Rich Freeman on 17 May 2019 17:40:21 -0700

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: [PLUG] PLUG Fusion room or DMR Talkgroup

On Fri, May 17, 2019 at 6:01 PM Keith C. Perry
<> wrote:
> That is not my understanding of how dynamic and static talkgroups work- that's a repeater terminology but if there is a way to do put a list of talksgroups in to monitor, I might try doing that so I don't have to switch to different one's manually when I think to do so.

In Brandmeister repeaters and hotspots are basically treated the same.
The main difference is that hotspots generally only support one
timeslot and are simplex.  You can have static and dynamic groups on

The network sends the hotspot/repeater any traffic on any dynamic or
static talkgroups it is subscribed to.  For dynamic talkgroups after a
timeout period it is unsubscribed, and static talkgroups are, well,
static.  In the event of a conflict I think BM decides what to send to
the hotspot based on what channel was last active and whatever other
rules it has.  The hotspot just broadcasts whatever it gets, so if it
has 10 groups subscribed each call might be going out on a different
group.  Then the radio unsquelches when it hears a call on the
selected group, or it unsquelches for everything if it is set to

> Yea, its the loss factor that you don't need much of to be unreadable.  That happens quite a bit on talkgroup 91 with international stations and of course mobile users.  Part of that is operating procedure too.  People don't realize with digital you really do need some lead time so that the communication goes out clean and consistent.

That is part of it.  Another big issue is with mic gain.  Most DMR
handsets do not have a mic level meter, and hams have this tendency to
overdrive mic audio on every mode, even though just about every
license question pool has questions about why you shouldn't do that
and why it is actually illegal on some modes, and the DMR ID
registration webpage makes you swear by your firstborn to turn down
your mic gain.

On SSB more audio gain does get you more output power, though if the
compression goes crazy you get less intelligibility (without
compression you overdrive the finals which is even worse).  On FM more
audio gain causes over-deviation, which is illegal and probably gets
clipped on the receiver's filter reducing intelligibility, and it
doesn't actually increase power at all.  On any digital mode too much
audio gain causes clipping, which just about everybody on this list
has probably heard and it basically just makes you about as
intelligible as a buzzsaw.

One thing I do like about the md380tools firmware is that you can
display a mic level when you're transmitting, and it always ends up
being too hot even with the lowest settings, causing me to move the
mic away from my mouth, which I'm sure everybody listening
appreciates.  I suspect all those cheap DMR radios have the same
problem, and you just don't realize it when you're transmitting unless
you get an honest signal report.

Philadelphia Linux Users Group         --
Announcements -
General Discussion  --