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My last Mailbag post has been some time ago. This does not mean i did not get some new items. AliExpress had (and still has) promotions where you can order (minimum) 3 items for around 5.99 Euro. This gave an opportunity to get several items below 2 Euro.Also some more expensive items where in my mailbag. I will split the backlog of my mailbag posts in several postings. Some postings are grouped around a topics so it will not be chronological. Also i will post some non electronic items. I will try to include some screenshots with prices. However price can change. Also sometimes what i actually payed is different (e.g. bundle discount). 

Small cheap shoulder bag.
It is a bit off topic, however as it is a nice cheap bag i decided to post this also on this mailbag bog post.

Two metal hobby knifes

Additional blades for the knifes (above)


This is a small cheap voice recorder with USB connector. It does not include memory, to use it an additional small SDcard is needed. The included internal LiPo battery can be charged via USB. Also the (not included) SDcard can be accessed. It has a small on/of switch to start and stop recording and also a status led. 



Waterproof (power) connectors. Don't know how waterproof they really are, however they where not expensive and look nice.

Some RF connectors ( BNC to SMA )




Two different sized telescopic antenna's. The long antenna was a bad buy. They are usable as antenna, however they are not very mechanical stable.  When using the long extended antenna the mechanical force became to big and it broke.  

Two PIR motion sensors

Mosquitto / MQTT

One of my first experiments starting with DigiPi on my Raspberry Pi 4 was to install MQTT ( Mosquitto )  

sudo remount

sudo apt-get install mosquitto
sudo apr-get install mosquitto-clients

sudo systemctl enable mosquitto
sudo systemctl start mosquitto
sudo systemctl status mosquitto

The commands above gave no special problems. To using mosquitto over the network additional setup is needed. This protection only demonstrates attention to safety of DigiPi. 

mosquitto -v 

1700517586: mosquitto version 2.0.11 starting
1700517586: Using default config.
1700517586: Starting in local only mode. Connections will only be possible from clients running on this machine.
1700517586: Create a configuration file which defines a listener to allow remote access.
1700517586: For more details see https://mosquitto.org/documentation/authentication-methods/
1700517586: Opening ipv4 listen socket on port 1883.
1700517586: Error: Address already in use
1700517586: Opening ipv6 listen socket on port 1883.
1700517586: Error: Address already in use

Local test

As (local) test i typed in a terminal screen (i used the browser terminal) to subscibe to mytest 

mosquitto_sub -d -t mytest

In another screen (for this i did log in using putty) i published "demo" to mytest

mosquitto_pub -d -t mytest -m "demo"

And got the expected response !
Perhaps i will later on use MQTT in combination with DireWolf
To use mosquitto over the network additional setup is needed. This protection only demonstrates attention to safety of DigiPi.

IntroAs i have a HAM licence I was looking for HAM software for my Raspberry Pi 4.
What often pops up is DireWolf, not the animal or the game!DireWolf is  “Decoded Information from Radio Emissions for Windows Or Linux Fans”)  and was developed by John Lagner, WB2OSZ. As the name implies it can run on PC's and even a Raspberry Pi.
Also i found DigiPi ( www.digipi.org  https://craiger.org/ ), the KM6LYW Radio DigiPi Project
DigiPi is a hot-spot for all amateur radio data modes, including APRS, ax.25, winlink email, ft8, js8cal, slowscanTV, PSK31, packet and even CW.  The implementation is an elegant, inexpensive, low-power, open-source Raspberry-Pi--based amateur radio data transceiver, managed exclusively by web browsers or smart-phone apps, with no bulky keyboards, monitors or complicated wiring.  At the digipi.org website you can download an image for the raspberry pi with the options mentioned above already installed (including DireWolf and a web-interface.
At this moment (november 2023) the DigiPi image is behind a paywall, and the password is available to patrons on the KM6LYW Patreon Page. Anything gets you access to the DigiPi image, even a dollar. According to KM6LYW the point is not to keep the software locked up, but to ultimately throttle the  questions and support load.  Plus it gives priority access to design  decisions, code contributions and early releases. DigiPi is community driven  and open source.
I made a small contribution and could download the image and put it on an sd card for my Raspberry using BalenaEtcher. (Also other sdcard writing tools can be used.)
I did not yet connect a ham radio and wanted to experiment with the software on my Raspberry and am interested in DireWolf and a sdcard with DigiPi seemed a nice way to start.
Also (as i am just starting up my HAM activities) i do not have one of the many transceivers on a list, that can be connected directly via USB to the DigiPi, however it also possible to interface over audio.  For experimenting i recommend to plug in a USB audio device in the USB (perhaps in the beginning with nothing connected) as the software does sense if no interface is available and in that case it will not go to some options.

The installation

There is sufficient info available to make the system work, however i had some special wishes and also wanted to experiment.
I want the network connection running over the wired ether-net interface, not over Wifi. Also i like to run some other software (The Mosquitto MQTT server) and perhaps later interface this with DireWolf.
Therefore i connected an ether net cable to my LAN and booted the system.
The DHCP server of my home-network did give the IP to the ether-net connection of the system. (The IP address of the Wifi is managed by the DigiPi).
What i did and not every time will mention is that installed parts needs to be activated (by (re-)starting the service or a reboot of the Pi). So see this as a general guide not an exact list of commands that always will work for you!

Timeserver / nameserver problem

I noticed the date and time on my pi where not correct.
Over the wired network i could reach the system  (using hostname  "DigiPi" or the IP address)
I did try to configure ntp, however i did not find the configuration files.
I made the decision to install ntp using "sudo apt-get install ntp"
However i did not succeed as the nameserver was missing and sites on the internet could not be reached by name.
At the bottom of dnsmasq.conf is 

#craiger hotspot stuff

#AutoHotspot Config
#stop DNSmasq from using resolv.conf
no-resolv
#Interface to use
interface=wlan0
bind-interfaces
dhcp-range=10.0.0.50,10.0.0.150,12h

I changed changed no-resolv to #no-resolve and after this domainnames on internet could be resolved.

Now i could install ntp using "sudo apt-get install ntp" however i did not investigate the  system sufficient !! :
During ntp install i noticed removal of "chrony" and that is (a better) alternative for ntp.
I expect the time was not updated as the timeserver on internet could not be reached by chrony. So better not install ntp !
At this point i could go back and create a fresh sdcard and i am sure i will need to do that some time however
 "sudo apt-get install chrony"
gave me back chrony and i noticed the date and time where now correct.

Some links:

• http://www.digipi.org
• https://craiger.org/digipi
• http://discord.gg/3X9bMjjwxw        (DigiPi live chat)
• http://groups.google.com/u/2/g/digipi     (Primary group/mailing list) 
• http://groups.io/g/digipi/     (old/depricated list, with some good info)

to be continued

A new mailbag post with some backlog mail.
(I planned to post this July mailbag begin Augustus, however it is already end August and some new interesting products have arrived for my next mailbag blogpost.

USB External soundcard.

As i want to experiment with audio signals i did buy an external to protect the sound chips of my computer


USB External soundcard.

Another sound card.
I was happy to have ordered 2 different cheap soundcards as my first experiments where more successful with this card that with the other one.

USB receiver
QRP Tranceiver Connectors More connectors
Nice storage bag for cables Cheap bluetooth USB led strip

A review of this product was already published on my blog
https://blog.jeronimus.net/2023/08/bluetooth-usb-led-strip.html

Air T split with valves

I want to make a ventilation system in my new shed using the Inline Blower.
This is a T splitter with 2 valves for the ventilation system. This corner pieces also to use for ventilation system Some more valves for the ventilation system Cable binders (black) Cable binders colored Heatshrink, always good to use for electronic projects, you can never have enough More connectors Connectors with a small cable Portable antenna
I hope to make a dedicated blogpost about this antenna  y Dupont / crocodile clip cabes
Mosquito killer lamp
And even more connectors