Building the test node with Ansible and Debops

Ansible and Debops

I spent some of my early professional years doing what is now known as ‘DevOps’. As well as developing software for data communications products like X.25 Packet Switched Nodes, I also developed test harnesses, build tools etc. Thus, I have always been drawn to tools that ease the process of building, configuring and managing software devices.

I came across Ansible some years ago and adopted it for my personal needs (I stopped developing software professionally about 25 years ago, but still ‘tinker’). Therefore it was natural that I would seek to leverage Ansible when building a packet node.

More recently, I came across Debops, which is a suite of ansible playbooks focused on the management of secure Debian-based [Linux] environments. This includes the Raspberry Pi that I intend to use as the hardware platform for the nodes.

The reason for this sidebar is that I have chosen to create Ansible Roles for each of the software components and distribute them as an Ansible Collection. By using Ansible to manage the node, I can ‘cookie-cutter’ additional nodes and manage their configuration centrally.

NB: The AWX Project is a trademark of Red Hat, Inc., used with permission

Getting back into Packet Radio

Background

Way back in the 80’s and 90’s I used to be very active on packet radio. I had a well-equipped shack in the good location (VHF-wise) and had links on VHF and UHF (70 cm and 23 cm).

As always, of course, life got in the way and I had to pack (sorry) all the packet stuff away. Then I moved to a new location down by the river here in St Neots with ridges on the west and north sides. The result is very poor VHF/UHF. I can get into my local repeaters – GB3OV and GB3PI – but that’s about it.

I’d pretty much forgotten about packet until I got involved with OARC during the COVID Lockdown. OARC has a very active Discord server with two channels devoted to packet radio. The result was a re-awakening of my interest and hence – eventually – this project.

What am I trying to do?

If you look at the Packet Link Map, you can clearly see that St Neots is in a bit of a desert as far as RF links are concerned. Apart from GB7BED, there’s nothing in VHF or UHF range, so the idea is to put something up that will serve the local HAM community and extend the UK Packet Network.

I’ll start with a test node that has local 1200 BPS access on VHF and Internet links to the rest of the network. Once this proves the concept, I’ll build a second node that will (hopefully) be located in a better location. If this is successful, I’ll add a 70cm 9600 BPS link and maybe an HF 300 BPS link. The latter will most likely be delivered via my Remote Shack

Updated Photographs of the remote shack

Here are some updated photographs of the remote shack.

This is a general view of the outer cabinet at the farm. Yes, it is on a slight slope.

With the outer doors and lid open, you can see the inner cabinet in its bubble-wrap blanket.

With the inner doors open you can see the internal layout.

On the bottom floor is the radio’s power supply, the UPS and the cabinet heater. Above that is the control board with all the electronics; and above that the Flex.

A not particularly interesting picture of the antenna; showing the fiberglass mast and the ATU board with ATU and the box containing the power take-off for the ATU.

Not shown in this picture is the antenna disconnect.

Remote station update

I realize that it’s been some time since I updated this blog.

The project is still active, but has been suspended due to the weather.

The station is running nicely in my back garden
The site has been surveyed and is suitable
The hold-up is the antenna:
- It’s going up in the trees
- I decided to wait until the leaves were off the trees
- By that time, the weather was appalling and ground too boggy to walk over.

I’ve had to postpone until the weather improves. Unfortunately, I will be overseas for several months, so we’re looking at June.

I’ll need to go with a simpler antenna and revise later.

Setting up a Remote Station – part 13 The Installed Station

The main image shows the installed station – but still in the garden. The top shelf has the Flex 6400 on it, the middle shelf the control system and the bottom has the UPS and power supplies. Hopefully, this will cut down on noise induction.

This image shows the control board before being installed in the cabinet.

Top left is the ancillaries board with an input jack from the ancillary 12V PSU, a couple of Power Poles to feed other 12V devices, the ESP8266 running ESPHome and code for the environmental sensors – an on-board Temp/Humidity sensor for the internal cabinet, and two 1-wire temperature sensors that will be placed in the space between the two cabinets and outside. On the far right is the Teltonika RUT951 router. In the picture it has its internal aerials on, but in the field it will have the 4G antennas and one of the wi-fi antennas connected to external antennas.

Below that is:

The Sonoff 4ch switch which controls the Remote On/Off and PTT on the Flex, and the 12V power to the remote auto ATU (not shown)
The Geekom Mini IT8 Windows PC
The Netgear Ethernet switch, and
The Raspberry Pi4 in its smart Argon One case.

Not shown in this image are any power leads. Also not shown in this image, but visible in the main one, are the two Tapo wi-fi switches that control the mains input to the main 12V PSU and the PC’s PSU. The switches are on the middle shelf in case the wi-fi doesn’t penetrate to the bottom shelf. I’m going to try them in the bottom today.

The station is now built, but I’m going to leave it in the garden for a week or so to accumulate sensor readings so I can decide if I need to add forced cooling. It will be located against a north facing wall, so won’t get any direct sun. It’s in a similar north-facing position in the garden, but will get a bit of early morning and late afternoon sun for the next week or so.

Setting up a Remote Station – Part 11 Screenshots

I thought I’d add some screenshots of what the control UI looks like.

The one above shows the main screen with the various controls on it. Only two need to be touched in normal circumstances: the Radio Control button and the Windows PC button. These both kick off automations that sequence through turning things on or off – they don’t control things directly.

At the top of the screen are a number of tell-tales that indicate the state of various components, plus basic propagation information.

You can also see the lightning detector and some elementary status info. if Blitzortung reports lightning within 25km, a script runs that sends a Pushover alert, waits a couple of minutes and then kicks off the Radio Power Off script as if the user had tapped the Radio Control button.

Lastly you can see the state of the ATU, you can toggle the Lock function on the ATU to disabled the auto-tune function, and see whether it is tuned or not.

This image shows more comprehensive propagation info.

Lastly, you have a screen with some system status information.

There are more screens accessible via the side menu bar, but these three cover 90% of what’s needed. I’ve seen some remote control screens that are, in my opinion, far too crowded with irrelevant information. All that does is hide important information and controls and overwhelm the user with noise. (again, my opinion).

incidentally, all these screens are produced using the standard controls provided with Home Assistant, plus some useful ham-related plugins (e.g. Blitzortung and HF Propogation)

Setting up a Remote Station – Part 10 Overview of the Final System

Hopefully the image above should help to understand what the station consists of. The station comprises:

a 240V network with the UPS at its core and feeding:
- two Tapo switches (one for the PC and one for the Radio PSU);
- the permanently-on auxiliary 12V PSU that powers the Sonoff, network switch and the ATU controller; and,
- the permanently-on PSUs for the Router and the Pi-based Station Controller.
A mixed wired and WiFi network connecting most devices.
The main Radio PSU – Flex – ATU – Antenna Disconnect RF chain.
The Sonoff that switches the Flex on and off and operates the PTT when needed.
The Pi-based Station Controller running Home Assistant.
The Windows 10 PC used for digital modes.

I hope this all make sense.

Moving on, the station has been operating from my home QTH for some time now whilst I scout out a suitable remote location. I’m glad to say that a local farmer has agreed to let me site the station on their land. The only downside is that the station needs to be outside, so I now need to source a suitable IP65 or IP66 (but ventilated) wall-mounted cabinet to house it all in. Not easy to find!

For the antenna, there is a convenient line of trees close by and a 10m high barn; to which they have agreed I can mount a 20m pole to be one end of the doublet antenna I intend to use – the other end being one of the trees. With luck I’ll be able to erect a decent doublet at 20m off the ground and fed by balanced feeder from the SG-230; which will be mounted 2-3m off the ground at a convenient location midway between the ends of the doublet – probably somewhere on the wall of the aforementioned barn. I’ll use a 12V combiner to feed power to the ATU and the antenna disconnect unit.

Setting up a Remote Station – Part 9 Nearly Complete

Let me start with an apology. This site has been off the air for some weeks due to a server move initiated by my hosting provider. They gave me plenty of warning, but unfortunately the move took place whilst I was away and unable to react. Hopefully all is well now.

Nearly complete

It’s been some time since I last posted on this topic because I have been away on an extended trip. However, I’m back now and am now very nearly (hopefully) at the point where I can move the completed station to its new location. Since the last update, I’ve been able to:

Resolve the networking issue I grappled with in the previous post by adding an intermediate Ethernet switch.
Rebuilt the Station Control Computer to run Home Assistant on its preferred operating system – Home Assistant OS. HAOS is a stripped down Linux built using BuildRoot: which is optimized for embedded devices.
As a consequence, I’ve also migrated a couple of the additional systemd services I used before, to use Home Assistant Addons, viz: The code to monitor the UPS, the code to monitor the Pi, and the code to control the fan in the Argon40 case I am using. For the UPS, I am now using NUT rather than APCUPSD. This forced me to change the code in the Windows PC as well.
I’ve also added integrations to display the current RF conditions and provide warnings of any local thunderstorms.

My main tasks still outstanding are:

To source an auto-disconnect for the antennas.
To build a 12V injector to feed power to the SG-230 ATU that will be located at the base of the antenna.
To enable the MQTT service on the router, so it can report status to Home Assistant
To work on the Home Assistant dashboard that will be used to control everything.
Develop automations to disconnect the antennas and power off the ATU if lightning is detected close by, or when the radio is off.

Once I have fixed the final location I can also:

Decide on what is needed to house everything, which will also let,
Lay everything out on a plywood base board,
Finalise cable lengths and source screened cables for everything.

So, actually there’s quite a lot still to do.

In the next post, I’ll summarize where we are and include some diagrams that should hopefully make everything clearer.

Romahome Pictures

New Antenna System – pt 2, What?

See https://wp.me/p4spp6-ih for part 1

I started off by seeing how I could get the best from using the fibreglass mast in the middle of the back fence. Unfortunately, the internal angle would be too small for a dipole erected in a horizontal Vee, so that left me with 13m to play with. Not much.

I could put a 30m dipole in (with the ends drooped) and could then have 20, 17, 15, 12 and 10m dipoles in a fan; but this would be a nightmare to set up, and the weight would probably be too much for the fibreglass mast . Also, conditions are still declining IMO, so I really want 40m (at least).

Luckily, a change in the garden provided me with more options. We’ve just put in a new shed in the bottom SE corner of the garden, and this gave me the idea of mounting a pole on the end of the shack (B on the plan) and another on the end of the shed (C on the plan). Add in a stub mast on the gable end (A) and I now have 36m to play with (albeit in an odd shape). Plus, the middle is roughly above the shack (see plan).

80m Doublet

This led me to the antenna I am actually building: an 80m doublet (with one drooped end) fed with ladderline from the shack. One side runs in a straight line from the gable end (A) to the shack (B). The other runs at right angles to the shed (C) and then back to the house (D). I’m going to model this to see if there are any reasons not to follow this path, but it looks good.

Tuner

The problem of course is that I really need a balanced tuner for this to work. Even without modelling, I foresee that the feedline will be unbalanced because of the odd shape. Putting this straight into an unbalanced tuner would be foolish. However, I do have the SG-230.

What I am doing is to install a 1:1 Guanella (Current) Balun on the end of the ladderline and connect the unbalanced output direct to the SG-230. The Balun should force the ladderline to be balanced and reduce radiation from the ladderline.

Provided the impedance swing is not beyond the capabilities of the SG-230 (and I’ve no clear idea of what those are), this should work. As the tuner will now be “hot” I’m installing an RF Choke on the coax from the tuner to kill any RF that wants to go down the outside of the shield.

The next part will cover building the antenna.