You need the probe because the G5 uses TAS to calculate the wind vector, which is not available until temperature is known.
But you don’t have to use the Garmin probe, the installation manual has alternatives, including at least one by Davtron. We used that when upgrading our training aircraft to dual G5, because the Davtron one was already installed. I’m at the phone right now and can’t look up the p/n but can do so if you are interested.
a screen which is otherwise a little bit tiny.
Today I had the opportunity to compare the G5 HSI with the G500 txi (7") side by side. It was a demonstration setup at my avionics shop. It turns out that the HSI
compass rose of both units has the same size ! It is still smaller than a KI525, but I would have thought the G5 was minuscule compared to everything else. I was wrong.
Online I saw a G5 next to an Aspen EFD1000 and the difference in compass size was minimal.
Now if they would only add a rotary button for course…
Does anyone know if it is possible to connect a temp probe to two devices? I have a temp probe on my JPI EDM 701, and a G5. It would be nice to provide the temp from the probe to the G5 too. One thought would be to just run a wire from the probe lead terminal on the EDM directly to the G5. Another would be to expose the wire connection at the probe and add a 2nd wire to the G5 from there. But there might be some electrical reasons this wouldn‘t work.
Edit:
Found answer to my case … G5/GAD13 only supports Garmin GTP 59 and Davtron C307PS probes today, so won‘t work in any case with EDM temp probe.
Normally you cannot, but it might work. Potential issues:
The sensors used on engines (CHT and EGT) are thermocouples, Type J or Type K. These produce a tiny voltage and it is critical to reference this voltage accurately to the ground terminal(s) of that instrument. You could connect the same thermocouple to two instrument inputs concurrently but you would need to make sure their grounds are very well interconnected, which may or may not be possible depending on how the ground is implemented inside the instrument. If the thermocouple interfaces are galvanically isolated then it would be easy but in the “cheap 1970s/80s stuff” like the EDM range this is not done because it would cost another $20… so they are relying on each probe running back to that instrument only and then its ground potential doesn’t matter.
There is no harm in trying though. But first measure the voltage between the probe grounds of the two instruments (with power on, etc). If it is zero, then re-check with an ohm-meter (with power off) and make sure they are actually interconnected via “something” (say, 1 ohm or less). Also check the voltage between each instrument’s ground and the airframe; again it should be zero. Then you can fairly safely run a nice thick wire between the two grounds. Re-test on a ground run with alternator on, etc. that both instruments read the same value and it is about right.
It would obviously help if the two instruments were wired up so they share the same (thick) ground power wire, and that wire goes to the airframe at just one point. If each has its own ground wire and airframe connection, then any current flowing in the airframe will make it impossible to share the thermocouple between them.
OAT probes are different. They are usually AD590 based. This is a 2-terminal semiconductor device which draws a current whose value in microamps equals the temp in Kelvin i.e. 293.16 uA at +20C. The Davtron etc OAT instruments use this. Just about everybody does, including the OAT option on a GTX330. These cannot be shared at all. Well, they easily could be but you would need to build a little current mirror circuit which takes in the probe current and emulates two probes out of it. (One could do the same for thermocouples) Throw in the interesting power schemes used and it gets a bit messy. And you want two OAT probes because if the one fails you cannot fly in IMC, most of the time 
Sadly I know quite a lot about this, having designed various thermocouple (and PT100, AD590, etc) instruments in the past.
I’m very impressed with the OAT probe , TAS and wind speed vector upgrade (see bottom G5). It’s all very well that one should know the wind from your pre-flight preparation. However, imagine being in a controlled “panic” if one ever had to do a forced landing or ditch, trim to best glide, look for a field, get a mayday call out etc. Being able to land directly into wind could easily save your life.
It was spot on accurate today. Also as a previous post asked, I have the latest software (installed yesterday) but the compass rose has not changed.
Apparently Garmin will make an announcement with regards to the G5 this week.
Speculation is: attitude source for legacy autopilots. Fingers crossed…
Speculation is: attitude source for legacy autopilots.
If they do, my money would be on an adaptor box, which converts the G5’s AHRS data into the KI256’s LVDT emulation. The EA100 and the GAD43 do basically that, AIUI, and one could design such a box for other products which have a pitch/roll output e.g. the Sandel SN3500.
So they just need to extract a bit of the GAD43 – trivial
airways wrote:
Speculation is: attitude source for legacy autopilots. Fingers crossed…
really?? this would be fantastic. I have a fully operational Century IIB AP on the Arrow 200. If Garmin really nails it then the first thing I am doing is getting rid of the vacuum system and mounting a dual G5 setup.
Magnetometer for the G5: will it work on an input from an old non-Garmin magnetometer, e.g. the King KMX 112 flux gate used in many older aircraft to slave the mechanical King K1525 HSI ?
From the workshop bills I have seen, the magnetometer installation is the single most expensive part, so not a trivial question.
Apologies if this has already been answered in the (long) thread – I have just skimmed it.
