GPS antenna splitter

[cjohngraham]

I have a SV system with HDX in my RV-7A and am installing a GPS 175 plus ARINC for the Dynon interface. The GPS 175 came with a GPS antenna. I already have a GPS antenna for the SV on my glare shield as well as one for a D3, so don't really want yet another one. Can I use a splitter to share the SV GPS with the GPS 175? If so, what specs should I look for in a splitter?

 

[Marc_J._Zeitlin]

No.

 

[Rhino]

You really need to curb that mouth of yours, Marc. It's so difficult to get you to shut up sometimes.

The SV-GPS-2020 is more than just a simple GPS antenna. It has active elements, so it can't be shared.

 

[BradThePilot]

The GPS2020 isn't really a GPS antenna like the Garmin 175 expects, and it's not really an "active" antenna per se either.

WAAS antennas for GPS navigators, such as the Garmin GA 35 or RAMI 801, are "active" GPS antennas and receive power through the coax in addition to sending the GPS signal to the attached receiver. This is distinct from earlier non-WAAS antennas which simply sensed the signal and passed it over the coax without needed any power to be supplied for internal electronics. Note than active WAAS antennas such as the GPS 35 cannot be shared between receivers.

The Dynon GPS2020 is different in that it has no coax connection but instead has power, ground, and RS-232 serial transmit and receive lines. If you hook up a serial analyizer to it, you will see what are essentially NMEA sentences being sent back to the attached Dynon devices.

The Garmin G175 wants an active antenna to receive the GPS signal so it can process it; the Dynon approach just wants something external to the display to receive and process the GPS signals and return the NMEA data stream back. Neither approach will work with the other; two antennas are what are required in such a situation.

 

[Rhino]

The Dynon antenna is active because it contains elements that process, send and receive data, rather than simply providing a path for RF to be sent or received. I didn't get into the details, because I didn't think that was necessary, and many homebuilders aren't interested in those details. Sometimes they're confused by them.

 

[BradThePilot]

The Dynon antenna is active because it contains elements that process, send and receive data, rather than simply providing a path for RF to be sent or received. I didn't get into the details, because I didn't think that was necessary, and many homebuilders aren't interested in those details. Sometimes they're confused by them.

Using the correct terminology can also help reduce or eliminate confusion. Anyone doing a search for ”active GPS antenna” won’t be lead to information similar to how the Dynon GPS pucks work. They’ll instead be lead to info about antennas with powered amplifiers ala the GPS 35, and confusion will grow.

 

[Rhino]

I did use the correct terminology. I just didn't add in the extra information that could have confused them.

 

[bbaggerman]

I'm with BradThePilot on this one. In the GPS world "active antenna" has a very specific meaning. To call the Dynon antenna which has a built in GPS an "active antenna" would be very misleading to most who are schooled in the art.

 

[Rhino]

Active antenna has a specific definition, and they existed well before GPS did. I should know, since I was working with them back then. That definition now includes active GPS antennas, but it is by no means limited to them. The GPS-2020 is an active antenna. I didn't introduce any misleading information. I simply stated a fact. Apparently some people have a problem with that.