I am happy to announce that I finished the development of 2 multiplexers based on SMD (Surface Mounting Devices) technology. These multiplexers will have the designation of NMEA2WIFI-SMD and NMEA4WIFI-SMD. They are fully compatible with the existing multiplexers that will now be referred to as NMEA2WIFI-TH and NMEA4WIFI-TH since they are based on Trough Hole technology. The NMEA4WIFI-TH multiplexer was also redesigned and is based on a more common ESP32 module. Both NMEA4WIFI multiplexers (SMD and TH) now use spring type connectors. On the contrary the NMEA2WIFI multiplexers (SMD and TH) use high-quality 1.5mm2 screw connectors.
During the research and development stage of the SMD multiplexers, many prototypes were built in order to get robust and resilient products. Between these intermediate units I kept 2 units that I call NMEA2WIFI-DEMO and NMEA4WIFI-DEMO which are identical to the standard units except for the RF (Radio Frequency) power they produce. Instead of throwing away these units I am giving the possibility to previous and future buyers of my multiplexers to get these DEMO units at a very small price. In the remaining part of this post I describe the difference in RF power taking the case of the NMEA4WIFI multiplexer as an example. The same results apply to the NMEA2WIFI multiplexer.
When I test the 2 multiplexers in my lab, at a distance of about 1 meter and using my Android Xiaomi Note 8 Pro, I note almost no difference. Here are the 2 cases:
In the case of a boat, both units should be usable in normal situations. I am able to use the DEMO unit in my house at a distance of 10 meters and with a thick wall between me and the multiplexer. In order to have a more precise idea of transmission range of both units I made an experiment in my garden shown in the picture below. For the 2 units, I show the wifi signal strength at several distances in terms of "number of bars", % of power and dBm.
The units work at the maximum distance I could go which was 50 meters. I noticed a slightly increase (or decrease?) of power at about 30 meters. I think that might have to do with a tree that exists at that distance.