News items for tag interference - Koos van den Hout

2018-08-13 Trying to receive amateur radio through local interference 1 month 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 1 month 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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2018-06-30 New 2 meter distance: 483 kilometers 2 months ago
While trying to get an idea of how much interference I have on the 2 meter band I still worked on my distance records: I had a contact with G8GXP which is a distance of 483 kilometers, a new record for me on the 2 meter band.

This is with S5/S6 interference on the 2 meter band as long as the sun is more than a bit above the horizon, which at the moment is very long. Some ferrite added to the solar power convertor already helped, but I guess the solar optimizers also need some work to clear the 2 meter band again.

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2018-06-27 Recorded the ISS contact today 2 months ago
Today was an ISS contact with Werner-Heisenberg-Gymnasium, Leverkusen, Germany and Schickhardt-Gymnasium, Herrenberg, Germany and most of the contact was going to be within range for me and it was at a usable time.

So I set up gpredict to track the ISS and the receive frequency and set up audacity to record the results. Which weren't great since 2 meter reception is now influenced by recently installed solar panels on the house next door.
Listen to audio attachment:

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2018-04-08 I participated in the EA RTTY Contest 2018 5 months ago
As planned I participated in the EA RTTY Contest edition 2018.

I had most of the time to play radio on Sunday so I decided to participate in the SO20DX (single operator 20 meter band outside Spain) category. I did make two contacts on the 40 meter band when I thought I wasn't going to find any new station the 20 meter band but I returned. And found more stations on the 20 meter band.

20 meter interference pattern
Interference pattern on the 20 meter band
Radio propagation was ok, best DX were some Asiatic Russia stations and a US station in Illinois. The local noise was bad and there were some new sources of interference active. The pattern as in the image (links to full view of the 2.5 kHz waterfall) which is very stable in frequency and has a tendency to stop and start, and at the stop the carriers move together. Also a more 'rattling' noise which sounded like an electrical problem.

In the end I made 81 contacts in total, 79 on the 20 meter band.
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2018-03-04 Trying a bit of radio at a holiday park 6 months ago
Last week we were staying in a holiday home in the Ardennen area in Belgium. Temperatures were constantly below zero which can make my fibermast break easily according to the instructions. I also forgot to bring a side cutter so setting up the fibermast with the rubber profile at every level would be hard to take down again. This made it a bad idea to leave it up overnight.

Due to the cold and me having a serious cold as well it took a few days before I got around to a bit of amateur radio. When I got around to setting up the mast it went reasonably well. The ground was frozen so I needed a hammer to get the pegs into the ground for the guy wires. The foot of the fibermast decided to slip away and the tip fell against a wall, but no damage.

When the mast was up and the dipole hanging the local RF noise turned to be at the same S8 level I am used to at home and it was very hard to make a contact. I tried 40 meter FT8 with transmit power dialed back to 25 watt since the radio itself started showing signs of RF interference. One partial contact was made (no full exchange of signal reports).

And then I noticed gardeners working on pruning bushes everywhere and working in my direction so I disassembled the mast again and took all the parts back in.

For next time I may find some plate to anchor the foot of the fibermast so it can't slip away. Maybe a plate with a big hole in it for the mast and two small holes for tent pegs.

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2018-01-15 I participated in the UBA PSK63 prefix contest 8 months ago
PSK63 contest As planned I participated in the UBA PSK63 prefix contest in the weekend. Activity was Saturday evening and Sunday morning interrupted by some good sleep.

Compared to my experiences in the ARRL RTTY roundup one weekend earlier the 40 meter band decided to act quite differently. On Saturday evening it was quite hard to make a contact. A lot of interference, no far away stations and it was hard to get heard by the other side. I stopped before 22:00 UTC (23:00 localtime) because I thought some sleep would be more effective than getting annoyed by the lack of contacts.

Indeed, Sunday morning things got better although I heard only nearby signals on the 40 meter band, including some Belgian stations. No serious DX. Belgian stations are good for extra multipliers so it was good for the score.

In the end I made 76 contacts. The last contact was started by a CQ I called at 11:59 UTC but it was only answered at 12:00, so it does count but I had to note it in the log as originating at 11:59 where the software normally logs the moment I see the callsign for the first time.

Log submitted and de Veron afdelingscompetitie updated.
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2018-01-08 I participated in the ARRL RTTY Roundup 2018 8 months ago
RTTY contest on websdr For the past weekend I had the ARRL RTTY Roundup planned, meaning I had reserved time in the family calendar. Other things had to happen too but I reserved time for contesting and made sure I had the right macros available before the contest started. I hoped to find time to set up the endfed antenna before the contest but that did not happen so it was the first thing to do when we got home at the beginning of Saturday evening.

In the contest I only operated on the 40 meter band. Most of the time I was able to participate were in the dark when I did not expect the 20 meter band to cooperate and I thought that operating in just one band would make me end higher in the rankings for that more specific category. Only after the contest I read the rules exactly and noticed that this specific contest does not differentiate between single and multi band operation.

In the end I made 95 contacts. Local noise is high in my current setup so only the strongest stations came through the noise. I made only one contact in CQ mode, the rest was search and pounce. Propagation wasn't really good until late in the evenings when I managed to score some US contacts. I did see someone from Prince Edwards Island in Canada but that station did not hear me return. I noticed WP2B did not give me a US state but a serial number and found out that is a US Virgin Island callsign, so that was a new country for me.

In the end a nice contest. For upcoming contests: check the rules / propagation predictions and plan my strategy.
Read the rest of I participated in the ARRL RTTY Roundup 2018

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2017-11-25 Portable operation close to my home 10 months ago
Today I had some time left and the choice was between staying at home and throwing out the endfed and making a lot of contacts in digital modes or going out and trying a nearby park and making a lot less contacts but learning about my options there.

Fibermast on parkbench I chose the latter one: I loaded my gear in the bicycle trailer and cycled to a nearby park, just outside the city limits of Utrecht. I took the fiber mast and used two elastic straps to tie it to a parkbench. The effect was that the mast was slanted but using it with the wire of the endfed twisted around it the fiber mast stayed up fine without needing its guy wires. And I forgot to bring the tent pegs anyway so I was unable to guy the mast.

I tried the endfed as a vertical with some slack at the bottom and the transformer at the bottom. This gave me a horrible standing wave ratio on 40 and 20 meters. I guess the endfed is only balanced when it is stretched. The quick fix was to add a common-mode choke in the coax to the radio. I also added a counterpoise wire to the earth of the endfed to be somewhat balanced again.

On the 40 meter band reception was ok but I could not understand a lot of stations. On the 20 meter band there was local interference.

In the end I logged one whole contact on the 40 meter band with an Italian special event station. He gave me a 4-4 report and I gave him a 5-9+. After a few tries I gave up making him log me as /portable so I logged it in my PE4KH log. The location is still within JO22NC so I logged in my home log.

As soon as the sun set it started cooling down and the grass got wet and I went home.

It's a nice location and quite reachable from home. It's 10 minutes cycling and in 10 minutes I had the mast and the radio set up.

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2017-09-08 I built a common mode choke 1 year ago
After the problems with the laptop controlling the radio when I participated in the SCC RTTY contest 2017 I decided to build a common mode choke. This is a filter that should keep the radio frequency signals at the side of the antenna.

Based on the simple design with a piece of PVC pipe with 8 windings of Aircell-7 coax I still had lying around. The PVC pipe was donated by a fellow radio amateur who had it in his junkbox.

I drew a pencil line on the pipe, decided where to drill holes for the coax cable (using a 16 millimeter drill) and where to drill holes for tiewraps to hold the coax. After drilling the holes it was a matter of winding the coax correctly, mounting the cable with tiewraps and soldering the connectors to the cable.

In the first testing the filter worked fine, completely stopping the interference to the keyboard of my "shack computer" and even reducing incoming noise on the 10 meter band.
Common mode choke: materials - KvdHout on FlickrCommon mode choke: materials
Common mode choke: finding where to drill holes - KvdHout on FlickrCommon mode choke: finding where to drill holes
Common mode choke: holes drilled - KvdHout on FlickrCommon mode choke: holes drilled
Common mode choke: cable mounted - KvdHout on FlickrCommon mode choke: cable mounted
Common mode choke: connectors done - KvdHout on FlickrCommon mode choke: connectors done

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2017-08-28 I participated in the SCC RTTY 2017 contest from the radioclub location 1 year ago
Again this year had the SCC RTTY contest in the same weekend as the barbeque of the radio club so the solution was to work in the contest from the location of the radio club. I set up with the endfed antenna in the available field.

That field is close to some houses so I had some interference. And the main problem was that the computer control between the laptop running fldigi (the contest logging software) and the radio regularly gave problems, usually leaving the radio in transmit mode. The laptop and the computer interface aren't shielded very well which is probably a reason, combined with the use of the endfed antenna which is known for causing interference since it's an asymmetric antenna.

In the end I made 53 contacts. Less than the number of contacts in previous SCC RTTY contest but I had limited time and local noise was higher than I expected. For a next time I am working on a common mode choke to limit interference to the computer and maybe some noise. And probably next time I contest at the radio club I will try to use a different antenna location.
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2017-04-24 Somewhat less HF interference by moving the antenna away 1 year ago
I was testing with noise on all radio bands with the LW-10 longwire antenna with tuner. I recently made the rope that hangs it out from the window a bit longer and I noticed the noise on the 10 meter amateur radio band had dropped a lot compared to the noise I experienced before and the noise on the antenna under our roof. In S-points: under the roof S8, with the 10/20/40m endfed S8, and with the longwire antenna S0.

On bands with lower frequencies (higher wavelengths) noiselevels were high, up to S9+ on 80m with a rattling noise in it. But this sudden change on the 10 meter band made me think there could be a pattern so I measured how much more distance I could move the antenna away from the house and maybe get lower noise levels on the 20m band too. After adding 1.60 meter of rope and rehanging the antenna the noise level on the 20 meter band also dropped from S8 to S7. Not the biggest improvement but it's something.

I'm now making some PSK qso's on the 20 meter band. At the S8 noise level this was getting impossible.

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2017-04-12 Trying the mini-whip as reception antenna 1 year ago
Recently I talked to a fellow radio amateur about my HF reception woes at home and he suggested trying the mini-whip antenna I built a few years ago as reception antenna, using an automatic switch to switch between the transmission and reception antenna.

For the first test I used the mini-whip antenna with the HF downconvertor and an RTL-SDR stick that I bought to receive amateur satellites to check the signal on the computer. The further I move away from the house the better signal I get (less noise, more signals sounding like the amateur radio signals I want). I do notice that when I turn the gain on the RTL-SDR up (or set it to automatic gain) that there is a repeating 'ticking' signal which sounds just like the ticking interference from my own PLC tests.

This could mean that a nearby neighbour has a PLC network without the notches for amateur radio. Or this is just an artefact of the high gain.

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2016-12-24 "Nice" view of the local noise 1 year ago
Waterfall display with noise in 20m jt65 band With HF conditions being bad I chose the JT65 mode in the hope of having a chance of making a contact. None happened, and the noise patterns in the waterfall display make it very clear how much local noise there is and how the local noise sources change frequencies and power.

Transmissions take 50 seconds in JT65 and start right at the beginning of the minute, at each yellow horizontal line in the waterfall display. The only valid JT65 signal is in the top right corner right of the '1400' marker.

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2016-11-17 De zoektocht naar niet-storende LED lampen 1 year ago
In onze keuken hadden we 5 spotjes met halogeen lampjes achter een dimmer om zo op het werkblad goed licht te hebben. Toen kort na elkaar 2 van die lampjes stukgingen was de conclusie dat er binnenkort wel meer stuk zouden gaan en dat dit een mooi moment was om aan LED lampen te beginnen.

Ondertussen zijn er dimbare LED lampen die ook halogeen spotjes kunnen vervangen. Alleen was de gedachte in mijn achterhoofd natuurlijk of ze dat ook kunnen zonder radiostoring op te leveren.

In de Electron, het verenigingsblad van de Veron heeft recent een stukje gestaan van een radio amateur die na eerdere storingen geen storing meer had na het vervangen van goedkope LED lampen door Philips LED lampen. Ik heb het er dus op gewaagd en 5 philips LED lampen gekocht, type LED Spot 8718696483824 van Philips, GU10 fitting, 4W (vervangt 35W) dimbaar, warm wit.

Het licht is inderdaad serieus anders dan van halogeen lampen, dus ze alle 5 tegelijk vervangen was een goed idee. En de storing is minimaal, pas als ik heel dichtbij kom met een kortegolfontvanger krijg ik een storing binnen die net zo goed via de electriciteitsdraden kan komen.

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2016-11-06 One source of interference found: osram halotronic htm 70 transformers 1 year ago
Recently I noticed one source of radio interference on 40 meter was the lighting in our bathroom. There are two sets of lights in the bathroom, one with a switch which causes heavy interference and one with a dimmer.

The lights in the bathroom are all 12volt based and the transformers are in a weird corner above the bathroom, but accessible for me. So I found out the "osram halotronic htm 70" electronic transformers (the specs read like switching power supplies) are quite audible on the 40 meter band. The other two a lot less than the switched one. Time to complain to Osram and/or replace them. The Osram Halotronic HTM 70 specifications at Osram say the maximum length of the wire after the transformer is 2 meters to keep RF interference below acceptible levels, I am not completely sure the complete wires until the lamps are shorter than that, so it may also be an installation fault.

Searching for "osram halotronic htm 70 interference" finds this interesting bit: Installation LED Leuchten in Spanndecke with:
Aber auch wenn "nur" der Meßwagen der Bundesnetzagentur vorbeikommt und Deine Konstruktion kostenpflichtig stillegt, kommt wenig Freude auf.
The German Bundesnetzagentur is a lot stricter in finding and stopping interference to amateur bands.

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2016-10-01 Avoiding the local noise with help of a websdr 1 year ago
Local radio noise at home is at high levels again and the HF propagation isn't cooperating very well. This means that it's hard to make contacts which can be frustrating when I finally get some radio time.

At the moment I am chasing the Miguel de Cervantes special event stations organized by the Spanish radio amateur club with radio operators active all over the Spanish country. With the distance it should not be too hard, but band conditions don't cooperate very well, especially when I can't hear the remote station due to local noise.

Solution: listen on the websdr in twente and transmit on my local radio with maximum power (100 watts). The delay in the audio from the websdr means I have to adjust my timing but it is good enough to get my callsign across and check whether the other side received it correctly. So I manage to make a few more SSB contacts, since this works better on SSB than on digital radio modes.

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2016-07-22 Complete powerdown does not help against RF noise 2 years ago
On wednesday everything in our house was switched off due to some electricity work. I prepared for this and made sure the radio was connected to a charged battery.

And the end result was that the noise levels around our house are at least the same when power is out. In the 20 meter band I noticed even stronger carriers which may be caused by the fact that the local VDSL modem was powered off at that time. I made one contact which I logged on paper with OE2YOTA the youngsters on the air camp in Austria.

I guess I will have less noise when the power fails in a wider area, as reported at This is what HF sounds like during a power outage at my QTH!

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2016-06-03 Luisteren naar de PI4AA ronde op 40m met lokale storing 2 years ago
Ik heb weer eens geluisterd naar de PI4AA uitzending. Dit keer heb ik geluisterd via de PI2NOS livestream en heb ik me daarna eens ingemeld via de inmeldronde op de 40 meter band omdat ik toch de endfed antenne had buiten gehangen vanwege een contest in het komende weekend. In SSB is de lokale storing erg duidelijk aanwezig. De storing is ongeveer S9 dus ik hoorde PI4AA zelf redelijk goed met een signaal wat daar net 10 dB boven zat. De meeste inmelders hoorde ik slecht of niet.

Hierbij een klein stukje met Remco PA3FYM als rondeleider.
Listen to audio attachment:
MP3 media: PI4AA ronde op 40m 20160603 (rightclick, select save-as to download)

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2016-05-02 Experiences with vectored VDSL and amateur radio transmissions 2 years ago
It is a while after my last report on Vectored VDSL and the influence of amateur radio transmissions and it's time to share the current experiences especially with the change to the DrayTek Vigor 130 VDSL modem.

The first conclusion is that the modem doesn't matter much. I am now used to the connection dropping and retraining when I start on a 'new' frequency. I haven't figured out yet what the exact definition of 'new' is, when I haven't been active for a number of days on 20M PSK31 the first transmission on that band can trigger the disconnect. There seems to be no direct influence on the maximum speed after the reconnect, it sometimes goes up. A serious change of frequency (different band or a different part of a band) can trigger another disconnect.

In the mean time an xs4all user shared after long debugging of vectored VDSL problems to have found the cause in the PLC (powerline communications) network devices as delivered by xs4all for television over IP. Yet another reason to not use PLC. But in the ideal world the lastmile connections for high speed would be fiber-based anyway.

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