MGL Avionics User Forum

Hi All!
After solving some problems with my V16 radio it finally started working properly which is great. But I think the reciving is not perfect. Transmitting with it is absolutely no problem, but if I fly a little further from the tower (5-10NM) the sound gets worse and worse and the tower can hardly be heard in the noise. Has anyone had a similar problem? Would love to fly a little further from the airport without worrying that I can't hear them!
Br
Mattias

I find my V16 to be remarkably sensitive. I can hear traffic 60 miles away clearly and I can pick up the AWOS from further away than any other radio I have tried. And this with a known poor antenna.

many wrote: ↑Sun Oct 30, 2022 3:57 pm ...the sound gets worse and worse and the tower can hardly be heard in the noise.

Can you be more specific?

'll try to explain this by saying that if I stand on the appron close to a strong transmitter, I have no problems at all with the sound, it's perfect BUT if I taxi away and line up for take off about 1nm away, the sound starts to weaken from the transmitter and get mixed up with background noice. Should it then also be any obstacles between the aircraft and the transmitter, the sound may become completely unreadable. If I take off and the obstacles disappear, the sound gets better for a while and then decreases the further I get from the transmitter. about 5-10nm! What I feel is that the signal is weak but why!? I would like to add that I have changing the antenna and making sure it is connected correctly!! All the time the transmission works perfectly and they read me without any problems!
I hope you understand a little better what I mean!!
Thanks for all help!
Mattias

You do not have a working antenna installation. Short or cable break or completely unsuitable antenna (i.e. not matched at VHF frequencies).

A quick check of the receiver sensitivity can be done quite easily.

The receiver due to it's dual receiver architecture is unusually sensitive. This means the receivers own noise (created by random electron flow) is much less than natures atmospheric background noise.

Ensure that everything is electrically quiet - nothing electronic in your aircraft is switched on except for the radio. Tune to an unused frequency and open the squelch fully. You should now easily hear the static noise which is the background radiation received via your antenna. While listening to this disconnect your antenna cable from the radio. There should be an instant, significant drop of the noise level you hear. The better your antenna tune the louder the background noise will be. If there is a serious problem with the antenna (like a short or break in connection) you will find very little change in noise level, if any. Should your radio's receive for some reason have lost sensitivity there will also not be a difference in noise level - and the noise level will be extremely low as well.

However - thus far we have not had a single receiver issue in our workshop - in fact we have only had very few V16's back for repairs since they were released.
Recorded repairs over roughly 2000 V16's shipped so far:

Only one transmitter output transistor failure has been recorded. A few power related issues (usually blowing the protection devices so repairs here are simple and cheap). One RS232 driver chip blown up (with a nice crater in the chip) and three loss of firmware cases - reloading firmware fixed that. These cases are likely due to very bad reflections on the antenna system (100% energy returned) - the reflected power causes havoc - the system immediately throttles power down when that happens but it takes a few milliseconds - sometimes too late to prevent damage. The reflected RF energy messes with the power system causing over voltage on the processor which can wipe its program storage. The last time this happened the person in charge sent us a photo of the cause - antenna cable short at the connector to the antenna itself - so you have a length of cable with a short at the end. This is the worst case scenario as you have a 100% power reflection and the length of the cable changes the phase angle of the reflected wave.
We have had a few cases reported of the large capacitors inside breaking off - it seems that can happen if the V16 is vertically mounted and you do a very hard landing. They don't break off during the DO-160 tests but regardless - once we became aware of this we glue these things on. Not aware that it has happened since.

Thanks for you input!! I have work to do!!!
//Mattias

thanks for the information