NBN Co. have recently published a very helpful article on Amateur Radio interference and the NBN. The PDF can be downloaded from the NBN website; click on the image below. You’ll also find plans for a simple 40m notch filter here, thanks to Andrew VK3FS.
Category: Step 4 – Techniques for Resolving Noise
The saga of the network switch and 20m QRM
These days, the internet is connected to just about everything electronic in the modern house, from TVs to refrigerators. My family and I are serious internet users, so when the new QTH was being built, I had the electricians run Cat6 cable to 14 outlets throughout the house. I installed a 24 port network IP […]
Caution when working with mains power
240V MAINS POWER IS DANGEROUS AND CAN KILL Some articles, case studies or posts may talk about the need to filter your main power supply. There are mains filter circuits and kits available online and some may be referenced on QRM Guru pages or external links. QRM Guru and its developers (and RASA) advise against […]
Noise Canceller Kit – from VK5TM
With thanks to Phil VK3VB for this case study Early March 2020 saw me working from home due to COVID-19. This led to re-establishment of the long-neglected shack, which was also the home-office. First, the digital modes were re-established with DSTAR, DMR and NXDN along with the standard 2m/70cm FM. Over the past few years, […]
Plasma TV RFI – symptoms & possible cures
Thankfully, not many people have plasma televisions these days. However, if you are unlucky enough to own one, or a neighbour still owns one, this is what you can expect to see and hear. The radiated RFI will be broadband and may extend from 160m up through the HF bands. It is likely to be […]
The truth about ferrites
These tests and experiments were performed by Ian Jackson VK3BUF in the QRM Guru test lab. Much has been said about the importance of applying ferrite clamps, rings and beads to radios and other domestic products to fight QRM. Articles on the correct placement of ferrite noise suppressors are common, but little has been written […]
DF Loop kit and noise cancelling techniques
The following case study sourced from Grant VK5GR One thing I have found very helpful for finding sources is to build this kit: https://www.minikits.com.au/electronic-kits/high-frequency/hf-active-antenna/EME234-HF-Active-Loop Click this link to visit minikits website. For the antenna, get some ½” soft copper pipe and form a loop about 30cm diametre and use that in place of the wire […]
The best thing you can do to reduce noise in your radio shack
We’ve spoken about the importance of having good house-keeping in your goal for a low noise environment. Other posts on QRM Guru talk about various techniques and tools you can use, but in this video Peter, VK3YE provides a great practical demonstration of how you can reduce noise in your shack. Using Ferrite rings and […]
Tracking and resolving Garage Door Controller noise – noisy PSU
Another noisy garage door causing havoc on HF. A group of hams decided to use QRM guru to help with some unknown RF noise. Using the DF Loop the garage door opener was found to be the cluprit The garage door controller was removed and taken to the workshop for further analysis. Model Herculife RDO-V12 […]
Tracking and resolving Garage Door Controller noise – software setting
Thanks David, a VK3 amateur for this article. Like many amateurs, I live on a suburban block surrounded by local neighbourhood RF hash. My noise level on 40M was typically S9 plus with crackling interference. In the past the basic checks were completed, LED lights, solar inverter etc and without any real conclusion, I became convinced […]