News items for tag interference - Koos van den Hout

2020-11-08 RF knowledge helps fix completely different problems 3 months ago
For work I currently spent quite a bit of time in video conferences. I have an external webcam from work which gives a better image than the built-in webcam, but it regularly started giving problems in the image. Hickups or blinking images, suggesting some communications problem between the webcam and the computer.

Since the webcam, a Microsoft lifecam studio, is still being sold and advertised as works good with Windows 10 I thought it wasn't the age of the webcam or a problem with the drivers.

So I tried a different solution which is almost the standard solution of a radio amateur for interference problem: add more ferrite to the cables. The USB cable is thin which suggests to me there is not a lot of room for good shielding. Pulling the USB cable through a ferrite core twice right after the USB plug made the problems go away.

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2020-01-13 I participated in the UBA PSK63 prefix contest 1 year ago
PSK63 contest in fldigi Like in previous years I participated in the UBA PSK63 Prefix Contest in the weekend.

Overall it was a nice contest, with 111 contacts in total which makes this a good contest score. I started in the 20 meter band on Saturday, moved to the 40 meter band after propagation died down due to the sun going down.

On Sunday morning I started on the 40 meter band but soon gave up, there was a lot of interference on that band. I switched to 20 meters and made some more contacts. In the end: 38 contacts in the 20 meter band and 73 in the 40 meter band.
Read the rest of I participated in the UBA PSK63 prefix contest

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2019-12-27 First radio contacts with the radio and antenna setup at a remote location 1 year ago
The main unit of the Kenwood TS-480SAT radio is now at a different location and the frontpanel is at home. With an OpenVPN connection between them so it's not exposed to the big bad internet.

And it's working! I currently have access to a 10/15/17/20 meter antenna and I have already heard stations I wouldn't dream of receiving at home. And the first country in SSB in the log that I only had in digital modes before: Ceuta and Melilla, the Spain enclaves in Africa.

Lag is minimal, audio is less delayed than listening to the utwente websdr to the same signal. Control works fine, so I can control the radio like I'm sitting behind it, including menu settings.

Comparing received signals on the local radio with the attic dipole and the remote radio is hell and heaven: local noise is S9+ and the remote location has almost no local noise (while still being in an urban environment) so I can hear even weak stations fine. I leave the noise blanker off most of the time because it's not needed to hear signals fine.

Not making loads and loads of contacts yet, propagation isn't cooperating very well and there aren't many people calling CQ. But when a somewhat special station calls CQ there are a lot of answers so there are numerous amateurs active. Or I guess they go to their set when they see an interesting callsign on the DX-cluster.

I also got morse keying by paddle working beforehand. Hearing the sidetone from the radio with just a bit of lag got annoying fast when doing morse at a bit of speed so the sidetone is now from the control unit and the sidetone in the radio is silent. It's still set to the same audio frequency as the sidetone in the control unit to allow for finding the zero beat frequency.

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2019-10-06 A new HF radio, with plans for remote operation 1 year ago
The last years I've been dealing with increasing levels of interference on the HF bands at home. One clear source is the rising numbers of solar panel installations, with a clear difference between hiring the cheapest installer versus hiring a good installer but paying more.

I don't want to start discussions with all neighbours about their solar installation and the latest news seems to be that the Dutch telecoms regulator takes the stance of solar panels being needed for our economy so radio amateurs have to accept the interference.

Moving house is not in our plans for the coming years so I started reading about the options for remote operations, where I can sit at home with the microphone and morse key looking at the display of the radio and hearing the audio while the receiving/sending part is at a remote site with a lot less interference.

I found out about RemoteRig which does just that, and with the right choice of radio allows complete remote operation over the Internet. With their offering I started looking at compatible HF radios and found a nice secondhand Kenwood TS-480SAT. This radio has better filtering options for SSB and morse than my Yaesu FT-857D.

The radio is now at home and I made the first few SSB contacts with it. The filtering already helped me understand stations better.

Now for the next steps, cables, remoterig units and other things. And a remote location. I have an offer from a fellow radio amateur to do the first tests at his house. When all that works out I'll go and find a nearby location to do the complete installation.

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2019-07-29 Tried receiving ISS SSTV with the FUNcube Dongle Pro+ 1 year ago
This evening had scheduled Amateur Radio on the International Space Station slow-scan TV transmissions so I took Arrow antenna, the new FUNcube Dongle Pro+, cables and laptop outside.

I found out gqrx crashes when the dongle is on the righthandside USB port of the laptop, so that one is out. On the backside port everything was working, and audio routing worked routing the analog output audio (created by qgrx) to the recording by audacity and the image decoding with qsstv. Gpredict was set up to control the reception frequency in gqrx, and this whole setup was working ok.

But the signal from the ISS looked very very weak in gqrx, just a small rise in level above the noise when I pointed at the general direction of the ISS. No idea why. No images were decoded from it.

After the pass I tried receiving some other sources with this setup and receiving the PI2NOS repeater went fine. But that's on the 70 centimeters band. I saw no activity on PI3UTR which would have enabled a test on 2 meters.

This needs more testing. Maybe something to hold the antenna cables so they don't get pulled from the laptop/radio during a pass.

Update: Most likely culprit: interference in the 2 meter amateur band. With a handheld radio that has received ISS packet sounds before I could now only hear them very faint in the noise. The local 2 meter noise is killing weak signal reception.

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2019-04-21 We hebben zonnepanelen aan laten leggen 1 year ago
We dachten er al een tijdje over na, en we zijn eind vorig jaar serieus gaan zoeken naar een kundige leverancier van zonnepanelen. We hebben eerder contact gehad met wat bedrijven maar die wilden er eigenlijk niet aan beginnen. Een leverancier wilde niets op vlakke plekken leggen en vond dat er dan te weinig panelen over bleven. Een ander reageerde ook moeilijk en gaf geen reactie meer toen we de offerte niet gelijk ondertekenden maar nog aanpassingen wilden. Blijkbaar zijn meerdere aanbieders van goedkope zonnepanelen er niet zo blij mee dat we graag wilden dat er echt iemand langs kwam om te kijken in plaats van dat de hele offerte gebaseerd was op wat er te zien is in de satellietbeelden op google maps.

Uiteindelijk wilde Radiair wel iemand langs sturen om een goede offerte te maken. Met die man de wensen besproken, de opties om ook op de uitbouw en de schuur panelen te leggen en dat ik graag de omvormers en optimizers goed wil ontstoren omdat ik zendamateur ben. Allemaal mogelijk. Na wat aanpassingen kwamen we op een offerte die volgens ons ook prima ging werken, dus die hebben we geaccepteerd. Het is vast duurder geworden dan andere aanbieders, maar hier werd er tenminste serieus naar de situatie gekeken en naar onze wensen geluisterd.

Ik had bij mijn acceptatie een bijlage bijgevoegd dat ik op alle optimizers ferrietkernen wilde installeren. Ook dat is prima gelukt en bij de overdracht van het project naar de uitvoerders was dat ook netjes overgedragen dus niemand keek er gek van op.

De monteur die het laatste werk kwam doen aan de aansluitingen is zelf ook zendamateur, dus die had alle aardingen en twists van kabels extra goed afgewerkt om te zorgen dat ik van mijn eigen panelen in ieder geval geen last zou krijgen.

Er zijn nu 11 panelen gelegd en die zijn sinds begin April in gebruik. De keuze van groepen waar de omvormers op terugleveren blijkt goed uit te vallen: de groepen met het meeste constante gebruik (koelkast, computers) hebben nu teruglevering dus een deel van het opgewekte vermogen wordt gelijk intern gebruikt. Maar daarna houden we bij goede zon zeker vermogen over, dus we leveren ook terug en de scriptjes die de stand van de slimme meter aflezen zien nu ook de tellers voor teruglevering oplopen.

Teruggeleverde energie wordt nu nog verrekend volgens de salderingsregeling, dus wat we terugleveren wordt weggestreept tegen wat we op andere momenten afnemen. Die salderingsregeling is natuurlijk niet eeuwig houdbaar: we leveren energie aan het net op een moment dat het net er niet perse behoefte aan heeft. Al zullen de netbeheerders en energieleveranciers tegenwoordig de zonsverwachting nauwkeurig in de gaten houden bij het plannen van de capaciteit. Een wolk voor de zon langs is bij mij al duidelijk zichtbaar in de teruggeleverde energie.

Tot nu toe hebben we alleen aardig zonnige dagen gehad. Ik ben benieuwd wat ze doen als het echt een hele dag bewolkt en regenachtig is.

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2019-01-08 Amateur radio resolutions for 2019 2 years ago
The last time I did those was in 2017: Reviewing my 2016 amateur radio resolutions, and the new ones for 2017 and the hindsight results for 2017/2018 are:
  • Improve the holiday/portable setup with solar power and a lightweight multiband inverted V
    No solar power (due to costs) but the portable setup is improved and tested: the fiber mast I bought for playing radio from several locations including amateur radio from a local park. Now to find more time to actually use it.
  • Keep doing the digimode contests
    That part went better in 2017 and I had less time and/or energy for contests in 2018. Also in 2018 the interference situation got worse. So my net results in contests improved in 2017 and got worse in 2018.
  • Maybe those satellites
    I tried at least receiving them a few times, but no contacts yet.
  • Get a 2m/70cm vertical antenna on the roof of the dormer
    It's there, it has already been upgraded to a bigger antenna with higher gain and it's mostly used for 2 meter FT8. But also for actual talking to other radio amateurs sometimes.
The Sotabeams newsletter had an item "Setting your targets for 2019" which had some nice ideas and which triggered me to write this post. Things I want to try :
  • Keep learning morse!
  • Get more countries on more HF bands in the log
  • Moonbounce on 2 meter
  • Those digimode contests, and maybe a few phone contests
  • Operate HF outside
  • At least one satellite contact

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2018-11-02 Stroomstoring afgelopen dinsdag 2 years ago
Er was een stroomstoring afgelopen dinsdag. Ik ontdekte dat op een hele typische manier: ik werd wakker voor de tijd van opstaan, wat me wel vaker overkomt en ik wilde op de wekker kijken maar die was donker.

Uiteindelijk was de stroomstoring van 06:23 tot 08:07, in een aardig gebied rondom ons huis. Helaas was er in de ochtenddrukte geen tijd om te testen wat het gevolg van deze uitval was voor het storingsniveau op de amateur radio HF banden.

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2018-08-13 Trying to receive amateur radio through local interference 2 years ago
This evening I tried several things to improve my chances of actually receiving anything other than the loudest stations in the upcoming SCC RTTY contest.

First try was with a borrowed receive loop indoor and using an HF upconvertor, an rtl-sdr dongle and gqrx as receiving software. This did not work for digital modes: letting wsjt-x (FT8 software) 'listen' to the audio output of gqrx gave no decodes.

Interesting detail: looking at the right piece of spectrum for FT8 showed that the frequency wasn't 100% stable, with frequencies slowly changing. Touching the rtl-sdr gave a bump in frequency.

Another attempt was with the loop indoor and reception on the FT-857D radio. Reception of a strong SSB station seemed somewhat better on the loop, but I heard no improvement of weaker stations.

So I moved the loop outside to the end of the garden and layed a long cable back to the radio setup. This made interference worse! It was already dark so this was not related to any solar panel setup, but some other source of interference on HF. The loop is supposed to receive less local interference but I could not get it to do that this time (it did work for SSB some other time).

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2018-08-12 More output power for PE4KH: I bought an HF linear amplifier 2 years ago
The reason for making the HP DPS-700 GB powersupply deliver a somewhat higher voltage and lots of amperes is that I made the decision to buy a HF linear amplifier. With such a device I get more output power on HF bands which should increase my chances in radio contests.

I have been looking at new and secondhand linear amplifiers for a while. Since this market is dominated by US customers most amplifiers will give 1000-1500 Watts output power at a serious price. The legal limit here in the Netherlands is 400 Watt unless I request a special license which will never happen since the radio station is surrounded by other houses. But there isn't much on offer below 400 Watt output power. I found RM Italy which sells linear amplifiers for CB and radio amateur use at more reasonable amounts of power and at a better price-point. I selected the RM Italy HLA300V plus which should give 300 Watts on HF bands.

I bought it online and it arrived fast. After soldering some cables to the power supply I was able to use it and it works as intended.

On the 20 meter band and 10 meter band it works with the endfed antenna (which can take 400 watts). On the 40 meter band it goes into protection mode instantly. It turns out the amplifier is quite sensitive to SWR problems, the endfed gives a 1:1.5 SWR. Maybe I can improve this a bit, the resonant point is below the 40 meter band.

Giving it 5 watt input power in digimodes will make 5 of the 7 output power LEDs light up. To get it to light up 5 LEDs in SSB mode I need to give it 10 watts power in that mode.

Propagation wasn't great this weekend so I spent most time in FT8 mode. With the help of the new amplifier I was able to get two new countries in the log: V51MA in Namibia and 9G5AR in Ghana.

The receive side is currently a different story. Interference levels are at an all-time high. The way I currently get reception for FT8 is by using the UTwente WebSDR for the receive side and feeding the audio to WSJT-X. With the delays and audio-processing introduced by the WebSDR I still get better and more decodes than from the local receiver.

For contesting that setup is not going to work. Most contests have a rule that all equipment for a contest station has to be on a limited area. For example the upcoming SCC RTTY contest has the rule:
All operation must take place from one operating site. Transmitter and receiver must be located within a 500-meter diameter circle.
I'm looking into using a receive loop to have less interference on reception.
Read the rest of More output power for PE4KH: I bought an HF linear amplifier

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