Category Archives: QRM

Contayner Over-The-Horizon Radar site polluting the HF spectrum

OTH radar Contayner on 7062 and 7103 kHz on 21 Oct. at 1847 UTC (Source: IARU Region 1 Newsletter)

Many thanks to SWLing Post contributor, Paul Evans, who writes:

The news from IARU Region 1 observer reports is all over the radio internet (including news sites and other blogs), but the extent of this [Russian] OTHR is grim. [Click here to read a recent ARRL News post.]

It is also entering service on a full-time basis, along with, potentially, a similar Chinese system.

Yes, it has been in testing for many years but is approaching multiple site use, soon. As the sunspot cycle comes back they may prove to be very limiting.

The antenna picture (for the transmit site) is impressive:
https://qrznow.com/russian-oth-radar-now-reported-to-be-everywhere/

(although I think that is of the old Woodpecker site, the Google Maps street view image looks somewhat different, see below).

However, it’s not so huge that it really stands out. It can be seen here:

in satellite view and can even be seen in street view here:

Note that the magic number in the phased arrays seems to be 9.

Rather worrying is that the UK continues to run, over many years now, OTHR from sovereign bases (ZC4) in Cyprus rather obviously aimed at use in Syria and Libya for use with the RAF and for Russian air space. It too can be seen on the salt marshes in the south of the island. As an active system it seems to be rather more cloaked than the Russian system, although there are some 360 degree images in Google Maps that show the towers. This was extremely annoying on the bands when the last solar cycle was near maximum from Bermuda because it was right in the main lobe when a Yagi was pointed towards Europe and was very loud. It was considerably narrower than the Russian system but occupied a solid chunk of band.

Paul, thank you for bringing this to our attention. I have seen chatter about the QRM this particular Russian OTH Radar site has created, but it seems other countries will soon be joining the OTHR QRM scene as well.

Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Hamvention Highlights: Affordable diversity reception with the SDRplay RSPduo

2 Replies

Each year at the Dayton Hamvention I enjoy checking out the latest radio products and services. This year (2019) I found an exceptional number of innovations and will share these in Hamvention Highlights posts. If you would like to check out 2019 Hamvention Highlights as I publish them, bookmark this tag: 2019 Hamvention Highlights

Diversity reception with the SDRplay RSPduo

Last year, during the 2018 Hamvention, SDRplay announced the RSPduo, a 14bit dual-tuner SDR. We posted a review of the RSPduo on the SWLing Post.

At the time, SDRplay mentioned that the RSPduo could eventually be used for diversity reception.

Diversity reception is the ability to combine or select two signals, from two (or more) antenna sources, that have been modulated with identical information-bearing signals, but which may vary in their fading/noise characteristics at any given instant.

In short, diversity reception gives one a powerful tool to mitigate fading and noise, and to improve a signal’s overall integrity.

Andy and Mike with SDRplay demonstrated SDRuno’s diversity reception functionality and noted that it will soon roll out as a free upgrade to SDRuno, SDRplay’s open SDR application.

I should note here that the SDRplay booth at the 2019 Hamvention was incredibly busy—no doubt, because the RSPduo must be one of the least expensive, most accessible, ways to experiment with diversity reception. Case in point: the new Elecraft K4D transceiver will support diversity reception, but the price is about $4,700 US; the RSPduo can be purchased for $280 US.

Based on the demonstration, this feature will be quite easy to use and I love how it has been implemented in the SDRuno GUI (graphical user interface).

To learn more about the RSPduo, check out SDRplay’s website or read our review. Of course, when SDRplay releases the diversity reception upgrade to SDRuno, we will make an announcement!

If you would like to follow other Hamvention Highlights, bookmark the tag: 2019 Hamvention Highlights

Arcing can produce nasty broadband radio interference

3 Replies

On this trip to Québec, indoor listening has been more productive than listening from our balcony.

I mentioned in a previous post that, this year, QRM levels here at the condo in Québec are higher on our balcony than they are inside the building.

I think I found the source.

A couple weeks ago, on my morning walk, I passed underneath some high voltage power lines about 1 km from the condo. I noticed the sound of arcing coming from a pole nearby. No doubt, something metal–a staple, a cable, a pin, etc.–is the culprit.

I pulled out my smart phone and made this short video. If you turn up the volume, you might hear the noise especially at the end of the clip.:

I took a portable radio back to the site later and heard the same broadband noise I heard from the condo.

Although we only rent this condo a couple months a year, I’ll try to report the noise to the Hydro Québec. I know that our utility company in the States must follow up with requests like this and do their best to eliminate unintentional sources of RFI. These issues can also be an indication of something in the system failing, so power companies can actually be quite grateful for the feedback.

If you have persistent broadband noise at home, check out some of the trouble shooting tutorials at K3RFI’s website for a little guidance.

Despite all of this noise, I’m pleased I can still receive a few of my favorite shortwave stations. And, of course, escape to the KiwiSDR network and hit the field from time to time!

No worries, though, I’ll be back at my home station soon and can once again enjoy a relatively RFI-free radio space!

Post readers: Have you ever been plagued with power line noise? What did you do about it? Any tips? Please comment!

Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

LED QRM jams maritime Automatic Identification System

5 Replies

(Source: Southgate ARC)

LED lights jam shipping Automatic Identification System

VERON report investigators from the Netherlands Radiocommunications Agency have discovered RF Pollution emitted by LED lights caused the loss of AIS shipping signals around 162 MHz

A Google English translation of the Radiocommunications Agency article reads:

In the mouth of the Waalhaven in the Nieuwe Maas in Rotterdam, ships from the electronic map have been missing for some time. The Port of Rotterdam Authority and skippers were completely in the dark about the cause of this.

In the busy Rotterdam port area, of which the Waalhaven is a part, it is important that you know where everyone is. A ship that automatically sends its position and data via AIS – and is therefore visible on the electronic navigation chart – not only increases safety, but also shortens the waiting times for the berths and waiting areas. And what about ships loading and unloading dangerous goods or passenger ships? These are continuously monitored. If such a ship is dropped, dangerous situations can arise.

During an investigation the inspectors of the Radiocommunications Agency quickly discovered that the frequency band for AIS signals was disturbed. And after several polls in the surroundings of the Waalhaven they came to a work of art. In an atelier near the mouth of the Waalhaven, an artist had made a work of art with the help of LED lights. All these lights appeared to be the key to the solution together with the power supply.

Because LED lights are indeed economical, but if you do not buy the right one or install them incorrectly, they cause a lot of problems. In this case, the frequencies of the AIS band were therefore disturbed. After the power of the lighting was switched off, the disruption was resolved. In retrospect, it appeared that the lighting and the power supply exceeded the interference limits. To prevent new failures, a solution is sought for the artist together with the business community.

The agency also regularly receives reports of disruptions of AIS reception from the Amsterdam port area. Here, too, we conduct an investigation. If something interesting comes out of this, you may read more about this in the next newsletter. To prevent disruptions, we regularly monitor frequency use (preventively). Especially in areas with busy shipping traffic.

Source Netherlands Radiocommunications Agency
https://magazines.
agentschaptelecom.nl/
ontwikkelingenindeether/2018/03/
schepen-verdwenen-van-de-elektronische-kaart

VERON in Google English
http://tinyurl.com/NetherlandsVERON

DARC asks that you send RF polluting LED bulbs to Elektor Magazine

7 Replies

(Source: Southgate ARC via Mike Hansgen)

LED Bulb RF Pollution – Elektor Magazine investigates

DARC, the German national amateur radio society, are requesting amateurs to send LED bulbs which pollute the RF spectrum to the magazine Elektor for investigation

A Google English translation reads:

Elektor-Verlag GmbH calls all readers and especially all radio amateurs to send non-compliant LED bulbs including power supplies. Elektor wants to investigate this EMC-technical and then forward it to the competent market surveillance of the BNetzA.

The reason for the action: As a result of a press release of the DARC in September 2017 on the significantly increasing interference of radio communications, other radio services and the DAB reception by non-EMC compliant LED bulbs Elektor had investigated such lamps (as well as LED strips). The result showed a progressive electromagnetic pollution.

The Federal Network Agency as competent authority for market surveillance in accordance with the EMVG has welcomed the call for the submission of suspicious copies. In addition, the Federal Agency would like to be informed if disturbing lamps attract attention. She then wants to investigate this situation and take the products out of the market, if they are still offered.

Please send suspicious copies

Elektor-Verlag GmbH
Kackertstr. 10
52072 Aachen

Please enclose a note with the words “EMC LED lamp” so that everything runs correctly in the inbox. You can also announce your submission via e-mail to redaktion@elektor.de with the subject “EMC-LED-Lamp”. Elektor Verlag GmbH then checks the lamp, publishes an update if necessary and informs the Federal Network Agency.

Here the link to the Elektor article from 23.04.2018
https://www.elektormagazine.de/news/bundesnetzagentur-zu-schicken-sie-uns-verdachtige-led-lampen

Source DARC http://darc.de/

2017 RF pollution from LED bulbs in Elektor Magazine
http://www.southgatearc.org/news/2017/september/rf-pollution-from-led-bulbs-in-elektor-magazine.htm

RSGB presentation on RF Interference

Can you help Luke identify this radio noise?

7 Replies

Many thanks to SWLing Post contributor, Luke Perry, who writes:

I am experiencing a issue with my shortwave reception at my part-time home. I have been helping out my mother so I have brought over my Sony portable, along with the Sony active antenna. I have a constant ‘clicking’ sound starting at about 5 kHz or thereabouts that make listening unbearable. As the video shows the problem is non-existent below 4 kHz. I tried moving the radio throughout the house thinking it could be something in the room and still get the same interference.

I was hoping that the filter on the active antenna would help but it does little to remedy the problem. I have no issues with MW or FM reception at all.

I have made a short YouTube video to document the problem in the hopes that one of the blog readers can identify it. I looked online at other instances of RFI and I could not find one that is similar. Hope that someone can help me!

https://youtu.be/OcEWAkdfmWw

Click here to view on YouTube.

After listening to the first few seconds of your recording, I thought it sounded a bit like an electric fence controller. However the interval between pops is nearly random, which suggests a different source. I suppose it’s possible a faulty fence controller could do this. I believe the only way you could defeat this noise (without shutting it down at the source) would be to use a radio with a durable noise blanker. Of course, I know of no portable radios with an NB function (though most SDRs and tabletop receivers include an NB).

Post readers: Can help Luke ID the source of this noise? Does it sound familiar to you? Please comment!