Re: ADC Clip when Transmitting

Neil Smith G4DBN

Totally expected behaviour as the radio is full duplex, so when you are not using the attenuator, you will see some peaks above the -10dBm overload level.  It certainly does it on the 0dBm output. The indicators stay active for a while after being triggered.

It isn't anything to worry about, you can always set DUO Menu 50 ATT ON TX to "ON" to stop it if you don't mind the additional clicking of the attenuator relay on PTT.

Neil G4DBN

On 21/11/2019 16:01, David via Groups.Io wrote:
Can confirm that the red ADC clip indicator comes up on my SW2 PC display when transmitting on my FDM-DUO.  I’ve had my FDM-DUO for around 4 years, but didn’t notice anything until May, when I’d hardly used it for 2 years because I’d being using an IC7300.  

Sole rig is now FDM-DUO + ART120.

I’m clearly not very observant, because I didn’t notice that the PK indicator was also flashing until Jim reported it!

Both indicators are suppressed on transmit if the receive Attenuator is active.  Indicators do not come up on receive whether or not attenuator active.  Short, screened usb leads in use and all leads have clip on ferrites.

David.   G8IIC

On 21 Nov 2019, at 15:11, Thomas McQuiggan <m7mcqio83ro@...> wrote:

Hi Jim, it's strange that you should post this message, because I was JUST about to post the same question! When I transmit (FDM DUO & DUO-ART), I see the PK light come on and it stays on for a few seconds after I stop transmitting. No idea why.

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