My Retevis RT95
Some time ago, Martin, DO3MAC, gave me the Retevis RT95. It immediately replaced, for short,
my Yaesu FT-8900R. One thing bothered me: it only had an SO259 connector.
Since I didn't have a PL to N adapter, I decided to equip the device with an N socket.
I called “Funkshop Heerdt” in Meerbusch to ask if they had such sockets.
“Bring the device to me!” Okay, since I had to go to Krefeld anyway,
I got off the subway at “Bovert.”
I was there for a total of 90 minutes. The installation of the socket was done in a few minutes.
After that, we talked about all kinds of things. It's a very cool store with cool people.
In the end, I took an N plug with me. For another device (or antenna?!) :-)
“Okay, how much do you want for it?”
“€25 – that's fine!”
€25 may sound like a lot at first. But that was for the socket that was installed,
the installation, and the N connector. And a delicious coffee – so the price is fair!
The device itself is quite good. A few peculiarities (dual-watch-Function with only one VFO, etc.)
But the technical documentation is terrible. Presumably,
the device is only used by people/radio amateurs who don't enjoy tinkering.
By chance, I discovered the website of “Miles Hilliard".
And I think everyone who knows me realizes that I immediately tried to replicate this.
And what can I say? It worked. SSTV (controlled via VOX) worked.
I also received responses. But the “VOX” bothered me.
So I took a closer look at the plug:
(Image © by Miles Hilliard!)
Okay, wow. It's more than you would ‘actually’ need.
But what do you really need? Sure, audio output and input.
I connected that to a cheap USB sound card.
PTT. Awesome. I connected GND and PTT to an Arduino relay-Board.
But how to control it? I had an old FTDI adapter lying around.
I looked in the software to see how to control the PTT. RTS and DTR.
So I connected the relay to VCC, GND, and DTR. What can I say?
I clicked on “Test PTT” in fldigi and the device went on air. Without any ‘VOX’.
So I got two very cheap USB-C-FTDI adapters from Amazon. And it works fine!
So I did a few days of FT4 on 2M and some SSTV on VHF and UHF.
But I looked at the assignment again… “Serial-Data”.
Right, this thing can also be programmed.
I found exactly one page on this and just thought, “WTF?”
Yes. RX and TX were really connected together.
(For comparison: the serial port for the Yaesu FT8900R with an Diode to Split RX/TX!)
Since I couldn't/didn't want to believe that, I took my plug apart. And indeed,
the resistance value on the circuit board between RX and TX is 0 ohms.
But that won't stop me from continuing to build “my” cable 😁
What exactly did I plan?
Well, initially just some SSTV and maybe fax/CW/FT4 on 2m. That all works fine.
But ultimately, I just want to have a USB cable/socket that goes to the PC/Pi and an RJ45 plug
on the other end that goes into the radio. This would allow me to run all
modes and also program the device.
To do this, I adapted Miles' circuit diagram to my plan :-D
Continue? Soon :-)
