TTN community is not going to deliver your investment required as you state yourself.
Covering Australia with gateways that have an average coverage radius of 30km is going to require a major investment and any commercial entity putting up that amount of money won’t use a network without SLAs. In my opinion best you can hope for is them peering with the TTN community network if they have sufficient business to cover the network cost and de not need to sell access (telco) to recover there investment.
Here is an interesting development that could be implemented in the AU915 band which is not possible in AS923. With the AU915 band, particularly for gateways in FSB1 to 5, having different receive and transmit frequencies allows the gateway to receive while transmitting.
I must admit the frequency separation between Rx and Tx frequencies in AU915 is smaller than in the US915 band and this will have an effect on performance. (FYI, scroll back to the beginning of this thread where you can see graphics showing the AU915 Tx frequencies overlap FSB 6,7 & 8).
Will be interesting to analyse and determine the requirements for external RF (antenna) filters required to prevent the transmitter overloading or deafening the receiver.
Some early ref designs had option for seperate Tx & Rx antenna ports - with no RF switch? If I recall I think some RAK? concentrator boards were like that - potential therefore possible for one GW site to have two ants physically seperated - horizontally offset by +/- say 10m on ultralow loss cable, with also vertical seperation (potentially more improtant if can keep them in respective vertical nulls - perhaps +2/-2m to +5/-5m, and potentially sith some level of RF attentauting material inbetween? May still require some filtering but make electrical task easier?
Hi Jeff, Just looking at Semtech data sheets and its only for the SX1302 chip (SX1303) and if I remember those early concentrator boards used the SX1301 chip.
Looks like the Tx-Rx isolation needs to be >50dB as this is the isolation they are using in the test diplexor. Fairly typical figure for a Full Duplex radio system so I expect the RF engineering (as you proposed) to be straightforward.
Limited reference design information currently published, some for CN430 and less for US915, but its a start and enough to get us thinking.
Yes but remember the SX130x (1,8,2,3) is the (Digital) BBand device and LoRa + legacy mod/demod not the actual RF where the black magic has to take place - there are seperate RF device(s) for front end (SX1256/7 etc. for most designs (think some used an equivalent from e.g. ADI)) depending on target band - typically handling 4/8 x 125Khz channels over 1Mhz spread IIRC and which can also be further isolated/shielded for RF TX/Rx path and interface to BBand is then just classic digital i/f -handling I/Q data. time to dig into old notes and refresh as I’m starting to forget a lot of the early stuff!
Hi Jeff, my assumption this only applies to SX1302 (03) is based on the modified packet forwarder code which is available on github only applies to the SX1302 (03). In that code I can see an extra configuration parameter "full_duplex": true, or "full_duplex": false, which I assume sends immediate or queues the data in Half-Duplex.
As you correctly point out it could also apply to the SX1301(8), but I assume only if the associated packet forwarder is modified.
time to dig into old notes and refresh as I’m starting to forget a lot of the early stuff! 