'77 M20J Avionics Upgrade Options

[Seth1001]

Hello Everyone,

I want to add LPV capability to my setup as well as an old-school DME rig and a digital ADI. I don't know exactly what DME module I want but I'm planning on adding an AV-30C as soon as they come out. As far as the GPS it's between an old Garmin 530W or a new GPS 175. I've attached some mockup photos for your review. Any other details or perils or options that you think I should consider? What would you do and why? Thanks in advance.

[carusoam]

DME has been official replaced by GPS... covered around here somewhere...

ADF as well... 

Maybe you want to keep them for a reason?

 A pair of GPS Receivers with WAAS capability that include VOR and ILS...

As far as new vs. old... the old devices can be a bit overwhelming while spinning knobs and pushing buttons in less than rational ways...

Since you asked...

I have the old style stuff, barely digital... 

Best regards,

-a-

[EricJ]

The middle pic may not be possible due to interference with structure behind the upper middle panel.   Not much fits there that has any depth to it.

 

[Ragsf15e]

As carusum said, don’t do DME.  The ifr gps will provide you with psuedo DME which is completely legal and useable for ifr.  

otherwise, go with the newer Garmin gps if you can afford that option.  It’s better and will be supported longer.

If you want to spend more money while doing this, replacing the adi with a G5 or GI275 will give you tons more information on your adi - like localizer, glideslope, speed, alt, heading, etc.  not needed for your goal of lpv approach capability, but certainly nice.

[Bob - S50]

I always seem to run contrary to the mainstream.  While GPS can be substituted for DME, that sometimes requires mental math.  And if the GPS system ever goes down (unlikely) you won't have that either.  If you want DME you might consider a KNS80 VOR/LOC/GS/DME in one box that can be had pretty cheaply these days.  I just bought a used one for $250 to keep as a backup for the one currently installed in our panel.  That guy had a second one for sale.

Between the GNS430 and GPS175, both have advantages.  The GPS175 will be supported longer and will allow easier loading of flightplans.  But the GNS430 has a Comm radio which the GPS175 does not.  The GNS430 would allow you to get rid of one of your nav/comms.  You might also consider the GNX375 instead of the GPS175 since that would allow you to get rid of your transponder and give you ADS-B OUT and IN.

People are starting to sell GTN650's too because they feel compelled to have the latest and greatest  GTN650Xi.  That would give you the GPS, Comm, VOR, LOC, GS and allow getting rid of a Nav/Comm

What you end up with depends on how many Navs and how many Comms you want, how much panel space you have, and how much you are willing to spend.

Good luck.

[Seth1001]

Yeah I understand the lack of any "real need" for DME. However, I would like to have IFR capability without the GPS working at all. In other words, I want two completely independent IFR packages. I also really like the features of the G5, but I hate the looks. I need the setup to maintain the original round dial look. I'm not looking to go full digital newest and best. I'm a big fan of the old school stuff. In fact I wouldn't even want to get rid of the ADF if it actually worked...which it doesn't. I wouldn't mind replacing it with the KNS80 that you speak of. Then I could keep my current comm/navs rigged to the current LOC/VOR, and hook up the 175 to the new (still old) one...especially since the AV-30 doesn't do glideslope or anything. Of course I think I can hook the same system to multiple VOR/LOCs. I'm really not sure. I can pick up an AV-30 and a GPS 175 for about 6k. What do shops typically charge to install those mugs? Millions?

[bradp]

Is this a forever or a sell plane.  Probably makes a difference how you’ll treat the project.  

Take the equipment price and add 75-100% of the equipment price and you have your installed price. 

Installation cost is going to be a “challenge” for the project.  

You want the most bang for your buck.  A 375 box will get you the most bang for your buck.  You’ll get rid of the ADF and KT76.  

But how will you present the data? SL-30 as an HSI? A third CDI?

 

[Oldguy]

Why the 530W? You do not appear to have anything that would paint on the 530, so a 430/650 would fit easier, and the 430 would be less costly and likely fit in the spot a radio is in. Less panel work = less $$$ spent. And I would actually recommend the Avidyne IFD 440 over the 430/650, but that's just my preference. Likely have a longer life than the 430 and less money then the 650.

If you want to go really old school, pull the VOR and put in a switch to go from GPS to NAV 2 (keeping your current radio with GS). You have space next to your panel lights and ELT switch. Pull the ADF and put the DME in there.

This keeps two separate IFR NAV systems - one RNAV/ILS and another DME/ILS.

While you are at it, get a 406 ELT if you don't have one, and put the switch where the current switch sits.

[Ragsf15e]

7 hours ago, Seth1001 said:

Yeah I understand the lack of any "real need" for DME. However, I would like to have IFR capability without the GPS working at all. In other words, I want two completely independent IFR packages. I also really like the features of the G5, but I hate the looks. I need the setup to maintain the original round dial look. I'm not looking to go full digital newest and best. I'm a big fan of the old school stuff. In fact I wouldn't even want to get rid of the ADF if it actually worked...which it doesn't. I wouldn't mind replacing it with the KNS80 that you speak of. Then I could keep my current comm/navs rigged to the current LOC/VOR, and hook up the 175 to the new (still old) one...especially since the AV-30 doesn't do glideslope or anything. Of course I think I can hook the same system to multiple VOR/LOCs. I'm really not sure. I can pick up an AV-30 and a GPS 175 for about 6k. What do shops typically charge to install those mugs? Millions?

Obviously it’s your money, but you don’t need a DME to fly ifr.  You can use one or two old school vor/ils and be just fine.  Especially if that’s the backup to a quality ifr gps.  If your single ifr gps fails while ifr, you’re required to report that to atc anyway and they’ll expect to provide extra assistance through the rest of the flight.

 

 

[Seth1001]

The 530W looks like a good deal mostly because I can get a used one for 5k. I haven't seen the 430W for any less than that so I figured I might as well have a bigger screen. I'm sure it has other features that the 430 doesn't have too. But like I said, I'm leaning towards the 175 because it's a new product and I could still keep both of my old KX-170s. I guess we'll see though. I'll probably fish around for a VOR/GS/DME rig to replace the ADF dealio. Then I'll put the AV-30 in place of that busted GPS. Then I'll mount the 175 in the center stack, possibly below the audio switch panel just to make sure everything fits. Bada Bing. Thanks for the input everyone.

[Seth1001]

41 minutes ago, Seth1001 said:

The 530W looks like a good deal mostly because I can get a used one for 5k. I haven't seen the 430W for any less than that so I figured I might as well have a bigger screen. I'm sure it has other features that the 430 doesn't have too. But like I said, I'm leaning towards the 175 because it's a new product and I could still keep both of my old KX-170s. I guess we'll see though. I'll probably fish around for a VOR/GS/DME rig to replace the ADF dealio. Then I'll put the AV-30 in place of that busted GPS. Then I'll mount the 175 in the center stack, possibly below the audio switch panel just to make sure everything fits. Bada Bing. Thanks for the input everyone.

Oh wait, I didn't realize the KNS80 was a huge center stack deal. I probably won't go with that. We'll see though. I'll come up with some way to get classic DME but that'll be further down the line if need be. Thanks again for the suggestions.

[MIm20c]

Unless you’re going install the entire thing yourself installing old equipment like DME’S will be a waste of money if they are not needed. The 5k 530w might have been a 24v only unit so be careful of that. I absolutely would buy an integrated gps/com or gps/nav/com to get rid of (keep for a spare) one of the 170’s. 

[Lake Aero]

On 3/29/2020 at 12:00 PM, Seth1001 said:

Yeah I understand the lack of any "real need" for DME. However, I would like to have IFR capability without the GPS working at all. In other words, I want two completely independent IFR packages. I also really like the features of the G5, but I hate the looks. I need the setup to maintain the original round dial look. I'm not looking to go full digital newest and best. I'm a big fan of the old school stuff. In fact I wouldn't even want to get rid of the ADF if it actually worked...which it doesn't. I wouldn't mind replacing it with the KNS80 that you speak of. Then I could keep my current comm/navs rigged to the current LOC/VOR, and hook up the 175 to the new (still old) one...especially since the AV-30 doesn't do glideslope or anything. Of course I think I can hook the same system to multiple VOR/LOCs. I'm really not sure. I can pick up an AV-30 and a GPS 175 for about 6k. What do shops typically charge to install those mugs? Millions?

Have you heard of GI275? It can be your AI/DG/HSI/MFD/EIS/CDI. People prefer because it fits in 3 1/8" hole. It can interface perfectly with GPS 175 to provide you the required information.