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.
Here are some pictures of the PCBs in the Xiegu G90 transceiver.
The Main unit.
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.
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.
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
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
I will not enter into
details on how to work with LQFP SMDs but, when you are removingthe STM32F103 use plenty of Flux.
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
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!
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.
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.
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.
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.
1 ianuarie 2021, 00:00 UTC – 31 decembrie 2021, 23:59 UTC
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,
Participantii pot alege una dintre cele 3
categorii in functie de puterea utilizata, indiferent de ce sistem de antene
HIGH POWER – Puterea maxima permisa,
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,
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
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
·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
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.
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
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.