My Fischer 37 " Lady Jane " Is basically featured with conventional Raymarine network and GPS antenna , the trio wind, depth, speed instruments, and a multi chartplotter / Radar C70 :
In November 2010, Reading this blog has strongly urged me get a multiplexer. Control its navigation and see instruments displayed with iPhone is really a challenging project. The navigation software iNavX is very attractive for its price and will be an excellent investment in view of continued improvement by its developer.
Purchased in December, the iMux is arrived with the new year. No problem for installation with SeaTalk. Just create a derivation from Seatalk wire. As indicated in the following diagram, you plug the red wire on the (+), negative on (-) and the yellow wire that send data on Seatalk connector (S) .. This works well of course and iPad tablet is fast becoming an indispensable.
The VHF radio on board will celebrate its thirtieth anniversary. Tremendous receiver, ST-144 is no longer on top of technology. Acquiring a DSC VHF / AIS has been programmed replacement. The model chosen RO4800 is now a classic, sold under three different brands (Radio Ocean, Geonav and Navicom), it comes from the same Asian supplier that has had some software problems at begining, now been resolved versions 2.02 and upper. Geonav model was chosen for its availability in stock.
The IMUX should make life easier to set up the information that must travel on the WiFi network destined for the iPhone or the iPad.
Step one : analysis of the wiring project
- VHF AIS transmits information to 38400 bps, the iMux has an input specifically designed for this. So AIS VHF OUT connector on the CH4 AIS.
- The information from the ASN out of the VHF are received by the iMux CH2.
- The radio needs information from the GPS to work properly, required information is available on the iMux RS422 NMEA OUT. This output is also connected to the NMEA IN Driver to communicate to him the info iNavX transmits the active Waypoint via WIFI.
Step two : completion of the preparatory document to wiring
Information from Seatalk send to iMux:
- Black wire (-) ST to IMUX ST SHLD
- Red wire (+) ST to IMUX Red
- Yellow Wire (data) ST to IMUX S
Information from DSC VHF
- Orange (+) to iMux CH2 A
- Black (-) to iMux CH2 B
AIS information coming from VHF radio
- Blue (+) to iMux CH4 A
- Gray (-) to iMux CH4 B
Warning : Given that suppliers taking liberties with NMEA standard, it may be necessary, either to connect the white wire (for this purpose) out of the connector on the iMux A CH4, either by inserting a resistor 1200 2000Ω for on the same white wire (see picture below).
GPS information from IMUX send to VHF radio
- Green (-) to iMux NMEA OUT B
- Yellow (+) to iMux NMEA OUT A
Problem to be fixed
In this configuration C70 chartplotter, receives no information about the AIS. Solution : also send information from the VHF NMEA input C70. The signal can feed four receivers following NMEA standards.
- C70 IN White (+) to AIS VHF-OUT (+) Blue
- C70 IN Green (-) AIS VHF-OUT (-) gray
With this wiring system, C70 can be switched off, all information from instruments and GPS are working on Seatalk network. iPad can also transmit route to pilot. For the same service the power consumption is greatly reduced and the readability much better. The C70 is still available including the use of radar in more difficult circumstances.
That's the theory, move on to practical work !
After completion of the wiring by following the wiring document step by step, the first test confirms the proper operation of the transfer of GPS data on the VHF, however iPad does not receive AIS information.
According to the iMux documentation providing by Brookhouse, the white wire (optional) is stripped and connected to the connector A CH4 In. No problem, Ships within 25 miles shown on the iPad (VHF antenna is placed mizzen). Note that it can insert a resistor 1200 up to 2000 Ω between the white wire and the connector A from the entrance of CH4 from the IMUX.
Being careful, this installation can now be done without too much trouble.
The end result :
Installation, texts, photos and screenshots of the author.
Note Francis :
The IMUX experienced disruptions in deliveries for several months. The unexpected volume of world orders added to the component supply problems have penalized the production of this company. Deliveries are scheduled to resume in early July, focusing first orders pending. It will probably wait a few weeks before they get back this great product.
Related article :
iMux, a multiplexer WiFi for iPad