# How to build a full-duplex gateway with only one SX1301 chip? **URL:** \ **Category:** Gateways\ **Created:** [June 28, 2019, 3:23am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578 "2019-06-28T03:23:12Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![David2044](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/david2044/32/26140_2.png) [@David2044](https://www.thethingsnetwork.org/forum/u/David2044)\ **Post date:** [June 28, 2019, 3:23am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/1 "2019-06-28T03:23:12Z")
Hi, Everyone! We all know that SX1301 can’t not receive any data from nodes when it transmit data, which means that the gateway is half-duplex. How can I achieve full-duplex with only one SX1301? Do I need any assistant chips? ---
**Author:** ![LoRaTracker](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/loratracker/32/48502_2.png) [@LoRaTracker](https://www.thethingsnetwork.org/forum/u/LoRaTracker)\ **Post date:** [June 28, 2019, 6:14am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/2 "2019-06-28T06:14:51Z")
For what purpose ? The nodes are limited to half duplex as well ? Is this for use within TTN or is it a bespoke application ? ---
**Author:** ![David2044](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/david2044/32/26140_2.png) [@David2044](https://www.thethingsnetwork.org/forum/u/David2044)\ **Post date:** [June 28, 2019, 7:48am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/3 "2019-06-28T07:48:10Z")
For the purpose of reducing the latency. The nodes are limited to half duplex. It is not used within TTN, we build our own loraserver. Some manufacturers said that they have achieve full-duplex gateway with only one sx1301, how they achieve that? ---
**Author:** ![LoRaTracker](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/loratracker/32/48502_2.png) [@LoRaTracker](https://www.thethingsnetwork.org/forum/u/LoRaTracker)\ **Post date:** [June 28, 2019, 7:53am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/4 "2019-06-28T07:53:51Z")
> [@David2044](#): > > Some manufacturers said that they have achieve full-duplex gateway with only one sx1301, how they achieve that? No idea, sounds a bit like Voodoo, full duplex to nodes that can only ever support half duplex. This is a support formum for TTN, not a general purpose LoRa or Semtech support forum. ---
**Author:** ![pe1mew](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/pe1mew/32/48520_2.png) [@pe1mew](https://www.thethingsnetwork.org/forum/u/pe1mew)\ **Post date:** [June 28, 2019, 7:58am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/5 "2019-06-28T07:58:15Z")
> [@David2044](#): > > For the purpose of reducing the latency I don’t see a problem with “latency”. The problem that might occur is that during a downlink a uplink packet is not received. This is solved by adding one or more gateways to the area that receive while this single gateway is transmitting. Adding duplex will not solve the issue because of the simplex nature of channel usage in LoRaWAN. ---
**Author:** ![David2044](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/david2044/32/26140_2.png) [@David2044](https://www.thethingsnetwork.org/forum/u/David2044)\ **Post date:** [June 28, 2019, 8:12am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/6 "2019-06-28T08:12:03Z")
You have to consider the cost, adding the gateway is a expensive way. What we are doing now is trying to reduce the cost. There are different types of node in a lora network, some nodes only upload the data to the gateway and don’t need the gateway’s ack frame. Some notes not only upload the data but also need the gateway’s ack frame which may contain the control information right after it upload the data. ---
**Author:** ![David2044](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/david2044/32/26140_2.png) [@David2044](https://www.thethingsnetwork.org/forum/u/David2044)\ **Post date:** [June 28, 2019, 8:15am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/7 "2019-06-28T08:15:08Z")
I’m sorry, I thought the forum is a general purpose LoRa forum ---
**Author:** ![pe1mew](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/pe1mew/32/48520_2.png) [@pe1mew](https://www.thethingsnetwork.org/forum/u/pe1mew)\ **Post date:** [June 28, 2019, 10:03am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/8 "2019-06-28T10:03:06Z")
No problem ---
**Author:** ![ianmangan](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/ianmangan/32/25844_2.png) [@ianmangan](https://www.thethingsnetwork.org/forum/u/ianmangan)\ **Post date:** [December 27, 2019, 2:55pm UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/9 "2019-12-27T14:55:26Z")
use sx1276 etc for point to point send - may be window problems? ---
**Author:** ![David2044](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/david2044/32/26140_2.png) [@David2044](https://www.thethingsnetwork.org/forum/u/David2044)\ **Post date:** [December 29, 2019, 12:27pm UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/10 "2019-12-29T12:27:31Z")
yes，some manufacturers seems to achieve that by using another sx1276. The sx1301 only responses for receive data and the SX1276 only responses for tx the downlink data. ---
**Author:** ![cslorabox](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/cslorabox/32/35697_2.png) [@cslorabox](https://www.thethingsnetwork.org/forum/u/cslorabox)\ **Post date:** [December 29, 2019, 3:18pm UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/11 "2019-12-29T15:18:39Z")
Most of the problem with duplex operation is needing a diplexer to keep the transmit energy out of the receive path. And that’s only even workable on band plans where transmit and receive frequencies differ (typically 900 MHz ones, not 868 ones). Cost wise you are probably better off putting up more ordinary gateways some distance apart but with overlapping coverage, since you get the economy of scale of using the same base-model hardware as everyone else, rather than paying the premium for something unusual. Efficiency wise, there are ways to make protocols which handle downlink vs. uplink capacity a lot better than LoRaWAN does. ---
**Author:** ![David2044](https://www.thethingsnetwork.org/forum/user_avatar/www.thethingsnetwork.org/david2044/32/26140_2.png) [@David2044](https://www.thethingsnetwork.org/forum/u/David2044)\ **Post date:** [December 30, 2019, 9:35am UTC](https://www.thethingsnetwork.org/forum/t/how-to-build-a-full-duplex-gateway-with-only-one-sx1301-chip/27578/12 "2019-12-30T09:35:06Z")
Thank you so much! yes, it do need a diplexer. > [@cslorabox](#): > > Efficiency wise, there are ways to make protocols which handle downlink vs. uplink capacity a lot better than LoRaWAN does. Could you please tell me some examples ?