News items for tag english - Koos van den Hout

2023-09-21 Upgrading the wifi at home: WPA3 personal, Wifi 6, guest wifi
I recently bought new wifi access points to upgrade the wifi at home. The main reason was the fact that the TP-Link TL-WDR4300 bought 9 years ago was sometimes 'hanging' which was solved by rebooting it. This was starting to get annoying, and the family wants stable wifi which doesn't need instructions which button to press for reboot.

The upgrade path was going somewhat 'prosumer': support for multiple wireless SSIDs with a main and a guest network, and I wanted an extra access point in the shed for working in the back garden, as tested in april Using the network switch in the shed as remote powerswitch.

The choice was to go with the Mikrotik access points. For the shed and garden I bought the and for the main access point in the house the hAP.ax3. The latter has support for the latest and greatest wifi standards, including wifi 6 and WPA3.

It took me a while to configure them, the Mikrotik routerOS userinterface exposes all the options networking in Linux has, but it takes knowledge of bridging, routing and firewalling to get it all correct and doing what I want.

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2023-09-20 Adding an RSS feed to my amateur radio site
A remark on triggered me: Quick reminder that there is a public RSS aggegator that combines all the ham radio blog feeds into one web site
Quick reminder that there is a public RSS aggegator that combines all the ham radio blog feeds into one web site:
And I wanted to add the latest from my site PE4KH Amateur Radio but there was no RSS feed available.

I've been wanting to add such a feed for a while but didn't get around to it. This was the trigger I needed. The perl script that generates the feed for has now been updated to allow for 'filtered' feeds for and other sites that have a specific part of the main feed.

And I moved the script to version control so I can work on it on the development server and deploy to production when it's working fine.

Update: you can now find my posts over there

The feed is now accepted and imported on PE4KH amateur radio -

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2023-09-17 I participated in the Scandinavian Activity Contest
CW contest filling the bands on a websdr This weekend was the morse edition of the Scandinavian Activity Contest and I decided to participate, mainly to get some more morse contesting experience.

I made 74 contacts, even some on the 10 meter band which cooperated Saturday afternoon.

Band      QSO   Points   Multipliers
80m          0       0       0
40m         13      13       9
20m         55      55      22
15m          0       0       0
10m          6       6       5
Total       74      74      36

Dupes:     0
Invalid:   0
QSO Total: 74
Score:     2.664 (Diff: 2.664)
BAND:      ALL

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2023-09-15 Attack attempts on sshd are back
Graph of fail2ban failed and banned in Grafana, showing a drop in banned IPs at the end of August 2023 and a rise starting 14 september 2023 I noticed two weeks ago the number of IPs causing failed sshd login attempts as measured by fail2ban was dropping. It was dropping so far I did some tests to make sure all the rules were still working.

Things have returned to 'normal' now, attempts are back and quite visible in the graphs.

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2023-09-13 I bought an RTL-SDR blog v4 dongle, and it's not working in Linux .. yet
A few weeks ago I saw 'buzz' all around about the RTL-SDR v4 dongle coming out: RTL-SDR Blog V4 Dongle Initial Release! and lots of people reporting clicking "buy now". I did the same, without even having a good reason to buy one. It is the third RTL-SDR dongle in the house, but the first one from RTL-SDR.COM. RTL-SDR dongles allow for the reception of radio signals in a wide range of frequencies where the processing of the signals is all done in the computer.

I ordered it through AliExpress but making sure I got the right version via RTLSDRBlog Store on AliExpress.

It arrived earlier and I can't get it to work with the Linux SDR software stack I use, even on the newest laptop, which uses:
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name             Version        Architecture Description
ii  gqrx-sdr         2.15.8-1build1 amd64        Software defined radio receiver
ii  gr-osmosdr       0.2.3-5build2  amd64        Gnuradio blocks from the OsmoSDR project
ii  librtlsdr0:amd64 0.6.0-4        amd64        Software defined radio receiver for Realtek RTL2832U (library)
The dongle is recognized, but there is just noise, no signal to decode, even when I try strong broadcast stations. The previous RTL-SDR dongle receives the same stations fine, so it's an amplification or tuning problem.

Checking the web finds librtlsdr/librtlsdr: Software to turn the RTL2832U into an SDR - GitHub which has a recent commit: add rtl-sdr blog v4 support · librtlsdr/librtlsdr@fe22586 · GitHub which sounds exactly like what I would need. So it's not working.. yet.

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2023-09-08 New electronics and amateur radio project: mains power filter
One of my ever nagging issues with amateur radio at home is the amount of interference I get, which makes receiving weak amateur radio signals very hard or even impossible.

The mains power cables coming into the house seem to be one of the main sources, which would explain why the source of the interference is hard to pinpoint: it's everywhere around the mains power wires in the walls and ceilings.

I found Clean Up Your Shack – 2019 which has plans for a mains filter that should improve matters.

I ordered parts from Mouser. The exact parts weren't always available, so I had to do some searching for comparable parts. Including a somewhat bigger case and different cable glands. All the ferrite was available from Mouser exactly as wanted.

The order got delivered quickly. The next step was to find time to actually work on this project!

Recently I found time to sort out what I have and what I still miss to build it all. The ferrites ordered are so big and heavy they come in protective packaging to keep them from cracking due to bumps or the package handling!

I also did a 'test fit' putting all the parts in the case I bought. I thought it might be a bit big until I fitted all the ferrite in: the ferrite is very big, so the case I bought isn't really oversized!

I found out I'm not perfectly done yet. I could use a step drill to get the holes in the case perfectly round and I found out the cable glands I bought did not come with the matching nuts. Time for some more on-line orders!


Parts ordered: mains power strip, the matching nuts for the cable glands and spade connectors. I checked which size step drill I would need and it turned out the hole for the cable gland is 15 millimeter and it would be easier to use a 16 millimeter drill.

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2023-09-06 New entity in amateur radio: Greenland
In interesting DX news I saw OX3LX Greenland - DX-World which is a new entity for me. I got OX3LX in the log on FT8 on 28 August.

I also set an alert for Greenland in morse which helped me get OX3XR in the log on 6 September.

Both contacts were confirmed pretty fast, I am now at 164 entities confirmed in total (any mode) and at 95 entities in morse.

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2023-09-03 Two more countries in morse confirmed
The search to get more countries confirmed in morse is continuing. At the end of July a team was active under the call 1A0C activating the entity Sovereign Militairy Order of Malta which is a catholic order with a lot of history. There is no territory for this entity, but internationally it is seen as a sovereign entity and radio amateurs like having yet another entity.

I got in the log with 1A0C and after donating to the good work of the Order of Malta Italian Relief Corps I got confirmation for these contacts.

Another new country in morse was Luxemburg where LX90RTL is active celebrating 90 years of broadcasting in Luxemburg with Radio Luxembourg. This contact is now also confirmed, and I am at 94 countries confirmed in morse code. The magic 100 for DXCC CW is getting closer.

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2023-08-29 Re-enabling grafana deb updates.. again
I did a manual apt update and saw an error message again for the grafana packages, which confirmed a posting I saw about grafana having to issue a new GPG key again.
root@gosper:~# apt update
Get:1 stable InRelease [5,984 B]
Err:1 stable InRelease
  The following signatures couldn't be verified because the public key is not av
ailable: NO_PUBKEY 963FA27710458545
Hit:2 beowulf InRelease
Hit:3 beowulf-security InRelease
Hit:4 beowulf-updates InRelease
Reading package lists... Done
Building dependency tree
Reading state information... Done
All packages are up to date.
W: An error occurred during the signature verification. The repository is not up
dated and the previous index files will be used. GPG error: https://packages.gra stable InRelease: The following signatures couldn't be verified
 because the public key is not available: NO_PUBKEY 963FA27710458545
W: Failed to fetch
The following signatures couldn't be verified because the public key is not avai
lable: NO_PUBKEY 963FA27710458545
W: Some index files failed to download. They have been ignored, or old ones used
And again the solution was to update the GPG key for grafana packages, as mentioned in Grafana security update: GPG signing key rotation | Grafana Labs.

I followed the same steps as in the update of the grafana signing key in june 2023 to get things working again.
root@gosper:~# cd /etc/apt/trusted.gpg.d/
root@gosper:/etc/apt/trusted.gpg.d# wget -q -O -  | gpg --dearmor > grafana.gpg
I also filed a bug with cron-apt because it hides the 'problem with this repository' error from me. Logged as #778 - cron-apt does not report repositories with GPG problems.

Found via James Tucker: "In case you missed it, grafana…" -

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2023-08-28 Hacking shopping carts with RF signals
My favourite mix of subjects: security (or lack of security) and RF signals.

Joseph Gabay has researched how shopping carts with wheel locks are locked and unlocked, and found out it's really easy to replay these signals. The signals for the shopping carts with wheel locks from Gatekeeper systems are at 7.9 kHz (ELF or extremely low frequency) and at 2.4 GHz (UHF or Ultra High Frequency and the license free range also used by WiFi and Bluetooth).

After a lot of work with a coil to act as a (bad) antenna for 7.9 kHz he found out the magnetic field of a speaker in a smartphone can also create the field and do replay attacks via audio files.

All of this at Control Shopping Cart Wheels With Your Phone! including the video of the Defon 29 presentation about this.

Now I really wonder how the shopping carts at our nearby supermarket work! I know it is a wire loop in the parking lot, I've seen the loop transmitter in the supermarket.

Found via Issac Kelly: "Somebody linked this to me rec…" - Mastodon


The nearby supermarket uses the Rocateq system which operates on 8.13 kHz. So I can probably do the same replay attacks to these carts. Found by taking a picture of the loop transmitter in the supermarket and checking for the name in some variations at the searchable FCC ID Database and finding COP Caster STD&OCS; COP User Manual Zhuhai Rocateq Technology which lists the VLF frequency: 8.13 kHz.

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IPv6 check

Running test...
, reachable as PGP encrypted e-mail preferred. PGP key 5BA9 368B E6F3 34E4 local copy PGP key 5BA9 368B E6F3 34E4 via keyservers

Meningen zijn die van mezelf, wat ik schrijf is beschermd door auteursrecht. Sommige publicaties bevatten een expliciete vermelding dat ze ongevraagd gedeeld mogen worden.
My opinions are my own, what I write is protected by copyrights. Some publications contain an explicit license statement which allows sharing without asking permission.
Other webprojects: Camp Wireless, wireless Internet access at campsites
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