Using selcall to identify calling radios

[Rob_Brookes]

This is one we get asked for every now and then as Dave uses a more complex system than this where the name of the portable or vehicle calling in, appears on the display of the SRM9030 at base. At the same time, the name of the person currently transmitting appears on the display of all portables within range.

There are three configuration files in the attached zip folder. All are for SRP9130 (or 9120) portable radios but by changing the radio type in the programming software and re-doing the button programming associated with the new control head layout, you can use the same configs in an SRM9030 base radio. You don't have to type the whole lot out again just to change radio models.

The two files called respectively :-

Generic Selcall First Radio
Generic Selcall Fourth Radio

Both use a specific numeric identifier that makes them unique. In the case of the first radio, this number is 11 and in the second the number is 14. (These numbers are much smaller than would normally be used in real life but the advantage if you can get away with two digits is that the noise is kept to a minimum. Normally selcall is sent using five digits, musical but noisy.)

If two SRP9130/9120 radios are programmed with one config each then when one transmits, it's callsign ("First Radio" or "Fourth Radio") will appear on the display of the other. It will remain visible for three seconds and then the display will revert to the name of the channel you are currently using, here 53a. Obviously you are expected to edit the current entries to something more meaningful than 'First Radio' etc.

The only thing that needs to be changed in each radio when they are being set up, is the Own Identity on the Selcall Options page of the programming software. However the numbers do have to be matched to the 'PhoneBook' list entries of course

The above method works when your team members each have their own personal radio. If a radio is given to another team member then the list in the 'PhoneBook' will need to be edited to reflect the new user. The PhoneBook can be exported and imported into any radio and so a master copy can be kept up to date.

The third file, called :-

Generic User Entered Selcall ID

Is used where your radios are not individually issued. When the radio is first switched on the display will show ID: at which point you enter the two-digit number you've been allocated with. This could quite easily be the order in which you appear in team membership list or any other system you devise providing any issued number is unique to you. After this, the radio will send it's new ID until it's switched off and on again where it will again ask you who you are. If you are one of those who struggle to remember a two-digit number, and I have met 'em, then enter '00' and all other radios will display a default name or entry as programmed into all radios.

As set up in these config files, the selcall sequence is sent as soon as the PTT is pressed rather than released so the sender's name appears on all screens immediately rather than when the transmission ceases.

These files are only suggestions and could be improved upon but they're a start if caller ID is what you're looking for.

In theory this can also be done using FFSK rather than selcall, and indeed it can. Unfortunately if GPS data is also selected, the FFSK messaging is turned off. We're asking TMC about that one as FFSK can be completely muted by using CTCSS so both GPS data and caller ID would be completely silent. Hopefully we'll be able to work this one later.

Please visit the download section of this site to obtain the latest copy of "Using selcall to identify calling radios" "Selcall.zip"

[Rob_Brookes]

TMC have recently released some additional information on this topic and the necessary bulletin is attached.

Please visit the downloads section of this site to obtain the latest copy of this file: "A9k-923_Selcall-ANI-V1_0[1].pdf"