31 decembrie 2020

Trick to protect the RJ45 connector tab

 Many transceivers have RJ45 connectors on the microphones and many of them broke at transport or even in the storage box when searching for stuff.

I do have a well equipped laboratory with all kind of stuff, including the proper tools to repair a broken RJ45 but... I do have a problem with colours! Yeah, I barely can distinguish between red and green, at least the red and the green used in wiring. And in resistor code. Traffic light pose no problem, I can see that green and that red so, no worry with me on the streets at the same time with you, HI.

So, I thought myself it's better to prevent than to cure (this came with the age, probably) so I searched for a quick, cheap and reliable solution to protect that little shit tab.

An ideea popped out from the void and here I am, making protective caps from some piece of heatshrink tube.

Find a suitable HS tube, put the connector inside it; the HS tube has to overpass the tab with around 3mm not more!

Then gently apply heat observing the molding. When it wrap the connector stop heating and cut the useless part outside the connector.

After that, gently move the HS tube to extract the connector.

And this is all... 

I suggest to use a dummy RJ45 or some kind of ethernet cable as a jig. 

Do not heat the HS tube with the real RJ45 inside, you may mess it up and cry a lot.

20 decembrie 2020

HiRes pictures from the XIEGU G90 transceiver

 Here are some pictures of the PCBs in the Xiegu G90 transceiver.

The Main unit.

        Control board.

PA RF Board

Reverse voltage protection detail

NTC (Negative Temperature Coefficient resistor) problem
There is a serious gap between the NTC which compensate the bias for the temperature increase and the PA RF transistor case. This is one potential cause for premature failure in the final stage especially in TX intensive modes like FT8.
The solution is to gently bent the pins of the NTC to make physicall contact between them and apply a small blob of thermal silicone GLUE, not usual paste.
This will prevent a future gap due to vibrations or shocks and will increase the mutual temperature transfer thus an adequate bias voltage. 



Schematic (work in progress)

-I removed the schematic as I found error in the AIC3204 area and I must redraw it. I will find a way to have it updated.

19 decembrie 2020

Xiegu G90 External Speaker modification

I like to hack the radios to add new features or to enhance the features already existing.

After playing a while with the G90 I found necessary to have an external speaker because the internal one, altough really loud, it lacks low frequency response.

Trying to connect an external communication speaker gone nowhere because the signal was too weak.

I do have some amplified speakers but I don't want to complicate the setup so, more gain was needed.

Therefore, I opened the Main unit of the radio and start looking inside.

To my surprise, the audio is routed from the LM386 audio power amplifier to the internal speakerphone or to external headphones  with a nice SMD relay. 

When the signal is going to the outside world (a.k.a) Headphones, a 100 Ohm resistor is in series with the HP which explain the low signal. 

I replaced that with 3 10 Ohm in paralell to have some sort of

load in case we shortcircuit the HP Jack. And this is very probable because the signal is going to the tip and to the ring of a stereo 3.5mm Jack. 

This is made to accommodate the usual Stereo Headphones every Chinese ham can buy from Shenzen.

Now the radio has external speaker without too much trouble. 

Because I am using modified Kenwood HS-5 Headphones the audio level is OK.

73 de Adrian yo3hjv @ December 2020

Xiegu G90 - reflashing Bootloader into Front panel microcontroller

After inspecting the Main unit of a brand new Xiegu G90 transceiver for some mods with the Front panel removed, the radio got into a fatal failure.


After separating the Front panel from the Main unit and reconnect it, the front panel shows: "Comm Lost" in red and no feedback from the panel to the Main unit was possible.

Hardware investigations showed 0 (zero) Ohm (Shortcircuit) between the Main unit (Tx UART) to Front Panel (Rx UART). Removing the Front panel, the shortcircuit was still present on DB9 pin#3. After breaking apart the Front panel case, the DB9 pin # 3 was traced directly to PA10 – USART 1 Rx on STM32F103RCT6 (LQFP64) microcontroller.

A higher current than usual was observed on the Power supply ammeter (around 100mA increase over the usual consumpition) and the chipset was hotter than usual.

A small cut was made on the PCB right near the uC to confirm the problem is on the chipset itself and that was confirmed by measuring it with a DMM the resistance between Pin # 43 and Pins#18, 31, 47, 63.

A replacement STM32F103 was ordered from Reichelt.


1.       Some  pre-requisites;

a.       Digital Multimeter

b.      Fine tip tweezers

c.       Various type of screwdrivers

d.      Magnifying  glasses and microscope

e.      Hot air soldering/desoldering station

f.        Fine tip soldering iron

2.       Must have:

a.       Desoldering braid

b.      Soldering flux

c.       4 pin male header straight in line 

d.      ST-Link V.2. A clone will do the job very well. 

e.      Some Dupont wires (female-to-female ones)

f.        A PC with 1 free USB 2.0  port.

g.       Antistatic wrist strap band.

3.       Software needed:

a.       STM32 ST-Link Utility - STSW-LINK007

b.      STM32 Cube Programmer   

I will not insist in dismantling the Front panel; it involves a lot of small screw and need a lot of attention to get to the bare PCB.


Please observe the ESD protection measures and wear the antistatic wrist strap; connect it to the GND of the Front panel PCB and use an ESD protected soldering iron.

There are some connectors there; the ones with flexible ribbon work by lifting the darker clips with the tip of the tweezer on both sides of the ribbon. Do not insert the tweezer between the ribbon and the locker!

The wired connector for the BAND UP/DOWN and MODE UP/DOWN has to be pulled from the PCB connector. Be gently with it!

Please, be carefull with the LCD and REMOVE IT before you start the work on changing the STM32F103! Put it in a small bag and forget about it untill you finished the job.

Use proper screwdrivers and keep track of the screw you removed.

I will not enter into details on how to work with LQFP SMDs but, when you are removing  the STM32F103 use plenty of Flux. 

Clean the PCB pads. Inspect them with a microscope or good magnifier for problems.

Carefully  place the new STM32F103 on the PCB paying attention to the pin numbering.

Clean the PCB with isopropillic alcohool. Better if you have an ultrasonic cleaning bay.

Now, it is time to take care about the connection to the ST-Link.

Near the RJ45 microphone connector there is a marked place for 4 pins in a single row. That is the SWD connector and there you must place a proper connector. I used a male connector but can me a female one.

Looking from the back of the PCB (opposide to the rotary encoders) and with the RJ45 connector on the right side, the 4 pins are on the lower right side and, from the left to the right they are:  Vcc (3.3 V),  SWDIO,  SWCLK and GND.

In the first stage, we will use the voltage supplied by the ST-LINK SWD (3.3V).

The Front panel is not connected to the Main unit!

Step 1:  Install the STM32 ST-Link Utility - STSW-LINK007 (https://www.st.com/en/development-tools/stsw-link007.html). Follow the instructions for registering the account on the ST webpage.

Start the program; Connect the ST-Link to the PC. Select ST_LINK > Firmware update.

Close the program.

Step 2: Install the STM32 Cube Programmer (https://www.st.com/en/development-tools/stm32cubeprog.html#get-software). 

Run it.

Step 3: Disconnect the ST-Link from the PC then reconnect ST-Link to PC.

Step 4: Connect DuPont female-to-female wires to GND, SWDIO, SWCLK and 3.3v on the ST-Link and then to the SWD pins on the PCB.


Step 6: On the STM32Cube Programmer, read the STM32F103 to check the connection. You should see a lot of FFFF's (here is an already programmed STM chip).

Step 7: On the STM32Cube Programmer, load the Bootloader .bin.

           BROWSE to select the file>

                   Check for the START address for writing the BL. Should be 0x0800000. Select "Verify programming".
            "Start programming"

The bootloader should be now programmed into the microcontroller.


This ends the first stage.

After this, carefully connect the DB9 connector to the Front panel.

Connect the Main unit to a power supply with 13.4 V.

Connect the DB9 cable to both Main unit and Front panel unit and proceed to normal FW update procedure as described on the Xiegu website (1.74 final).

Special thanks to Simon SA7SSE!

Thanks Konrad Beckman for SWD pinout: https://twitter.com/kbeckmann/status/1286574402268798977

and for G90 tools to extract the firmware: https://github.com/OpenHamradioFirmware/G90Tools

Maybe you want to see my findings about the hardware of this radio: https://github.com/yo3hjv/XIEGU-G90/wiki

 A nice lecture about good practice in ESD protection:


The former and the new STM32 chip:

The happy G90 with replaced LEDs:

Adrian YO3HJV @ December, 2020



13 decembrie 2020

RTL-SDR gain steps

 It was hard to find the gain steps for a NOOELEC SDR therefore i will put them here:




Generic SDR



























































03 decembrie 2020

Shack dual time Clock with POS VFD

A few years ago I came around a nice POS Vacuum Fluorescent Display.

The model I have is CD7220 and it is designed to show information about a customer purchasing  in a nice blue-green colour onto a Vacuum Fluorescent Display with 2 rows and 20 columns.

I put it on my bench and gave it a long look seeing on it's two rows a lot of possible things. From clock to some informations extracted from CI-V from my ICOM radios, various configurations scrolled in my imagination.

I started to search for some documentation and found the datasheet then started to look inside to see how it was interfaced with the POS cashier machine.

The VFD is interfaced via RJ45 connector and from the signal perspective, a HIN232 circuit handle the conversion between RS232 serial COM port to TTL UART. Basically, this circuit is a clone of Maxim's MAX232 RS232<>TTL level convertor.

To drive the VFD I choosed a small Arduino NANO; the RTC is a DS1307.

The backup battery, a rechargable Li cell was dead and I replaced with a 5 V/4F capacitor. This is enough to keep the time for some time when power is off.

Because the circuits in the VFD need 24V, I put inside a DC/DC boost convertor so I can power the board with anything above 5V and below 24V.  Yeah, I know, this is too big for this project but this was laying on my junk boxes here... You can use any boost DC/TS that can sustain 5W in a close box for extended periods of time.

The RTC module is connected to Arduino via I2C.

To set the RTC actual Time and Date I used the example that came with the DS1307 library; just upload it into the Nano and start Serial monitor.

After setting the Time and Date as above, use the code provided on the Github, insert the correct UTC offset for your region and then upload the code to Arduino.

The code is commented and it is self explanatory; before you upload it, check the correct offset for UTC. 

24 noiembrie 2020

Xiegu G90 firmware programming serial cable

 Ta daaaaaaa.....

This is the schematic of the Xiegu G90 firmware programming serial cable!

A simple FTDI USB<>TTL chip and a stereo cable with a 3.5mm Stereo audio jack. Simple and efficient.

The TTL level is 3v3.

Here is the schematic:

13 noiembrie 2020


 Very sad news just received from the daughter of John, ON4UN

It is with sadness, but also gratitude and pride, I have to let you know my father John ON4UN, has become silent key.

John’s health has steadily deteriorated throughout the year, but in the last few weeks he was home with us where he peacefully passed away yesterday November 9.

Ham Radio, and especially Low Band DXing, were my father’s lifelong passion and always had a strong presence in our house. Sometimes literally, when many of you paid us a visit or a group of DX’ers came over for a weekend of contesting. At other times in the background, when my dad was working on a project or experimenting with new equipment or antennas.

Though I don’t have a call-sign, I very much feel part of the big radio family and always will. I am very proud of everything my father has accomplished together with you, and I am grateful to the many of you who have given him so much joy over the years. We will miss him dearly, but we take comfort looking back on the beautiful life he lived as a member of the wonderful Ham Radio community.

We are planning a digital farewell ceremony on Saturday November 21st and will keep you updated on practicalities.

If you would like to send us a message please mail to ON4UN.SK@gmail.com – John’s old e-mail account is not in use anymore.

In the meantime, you can pay him a visit at QRZ.com where he always kept his resume up to date.

Marleen Devoldere


31 octombrie 2020

RaspberryPi + RTL-SDR iGate

 -Schimbarea frecventei de lucru:  sudo nano /usr/local/bin/dw.sh

-Starile iGate: sudo nano -c sdr.conf


-rtl_fm -f 144.80M - | direwolf -c sdr.conf -r 24000 -D 1 -

-sudo systemctl status direwolf

-sudo journalctl -o cat -af -u direwolf

-sudo systemctl enable direwolf

-sudo systemctl start direwolf

-sudo systemctl stop direwolf

29 septembrie 2020

2021 - BANDS ALIVE - O initiativa a True Blue DXer's Club

Un concurs intins pe un an; primul an al unui nou ciclu Solar in care ne asteptam ca propagarea in HF sa se imbunatateasca.

Fiecare legatura se adauga la punctajul care la final, in ianuarie 2021 te va aseza pe tabela.

Doar legaturi in CW si SSB, moduri de lucru "traditionale" in care ai ocazia sa
faci o legatura prin radio cu un ALT OM.

Se fac legaturi doar in benzile HF "clasice, 160m, 80m, 40m, 20m, 15m, 10m.

QRP - 5W PeP


HIGH POWER - Maxim din autorizatie.

Esti interesat? OK, uite, mai jos este regulamentul. Este simplu si clar. Oricine poate participa. Orice legatura conteaza. 

Fara incrancenare, este o cursa pe un an intreg, pastrati-va rasuflarea si faceti QSO-uri!

The True Blue DXers Club


“Bands Alive”

Ultra-maraton CW/SSB DX - 2021



Odata cu inceperea noului ciclu solar, conditiile de propagare in benzile de unde scurte (HF) sunt asteptate sa se imbunatateasca treptat pe parcursul anului 2021; aceasta noua initiativa este destinata sa ofere vanatorilor de DX-uri motivatia de a realiza legaturi si, drept urmare, sa sustina, sa imbunatateasca si sa promoveze activitatea radioamatorilor prin utilizarea modurilor de comunicatie “traditionale” ca telegrafia (CW) si fonia (SSB). Prin aceasta initiativa inedita, pe care o numim “Ultra-maraton”, ne dorim sa motivam operatorii sa realizeze pe parcursul intregului an legaturi cu indicative unice DX.

Perioada de desfasurare

1 ianuarie 2021, 00:00 UTC  – 31 decembrie 2021, 23:59 UTC

Moduri de lucru

CW si SSB. Intrebare: De ce nu si MIXT? Raspuns: din motive de simplitate. Pot fi utilizate diverse programe pentru log. Tinerea scorului si livrarea log-urilor se poate realiza cu o plaja variata de programe de concurs; nu toate suporta modul “mixt”. Mai multe detalii despre programele ce pot fi utilizate vor fi furnizate pe site, ulterior.


Participantii pot alege una dintre cele 3 categorii in functie de puterea utilizata, indiferent de ce sistem de antene folosesc:

HIGH POWER – Puterea maxima permisa, potrivit autorizatiei

LOW POWER – 100W maxim

QRP – 5W maxim


10, 15, 20, 40, 80 si 160 metri.

Intrebare: De ce nu si benzile WARC? Raspuns: Din acelasi motiv pentru care nu exista si participare la “mixt”. Mai multe detalii despre programele ce pot fi utilizate vor fi furnizate pe site, ulterior.

Scopul concursului

Orice participant la un concurs CQ WW DX va intelege scopul acestei competitii, care este acumularea de punctaj maxim. Spre deosebire de concursurile clasice ce se desfasoara pe o durata de 48 de ore,  acesta se desfasoara pe intreaga durata a anului calendaristic, din acest motiv este “Ultra-maraton”. Numarul de puncte se calculeaza astfel:


Scorul final este totalul punctelor din legaturi (QSO) inmultit cu suma zonelor si a tarilor (CQ Zones si DXCC). Ex:  1000 puncte din QSO  x (30 Zone + 70 tari DXCC) = 100,000 (scor total).


Statiile pot fi contactate o singura data in fiecare banda pe intreaga durata a Ultra-maratonului. Punctarea legaturilor se realizeaza in functie de locatia statiei cu care s-a realizat legatura:

·         Contacte intre statii pe continente diferite – 3 puncte;

·         Contacte intre statii din tari diferite, pe acelasi continent – 1 punct; Exceptie fac legaturile intre statiile din tari aflate in limitele Continentului Nord-American.

·         Contacte intre statii aflate in aceeasi tara – 0 puncte dar conteaza pentru multiplicatorii de tara si Zona.


Sunt doua tipuri de multiplicatori:

Zona – Cate un punct pentru legaturi cu fiecare Zona CQ diferita in fiecare banda. Sunt aplicabile regulile de la CQ Worked All Zones;

Tara – Cate un punct pentru legaturi cu fiecare tara diferita in fiecare banda. Lista Entitatilor DXCC, lista de multiplicatori WAE (Worked All Europe) ,  IG9/IH9 precum si limitele continentale sunt aplicabile in definirea multiplicatorilor de tara. Statiile maritim-mobil sunt punctate doar pentru multiplicatorul de zona.

Software pentru log

Participarea la acest eveniment poate fi posibila practic prin utilizarea unuia din programele existente ce sustin concursul CW WW DX. Aceste programe pot actualiza automat scorul la fiecare legatura efectuata si vor evita legaturile duble, vor indica ce Zone si ce entitati DXCC au fost deja lucrate, lasandu-va sa va concentrati pe ceea ce este important, efectuarea de legaturi.


Pentru a putea participa la Ultra-maraton, trebuie sa va anuntati participarea prin inscrierea in sectiunea dedicata a site-ului TBDXC. Participarea este deschisa tuturor radioamatorilor, nu este necesara inregistrarea in randul membrilor Clubului!

Dupa inscriere, trebuie sa alegeti in ce categorie participati indicand clasa de putere si modul de lucru. Acestea nu mai pot fi ulterior modificate.

Veti putea apoi incarca in baza de date rezultatele oricand veti dori (punctaj, entitati DXCC, Zone WAZ precum si scorul total, astfel cum este calculat de programul de log). Pozitia voastra in clasamentul Ultra-maratonului publicat pe site va fi actualizata de fiecare data cand veti incarca datele.


In acest moment, ele consista in certificate. Acestea vor fi atribuite primelor cinci statii din clasament pentru CW, SSB si pentru clasele HIGH, LOW si QRP. Vor fi atribuite certificate si primelor trei statii clasate in ordinea punctelor pe fiecare continent, pentru CW si SSB, indiferent de clasa de putere.

Suntem in discutii preliminare cu o serie de sponsori urmand ca, in situatia in care numarul de participanti va fi considerabil (de ordinul sutelor), sa putem oferi premii in echipamente de


Pentru majoritatea participantilor, legaturile din acest concurs intins pe o perioada de un an nu vor fi verificate. Cu toate acestea, competitorii care se califica in categoriile pentru care se elibereaza un certificat vor trebui sa furnizeze un log in format “adif” in cursul lunii Ianuarie 2021 care sa contina toate legaturile efectuate in cadrul Ultra-maratonului. Absenta logului va conduce automat la descalificare.

Logurile vor fi verificate de catre Comitetul de Concurs al Clubului care va solicita lamurirea ei de catre participant. In cazul in care participantul nu va putea lamuri problema sesizata de Comitet, acesta va fi descalificat.

12 septembrie 2020

"Soundcard I/O: Failed at 48kHz and 8kHz, giving up".

After playing with various Virtual audio "cables" and lot of tweaking I finally mess up the sound configuration. In the HamRadio Deluxe  I got this idiot error:

"Soundcard I/O: Failed at 48kHz and 8kHz, giving up".

I tried to find a solution on the internet, found a guy or two with the same problem but the answer he get was useless... Some even suggested to modify settings of the system pagefile! DOH!!!

So, i tried other applications/programs but all showed the same kind of error, that pointed to some impossibility to access the soundcard.

I will not enter in details because I now you want the easy solution...


1. Click the WINDOWS key (left, down on the keyboard).

2. Write "privacy" and you will notice a selection will occur. Choose "Microphone Privacy Settings". A new window will open.

3. In the new window, under the "Allow apps to access your microphone" select "ON".

Thats it!
73 de YO3HJV

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