DMRGateway is software developed by, Jonathan Naylor, the author of MMDVMHost
and ircDDBGateway to allow an MMDVM repeater or hotspot to
connect to multiple DMR networks (eg. BrandMeister) and XLX servers. It does this by
translating DMR Talkgroups between MMDVMHost and the DMR
network or XLX server. Currently it supports two DMR networks –
Brandmeister and DMR+, and XLX reflectors. Talkgroup definitions
can be changed in the dmrgateway.ini file but defaults are TG 9 for
Brandmeister, TG 8 for DMR+, and TG 6 for XLX. XLX is often refered to
as DMR+ is not used as much. The DMR-MARC organistaion is taking steps
to allow DMR+ (XLX) to connect to its network.
D-Star transmissions only go to D-Star reflector --> Only heard by D-Star radios.
DMR transmissions only go to Brandmeister Network --> Only heard by DMR radios.
Transcoding overcomes this limitiation.
For transcoding, each XLX module needs an AMBE Server instance with a hardware AMBE chip. A XLX reflectors which is cross-connected to a XRF reflector requires an AMBE Server. If a repeater or hotspot is connected to such an XLX reflector, D-Star transmissions will be transcoded to DMR and vice versa.
DMR Gateway will only pass traffic to the different networks if it's referenced in a rewrite rule in the .ini file.
TGRewrite allows you to translate one talk group ID to another, and to alter the time slot. TGRewrite can also be used to route a talk group and slot combination to a particular network. 'from' applies to DMR frames entering the Gateway via MMDVMHost (RF), and 'to' is where they are routed on the network side (Net). The rules apply to DMR frames traversing the gateway in both directions.
See this wiki for more details:
In an ideal world, Bit Error Rate (BER) should be zero percent, however, if the BER is
consistantly high it might indicate that the MMDVM is off frequency and the RX Offset
has to be adjusted. Select Expert Mode and then MMDVMHost on the dashboard.
Begin with an offset of say -500 offsets, and step up by 100, and see how that
affects the BER. Then hone in with smaller increments to optimise ths setting.
A description of the process can be found here.
Adjust RX/TX Offset (BER) for MMDVM Hotspot: https://www.ailunce.com/blog/How-to-set-Rx-Tx-Offset
Adjusting the TX Offset is a little more difficult without expensive test equipment. One suggestion is to get feedback from fellow amateurs as to the BER they are getting from your transmissions. Assuming they have adjusted their own RX Offset, they can give reports as you use a simialar technique to setting the RX Offset by progressive increments.