Hello Hans-Jürgen,
The observed sawtooth looks like the phase wraparound of the VNA that you use for your frequency measurement. Each time a step from +10Hz to -10Hz (or vice-versa) occurs, the real frequency curve just continues to go up or down. There should be an option in your software to show the unwrapped frequency.
I used the same VCTCXO in my 40MHz PLL, it didn't show any such non-linear effect.
73 Jean
Hi Tjalling,
Thank you for your interest. The documentation file size is too big for a forum attachment, so please drop me an email (dj0vl@gmx.de) and I will send you the sketch and some documentation.
73 Jean
PS: This applies to everyone else too: If you are interested in the LMP92066 programming sketch, please contact me by email.
Hi Alberto,
By applying 12V to the RX, you may have fried the input transformer, which has a DC connection from input to ground. There is a ESD suppression diode at the RX as well that may be damaged. Both parts are on stock at digikey.
73 Jean DJ0VL
Hi all,
Please send me an Email if you are interested in the programming software for the LMP92066 and the documentation.
The documentation is available in German/English/French.
73 Jean
You can describe how you did it.... ?
73 de Robert
Hello Robert,
It's a small sketch running on an Arduino Nano (or Raspi Pi Pico with small adaption). The Arduino connects to the LMP92066 via testpads on the board. Some commands send to the Arduino by a terminal program read/write registers of the LMP92066. The main task was to read and understand the datasheet and to figure out the I2C wiring on the board 
In case of interest, I can publish the sketch and some instructions for use (in German).
73 Jean
Display MoreHello Jean,
thank you for your answer.
No, I was referreing to the board with the BLC9G27XS-380AVT transistors.
Kind regards
Matthias
Hello Matthias,
Ok, my assumption was wrong - sorry.
Looking at the picture, your PA might use a LMP92066 for the bias voltage generation.
I've written a tiny tool for the programming of those LMP92066, adjusting the bias voltage and the LUT of the peak transistor was no big deal (at least with my BLC9G22XS-400AVT PA).
73 Jean
Hi Andrea,
Good luck with the modification. Please email me if you need to reprogram the digital potentiometer.
I'm not yet done with HF modifications. Without any changes to the signal path, the small signal gain at 2.4GHz is some 3dB lower compared to 2.6GHz.
73 Jean
Hi,
My DC bias modification for the BLF8G27LS-140V is quite simple. I removed two resistors in the bias path of the peak transistor (marked as ‘1’ and ‘2’ in the attached picture) and connected the bias by a wire (endpoints marked as ‘3’ and ‘4’). The wire connects the switched bias voltage to the peak transistor’s gate.
I guess that it would be possible to change the potentiometer range to the desired value by reverse engineering of the bias circuit, however I’ve chosen the simple way. The transistors seem to be well matched, as their bias currents are nearly identical with their gates connected in parallel.
73 Jean DJ0VL
Hello Matthias,
I did some bias-adjustment tests on the PA that was sold as „ …4x BLF8G27LS-140V – STEREO ..:)“, assuming this is the PA we are talking about.
This PA uses a programmable 8bit potentiometer for the bias adjustment of the main and the peak transistors (as part of an analogue temperature compensated bias network). Unfortunately, the programmable bias voltage range of the peak transistor is limited to 0.4-0.6V.
As the PA uses the same transistor type for main and for peak channel, I simply connected the bias of the peak transistor in parallel to the main transistor and set the bias current to 1A per transistor.
73 Jean DJ0VL
PS: the other PA (2x BLC9G22XS-400AVT-2) that use the LMP92066 for the bias generation can be programmed to set the peak transistor to mode AB without any hardware modification.
Hallo Patrick,
Ok, dann hast du sicher auch schon in den Windows Sound-Einstellungen die 'Lautstärke' des Mikrofons auf Maximum gesetzt. Du hast oben nicht geschrieben, welche Werte die ALC-Anzeige der SDRC erreicht, vermutlich dann auch weit von 100% entfernt?
Der Indikator bei Vox-Gain im TX-Fenster zeigt dir den Mikrofonpegel, wie er von Windows geliefert wird. Der sollte auch deutlich ausschlagen. Ich habe auch mindestens ein Mikrofon, das über den Analogeingang am PC zu wenig Pegel generiert. Mit mehreren USB-Mikrofonen (z.B Sennheiser PC8 oder analoge Mikrofone an einem Behringer UM2) habe ich unter WIndows10 kein Pegelproblem.
In den Windows Sound Einstellungen erreiche ich beim Mikrofon Test bei eingestellter Lautstärke von ca. 50 auch nicht mehr als 30%, beim normalen Besprechen sind es eher 10-15%. Mit +10dB Microphone Boost in der SDRC reicht das locker aus.
Du schreibst oben, dass du mit einem CW-Signal den Level der PSK-Bake erreichst. Mit deiner PA/Kabellänge/Spiegelgröße solltest du mit einem CW-Signal fast den Level der CW-Baken erreichen, selbst wenn das POTY-Feed nicht optimal auf zirkulare Polarisation abgeglichen ist. Dann kannst du zumindest den HF-Pfad als ok ansehen und das sollte bzgl. HF auch für ein verständliches SSB Signal ausreichen.
73 Jean DJ0VL
Hallo Patrick,
Hast du schon versucht, in den Sendeoptionen unter "Audio -> Gains" den "Microphone Boost" hochzudrehen?
73 Jean DJ0VL
Ja, das ist korrekt. Um die Inhaltssprachen Deutsch und Englisch gleichzeitig zu sehen muss man jedoch eingeloggt ist. Als Gast kann nur Deutsch oder Englisch gewählt werden, nicht beides gleichzeitig.
73 Jean
Hallo Armin,
Die Beiträge sind noch alle vorhanden, vermutlich hängt das Problem mit Javascript resp. der eingestellten Sprache zusammen.
Möglicherweise musst du auf Englisch umschalten, um die restlichen Beiträge zu sehen.
73 Jean
Hi,
The main issue with the W3PM based design is the usage of fractional-N mode for the correction of the Si5351a output frequencies.
There have been several discussions showing that a clean output cannot be realized when using an Si5351 in fractional-N mode (as required for the frequency corrections with this design).
An Si5351running with integer mode is able to generate 25MHz and 40Mhz with a signal quality that is good enough for QO-100 operation.
73 Jean DJ0VL
Hi all,
I do not own nor intend to buy a DX-Patrol groundstation. This said, I would be disappointed seing an offset of 200Hz between RX and TX with a setup claiming to be GPS locked.
In principle, the ADF4351 can be programmed to output the exact frequency for generating the LNB LO of 10057,0 MHz as required for an IF of 432,5 MHz. The trick is to calculate using fractions and not trying to solve the fraction.
According to the datasheet, the output frequency of the ADF4351 calculates to RFOUT = fPFD × (INT + (FRAC/MOD))
Assuming fPDF as 10Mhz, 1650.379487xxx MHz can be generated exactly (meaning exactly 64 * 10057/390) with e.g. INT=165, FRAC = 37 and MOD = 975.
73 Jean DJ0VL
Hi Peter,
On the NB-Transponder, the signal seemed to move in from lower frequencies, see the noise level shape. A few seconds after taking the screenshot, a huge signal (20 or more carriers spread around 100 kHz) swept in from the lower band end. Unfortunately, the signal was shut down before I could make another screenshot.
73 Jean DJ0VL
Hi Peter,
The incident was also visible on the NB-Transponder where all signals - including the beacons - faided away for some 30 sec.
73 Jean DJ0VL
Hello Rene
Thank you for the details on your nice setup with a Raspi for the beacon generation. For my test (I wanted to double-check the stability of a recently build homebrew GPSDO in addition to some ADEV measurements), I used my Pluto with just the SPF5189 driver into a 75cm dish with helix feed.
The reports given by Edson nicely reflect the output level difference.
73 Jean DJ0VL
Hi all,
My beacon transmission on Tuesday was just a short test for the stability of a new homebrew GPSDO. So far I do not intend to operate the beacon on a regular base.
Nevertheless nice to read that he signal could be received with 1-2 db higher SNR levels as I experienced with my 75cm dish.
73 Jean DJ0VL
Korrekt, es gehen keine 64K Einzelpakete übers Ethernet, der PC sendet jedoch mehrere 64K am Stück und damit gehen Pakete verloren, da zumindest meine Fritzbox 7490 Probleme mit der Flusskontrolle hat. Das sollte die Aussage sein.
73 Jean
