Retevis  RB22
The RB22 is a new Retevis entry into the DMR world. It's one of the smaller handhelds but has a nice feel and good performance.
 
 
In the Box
Included with the RB22 handheld are the:
-  Antenna
-  7.4V 1900mAh  Li-pol Battery
-  AC Charger and Charger Base
-  Belt Clip
-  User Manual
 
 
General Description
-   UHF Handheld   DMR / Analog 
-   Size:  4.00 x 2.1 x 1.4"  (102 x 54 x 35mm)
-   Weight: 8.3oz (235g)
-   400-480 MHz 
-   User Manual

 
-   5w transmit
-   4000 channels
-   16 zones (250 Chan / zone)
-   128 Contacts (Talk Groups)


FCC Certification:  2ASNSRB22
 

Enclosure

The body of the RB22 profile is only 4" tall and has a very comfortable feel. The large semi-keypad provides all of the necessary functionality with the exception of the number pad. The LCD images shown below make it easy to use and navigate. The green button on the front as well as the two function keys under the PTT are programmable function keys.
 

click on image to enlarge

Transmitter
 
The frequency range of this radio is UHF 400-480 MHz, supporting both DMR and Analog (NB/WB).
 
The power levels hold very close to the specifications showing 1W and 5W. Power levels are listed below and were taken using a calibrated Bird Termaline wattmeter.
 

 
Simplex Operation / Hotspot
 
Although the RB22 performs well on a DMR repeater, there is something to note when using simplex.
When the TX and RX frequencies are the same (simplex), Time Slots are irrelevant.
 
Most newer ham DMR radios are still time slot dependant on simplex. The adopted standard is TG 99, TS1, CC1.  The RB22 does not follow those rules. There are 3 Time Slot selections: TS1, TS2 and ON. When programming a simplex channel, TS must be set to ON.
 
When set to simplex, the transmitter seems to use both time slots simultaneously. I was still able to use my single input hotspot, but the BER (bit error rate) showed approx 3.0%.
 
 
Microphone / Speaker
 
A nice feature in the RB22 is the adjustable microphone gain option. The ideal settings on my radio are MIC1=8dB / MIC2=10dB. Anything much higher is over driven to the point of distortion. My audio reports on the local repeaters and hotspot have been excellent
 
 
Receiver
 
The receiver sensitivity is very good on both digital and analog and the receive audio quality is great.
  
 
Display
 
The multicolor high resolution screen size is 1.77" diagonal. The examples below show a sampling of the resolution, symbols and graphics. To simplify your selection, the icons and menus that appear are selectable within the software.
 

Click on image to Enlarge

 
Software
 
The software is a bit different than most. The standard programming sequence is:
(1)  Create a Talk Group list in the Contact area.
(2)  Create your channels in the Channel area
(3)  Move the desired channels into one or more Zones.
 
The RB22 software.
(1a)  Create a Talk Group list in the Contact area.
(1b)  Create a Duplicate entry in the RX Group List (There is no default option)
(2)  Create a Zone
(3)  Individually build each channel within that zone. 
     If the same channel is to appear in 2 separate zones, each must be built separately.
  
Software Observations:
- No re-sequencing of channels within zones
- New lines cannot be inserted (all channels added to bottom of list)
- No cut / paste
- No channel or zone import / export  (.csv)

Always take a Software backup before, during and after making changes.
 
Note 1: There are 3 Time Slot options. TS1, TS2 and ON. When operating on simplex or using a Hotspot, the Receive Time Slot needs to be set to ON.
 
Note 2: The software defaults to 25kHz for DMR. This Must be changed to 12.5kHz when programming a channel.
 
 
Firmware
 
As additional features and future enhancements are developed, the radio can be updated to latest model. Updates can be done using a Windows computer in about 5 minutes.
 
 
Programming Cable
 
The RB22 uses a programming cable with the UART chip inside the USB connector. This is the same cable used by many analog handhelds with a standard K1 connector.
 
Concern: I have two Retevis cables, one uses a Prolific UART chip, the other, a CH340. The Prolific cable works perfectly, however the CH340 cable does not. When trying to upload/download, there is an error message 'Data Mistake'. 
 
Both cables (Prolific and CH340) will program my RT73 mobile, but only the Prolific cable will program the RB22.
- This was tested on both my Windows10 PC and laptop.
- CH340 Drivers were updated to the latest version.
- I tries a second cable with a CH340 that also failed.
- Retevis has been made aware of this cable issue.
 

  Charger
 
The charger is a standard two piece assembly with an AC to 12V power adapter and charger base. The indicators are Red while charging and Green when ready.
  Conclusion
 
The RB22 is a good performing DMR handheld that was initially designed for commercial use, but easily adaptable to ham radio repeaters. If you can live without the Promiscuous mode and the User DB, you will be pleased with the performance and ease of operation of this UHF handheld.
 
 
The Features include:
-  Small size
-  Bright color display
-  Programmable microphone gain
 
Concerns:
-  Simplex / Hotspot operation
 
 
Notes:
 
I highly recommend using the latest Firmware and Software for the latest fixes and features.
The latest stable release of the RB22 software can be found at the Retevis website.
Select 'Support', Then 'Firmware/Software'.
 
 
Note: This equipment was received for the purpose of a fair and unbiased review. All findings are factual based on the equipment I received. Any issues found have been reported both here and back to the seller or manufacturer.