Signal in to audio out (RF to Audio Latency)

Michael N3LI

Good morning all,

I have seen some comments in other forums and in person with people noting that the Flex 6000 series is not applicable for contesting, or digital modes like Winlink/VARA.

While it is true that those statements are pure BS, I do both, and for my money the Winlink-Flex combo is tremendous, and I've done well contesting with the radios as well.

But it did make me curious - what is the signal in to audio out time lag of the radios?

Mike-VA3MW

It is based on your filter selection in SmartSDR. If you require the fastest audio possible for digital operation, you want to move the slider to lowest lantency.

For V3.3.33 of SmartSDR and measuring the audio from the back of the radio (not PC Audio) it is 57ms from the time the RF is received at the antenna to the point it is available as audio.

The Delta on these 2 signals is 57ms. The purple is the RF signal being sent to the radio and the yellow is the AF signal from the radio.

If you require very sharp filters, then it takes more time to process. By sliding the sliders all the way to the right, you can see it is about 168ms.

These numbers are as current as yesterday when I made the measurements.

Mike

KD0RC

Here is how I am set up. For voice, I just left it at the default.

For digital I set it to the lowest latency as there is no real need for sharp filters here. The reason is that I leave the entire 3 KHz bandwidth open so that I can see all the activity in the passband at once. Also, digital modes benefit the most from low latency.

For CW, I was doing some experiments to see how sharp the filters really are, and I just left it there. I totally forgot that I did that! I will probably return it to the default Auto setting. I don't notice the extra latency in normal CW operations. Full disclosure - I do very little contesting, so it is much less noticeable in casual operation.

Michael N3LI

Okay - 57 ms is not an issue that I can see. A few folks were claiming around 500 ms, and that just seemed odd. Thanks much Mike.

Len, I've never actually messed with the filter options - I might give that a try, although the latency involved with digital hasn't been an issue yet.

Thanks all! - 73 Mike N3LI -