Topics

test points


Evan Hand
 

Gerard,
The Si5351 does generate square waves.  As the frequency goes up, the square wave tends to round off, that or my scope (100MHz) may be filtering the signal at the 70MHz and 45MHz areas of the transceiver.  Regardless, I too have corrupted sine waves on the other two clocks, the high one almost a sine wave.  This could also be related to how long the signal runs are from the Si5351 to the mixers.

Good luck with the new antenna.  That is the most important area for good operation.
73
Evan
AC9TU


Gerard
 

Hello Evan,
Thanks for the measures.
It’s exactly the same signal I’m getting.
On the other hand, the other 2 clocks are perfectly sinusoidal.
So everything is normal for me.
I am waiting to receive a reception antenna that I ordered from Jeff. I would then redo reception tests.
Cdt


Evan Hand
 

Gerard,

You are correct on Q12 collector voltage error in the documentation.  I do not have access to correct that document as it came from someone else.

Here are the two waveforms on either side of R110:


The probe is compensated, so the ripple is from the Si5351.  Of course, the higher Vpp is the side closest to the Si5351 (Raduino).  This was while connected to a dummy load, so there was no audio on the signal.

Hope this helps
73
Evan
AC9TU


Mitchel Rought
 

thanks , this will help a lot, I am determined that this radio will work


Gerard
 

Hello,
I worked a lot on my µBitx (Homemade) in reception mode. I really went through the whole editing and I also switched with Evan.
The only i have found technical documentation is this one. There must be an error on the voltage of the collector of Q12. Indeed it is the same mounting as Q32. The voltage must therefore be 10/11 volts.
By cons my signal in clock0 is more a sinusoidal signal with the top screened (Almost like square in fact) at the R110. There, it seems to me modulated in amplitude with the reception (?) on this documentation (See 12MHZ UFI Auttorri doc)
if possible Evan, to check with the oscillo on the two sides of R110, to see. thanks

cdt


Evan Hand
 

Michel,
The short answer is no, there is not a set of oscilloscope or signal level traces for the TPs on the schematic.  You should note that the input signal levels are very low on the receiver side, on the order of microvolts, so most oscilloscopes will not be able to measure them.  Some of us have captured traces for the driver and PA side of the transmitter, however, those were for v5 or earlier.

The most effective troubleshooting seems to be with signal tracing.  This works for the CW transmitter starting with the Clock2 LO that generates the CW signal at TP12 and going through TP2, TP1, and so on to the drivers and PA to the antenna.  Once past the base of Q90, starting with the collector, the signal is strong enough to capture the waveforms.  OTE, they are not pretty, as the rig does rely on filtering to smooth out the signals before applying to the antenna.  You just need to know that the frequency is correct and that the signal is increasing as you move closer to the antenna.  If you get this section to work on CW, then the power side of the RF is done.  

As far as the receiver signals,  I have not done that tracing.  Seems like the most successful method that I have seen os to inject a low-level signal that matches each expected frequency starting with the audio section and working towards the antenna again.  When you lose the signal, you have found the stage that has the issue.

When you combine the static voltage tests, I do not know of a problem that could not be solved.

Above are what I have experienced or read.  I may be in error, so all should verify.
73
Evan
AC9TU


Reed N
 

http://www.hfsignals.com/wp-content/uploads/2019/12/ubitxv6.pdf
^ that's the schematic for the v6 board. Is that what you were looking for, or something else?


Reed


Mitchel Rought
 

is there a chart or diagram that lists the various reference points and their signals for the ubitx v6 board