kshaw

Anyone know if these will work with a Mode S transponder?

At Oshkosh this year, I dropped by the Bendix-King booth and learned that they are selling new fronts for the King 155 and 165 radios. The new fronts include new LCD or LED displays (depending on the model), new knobs, and new plastic covers over the digits. The price seemed reasonable enough for avionics. If you can't find a replacement display, check out this option.

The STC for the KT-74 listed a couple of WAAS GPS units that were approved as input to the KT-74 in addition to the Garmins. I would think that those would be much less expensive than the Garmin.

My install in a Piper Cherokee was around $1000 and it took the avionics shop most of a day. They did software upgrades to my transponer and Garmin GPS, repIaced my RG-58 Coaxial with RG-400, and did the plumbing and connection for the squat switch. I replaced a King 76C so I did not have to change the tray and only minor changes to the connector. I did not elect to have the altitude allert installed or TIS connected to my Garmin 430W.

There are only a couple of wires to the Garmin 430W: one for the GPS input and another if you want TIS (not TIS-B ) displayed on the G430W. You can also connect to the audito panel if you want to use the altitude alert feature. The connection to the audio panel requires you to use the KT-74 tray. If you have RG-58 coaxial cable for the transponder, you have to replace it with RG-400. The STC lists a specific speed switch which sells for about $100. The wiring pinouts are in the STC; the requirement for newer coaxial cabling is part of the King KT-74 installation manual but not discussed in the STC.

You need to install the new tray only if you are connecting the transponder to the audio panel for altitude deviation alerts and such. .

The King 74 still needs an altitude encoder. The old Narco Mode C encoder that I was using for my KT-76C worked fine. The STC for the Trig 31 is similar to the King 74 STC but there are several differences as well. There are also differences in pin outs. The King 74 STC permits several GPS units beyond the Garmin 430w/ 530w to be used including the newer Garmin GTNs. You only need to install the new KT-74 tray if you want to connect it to your audio panel for altitude and traffic alerts. All other features work fine with your old tray and connector but connections have to be made to your speed sensor switch, to the GPS for ADS-B input, and another connection to your GPS unit if you want TIS displays on your GPS.

Actually, the KT 74 only needs the new tray if you plan to connect the KT74 to your audio panel. You would connect to the audio panel for altitude deviation alerts or TIS-A traffic alerts. Those connections are not required for an ADS-B installation. My avionics shop recommended that if you do the TIS-A traffic alerts to also install a mute switch so that KT74 traffic reports relating to other planes in the pattern do not drown out your communications with the tower while on approach.

If you still have the RG-58 cable, it will have to be upgraded. My avionics shop said that the King installation instructions for the KT74 require the upgrade even if you are installing the transponder for just Mode S. I believe that they upgraded mine to RG-400.

This installation was on a Cherokee but the STC did not distinguish between retractables when discussing the requirement for the switch. Seems logical that your current switch could be used if it meets the same trigger speeds but I would discuss with the avionics shop you plan to use for the installation. I understand that the Garmin transponder does not require a switch, but uses the GPS speed as a trigger instead.

I just had the ADS-B out installation done with my KT74 and Garmin 430W at Lancaster Avionics, PA. Installation went well. They were able to do the ADS-B out installation using the existing 76A tray and existing connector but you need the new tray if they connect the transponder to the audio panel for the altitude alerts. I had an autopilot and did not believe that I would need that feature. The STC calls for a speed sensor switch that triggers at about 34 knots to determine ground/flight status. The switch runs about $100. They updated the transponder from version 3.9 to 3.12 and my Garmin to version 5.10 and they had to upgrade my transponder coaxial cable from RG-58 to RG-400. I have made two flights since installation and it works well with Wing-X. I also sent the email to the FAA for a performance report [ '9-AWA-AFS-300-ADSB-AvionicsCheck@faa.gov' with my tail number, transponder make and model, and GPS make and model ] and the report showed no errors and good performance. The FAA report is not required but does give some assurance that everything works. I am all set.

The JPI 730 and 830 have use the same head and same firmware. The only difference is the bundling of sensors included with each, so define what you need and compare prices between the 830 bundle and the 730 plus the sensors you actually need.

Garmin 5.20 out now.

Dale, I have the same setup as you do but no ADS-B out until the end of the month. I have seen the ghost plane too. Really scary the first time you see it; I kept looking for another plane under me. You really need the filter because you will pick up aircraft at FL42 that is not really a factor for GA planes.

I have a King KT-76C with tray in excellent condition. Working fine when I replaced with my KT-74 but no yellow tag. Will take $1100.