Winston Lawrence

KD2WLL - Amateur Radio Notes

RT73 HowTo:
Bugs, Gotchas and workarounds.


Retevis RT73 Configuration and Firmware at the time this was written..

 Name Description
 Model Number DR300UV
 Firmware Version 109E.D4.EARSAB.007
 Version Date Nov 27 2020
 Firmware ID DRS-300UV

The Retevis (Ailunce/Kydera etc) RT73 appears to be a nice radio So far, but it is hampered by the poorly executed (technical term is "sucks") software. There are bugs and missing features in the basic firmware that can clearly be corrected or added given time> For example power levels, why only high and low? Where is the import and export capability for contacts, channels, zones? The main problem is with the CPS which is missing some basic capabilities, like the noted import also manages to change fields at times on its own, writing its own values to the radio when saving the codeplug. To be fair the firmware and the CPS has improved to the point that it is mostly useable - but you still need workarounds.

1. Random lockouts

The radio will sometimes enter into a lockout condition in a couple of different scenarios (example). One scenario is triggered by a random transmission which causes the radio to enter a lockout condition. If the random transmission is triggered by the USB cable being connected to the PC, then it can usually be corrected by telling the CPS to READ the configuration from the radio. Also related to the random transmission, is having the USB cable connected to the computer while operating the radio. This is related to the random transmission because there is a good chance that you are going to press the PTT key which will result in the same behavior as the random transmission. There is also a scenario where leaving the USB cable connected while closing out and exiting the CPS software on the PC will then trigger a random transmission with the results as already noted. In all of the random transmission cases, reading the codeplug back from the radio via the CPS, appears to clear whatever flag or memory corruption occured and puts the radio back in business. Just disconnect the USB cable when the READ operation is completed.

Another lockout condition occurs when updating the firmware. This has been fairly consistent athough I have only updated the firmware three times to date. When the firmware is loaded everything appears to be okay but the radio is locked. It appears that when you update the firmware you have to also write a codeplug back to the radio, hopefully a copy of the last codeplug one you created.

Again, all of these lockups, except for the firmware update one, were cleared by READING the radio configuration with the CPS.

2. Random Transmission

Random transmissions seem to occur when the USB cable is connected to the PC and a radio transmit operation begins. The transmission may be intentional in that you have written a codeplug to the radio and are testing it from the radio. Or, the transmission is triggered by the CPS somehow while connected via the USB cable to the radio. The transmission will last until the radio timeout (TOT) value is met. I have my TOT value set to 30 seconds while I am testing. The default value, either 60 or 180 seconds, is too long to wait before getting control back of the radio and since you ARE transmitting you may indeed be causing interference. Forcing the transmission to stop, by powering off the radio for example, will work but also seems like it may have locked up the radio to a point where just READIING the CPS as a recovery option does not always recover from the lockout.

3. Factory Reset

This does NOT actually perform a factory reset. The MENU option, when selected, just creates a "soft reset" back to the last codeplug that was stored. If the last stored codeplug is the cause of a problem then the closest you can get to a factory reset would be to load the base codeplug that comes with each new firmware version. You could also load the original (buggy) firmware but I can't think of any good reason to go back that far.

4. CSV: Loading Contacts, channels, zones, groups etc.

You can also load external contacts from a .CSV file. One reason to do this is that you can edit, update and sort an external .CSV file and then import it back. You WILL have to carefully check any zones/channels/groups that used the earlier contacts as they will need to be corrected. The channel refernce to the contacts is simply to the position in the list so any change other than simply adding to the end of the previous contact list will change the numbering/position of the contacts.
There was no way that I found to load channels (DMR talkgroups) with the Retevis CPS however the Kydera ham radio forum ( came to the rescue. Forum member MM7DBT has written a codeplug transformer that lets you read and write a codeplug to the file system (not the radio) as well as export and import CSV versions of the contacts and zone-channels. You can EASILY edit update and change the .CSV so duplicating a zone adding channels etc can be done to the CSV imported back to the codeplug editor which then writes the codeplug that the Retevis CPS can handle. This is much needed functionality which is inexplicably missing from the stock Retevis editor.

5. Promiscuous Mode

The ability to program one of the buttons for "Promiscuous Mode" was added in a later firmware update: .Enable "Mandatory mode" on a key. When you press it, "promiscuous mode on " appears and will toggle off if pressed again. You can also create an RX group with all of the talkgroups that you are interested in monitoring as a similar option so that it will receive any incoming calls.

6. CPS issues

The CPS does introduce errors/changes to fields that should not be changed on occasion. One example occured when I was creating a codeplu - I had about 16 channels defined in a zone and was trying to write the timeslot for the repeater as slot 1. I.E. the RX TIME value was Slot 1 and the TX Time value was slot 1. No go the value was changed in the CPS but when written to the radio and immediately read back, both values were set to "ON". I tried several ways, closing the CPS and restarting turning the radio OFF and then back on. The CPS refused to update the values. My workaround was to split the repeater zone into two zones so all of my "admin" type channel definitions (2) Parrot (1) Echo, (1) Status and a local chat were all in one zone and the BM Talkgroups were in another and at that point when I had less than 16 channels in the zone it is working fine. I haven't gone back and tried to add more channels to see if the problem occurs again but the radio is supposed to support something like 250 channels in a zone and I was certainly nowhere near that - maybe 16 channels ) magic number for the RT73?

'73 KD2WLL