Winston Lawrence

KD2WLL - Amateur Radio Notes

Ham Radio Glossary and notes.

    A connection to Talk Group 4000 on the Brandmeister network should result in a disconnection from any active talkgroups, along with a "Not Linked" message being returned.
A Private Call connection to 4000 is a request to disconnect from all reflectors. Another approach may be to connect to Talkgroup 9 which is a local talkgroup and should result in being disconnected from any currently active talk groups.
    Overview and sequence diagram on how DMR connections are made. DMR Connection Sequence
    The FCC rule states: Each amateur station, except a space station or telecommand station, must transmit its assigned call sign on its transmitting channel at the end of each communication, and at least every 10 minutes during a communication ...
    Parrot is deceptively simple in that it is a network audio server that allows you to speak, records your words and then plays them back to you. When it is working this lets you know that: your radio is configured correctly; your connection to the repeater is configured correctly; you get to hear your own words played back to you so you have a good idea how your connection sounds to other people.
    Unfortunately parrot configuration can be somewhat of a dark art in itself. Parrot is normally setup as a private call not group call and on the Brandmeister network it is 9990 and if you are going through your own hotspot connected to the Brandmeister network you're done.
    If you are conecting to a repeater you need to know if "private calls" are even allowed through the repeater and do they support parrot? If the repeater allows private calls and directly connects to Brandmeister then you are done.
    Some repeaters are linked and go through bridges to connect to Brandmeister. There is no standard and there is no guessing you will have to research how (or if) Parrot is supported. For example on one of my local repeaters Parrot must be configured as a group call to talkgroup 9998 because it routes Brandmeister traffic through a linked repeater which connects to Brandmeister indirectly through a c-bridge. The c-bridge is what required the group call configuration - again, somewhat of a "dark art".
    Promiscuous mode lets you listen to all available talk groups for a given repeater (or hotspot) on any time slot. Most articles that discuss setting up a codeplug or connecting with a DMR repeater should probably lead with "Enable promiscuous mode on your radio". With promiscuous mode "ON" and the repeater silent you know that nothing is being transmitted or received - you do not have to look at your radio to see if the silence is accompanied by read and/or green LED's loghting up - which arguable you shouldn't be doing anyway if you were say operating-a-motor-vehicle. When you listen with promiscuous mode "off" it's a crap-shoot since you will only hear traffic for the timeslot and talkgroup(s) and color codes that you are monitoring.
    The repeater can only have one active talkgroup, on a given timeslot, transmitting at a time. When you don't get the expected results, it could be because another talkgroup, that you can't hear, is active.
    You are unlikely to make friends on the repeater when you "key up" into an ongoing QSO or worse net-event. The "I didn't hear anything" defense only goes so far when you are the source of QRM to active sessions.
    The RT73 radio has a promiscuous mode. Enable it on a short key (mic or radio button) as "Mandatory mode". When it is pressed, "promiscuous mode on" appears as a toggle (press again to turn off).
    The TYT MD-9600 / Retevis RT90 has a promiscuous mode. Uncheck the "Group Call Match" setting.
    Talker Alias when supported, allows your radio to receive contact information from the transmitting radio. This works like the DMRID contact database except you don't need to keep the contact information in your radio. If you are using the Brandmeister system then Brandmeister will create a "Talker Alias" string (your callsign plus the information defined in the APRS TEXT field) if the transmitting radio doesn’t send one.Most repeaters don't support Talker Alias, most hotspots do now. The Retevis RT73 does not at this time support Talker Alias reception.
    The connectors work in tandem to make the connection. You would typically find the female SO-239 jack on the radio and the male PL-259 plug on the cable. Together they create what is called a UHF connection. The "consensus" these days is that these conectors work better at HF frequencies and that there are mored modern connectors available for working at VHF and UHF frequencies.

'73 KD2WLL