Watt meter calibration

[Trucker]

I am currently using v2.9.6 of Thetis. I watched Richie's latest video on calibrating the PA.
I am using an Autek WM-1 external watt meter which is reasonably accurate. Using it with other radios I have, it is consistent between them as far as comparing its readings to the radio's display.
But, with my 8000DLE the internal Forward power meter is way off compared to the WM-1.
Obviously I used the WM-1 to Calibrate the PA settings. At 200 watts on the WM-1 the Forward Power meter in Thetis shows 512 watts! Off just a bit!
I have searched thru the forums and there is mention of calibrating the Forward power meter in settings. Under the Meter tab, I only have settings for color and meter style. I did find an old post showing an additional part of that same tab with settings for different power levels for the Forward power meter.
Has that function been removed from 2.9.6? Or is it in another place?
I don't plan to take the WM-1 out of line. But, it would be nice if the display in Thetis could show something close to what the external meter shows.
James
WD5GWY

[FM5GB]

Hi James,

you may adjust the Thetis wattmeter in SetUp /PA Settings/Watt Meter. You may linearise the scale in 10 W increments.
Be carefull not to fry your PA.

73s Phil FM5GB

[Trucker]

Hi James,

you may adjust the Thetis wattmeter in SetUp /PA Settings/Watt Meter. You may linearise the scale in 10 W increments.
Be carefull not to fry your PA.

73s Phil FM5GB

Thank you Phil!! I don't know how I overlooked that.
James
WD5GWY

[Trucker]

Phil, thanks for the reply. I found the settings tab you mentioned. I think there is a step I am missing somewhere.
Trying to follow the steps in the box below the offsets, I cannot seem to get the display Forward power meter to match my outboard watt meter very close at all.
I originally calibrated the PA using the Tune Slider per the latest PA Calibration video posted by Ritchie for v2.9.6.
He does mention in his video that the Forward power meter is off. But, didn't mention how to adjust it.
I am wondering if when adjusting the Forward power meter should I select in Transmit/ use Tune Slider as I am currently using for the PA calibration. Or for adjusting the Forward power meter in Thetis, used the " use Drive Slider" selection?
It gets a bit confusing! I have made several contacts and have been watching my outboard WM-1 watt meter for output power and ignoring ( well, trying to ignore) the Forward power meter in Thetis.
If I set my power output according to the Tune Slider my outboard meter reading matches the points along the Tune Slider pretty close. But, if I look at the Forward Power meter in Thetis it gets way off.
I was hoping I could somehow sync everything up pretty close. But, it seems not that easy to do.
James
WD5GWY

[w-u-2-o]

Drive calibration (PA Gain calibration) is completely separate and distinct from Watt Meter calibration. One has absolutely nothing to do with the other.

Even if you haven't performed any sort of PA Gain calibration, your (better calibrated and more accurate) external power meter will provide the reference reading for whatever power is coming out of your ANAN.

1. Go to Setup > Transmit, in the Tune section select the Use Drive Slider option.

2. Go to Setup > PA Settings > Watt Meter.

3. Using TUN and the drive slider, set the drive level to obtain 20W on your external power meter. It doesn't matter if the drive slider is calibrated or not, just set it to wherever it needs to be to get 20W.

4. Adjust the 20W trim value so that the forward power reading in Thetis reads 20W, or as close as you can get.

5. Repeat steps 3 and 4 for all other trim steps, 40W through 200W.

This adjustment is global for all bands/frequencies. Therefore it will not be exact on all bands/frequencies. Unfortunately the hardware is not capable of very accurate power measurement.

It is best to perform this calibration while operating into a dummy load so that antenna impedance does not affect the power readings. Again, the hardware in the ANAN is not the best at power measurement, anything but a perfect 1:1 impedance match may affect the readings obtained.

[Trucker]

Thank you Scott. I followed your instructions and the Forward Power meter now reads much closer to my WM-1.
I always used a Cantenna I have had for years to do any sort of transmit adjustments.
Even though some of the things about the Anan radios can seem to be a bit daunting, I still like the end results.
It is certainly a learning experience!
James
WD5GWY