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EU1KY Antenna Analyser. / Ukraine XVTR 144 TCXO



EU1KY its fb  Antenna Analyser project the software  is still further developed
The latest fw 040  KD8CEC  offers even FT8 and other digi modes TX 
 Will need i2c  GPS clock and the frequency has to be corrected in the 200Hz window for WSPR
                                       
 
STM32F746G Discovery board used in  EU1KY A.A.
Nice but some boards have a short circuit issue with JP2 external 5V supply.
The soldering of this JP5 pins caused short to mass. 
The jp2 solder pad above has an extreme smal isolation gap,  just a few 0.01 mm ! 
And the mass plane around it has a small edge of the mask uncovered !
Almost impossible to avoid solder bridges.
Both of my Discovery board's suffered short circuit right out the box. I heard of at least 2 other cases.
This is a weak spot, i would say a design flaw. To fix it this i removed JP2 it's glued. Then carefully remove all solder from the 5V pad until all !  shorts are gone. Then re-solder applying absolute minimum solder.
Warning! the pad's are very skinny and easy rib off!
The Discovery document does not show reverse and over voltage supply protection
I used a diode against reverse polarity.
That can easily happen with the simple key less header connector.
 The JP2 must be glued again to avoid ripping it off .
Now i can use the external 5V . The easy way is avoid  JP2 and connect a wire to the 5V  pads at the power select jumpers.


2nd port connected over 10n C glued to oscillator Si5351a CLK2 pin6.
The new PCB design  CLK2 now with connector but no integrated ESD protection.


BAND_FMAX differs between 2 units

GBLC03c    protect both external connections 

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Next subject :  116MHz TCXO  for UT5JCW 144 XVTR in the K3

Upon my question about an option for a more stable l.o. in their fb XVTR's 
Transvertershop replied with a simple but clear  : NO  ;-)

so i had to do it myself and found the Rojon 116MHz TCXO on eBay
                                         
                             





The Rojon tcxo 116MHz from eBay does not fit on the very compact 144 XVTR.
After receiving the tcxo i had to act to make it work a.s.p. to prevent that this device end's up in the unvollendete box.
Added the TCXO on a small extension to the existing 144 band power control.   
 5V from the K3  I/O unit is token from the band-switch PCB so it is simple.
The XVTR is easy to remove 2 Dupont connectors 1 SMA 2 screws in the left panel.
The on-board 58 x 2 MHz oscillator is disabled by shorting the x-tal over R4.
A 4p7  to C10 / collector Q2  injects the external 116MHz. With R4 shorted,  Q2 is in hi-z , L2 can / must be tuned lower to adjust the level at C10 up to about the same i had seen with the on-board  oscillator.
The 144.000 tuning frequency is now almost exact and the K3 XVTR 2 offset is set to 0 again.
The frequency stability is upgraded to 0.1ppm  not drifting like with a simple x-tal.
The ROJON TCXO outputs a sine wave that is my DSO shows a nice Sinusoid shape
not that a pure Sinus shape is needed for an mixer injection signal.
More important is  spectral purity and stability.
That seems  very okay with the Rojan 116MHz TCXO The XVTR is now rock stable right after power-up and suitable for WSPR mode that needs a stable exact working frequency
For FT8 the original on board x-tal based l.o. is good enough.


 ---------------------------------------------------------------------------------------------------------------------
WSPR
first 630m USA after 10 day's
TimestampCallMHzSNRDriftGridPwrReporterRGridkmaz# Spots
 2019-04-22 21:02  VK7DIK  3.570141  -28  0  QE38cu  5  PA0O  JO33hg  16733  308  2 
 2019-04-23 03:52  KG5VRQ  3.570086  -17  0  EM30hf  100  PA0O  JO33hg  7974  38  1 
 2019-04-23 03:10  N1FXP  1.837994  -29  0  EL86xq  5  PA0O  JO33hg  7576  40  8 
 2019-04-23 02:20  KJ4IIH  1.838100  -13  0  EL88wv  10  PA0O  JO33hg  7395  41  2 
 2019-04-22 23:24  PA0O  5.366251  -27  0  JO33hg  2  W4ATV  EM64or  7195  295  3 
 2019-04-23 02:48  PA0O  5.366251  -26  0  JO33hg  2  W3PM  EM64or  7195  295  6 
 2019-04-23 03:58  PA0O  3.570151  -29  0  JO33hg  2  KX4AZ  EM83hw  7052  292  1 
 2019-04-23 03:58  PA0O  3.570150  -22  0  JO33hg  2  KM4RK  EM93  6945  290  4 
 2019-04-23 02:36  PA0O  3.570151  -28  0  JO33hg  2  K9AN  EN50wc  6829  300  5 
 2019-04-23 04:34  KC9NBV  3.570043  -21  0  EM69oe  1  PA0O  JO33hg  6827  43  4 
 2019-04-23 02:02  K0JD  3.570154  -24  0  EN62bv  5  PA0O  JO33hg  6589  44  3 
 2019-04-23 03:48  PA0O  3.570141  -14  0  JO33hg  2  WD4ELG  FM06  6577  291  3 
 2019-04-23 02:56  PA0O  1.838150  -30  0  JO33hg  2  WA3TTS  EN90xn  6316  295  1 
 2019-04-23 04:34  W8AC  3.570030  -13  0  EN91jm  5  PA0O  JO33hg  6311  46  12 
 2019-04-23 03:48  PA0O  3.570151  -25  0  JO33hg  2  W8AC  EN91jm  6311  297  4 
 2019-04-23 02:36  PA0O  3.570151  -29  0  JO33hg  2  WB2TNC  FM18nx  6245  292  4 
 2019-04-23 04:22  PA0O  3.570152  -28  0  JO33hg  2  W3BX  FM19qc  6220  292  1 
 2019-04-23 04:22  PA0O  3.570153  -28  0  JO33hg  2  NE3RD  FM19  6217  292  1 
 2019-04-23 04:22  PA0O  3.570169  -20  0  JO33hg  2  KD4IZ  FM19oo  6192  292  1 
 2019-04-23 03:50  WA3U  0.475635  -27  0  FM29co  5  PA0O  JO33hg  6130  46  2 
 2019-04-23 04:30  WA3DNM  3.570084  -20  0  FM29fw  5  PA0O  JO33hg  6089  47  5 
 2019-04-23 02:48  PA0O  5.366251  -12  0  JO33hg  2  KD2OM  FN12gx  5975  296  22 
 2019-04-23 02:48  PA0O  5.366251  -26  0  JO33hg  2  WA2ZKD  FN13ed  5973  296  17 
 2019-04-23 02:38  KA2ENE  3.570111  -23  0  FN13fe  5  PA0O  JO33hg  5965  48  6 
 2019-04-23 02:36  PA0O  3.570149  -26  0  JO33hg  2  KA2ENE  FN13fe  5965  296  3 
 2019-04-23 02:36  PA0O  3.570151  -25  0  JO33hg  2  N2NOM  FN22bg  5933  294  5 
 2019-04-23 00:18  PA0O  3.570153  -17  0  JO33hg  2  N2HQI  FN13sa  5912  295  5 
 2019-04-23 02:36  PA0O  3.570153  -22  -1  JO33hg  2  KC2STA1  FN22vx  5779  294  2 
 2019-04-23 04:22  PA0O  3.570152  -20  0  JO33hg  2  WA9WTK  FN42fk  5654  291  1 
 2019-04-22 23:42  WA9WTK  3.570062  -14  0  FN42fk  10  PA0O  JO33hg  5654  49  2 
 2019-04-23 02:52  VA1VM  3.570131  -15  0  FN85ij  1  PA0O  JO33hg  4934  53  2
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Comments

Writer Jordan said…
"Your post on the EU1KY antenna analyzer is fascinating, and I was impressed with the PCB layout services. It's clear that a lot of thought and effort went into designing the circuit board. As someone who's not an expert in PCB layout, it's great to know that there are professional services out there that can help with this process. Thanks for sharing your insights!"



March 6, 2023 at 11:57 AM
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