User manual GARMIN CNX 80 INTEGRATED AVIONICS SYSTEM CNX80

[. . . ] If the airplane is open and the coax accessible it is far cheaper to replace it than leave what's been in the airplane for many years and hope for the best. The CNX80 install manual states that the typical loss at a connector crimp is 0. 2 db. However we have seen many where the loss due to an old crimp that has worked loose or was poor quality to begin with can be 10 times this number, significantly degrading the Nav/Comm or GPS performance. In all cases, it is best to check the antenna and coax using an antenna analyzer as discussed below. Installation Problems This is one of the reasons Garmin requires IFR capable systems to be installed by a Garmin distributor using proper tools and techniques. [. . . ] The amount of the wave reflected back depends on how bad the mismatch is. The same can be said for received signals during an ILS approach or VOR navigation. The combination of the original wave traveling down the coaxial cable (towards the antenna during transmit or opposite during receive) and the reflecting wave is called a standing wave. The ratio of the two above described waves is known as the Standing Wave Ratio. The result is presented as a figure describing the power absorption of the antenna. A value of 2:1 VSWR, which is equal to 90% power absorption, is considered very good for a small antenna: 3:1 is considered acceptable, which is equal to 75% power absorption which for aviation is approaching marginal capability. From this point, the higher the VSWR ratio the more rapidly antenna performance falls off. Hopefully reviewing some of these common problems will help you avoid them in the future. GTX 32 and 33 Interface The GTX 32 and 33 are remote mounted Mode C and Mode S transponders respectively. Both of these will be integrated to the CNX80 in V2. 0 software and can be used as the SL70R is used today, allowing for significant space savings in your cockpit panel. In addition the GTX 33 Mode S transponder will provide TIS traffic service as the GTX 330 does, which will be displayed on the CNX80 traffic page that will be implemented in V2. 0. You may also tie this traffic source into your MX20 and be able to display traffic on either display. A separate STC will be done to accommodate these installations. We will notify CNX80 users when this STC is complete. Auto Suspend In Holding We've found a minor problem in V1. x software that occurs occasionally in course reversals in a holding pattern during approach. As mentioned in our first newsletter, if you are performing a course reversal in a holding pattern in lieu of a procedure turn, the database is constructed in such a way as to accomplish the course reversal and perform one turn in holding. This allows for altitude loss if required before commencing the approach. If you do not need to lose altitude and just want to complete the course reversal for the approach, then you would press the SUSP key once established inbound. This eliminates the one turn in holding and allows the system to sequence to the final approach leg. The problem occurs when you attempt to sequence to the FAF by pressing SUSP prior to the system sequencing to the hold leg type on the FROM-TO-NEXT line on the bottom of the flight plan or map page, which may result in not being able to un-SUSPend the system (i. e. [. . . ] When those systems come into service, we will evaluate the CNX80 engine with those systems and determine compatibility with those systems at that time. Meggitt Magic Interface I recently had the chance to fly a new Meggitt Magic EFIS install in a Twin Commander with dual CNX80s and an MX20 with WSI datalinked weather. In general, the install went very well and the overall performance was very good with the autopilot. We do not currently cover this specific interface in the STC data, but this can typically be accomplished through field approval without significant difficulty. [. . . ]