-36Khz image poor rejection , only -15db

[nizar33]

UHSDR Firmare Defect Issue (Bug) Template 1.0

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Your Issue Data goes here:

Your firmware version: 2.9.41
Your bootloader version: 4.0.0

Hardware

• UI Board: mcHF 0.x / OVI40 1.x
• RF Board: mcHF 0.x / OVI40 1.x

Describe the issue:

Place tell us what does not work and how others can reproduce the issue (list related settings, steps to do, etc.):

First thank you very much for the great and wonderfull work developpement.
Congratulation for the wide sucess.
We have on audio output a poor -36Khz Image rejection (only -15db rejection) at -24Khz (-22db) at -12Khz (-25db) , so we can receive for example FT8 signals at 14110 Khz as well as at 14074Khz with only -15db rejection, note that IQ Auto-balancing was set to "ON" and no image issues seems on Spectrum scope nor on S-meter they are both clean , only on audio output signals, othewise reception has a good quality except this issues,
May be I miss some thing to adjust, please Helpe
Thank you very much

Your relevant settings

Hint: most of the information can be seen on a screenshot of the main display.

You have audio related problems:

• DEMODULATION MODE: LSB/...
• Filter: 2K7 LPF
• Noise blanker setting: 0
• Noise reduction: OFF

You have display (also fill if audio problem) related problems:

• Display resolution: 320x240 / 480x320
• Display connected via: Parallel / SPI
• Touchscreen:No
• Magnify: 1x
• Spectrum: Scope

Other settings you consider as relevant:

• ...

[df8oe]

I cannot confirm. At my mcHFs there is only one "mirror" (it is "at the opposite side of LO" in Xlate distance) and this one is suppressed >55dB with automatic IQ correction - no other RX mirrors. I think there is a hardware issue at your device.

[df8oe]

I have just heard you own R928Plus - not mcHF!

Poor man - if so :)

This clone uses hardware where you are stuck to the firmware ir was sold with. No update possibility because incompatibility! Chinese cloners developed a PCB using experimental features in a very early stage which were in firmware and are targeted to OVI40 - but they never asked where developement will move to or what is coming up in future so they are completely errored..

The R928 I have yesterday opened showed no toroids fitted for LPF - another absoulte no-go.

Is the issue related to R928Plus?

[nizar33]

Thank you very much for quick response , yes it's a RS928 plus .... very poor really .... pse if any adjustement proposal or modification ?? may be sound card Sample Rate software adjustement , if it's possible and How ?? a facebook friend has an original McHF Kit and your newest FW d2.9.42 and he has approximatly the same audio images issues, the problem was not present on spectrum nor on Smeter indicator , it's only on decoded audio output, that's may mean it's not a commun hardware problem, just a thought , we are many OM's to have this problem Please if possible helpe Thank you very much

[df8oe]

I never have had that on mcHF - never. And we never have had any issue reports about something like this (which are firmware related - of course RX mixer hardware issues can cause this).

Hardware problem in R928Plus is that it uses SI5351 and relies upon LO is always 4 x f(working). But that is not so - we are going a complete different approach on OVI40 where SI5351 is used.

Modification:
Desolder SI5351 and 27MHz TCXO and add SI570. Footprints are present - I have not tested if it will work. But on mcHF and its clones you cannot use SI5351 - it is a complete different approach and only works on a handful firmware releases (where we first add SI5351 support to see if it works in general and then quick switched to our "OVI40 related working way")!

[DD4WH]

Sorry folks:
There will be NO SUPPORT for cloned radios from my side, not on the hardware and not on the software side.
You all knew in advance what your are buying: a clone.
So you have to live with the fact, that the clone you bought does not work properly.
It would be nice if you tell all your HAM Radio colleagues on the "clone" social networks that the clone you bought is not working.
73 Frank

[df8oe]

That is my way of thinking, too. No further hints, no further support. My hint ar my last post was the only one I have given.

Again: there is no issue report from any mcHF owner about that - so it seems to be hardware related and not UHSDR related - so I will close this issue.

[nizar33]

Thank you very much for your promped responses , i Made the bad choice to by a clone, it may be due to not weld the (mosfets) finals ..... Good Continuation on this great Ham Project . thanks

[df8oe]

But:
mcHF is a DIY project and there is no way to legally buy a "ready one"! You can turn it like you want: if you do not want to build it you only can buy a "used one" from another OM who offers his self build one...