Installation of TAS 600, antenna placement

[Magnum]

Hi,

I have a Ryan 9900BX TAS (Avidyne TAS 620) system here which I plan to get installed in my M20J by an avionics shop here in Germany.

The installation manual says that the top antenna should be placed as much forward as possible for best performance. Unfortunately the best place is already occupied by the GA 35 GPS antenna. Does someone have a TAS installation with the antenna installed more to the tail and can say something about the performance? A possible space would be between the two COM antennas. Maybe it is possible to relocate the GPS antenna, but I am not sure if that works.

Thanks for your replies,

Magnus

[Piloto]

I would relocate the GPS antenna in between the COM antennas and locate TAS antenna at the previous GPS antenna location. The TAS 620 uses the two antennas combined for bearing determination. So for best performance the traffic needs to be in view of both antennas (top and bottom)

José

[Magnum]

Jose,

thanks for the reply. I check if the avionics shop can relocate the antenna.

[Awful_Charlie]

I had Avionik Straubing install my TAS605. Top antenna is between the Com antennas, bottom antenna is in the centre section of the belly panel with a big ground plane sheet. My GPS antennas are in the baggage door area. All seems to work!

[StevenL757]

Agree with Jose - move that forward-most GA35 to at least 24 inches aft of the front COM blade.  Put the new upper TAS antenna where that front GA35 is presently.  This satisfies your "more than 2 feet from a COM blade" GPS antenna placement requirement, as well as satisfies the positioning for the TAS antenna.

[Magnum]

Thanks for the replys.

@Awful_Charlie: Avionik Straubing will do my installation, too. They told me now that they often put the top antenna between the Com antennas on Mooneys, so even if it is not the best place, it seems to work quite well. Do you have the ADS-B option installed yet?

[Awful_Charlie]

The Avidyne ADS-B option is a very sore point - when I bought the unit in 2012 it was 'just around the corner' and currently they are saying 'Fall 2016'. Last year it was 'coming soon' too, and on that basis I left the pre-purchased IFDs on the shelf so I could do both installs at once (without an aircraft, it takes me 8 hours to get between home and Straubing, add another 2 hours if I want my car back in the interim, so I don't want to do any more trips than absolutely necessary). Apparently the hardware is available now, but it is waiting on software. When I enquired at Friedrichshafen, I was told that the software was field upgradeable, and that the hardware could be shipped in advance so the installation could be done, and then a quick day trip to Straubing for the software. When I got to Straubing though, they told me the unit would have to go back to the US for the software, so doing the hardware now made no sense! You can see some of the history at http://www.avidynelive.com/forum_posts.asp?TID=757&title=ok-nearly-end-of-summer

With the deadline approaching for 8.33 I had to bite the bullet and get the IFDs installed, as with the number of delays to the -A upgrade, I don't have any confidence in the 'Fall 2016' date now either. Consequently I'll have to use up more holiday or write off weekends to go back again :-(

The majority of times I get bearing errors is when on the ground, maybe because the lower aerial is so close to the ground and gets reflections from the ground/under-wing surface. Typically I might get this whilst waiting at the holding point at right angles to the runway direction, when an aircraft on downwind may jump between left and right, but on the whole when  airborne it is fine

[Magnum]

Awful_Charlie,

thanks for your info and the link to the Avidyne forum. So to get the ADS-B option needs putting in a new box. As I have the TAS 620 "laying here around" other solutions (like the L3 Lynx or GTS-800) don't make economical sense, and upgrading to -A will take a long time and lots of $$$. Therefore I'll talk to Avionik Straubing about relocating the antennas to get the best performance without ADS-B.

BTW: If you need a lift from Straubing to Basel, I fly severeal times from Neuhausen ob Eck (EDSN) to Straubing and back.