F5AGL
Neuling
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Posts: 6
Je suis un lama!
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IQ calibration problem
« on: 27. February 2021, 06:50:37 »
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Hello,
I am bored with the IQ calibration phase of my mcHF (M0NKA kit version 0.6.3).
I am having trouble reducing the carrier to 3.600 MHz LSB (mcHF to 3.624 MHz USB). The problem is the same on the other tapes.
I installed the latest firmware and bootloader:
- Firmware: D2.11.95
- Bootloader: 5.0.4
The problem remains the same.
Do you have any indication of the possible origin of this problem?
73 qro
Gilles, F5AGL
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F5AGL
Neuling
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Posts: 6
Je suis un lama!
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Re:IQ calibration problem
« Reply #2 on: 27. February 2021, 09:33:02 »
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yes, i think i can say the suppression is very bad.
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F5AGL
Neuling
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Posts: 6
Je suis un lama!
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Re:IQ calibration problem
« Reply #4 on: 27. February 2021, 16:41:40 »
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Thanks for your help.
I follow signal from IQ oscillator to mixer, solderings at input transformer (T4), audio signal from UI board to RF bard, all links seems ok with ohmmeter. 
Could it be a configuration problem ?
Gilles F5AGL
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F5AGL
Neuling
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Posts: 6
Je suis un lama!
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Re:IQ calibration problem
« Reply #6 on: 27. February 2021, 19:33:09 »
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At the first power up, i had a problem with C105 (10 uF PA part). Fuse blow up. I replaced C105 and after that mcHF was OK. RX is all ok. TX seems to be quite ok (5-10W). But i have this pb of IQ calibration. If I put 127 for TX Phase on 80m for example, side carrier reduce a little bit. But i can't cancel it as it could be. I test all links around TX Mixer, LO, etc... I have no scope at this moment... I tried with +6kHz translation in place of -12, it's the same...
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F5AGL
Neuling
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Posts: 6
Je suis un lama!
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Re:IQ calibration problem
« Reply #8 on: 28. February 2021, 10:07:54 »
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yes, that's right, i'm going to test this with a scope.
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peter_77
Urgestein
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Posts: 735
THE mcHF and UHSDR forum !
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Re:IQ calibration problem
« Reply #9 on: 28. February 2021, 15:02:58 »
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| IQ calibration only works if hardware chain is defective. |
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Is that sentence really true or is there a "not" missing before defective ?! 
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F5AGL
Neuling
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Posts: 6
Je suis un lama!
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Re:IQ calibration problem
« Reply #11 on: 28. February 2021, 16:49:19 »
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I had understoodd !
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