On Tuesday, June 16, 2015 at 8:31:58 PM UTC-5, Dan Marotta wrote:
I installed my TT-22 myself so cost was limited to coaxial cable a
TNC for the transponder and a BNC for the antenna plus the cost of
the antenna.* Then I paid an avionics shop to test the
installation.* I don't recall what that cost.* BTW, my LAK-17a is
EXPERIMENTAL.




On 6/16/2015 1:05 PM,
wrote:



On Tuesday, June 16, 2015 at 2:32:53 PM UTC-4, jfitch wrote:


On Tuesday, June 16, 2015 at 11:04:56 AM UTC-7, son_of_flubber wrote:


On Tuesday, June 16, 2015 at 1:44:47 PM UTC-4, Steve Leonard wrote:



On Tuesday, June 16, 2015 at 12:19:19 PM UTC-5, son_of_flubber wrote:



Is it reasonable to argue that a Trig TT21 (130 watt) should be acceptable for glider use due to my lower speed, rather than just the TT22 (250 watt)? Is there any chance that the FAA would grandfather in TT21s in any new regulations?



Son, your transponder (TT21) is already acceptable. No need to "grandfather" it.



My limited understanding... Due to the 130 watt output, the TT21 is not 2020 compliant, so even if I invested in a TSO'd GPS source, I could not use the TT21's ADS-B out capability. The 250 watt 2020 requirement is based on the closing speed of two aircraft and since a glider is slow (or stationary in wave) I'd conjecture that it was not needed. ADS-B out at 130 watts is much better than no ADS-B out.

From Trig website:

What are the differences between the TT21 and TT22?
Both models have the same physical dimensions and advantages of size and ease of installation. The TT21 is a 130 watt Class 2 transponder; this makes it ideal for light sports and regular GA use. The TT22 is a 250 watt Class 1 transponder, ideally suited to higher performance and/or high altitude performance types.
In the U.S. the FAA has stated that Class 1 transponders must be used to be '2020 complaint' For U.S. customers Trig recommends the TT22 unit for this reason.


A very cursory reading of TSO-C199 suggests that a TT21 would work for this, probably needing a firmware update. The transmit power required appears to be 70 watts.

If the proposed rule making and TS0-C199 equipment could be so aligned that existing ADB compliant installations (in gliders there are only 2 or 3 brands), preferably with cheap or existing GPS receivers can be made to work (and I can see no reason why it would be technically difficult) then for many private gliders the cost would be low. For gliders with no current Mode S transponder, the costs would be approximately what a transponder install costs today ($3K maybe?).


What do people see for transponder install costs? There seems to be quite
a few already installed out there, but I haven't heard what it takes
beyond what the units cost.

Matt





--

Dan Marotta

Same as Dan, installed the Microair many years ago myself in my Experimental glider. VFR only transponder check runs $100 in our Chicago area club, an avionics shop does all club gliders and tow ships as well as on average 10 private gliders, no fuss.