100W Output using Thetis

[JohnFT61]

I seem to have an issue getting 100W output while using Thetis. This is especially true on the 12M band (I haven't tried every band yet, working up from 6M). Even if I changed the transmit gain numbers, it would still only get very close to 100W. I am guessing I shouldn't have to do that, because then the offset numbers only go so far at each of the power settings, and I have noticed will be good enough?

I also tried pihpsdr, and it seems to be better (96W without any adjustments with PA Gain), but the gain is already set at it's lowest point.



John
N2KBE

[laurencebarker]

I think the gain of the P2 Saturn & TX combination is lower, and you do need to update the TX gain

My Saturn has had various resistors in the TX replaced and replaced back again and probably isn't the best for reference measurements.

[JohnFT61]

I am not sure it is a gain issue, because the gain at 6M (twice the frequency is OK (just a little low, which can be adjusted). I think the issue may be the 12M LPF. I put the values into a simulator, and the cut-off is right at the band edge. Perhaps too close, when considering the tolerances of the inductor and capacitors. If I find some time, I may sweep the PA, to see the response.

It would be interesting to see the response of all the amateur bands (PA ~~> LPF).


John
N2KBE

[JohnFT61]

Sorry, I see the LPF I was looking at is for both the 15 and 17M bands. The one before that is for the 10 and 12M bands. Will continue to investigate why the power is low. May still sweep all the bands to check.



John
n2KBE

[laurencebarker]

it's not speculation: we know the output is lower and the gain needs to be reduced. I just don't know by how much.

[KI4P]

not sure this post belongs here or by its self. after reading this and doing a PA calibration the second time, once following Richies you tube video and again tonight following procedure in Thetis manual section 3.8, all bands show power slightly over a 100 watts except 10 and 17 meters, they both have around 76 watts out. this is using Thetis v2.10.1, dont use PI but may try that at a latter time, dont know why that should mater but, who knows! By way rig is the G2 plain!
Richard