MGL Avionics User Forum

I have an RV6 which had a king KY97a radio going to a DRE 244e intercom. I removed the King radio and replaced it with the V16, but still running it through the DRE intercom. The V16 radio seems to be working fine (only tried it within the hangar), but there is a this very distinct, but not really loud, beep occurring that has a period of about one second. When I turn the radio on there is a short duration squelch noise, then the radio goes relatively quiet, then after 10 to 15 seconds this short beep with a period of about one second starts. The loudness of the beep does not seem to vary significantly with volume or squelch settings. The green light on the V16 unit also flashes at abut the same period. I tried my hand held radio in the vicinity of the cockpit and it does not have the beep. The KY97a and intercom worked fine before I replaced the radio.
I'm looking for any thoughts on what the beeping problem might be. Removal of the DRE intercom is possible - just more wiring to install.
My intent was to later on install a Dynon intercom and have the V16 as com 1 and the KY97a radio as a second com.

Further to the previous post, when I removed the power from the intercom the beeping went away.

Has anyone used the V16 with the Dynon intercom? - any problems?

Please make sure you have configured the AUX input OFF using the V16 setup menu if you are not using it - this is a very high impedance input (on purpose) and if left uncorrected can pick up signals from all sorts of sources. You can also connected it to audio input ground on the radio which eliminates any interference.

If you are using it - make sure you have used good quality shielded audio cable and the shield is only connected to ground on one side (any audio ground from the source equipment should then have its own ground wire inside the shielded cable - so you would normally use a two core shielded cable).

Also, if your VOX is switched off - it can pick up interfering signals from your mic inputs. Also important to use proper audio shielding techniques here. It is less likely to pick up interference here because the mic inputs are very low impedance but you are connecting longer wires which can negate that to some extent.

Thank you for the quick reply Rainier. I am using aircraft shielded cable and have the AUX to off. I removed my DRE intercom but am still using some of the previously installed jacks and wires. Essentially trying to wire it as laid out in the V16 manual. Currently the receive works very well but I have to use a very low mic gain (about -10) to get the transmit to work. I have a Dynon EFIS and still have to do the serial connection to the Razor head and AUX input to the V16. Will try to clean up the wiring a bit too. Will let you know how it goes.

You are using an intercom so its normal to have a somewhat unusual mic gain - depends very much on the intercom and most of them allow you to set the level. If yours can do that set it as high as it can go and compensate on the V16 side - make that lower. This way you reduce the sensitivity of the V16 to effects such as RF feedback (which can be amplified via an external intercom).

The easiest way to set the correct MIC level is to select an unused frequency and press PTT - talk into the MIC then let go and keep talking - listen to the side tone (make sure it is switched on and your intercom routes the side tone from the V16) - the two sound levels must be the same - it sounds slightly different depending on PTT or not (There are additional filters in the RF path and you listen to what goes out on air).
Set the MIC gain until it's the same. The reason this works is because the TX uses a wide range digital modulator that controls the audio level that goes on air in order to create the best possible modulation for maximum range (it's not just power that makes range - modulation is just as important). So the TX has sort of a very fast acting automatic gain control (it's so good it can never overmodulate no matter what you throw at it). So that is your reference.

On the V16 audio out side you of course have the RX and intercom volume control. Those are relevant in your case and again should be set quite high and your intercom input level control as low as possible for the same reasons mentioned above. The V16 intercom volume is still relevant for the side tone during TX and of course the RX needs to come through.

Hope that sheds a light on the V16 and intercoms. Intercoms are not all created equal and some are more difficult to set up than others - does not make them worse (usually it means they are more flexible or have more functionality) - but it does mean you need to know how to set this kind of thing up - a novice can easily make basic mistakes resulting in a overall system that performs poorly or not at all.