HL2 S-Meter Power very high and wrong

[Miguel Lucena EC7ZV]

Hi,

I have started my new Hermes LT2 and I have problems with the S-Meter.

The power measurement in watts that the Thetis program and the PowerSDR program give me are the same and very high.

My external meter says that I have 3 watts on the antenna, the Thetis or PowerSDR says that I am giving > 65 watts.

I have checked the setup of the programs and it does not solve it. Could it be a problem with the ADC of the Hermes LT2?

Thanks

[DL1YCF]

Most likely, the two constants (C1 and C2) in conversion from ADC reading to
power are not correct, these are set in the software depending on
the radio model.

The formula used is

Power = (ADC/4095)*(ADC/4095)*C1*C1 / C2

and the idea is that the ADC reading is in the range 0 - 4095.

For HL2, the constants are C1=3.3 and C2=1.4,

compare this e.g. with

HERMES: C1=3.3 C2=0.095
ORION2: C1=5.0 C2=0.08

and you see that you easily get a reading which is 15-20 times too large
just by using software that does not properly recognize a HL2.

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[Miguel Lucena EC7ZV]

Where are the variables C1 and C2 in Thetis or PowerSDR?

Thanks

[Miguel Lucena EC7ZV]

Solved, I needed the patch and everything works

Beta release of Thetis v2.9.0.6-HL2

[DL1YCF]

The programs should look which board there is
and use the correct values. Perhaps there is a „HL2“ checkbox
somewhere?

Grepping for 0.095 in the Thetis source code, I find
in Console/console.cs constants which are slightly
different from what I wrote. It seems you cannot set these
constants from the user interface but I cannot tell.


public float computeRefPower()
{
float adc = 0;
const float alpha = 0.90f;

float bridge_volt = 0;
float refvoltage = 0;
int adc_cal_offset = 0;

switch (current_hpsdr_model)
{
case HPSDRModel.ANAN100:
case HPSDRModel.ANAN100B:
bridge_volt = 0.095f;
if (tx_band == Band.B6M)
bridge_volt = 0.5f;
refvoltage = 3.3f;
adc_cal_offset = 3;
break;
case HPSDRModel.ANAN100D:
bridge_volt = 0.095f;
if (tx_band == Band.B6M)
bridge_volt = 0.5f;
refvoltage = 3.3f;
adc_cal_offset = 3;
break;
case HPSDRModel.ANAN200D:
bridge_volt = 0.108f;
if (tx_band == Band.B6M)
bridge_volt = 0.5f;
refvoltage = 5.0f;
adc_cal_offset = 2;
break;
case HPSDRModel.ANAN7000D:
bridge_volt = 0.15f;
if (tx_band == Band.B6M)
bridge_volt = 0.7f;
refvoltage = 5.0f;
adc_cal_offset = 28;
break;
case HPSDRModel.ORIONMKII:
case HPSDRModel.ANAN8000D:
bridge_volt = 0.08f;
if (tx_band == Band.B6M)
bridge_volt = 0.08f;
refvoltage = 5.0f;
adc_cal_offset = 16;
break;
case HPSDRModel.HERMESLITE:
bridge_volt = 1.8f;
refvoltage = 3.3f;
adc_cal_offset = 3;
break;
default:
bridge_volt = 0.09f;
if (tx_band == Band.B6M)
bridge_volt = 0.09f;
refvoltage = 3.3f;
adc_cal_offset = 3;
break;

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