ADC LED level

[Claude]

Hi,

I noticed that the A-ATT level on receive is very loud, often rendering both ADC LED 75 and 100 in front of the HL2 to be constantly lit. I often get ADC overload on the screen under certain receive conditions.

As found from this link it is said :
under Run Mode section 3 ADC Good Level
On indicates the HL2 ADC is seeing more than 75% of the available range. Adjust the LNA to see this LED on or flashing occasionally.

and under section 4 ADC Clip
On indicates the HL2 ADC is seeing maximum values. Adjust the LNA to to see this LED rarely flash. Occasional flashes, 1-5 very short flashes per second, are okay.

So for example, on 40m band, I adjust the S-ATT to -16, ADC 75 flashes occasionnaly and sometime a blip from 100 LED occurs.

If I set to A-ATT, it drops the ADC level to -27 and both 75 and 100 LED are lit solid.

By what I could read, I understand that A-ATT will seek peak value and reduce from 3dB to obtain optimum ADC level but the level seems too strong as per the instructions.

Is there a A-ATT offset in thetis so that can be adjusted ?

I most of the time run under S-ATT to adjust the ADC level but rf conditions and band choice makes me tweak that setting all the time. I would like the A-ATT work without having the ADC overload come on the screen.

Noticed under v3.11 and now v3.12.

Thank you.

[Reid Campbell]

Hi Claude,

Whoo, that a bit sore on the eyes

On 10/02/2026 20:46, Claude wrote:

Hi,

I noticed that the A-ATT level on receive is very loud, often rendering both ADC LED 75 and 100 in front of the HL2 to be constantly lit. I often get ADC overload on the screen under certain receive conditions.

You say you using A-ATT (Auto Attenuate), so you should never see ADC overload. If you are, then you are setting S-ATT.

In order to get the maximum benefit from the ADC, you need to adjust the gain so that the total level of all signals is below the full range of the ADC. The A-ATT setting does that by adjusting the attenuation/gain of the LNA to briefly put the ADC into over load and then back off by 3 dB. This is not noticed as the period in over load is small and the amount of over load is slight.

When going for maximum dynamic range, the input signal level will always be over the 75% mark, so both led will be on, all the time. This is not a cause of concern but shows that the system is working correctly.

I run A-ATT all the time and never see a problem. I also run auto AGC and some of the auto display setting which auto adjusts the noise floor and when I switch bands, everything is taking care off.

Cheers

Reid Mi0BOT

As found from this link it is said :
under Run Mode section 3 ADC Good Level
On indicates the HL2 ADC is seeing more than 75% of the available range. Adjust the LNA to see this LED on or flashing occasionally.

and under section 4 ADC Clip
On indicates the HL2 ADC is seeing maximum values. Adjust the LNA to to see this LED rarely flash. Occasional flashes, 1-5 very short flashes per second, are okay.

So for example, on 40m band, I adjust the S-ATT to -16, ADC 75 flashes occasionnaly and sometime a blip from 100 LED occurs.

If I set to A-ATT, it drops the ADC level to -27 and both 75 and 100 LED are lit solid.

By what I could read, I understand that A-ATT will seek peak value and reduce from 3dB to obtain optimum ADC level but the level seems too strong as per the instructions.

Is there a A-ATT offset in thetis so that can be adjusted ?

I most of the time run under S-ATT to adjust the ADC level but rf conditions and band choice makes me tweak that setting all the time. I would like the A-ATT work without having the ADC overload come on the screen.

Noticed under v3.11 and now v3.12.

Thank you.

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