(tr)usdx calibration

[9a5yy]

Hello!

I uploaded firmaware succesfuly to my trudsx. RX works fine.
Do I need to do any calibration of my trusdx before TX like with QCX-mini and mcHF or not?

73 de Neven, 9A5YY

[AC9YY]

Check your power output and efficiency on all 5 bands and if they look good use it as is, otherwise you can use a NanoVNA to tweak the coils. You may also need to adjust the reference frequency, both of mine needed adjusted as they were off about 500 Hz and I used my Xiegu G90 as a reference.

[9a5yy]

Hello!

I checked power output and efficiency on all 5 bands. The results are here:

band pwr eff
80m 0.79W 79%
60m 0.38W 63%
40m 0.31W 62%
30m 0.54W 77%
20m 0.33W 66%

How does it look you? Are the results OK?
I used usb power supply because I still don't have jack for main power supply connector.
I will adjust the reference frequency later.

Thanks for help.

73 de Neven, 9A5YY

[AC9YY]

Hi Neven,

You're looking for an efficiency of 80+ or higher, but I have not tested if that is true on USB power. Your power levels look good for USB power. I would not be surprised if tweaking the coils for 20, 40 and 60 meters doesn't give some improvement. When you can run it on 13.8 volts try it again and see where you are at. Did you need to adjust your reference frequency?

73
Jim
AC9YY

[va3rr]

Neven;
I am also waiting on appropriate DC barrel connectors as well as rotary encoders. After some tweaking of my first RF board, here are my USB RF output and efficiency at 5V.
Band pwr eff. dBm
80m 0.77W 84% 28.9
60m 0.88W 88% 28.9
40m 0.67W 88% 27.1
30m 0.84W 93% 28.9
20m 0.73W 81% 28.6

I will check power again using my QRP Labs dummy load when I find a moment.

[Faraaz VK4JJ]

Neven;
I am also waiting on appropriate DC barrel connectors as well as rotary encoders. After some tweaking of my first RF board, here are my USB RF output and efficiency at 5V.
Band pwr eff. dBm
80m 0.77W 84% 28.9
60m 0.88W 88% 28.9
40m 0.67W 88% 27.1
30m 0.84W 93% 28.9
20m 0.73W 81% 28.6

I will check power again using my QRP Labs dummy load when I find a moment.

Excellent results - well done!!

[9a5yy]

Hello!

Thanks for suggestions. I still didn't connect 13.8V or 12V to the main power supply connector. As soon as I do this I will let you know results. I didn't change reference frequency because frequency is accurate when I listen it at FT-817ND. I will try later to do some tweaking and look for an efficiency of 80+ or higher.

73 de Neven, 9A5YY

[9a5yy]

Hello!

I checked power output and efficiency on all 5 bands again with 12V power supply.
The results are here:

band pwr eff
80m 6.40W 72%
60m 3.17W 70%
40m 2.73W 69%
30m 4.55W 71%
20m 2.94W 62%

It seems I should do some tweaking to optimize pwr and eff.
What do you suggest me to do?
Is it possible to do it without nano VNA?
Is yes what is the procedure?

73 de Neven, 9A5YY

[Faraaz VK4JJ]

Have you searched this forum for any tuning advice? Have you watched Manuel's video? Read my writeup of Manuel's instructions that is a stickied post?

[9a5yy]

Hello Faraaz!

Yes, I watched Manuel's video before. He used Nano VNA which I don't own. I found your pdf with procedure for optimisation. Now it's more clear to me what should I do. I should skip part where Nano VNA is needed but power and efficiency optimisation I can do without VNA. Thanks for help. As soon as I do
optimization I will let you know the results.

73 de Neven, 9A5YY

[AC9YY]

I have found on every band if I go up or down X00 KHz from the band edges I can find a sweet spot into a dummy load where I get over 8 Watts, for example on 30 meters on my built unit that is around 9.8 MHz and 9.5 MHz on my kit. The peak for 80 meters on the built unit is actually within the band at 3.657 MHz showing 7.3 watts on my external power meter and 8.4 watts on the built-in power meter. Both meters show 1.12 for SWR (MFJ-264), but show 1:1 using an old Ethernet thinnet terminator. Is this a valid test of the resonance of the filter(s) or is the NanaoVNA still the best method?

So, I went out for a run and started to wonder if maybe I dropped the frequency below the dip for the first harmonic and I was reading those harmonics as part of the power output. I had that happen on my uBitx when I swapped transistors to flatten out the output across the bands. First of all, 8.2 watts on the built (tr)uSDX shows 7.2 watts on my LP-100A meter into a dummy load.

TinySA Scan

truSDX built 9.7 MHz_2022-03-31_18-33-24.jpg (171.55 KiB) Viewed 2684 times

The harmonics actually look very good, so perhaps the coils need some tweaking. 7 watts+ is very impressive.

[9a5yy]

Hello!

Finally, I removed 1 turn at L41, L31 and L11. At L21 and L51 I made some tweaking. After removing 1 turn at coils the output power is increased at 60m, 40m and 20m. I didn't use Nano VNA. The results are here for 12V:

band pwr eff
80m 4.48W 74%
60m 3.88W 71%
40m 4.16W 74%
30m 4.58W 71%
20m 4.22W 63%

73 de Neven, 9A5YY

[SteveY]

I get how to make the adjustments but can’t figure out how to get the old to display the power and efficiency. Could someone point out the setting to me?
I found it, CW mode….