Connect GPS to SynScan V3

[JTB]

Hello,

I am very new to Astronomy and with the current 'crisis' I have had a bit of time to look at my setup and decided that adding a GPS to the SynScan controller would be 'simple' and a nice option to have when moving sites.

As best as I can make out you need to connect the serial NMEA output of a GPS receiver at 4800 Baud to the input of the controller via the RJ11 connector and configure the handset to accept GPS data. My SynScan AZ V3 handset is hardware version 3.06 and the firmware is 3.39 which I believe should support the GPS option?

So before getting the cables made up I plugged the handset into a power source, WITHOUT any other connections, then looked for the GPS options in the menu but I could not find them. Is this because it could not detect any GPS input or is there something about the handset version that doesn't support this option?

 

Is it also possible, using a different interface, to link the GPS to Stellarium running on a laptop?

 

I have looked on the internet and several sites and YouTube videos to find out the above but when I look for the options in Stellarium I was unable to find any.

Your assistance would be appreciated!

 

[Bignerdguy]

I have the Orion v3 hand controller which is the same as the Synscan version.  The GPS has a cable with an adapter that ends in a RJ-12/11 connection to plug into the HC.  You need to be sure this is plugged in when you power the HC on.  There are no menus to setup, detection is automatic.  The HC will see the GPS device and immediately try to locate itself and find the date/time.  You will have an abbreviated setup process as a result as the location and time/date are done for you.  However keep the GPS antenna away from all metal as it will interfere with the GPS signal.  The HC may take a minute or two to find and setup the GPS info so be patient.

[JTB]

Thanks for the infomation. I tried it again but still no luck -  this time.

looking at the specs for SynScan it says it used NMEA V3. This has  a diiferent message sentence in GPRMC than the NMEA 0183 V2.2 that I am using which I think will cause this problem?

V3 is also known as the 'high speed' interface version so I wondered if they are still using the standard baud rate of 4800?

 

After looking a bit more into the menu I have found a GPS option on the SynScan so it looks very likely that this firmware version does support this function.

So the 2 things I would like to find out is -

1. Is Synscan Agnostic to the message sentences i.e. do they HAVE to be in NMEA V2.3 or greater or it doesn't care?

2. Does SynScan still use 4800 baud or is it using a high speed?

 

ANY help would be appreciated

 

[garryblueboy]

Skywatcher have a dedicated GPS module as far as I can recall no other ones work 

[Cornelius Varley]

1 hour ago, garryblueboy said:

Skywatcher have a dedicated GPS module as far as I can recall no other ones work 

I think this is true. Some time ago I believe that a firmware update was released that deliberately blocked third party gps units from working with the handset.

[JTB]

I found a video on YouTube demonstrating the Skywatcher GPS and displaying the 4 general GPS Sentences from it and they 'looked' the same as stanard V2.3 + sentences. I have a couple of old GPS units the both put out V2.2 messages  that differ slightly in the GPRMC sentence from V2.3 onwards.

Is it possible that the 'cheap' units for sale on eBay still use V2.2  just to keep the price down and it is this that causes the problem?

 

Sorry that I am having to be 'careful' with my spending but it would be REALLY helpfulful to me if someone who has one of these could capture a sample of these messages and determine what Baud rate is being used. This could be done by using software or simply connecting the GPS to a serial port using Putty.

I also suspect that they are probably using a higher Baud rate than normal just to make things interesting.

 

John

 

 

[Paul M]

8 hours ago, garryblueboy said:

Skywatcher have a dedicated GPS module as far as I can recall no other ones work 

Indeed, I have the Skywatcher GPS "mouse" and it connects to the handset and just works, period.

No setting up, no thinking about it! 

[jeff1960]

I think that this is what you want.

https://github.com/tazounet/SynScanGPS