Dual Control Heads with GPS Tracking

Rob Brookes' Blog - MRMap and Communications Info

Dual Control Heads with GPS Tracking

Postby Rob_Brookes » Mon Apr 18, 2011 12:06 pm

With apologies to all those who've been contacting me direct regarding broken links for the files described in this post. I've added the files directly to the post and they should now download. If this also fails then please contact me directly and I'll send you the DropBox links to download directly from me.

On a point raised, this method of two control heads AND GPS tracking only works if the particular radio isn't being used as a 'base' radio actually doing the tracking of portables etc on the hill. The reason for this is that in order to track other radios, you have to have your SRM programmed with an own data address of 1. For it to be tracked by a base and so appear on MRMap, the ODA has to be a unique number other than 1. Unfortunately it can't be both so you can have two control heads and GPS tracking or you can have two control heads and use the same radio as a 'base' in your vehicle etc.

Attached is a quick version of the results of work initiated by Steve Fletcher of Bolton team. His requirement was for both GPS tracking of a vehicle and for the provision of dual control heads in the same vehicle. This latter configuration is the layout used by some teams in C3 (incident
control) vehicles where both the driver and the incident control position within the vehicle have access to the radio. This can already be done of course but the method used has always precluded the ability to also track the location of the vehicle. At Steve's request, the engineers at Team Simoco have worked through the problem and offer the attached solution. The method makes use of a standard MA-ASIGF accessory board, the type already used for GPS tracking of vehicles, but makes a change to the condition of two of the links on the board. These are 7 and 24. They are zero ohm resistors and so removing the link means just that and adding a link merely requires that you bridge the pads associated with that link. Trying to recover and re-use a removed link is both difficult and unnecessary. Just put a blob of solder across the pads.

Most of you who might want to carry out this modification will already have GPS MA-ASIGF boards fitted to your vehicles and so won't need the documentation on how this is done in the first place.
For those new to this, you need to read the Simoco document A9k-465 which is also attached. The modified version effectively replaces page two of the Simoco document. The photo supplied by Steve shows two SRM9030 control heads, both of which display exactly the same thing in the vehicle, here the latitude and longitude of its current position. In fact as far as we know, any of the normally used control heads can be twinned together but they must both be of the same type.

Simoco have tested this configuration and Steve has confirmed that it does what it's supposed to do, two control heads both controlling the same radio and GPS tracking of the vehicle. All this from a single SRM9030 radio!

With thanks to Steve for passing on this information and to the Simoco engineers, UK and Australian, who worked it out for us.

Dual SRM9030 Control Heads with GPS Tracking of the vehicle
Modified Ak9-465.pdf

The unmodified original Simoco document for dual control heads, No GPS
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