Orion MKII amplifier output quality and bias adjustment

tok2010
Posts: 4
Joined: Sun Apr 09, 2017 9:18 pm

Orion MKII amplifier output quality and bias adjustment

Postby tok2010 » Tue Sep 15, 2020 5:07 am

Hi All,

Last year, I purchased a second hand Orion MKII board from W6 guy.
I left it for several months, and recently I started the mount of it in a case to make use of it. So far I used Hermes for long time, so my experience is limited to this nice Hermes.

Compared with Hermes, the TX output quality of Orion MK II is not good in terms of harmonics and IMD.

The output power of Orion is around 800mW with Drive 100 on Thetis with H/W 7000DLE selected and the default PA settings. The IMD is around 35 dB for almost all bands. The higher the band, the better IMD. For the harmonics, it is not compared with Hermes.

This is a second hand Orion, so I would like to adjust again the bias voltage of the final push-pull amplifier of this Orion. FYI, OC output sink driver was damaged and I was obliged to replaced it. I couldn’t rely on the current board setting.

Has anyone tried to adjust bias voltages? Or is the TX output quality of Orion as I described?

Your comments would be much appreciated.

Regards,
Tokio
ja1cca
dj1yr
Posts: 27
Joined: Mon Apr 10, 2017 2:32 am

Re: Orion MKII amplifier output quality and bias adjustment

Postby dj1yr » Tue Sep 15, 2020 12:23 pm

Hi,

I once measured my Orion MK2.
The PDF is in German but the pictures speak for themselves.

Your board seems to be ok.

73'René
Attachments
IMD Orion MK2.pdf
(1.99 MiB) Downloaded 34 times
tok2010
Posts: 4
Joined: Sun Apr 09, 2017 9:18 pm

Re: Orion MKII amplifier output quality and bias adjustment

Postby tok2010 » Tue Sep 15, 2020 12:50 pm

Hi René

Thank you very much for your document on measuring IMD.
The screenshot is almost the same as my measurement.
As a result, my Orion TX seems to be good.

To get 2000mW, do you remember how to adjust PA setting?
My settings, as default, are around 50 in set-up menu with Thetis and 7000DLE selected.

73,
Tokio
ja1cca
tok2010
Posts: 4
Joined: Sun Apr 09, 2017 9:18 pm

Re: Orion MKII amplifier output quality and bias adjustment

Postby tok2010 » Sun Sep 20, 2020 4:50 am

HI All,

I measured the output power of my Orion MKII by PA Setting to 46.5 for 40 meters band (7000DLE selected).
The power is around 2,060mW and the IMD is around 35dB. The IMD is almost the same as the PA setting 53.3.

My Orion MKII amplifier is good enough to use it.

Is Orion MKII designed for 3W or 2W?

73,
Tokio
ja1cca
Attachments
fullsizeoutput_bda.jpeg
The output by "TUNE"
fullsizeoutput_bda.jpeg (108.4 KiB) Viewed 277 times
fullsizeoutput_bd8.jpeg
The output by 2-Tone
fullsizeoutput_bd8.jpeg (129.98 KiB) Viewed 277 times

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