Winston Lawrence

KD2WLL - Amateur Radio Notes

RT73 HowTo:
Building a codeplug for two simplex hotspots.

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

These are my notes from creating a basic codeplug for two simplex hotspots. One hotspot, GallifreyAlpha, is configured for the TGIF DMR network and is primarily used in the car. The other hotspot, GallifreyBeta, is configured for the BrandMeister DMR network and is primarily setup in the house.

RT73 Zone-channel hotspot codeplug configuration for TGIF network

RT73 Zone-channel hotspot codeplug configuration for Brandmeister network

I'm not going to describe how to configure the hotspot for Brandmeister and TGIF networks. I'm also not covering the basics of getting the radio setup. The assumption is that you have taken the radio out of the box, applied for and configured your DMRID into the radio and set up the basic parameters needed to use the radio like the name of your radio and enabling Front Panel Programming etc. Just note that I am using TWO simplex hotspots above and not a single duplex hotspot or single simplex hotspot with the additional scripts to allow the TGIF and Brandmeister network to co-exist as DMR networks. This means that the two hotspots have two different frequencies assigned, assuming that you would at some point wish to have them running simultaneously.

Also, note that what is displayed above are the required columns you need to complete when using the CPS software. There are other columns, most of which are grayed out anyway since the above definitions are for digital channels as shown in the first column defined as CH Mode.

A strong suggestion is to stick with defining a channel as "digital" or "analog" ONLY. The RT73 has some weird additional options "A&D,TX-A" and A&D,TX-D" that given the state of the CPS are more than likely to bring problems if you use them and will in any case make troubleshooting these oddball modes more of a problem if you later have operational issues.

The LAST column, labeled contacts in the above images show contacts defined within the CPS. You must define the contacts before you define the channels. the contacts column is actually a dropdown list where you choose one of the contacts you have created. Also, note that the actual contact definition for the "LCL-Parrot" entry ( Note02 ) shown is a private call the other entries shown are defined as "group call".

The second-to-last column labeled GCL stands for Group Control List. You define the GCL entries after you define contacts. GCL entries contain one (or more) contacts. In general, it is a good idea to define one GCL entry per contact ( Note01 ). You can look at the GCL entry as telling the radio that when you transmit to a contact - this is where the radio should be directing the response (I'm oversimplifying). What I have done instead of one-to-one, is to place multiple talkgroup contact entries into a few GCL definitions. For example:

GCL Name Contains Contact entries
HSALPHA:   LCL-01; LCL-09; TGIF-31665
HSALPHA-US:   LCL-09; T110-N.Ame; T204-Tec1
HSBETA:   LCL-01; LCL-09
HSBETA-US:   LCL-09; B93-N.Amer; B3136-NY; B31621-HRC

You could just create one giant GCL entry and put all of your contacts in it but it's probably not a good operations practice if you have a lot of contacts as you will receive audio from any of the talkgroups that have activity within that GCL group. So for example, if you key up and talk on say the talkgroup defined above as B93-N.Amer you could be hearing audio from any of the talkgroups defined in the HSBETA-US GCL group list (i.e. LCL-09; B93-N.Amer; B3136-NY or B31621-HRC). If these are busy talkgroups then you should probably define them as one to one as previously noted. If the talkgroups are less busy then you can put multiple talkgroups into a GCL entry as long as you can tell when you get a response, which talkgroup is active which may not be the talkgroup you keyed up and which will not hear your response if you don't change to that talkgroup before responding. This is also a good reason why YOU say which talkgroup YOU are speaking on when you are looking to get a QSL - the folks receiving may be listening to multiple sources and unless you state it - may not know which talkgroup you are on.

"CH Name is the name for this channel. You can make it anything you like but if you don't have some consistent schema in mind then you are going to be hopelessly lost after you have defined a dozen of these to use in half a dozen or more zones. In general, the first letter of the name in my schema defines the type of talkgroup application so "A" means any DMR network. "B" means a Brandmeister network talkgroup and "T" means the TGIF network talkgroup. The numbers following the first letter are the network talkgroup number and the information after the number is a shortcut version of the talkgroup name.

"RX Freq and TX Freq are the hotspot (or repeater) transmit and receive frequencies. In the case of a (simplex) hotspot or repeater, they will be the same.

"Power:  The RT73 can, as of this writing, transmit on low power (about 5 watts) and high power (about 20 watts). You only need "low" power to talk to your "hotspot" receiver, which is probably only a couple of feet distant from the radio.

"RX Time and TX Time":: The RT73 name for the receive Time slot is RX Time. TX Time is the transmit time slot. On most hotspots, Transmit (TX) Time Slot is 2.  Set the RX time slot to ON.

Wrapping this up "RX Only" is "OFF" as this is not a receive only definition "Rx CC and TX CC" are the color code definitions - for my hotspots it is 1. SAVE the configuration to the filesystem and the WRITE the codeplug to the radio.

Note01: As an example, if you have a contact named "buddy" you define a GCL entry named "buddy" and the value/content of that GCL entry is the "buddy" contact you defined. You of course don't have to name the GCL entry with the same name as the contact(s) it contains but choose something that makes sense to you so that when you need to choose the GCL you have a good idea what it contains.

Note02:  That private call parrot definition may require a GCL entry - in my hotspot the parrot private call response is RETURNED by the hotspot, to local talkgroup 9. If you dont have talkgroup 9 defined in the GCL for LCL-Parrot you will not hear the parrot response. So my GCL parrot entry would need to have at minimum the LCL-Parrot contact AND the LCL-09 entry defined.

'73 KD2WLL