Compared to the old ICOM:
The screens are comparably sunlight readable but the new radio is much better due to the thicker font etc
The NAV screens do indeed pop up only when a valid signal is received
I think that is a crap implementation. It would be much better to have the screen showing all the time and just show a flag or whatever. Then you would have a continuous opportunity to config e.g. the OBS. Only an idiot would have done it this way; it is contrary to the way one uses avionics. But for emergency use, this is fine.
Following a loss of signal, the NAV screen stays up for a few seconds.
I don’t have a pic of the ILS screen (got a video but it was badly out of focus) but it works. It shows a GS even if the LOC is not present, which is like all the old mechanical avionics. So either a valid LOC or a valid GS brings up the ILS screen.
I had only embarrassingly crap test gear (the usual UK small avionics shop stuff) to test it with.
Regarding the sidetone, it is actually fine. The problem was the Bose X headset.
Between about 2000 and 2003, Bose shipped thousands of these with defective mikes, with an output about 1/3 of what it should be. In the USA, they replaced them under an indefinite warranty but here they washed their hands of it. I replaced three of the mikes at my cost (£160 each) but seemingly not this one. This Bose X headset, with two jacks, is one I am keeping in case I fly in somebody else’s plane, which I rarely do. Since then I sold 2 on Ebay, and replaced them with A20s.
With the Bose A20, Lemo plug but with the Lemo to twin jacks adapter cable, the sidetone works perfectly.
I tested it with both the whip antenna and the aircraft antenna (via a BNC-BNC lead) and both work fine, with very good voice quality, especially with the A20 which sounds superb.
A negative point is that when the headset adaptor is screwed in (held by two screws) the radio cannot be used by itself. You need a headset. There is no menu config to select internal or external operation. On the ICOMs that was also the case but the headset adapter unplugs instantly. This one needs a screwdriver. Obviously, whether this matters depends on how you plan to use it. In an aircraft, in flight, the radio is unusable without a headset. But you will need to use the headset even if you just want to collect a departure or startup clearance.
I have just done a flight test, VOR and ILS, and it works great.
I did a movie of it, with a fixed unattended camera setup, showing it next to the Sandel SN3500 EHSI. Unfortunately the quality is crap, due to reflections on the screen of the radio, which render the radio’s LCD display invisible most of the time.
It was all done using the whip antenna.
VOR is picked up from > 20nm away, and the cone of uncertainty is slightly smaller than with the KX155A/165A radios and the SN3500 EHSI (fed from the radios via lateral composite). The accuracy is better than 0.5 degree and certainly as good as any of my fixed avionics.
ILS was picked up perfectly from Lydd’s (EGMD) 14D DME arc and worked perfectly all the way down to the MAP. The accuracy was also at least as good as what I have in the panel.
If I can get something out of the video I might upload it somewhere… but I am not doing another movie. Too much hassle setting it all up.
A further update:
Testing it with a modulated signal generator (Marconi 2024) it seems bang on. There is just a tiny signal level sensitivity – of the order of 0.5 degree on the VOR radial, between the minimum valid signal and a signal at the top end of what it might see. On the GS there is no signal sensitivity whatsoever and it is spot on.
I uploaded my crappy ILS test video here
You can glimpse the LOC and (more often the) GS indications at times. They match the Sandel SN3500 indications as closely as can be seen. I pay $60/year for Vimeo so may as well leave this up there 
This is EGMD ILS21 and the video starts just before intercepting the western end of the DME arc.
I haven’t sanitised it yet for pilot errors 
A bench test coming up soon…
Video isn’t readable but thanks for it :)
I probably buy this model as soon it will be available in Poland.
Btw. nice plane.
The video does just about show the accuracy of the LOC+GS indicators (you can see them intermittently) which is what matters.
I am uploading a bench test video right now, which should be online tomorrow. The 750 radio is very accurate, especially for ILS which is by far the more likely emergency use for it (nobody will be doing VOR tracking if his aircraft electrics fail – you should have a handheld moving map GPS for that situation). It’s more accurate than my signal generator.
Bench test
Nice setup Peter. Now show me how you generate a glideslope
The video is very much out of focus unfortunately.
nobody will be doing VOR tracking if his aircraft electrics fail – you should have a handheld moving map GPS for that situation
Nobody has been doing any VOR tracking since around 1995 even if the electronics are perfectly functional
One question though: With my old ICOM handheld radio, it is quite tedious to switch back and forth between VOR and COM modes, because it has no frequency or OBS memory and you need to type in the frequencies and bearing all the time. For me, the COM part will always remain the most important part of these devices anyway, so this must be the part that has to work without much hassle. And it should continue to receive the selected COM frequency while displaying VOR/ILS/GPS data, which is something my ICOM can’t. But I suppose your new toy can do all that, after all, it is 30 years younger… ?
The GS is done the same way as a LOC. The carrier frequency is just different – in the 300MHz range – and the modulation depth is different. The same 90Hz and 150Hz tones are used. My video above shows the GS working. The radio shows the GS as just small arrows on the side – not as a horizontal bar. The arrows should be clearly visible.
What I can’t do is generate a LOC and GS at the same time. That needs two modulators and two signal generators. However all the mechanical avionics, and this radio, don’t need a LOC to display a GS. The later stuff, including my SN3500 EHSI, suppress the GS unless a valid LOC is present.
I don’t know if you can use it as a radio while doing a VOR or ILS with it. I haven’t read the manual yet I suspect probably not, because it would require duplication of all the RF stuff. OTOH they obviously do have two RF receivers on the ILS… I linked the manual earlier on, I think.
