HL2 Serial interface to my homebrew amplifier

[dsolbe...@gmail.com]

I just finished connecting the serial output from the HL2 to my homebrew 1KW solid state amplifier, which uses an Arduino Mega microcontroller.

My thanks to Bill for providing me with the DB9 interface board!

I interfaced the Hardrock 50 interface board to a Raspberry Pi running Node Red, using a Silicon Labs TTL to USB converter. Node Red is a flow based programming application.  The server runs on the Pi and the user interface is a Web browser.  I had already replaced a Visual Studio application that I had been using to communicate with the Arduino in the amplifier with Node Red.  My overall goal is to eliminate as much as possible my dependence on Windows com ports.

I now have two serial ports, one to the HL2 and the other to my amplifier controller,  Attached is a screen shot showing the interaction between Spark SDR and Node Red. There is a Groupio forum for Node Red and Ham radio https://groups.io/g/nodered-hamradio/topics  There are over100 flows that other hams have developed to interface to radios, amplifier, tuners, etc.  I found one for my Elecraft KAT500 tuner, so I will be adding that functionality to my station control web page.

73 Don K9AQ

[Bill Cox]

Wow, that's awesome!  I'm in a rental and am trying to keep neighbors from getting upset about my 40 meter long wire antenna, so I'm keeping my power output to about 50W for now.  When we get a place of our own I want to build one of those amps.

73, Bill ak3q

--
You received this message because you are subscribed to the Google Groups "Hermes-Lite" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hermes-lite...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/hermes-lite/faf4abb3-f3ea-4fdc-9659-41c89240a76en%40googlegroups.com.

[dsolbe...@gmail.com]

Bill,

Again thanks for the DB9 board.  Building an amp like mine is not an easy project, and it is not a kit.  There are changes that I would make if I was doing it again.  Since you have experience with the Hardrock 50, you might want to consider building a Hardrock 500 instead.

73,

Don K9AQ

[Alan Hyde]

Hi Don

I'm a long time Nodered user (controls vineyard irrigation system using LoRaWAN controllers). I've just got my new HL2 and have been waiting months for my Hardrock 50 to arrive down here in Oz (still stuck in NJ airport). I would be interested in any more details you have about how you are interfacing Nodered with the amp and radio - what is the messaging protocol. Do I understand correctly that Nodered is brokering msgs between the radio and the amplifier?

73 Alan VK2ATW

[dsolbe...@gmail.com]

Alan,

Yes, Node Red is communicating with both the HL2 and my amplifier.   The HL2 sends out the FA CAT command.  You need to get one of the DB9 interface kits for the Hardrock 50 interface, which sets the correct TTL level.  I then used a TTL to USB converter to connect to the USB port on the Raspberry Pi that is running Node Red (you could also connect it directly to the GPIO serial pins).

I configured a node to parse the FA command.  My amplifier is a homebrew 1KW solid state and it has an Arduino microcontroller for monitoring and protection,. I wrote a desk top application, using Visual Studio, to monitor and control the amp.  Node Red was later used to replace Visual Studio.  When I wrote the Arduino software, I was running an Elecraft KX3 which has a serial port for interfacing to an external amplifier.  I used a CAT command that was unique to Elecraft, the band command, BN:  I send a BN; to the radio and it responds with the band number, which I then use to select the correct low pass filter.

I later replaced the KX3 with a K3, which also supports the BN command.  I am generating the BN command in 
Node Red.  I parse the FA command to get the frequency and then use switch statements to generate the BN command.

The other commands that I send back and forth from the amplifier to Node Red are just very basic serial strings.  

My Node Red flow is still a work in progress.  I use a FreqEZ remote antenna switch controller, which also runs on a Raspberry Pi, with a Visual Studio desktop console.  FreqEZ can communicate with a logging program or DX Labs Commander, using UDP XML packets.  I have added that functionality to my Node Red flow but it isn't working correctly.  I generate what looks to me to be the correct serial string but FreqEZ isn't accepting it.  Hopefully I can get that working soon.  There is some additional cosmetic work that I want to do for the buttons.

73,

Don K9AQ

[Alan Hyde]

Thanks Don...good to hear of your approach and success so far. I plan to start experimenting along the same lines while I wait for the amp to arrive. I have one of Bill's boards already so the pieces are slowly coming together. My rather vague aim is to have a shack dashboard hosted by Nodered with as many of the controls/switches/relays etc controlled from there, either automatically or manually. Also have as many variables, such as temperatures, monitored with alerts raised as appropriate. I'll start by getting Nodered talking to the HL2 using your TTL to USB approach.

Thanks again for sharing your experience to date.

73,

Alan VK2ATE

[DL1YCF]

Following all the discussions on how to improve the „connectivity“ of the HL2,
it should be remembered that protocol 2 has these „Alex words“, 32-bit words
that are stored in the FPGA and constantly shifted into a shift register, thus
providing 32 freely available I/O lines (one could equally well use I2C for this).

It would be straightforward to add such a 32-bit „HL2 word“ to protocol 1, and
I think it is also manageable to have these „i2c extenders“ on the Hl2 board.

On the software side, a universal GUI for setting all the 32 lines is
an over-load, but if there is some consensus of how to set the bits, say:

bits 0-15 have a different pattern for each band
bit 16 follows PTT state
bit 17 is set if the mode is CW

(and whatever you think is reasonable), then it is quite straightforward
to build this into SDR software (for piHPSDR, I can do this in 15 minutes).

Of course, for remote operation you have to make an interface from these
32 (TTL digital) outputs to whatever you want, but in principle you then
can do crazy things like switching a Drake L7 PA between „CW“ and „SSB“
mode (high and low anode voltage).

So I think to have two MCP23017 (just as an example) on the board which
are loaded with a 32-bit pattern that is in the protocol would open up
a very versatile "universe of connectivity“.

Yours, Christoph DL1YCF.

[Alan Hyde]

Christoph

What you are describing is just beyond my level of knowledge I'm afraid, FPGA's are still a mystery to me. I follow you in principle and I guess what is encouraging is the openness and expandability of the Hermes platform (which is one reason I went this route). I think with tools like Nodered, the Hermes, what Bill is planning with his new board and I2C interface, all sorts of possibilities await us!

73

Alan VK2ATW