there are also connectors for headphones (stereo), two cinch line out connectors to connect to an external amplifier, a jack for the external AC/DC power supply and the 230 VAC socket.
Listening to the radio
The operation of the GR-216 is straight-forward using easy-to-operate knobs and switches. The tuning knob rotates smoothly and can be operated by the tip of your finger. This makes tuning easy like one is used to from regular shortwave receivers. There are also up/down switches for scanning or just to change channels step by step. The volume knob increases or decreases the loudspeaker volume in steps from 0 to18. By pressing the volume knob you can also adjust bass, midtones and treble in steps from -12 to +12. This lets you set the sound to your personal liking. The mode selector knob has three settings: AM (medium- and shortwave), DRM and FM.
Using the radio on FM (87.5 - 108.0 MHz)
Turn on the radio by pressing the ON/OFF button. Set the band switch to "FM". The scanning on FM works fine. Press and hold either the "|<<" or ">>|" button until a beep tone is heard, then release the button. The GR-216 now starts scanning for FM stations. The sensitivity is good and most of the FM stations come in loud and clear. Even the less powerful local broadcasting stations are received without noise just by using the telescopic antenna. Tuning can be done in 100 kHz or 50 kHz steps. When using the "|<<" or ">>|" buttons the frequency step is always 100 kHz. When tuning the frequency with the rotary knob it is possible to select 50 or 100 kHz. When the knob is rotated the text „Slow“ or „Fast“ is displayed in the upper right corner of the display. Select the channel step by pressing the tuning knob once. This function only works with the tuning knob.
Using the radio on AM (531 - 1620 kHz)
First decide on the channel spacing in the area where you live. In Europe the channel spacing is 9 kHz and this should be selected once from the Settings Menu by briefly pressing the button MENU/INFO, then select MW Step by rotating the tuning knob. Press the tuning knob once and rotate it until the MW step is 9 kHz. Press the button MENU/INFO twice to store the channel spacing. Set the band switch to "AM". Press the BAND button longer than 2 seconds to jump back to the medium wave band. The scanning and tuning is similar to the tuning procedure described in "Using the radio on FM ". The only difference is that you can select Fast tuning (9 kHz steps) or Slow tuning in 1 kHz steps. When using the "|<<" or ">>|" buttons the frequency step is always 9 kHz. A 50 kW transmitter located 150 km away was well received at all times during the day only by using the built-in ferrite antenna. Care should be taken to turn the radio a little in order to find the best signal strength due to the directivity of the ferrite rod. During the evening hours many foreign stations can be received clearly. There is not much difference when switching to an active antenna outside so for most locations the internal antenna does a good job.
Using the radio on Short Wave in AM mode (2.3 - 26.1 MHz)
Set the band switch to "AM". Select the desired shortwave band by pressing the BAND button until the desired band appears in the display. Tuning on short wave is similar to the tuning on medium wave. In Fast Tuning mode or using the "|<<" or ">>|" buttons the frequency step is always 5 kHz. When the Tuning knob is used it is possible to use either 1 kHz or 5 kHz channel steps. Generally the scanning can be used when tuning the shortwave band. But depending on the noise level in the band the scanning method can be somewhat problematic as the receiver will lock on both noise and broadcasing stations. Sometimes it will be better to use the "|<<" or ">>|" buttons or to use the Tuning knob to search the bands. The active whip antenna in GR-216 works very well and sometimes there is very little difference in reception when changing to an external antenna. If there is lots of noise in the room (LED lamps, switched power supplies etc.) where the radio is used one will definitely want to use an external antenna. As the shortwave propagation is different during day and night as well as the shortwave bands also depend on the time of the day it should be kept in mind that not every band is possible to use as could be expected. Generally the lower frequency bands tend to be more active during the dark hours of the day while the higher bands are most active during daylight.
Using the radio on DRM (Medium- and Shortwave Wave)
The frequency range for DRM is the same as for the medium wave and shortwave bands. When setting the Band Switch has been set to DRM, the speaker will remain silent until a DRM frequency has been selected and detected by using the Tuning knob or the "|<<" or ">>|" buttons. It takes a few seconds until the station label shows up in the display and the audio is decoded. An alternative method looking for DRM is to search for the characteristic DRM noise in AM mode and then switch over to DRM. The reception and decoding of the audio in digital mode is sometimes depending on the mode and bitrate used the broadcaster. Practical tests with the GR-216 placed on a table in a room showed varied results. For instance Voice of Nigeria 5600 km away could be well received without audio drop-outs even with the telescopic antenna fully collapsed. Voice of Nigeria uses a low bitrate of 9.1 kbps. Listening to Radio Romania 1500 km away is sometimes troublesome because they use a higher bitrate of 20.96 kbps. BBC from Singapore at a distance of 9600 km uses 16.92 kbps is difficult to receive in Scandinavia with the telescopic antenna because we are not in the target area. Even though DRM reception can be possible over great distances, it should be kept in mind that DRM reception needs a strong and stable signal. The sound quality in DRM mode is generally very clear and almost as good as FM stations. Generally speaking, DRM reception sometimes profits quite a lot from the use of an external antenna as DRM is vulnerable to Fading, noise, thunderstorms and crackle noises.
Storing and reading Frequencies in the Memory Banks
The received AM, DRM and FM frequencies can be stored in any of the five memory banks in VF mode (View Frequency). There are four memory slots in each memory bank which means that there are 20 memory channels for each band. To select a memory frequency, press one of the keys 1, 2, 3, 4 or 5 briefly until the list shows up, then scroll down by pressing the key repeatedly until desired slot is found. The channel will be selected after a second or so.
Selecting stored DRM frequencies from the VM List
When the GR-216 receives and decodes a DRM station the station will automatically be added to the VM (View Memory) list which can store 200 DRM stations. Select VM with the VF/VM button and rotate the Tuning knob or press the "|<<" or ">>|" buttons to scroll through the list of previously received DRM radio stations. If the selected service is active the GR-216 starts playing the broadcast. The VM memories are only available to store DRM stations. The stations in the list can be edited from the "DRM VM Manage menu".
How to load a new firmware to the GR-216
1 . What you need if you want to load a new firmware:
The ZIP file with the new Firmware
One USB stick)
A computer
Your GR-216 Receiver

2. Prepare the USB stick and the Firmware files:
Unzip the Firmware file to a temporary directory. You will find some files, and one should be named "part1.bin".
Copy the file named part1.bin to the USB Stick.
Remove the USB Stick safely from the computer.3. Step by step instructions to upgrade:

To check the firmware version, go to Menu ---> About. The firmware version should be something like "SW: 1.0 Build156m".
Power off the receiver by pulling out the DC plug from the GR-216
Insert the USB stick with the firmware files into GR-216 USB port on the front.
Power on the receiver by inserting the DC plug to the GR-216.
The loading of the new firmware starts automatically. The update files will be verified and then the update follows. At the end a message "Update successful" is displayed.
Remove the USB stick from the GR-216. The part1.bin has been renamed in the update process. In case you would like to update another receiver, it must be renamed again to part1.bin.
Do not turn off the power during the upgrade procedure, otherwise the receiver might be damaged!

All your preset stations and other saved data in the Set-Up Menu will remain untouched by the update. You don't have to set the clock and the date etc. all over again. 

Technical data

Frequency range, FM: 87.5 - 108.0 MHz
Frequency range, AM: 531 - 1620 kHz
Frequency range, SW: 2.3 - 26.1 MHz
Tuning step 50 kHz or 100 kHz
MW: 1 kHz or 9 (10) kHz
SW: 1 kHz or 5 kHz
Antenna FM & SW: Telescopic antenna
MW: Ferrite antenna
Active antennas on MW and SW
External Antenna sockets FM: BNC
Internal / External antenna switch. 
Station memory slots: 60
Tuning system: Manual (rotary knob)
Auto-scan (Up / Down)
Preset buttons (VF)
DRM Memories (VM)
Tone controls Bass
Stereo reception: Headphones or Line Out connectors
Clock: 24 Hour clock, dual Alarm clock (radio or buzzer)
Sleep timer. 
Display: Multi-function LCD.
Power supply, internal: 230V / 50 Hz AC
Power consumption Normal use: 13 Watt
Stand-by: 7 Watt
Power supply, external: 9 V DC
Power consumption Normal use: 5.6 Watt
Stand-by: 0.7 Watt
Loudspeaker 77 mm Ø
AF output power: 4 W
Measurements (without knobs): 240 mm (w)x 120 mm (h) x 150 mm (d)
Weight (total): 2155 g
Weight (230 V power supply): 705 g
Supplied accessories: 230 VAC power cord
230 VAC / 9 VDC power supply
User's manual
Looking back
It all began in January 2017 when I had the privilege of getting one sample of the GR-216 from Gospell for evaluation. The sample I got was completely hand made and later on in March I got a new cabinet and knobs out of the production. Together with Gospell I made several suggestions for changes and improvements that have been implied in the software. The radio I have here will get a few more firmware updates before the product is completed. I am still waiting for the implementation of the logging of DRM transmissions. Therefore it would be wise to look back at this page now and then for updates on the radio. My sincere thanks to Gospell and Mr. H. C. Liu for their confidence.  
Source and Credit :-
Forwarded by:- Shri. Alokesh Gupta

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