Step 2 – Locating the noise source

Direction Finding (DF) Loop Antenna Kit

For now, we are no longer selling DF Loop Antenna kits. All the parts are readily available either from your local electronics retailer or from various on-line stored. This video explains how to build the DF Loop Antenna

Finding power line noise using a VHF AM receiver

Thanks to George Smith G8AOJ and the RSGB. “For several months I had been experiencing random variable level wide-band impulsive noise across the whole 2m band. This manifested itself at times as a strength seven continuous crackling noise.” Read on to see how George traced the offending noise source. This article is copyright of the […]

Finding and killing QRM in the home with ferrite toroids & snap-ons

From Josh KI6NAZ Josh has put together a great Youtube video on reducing RFI in and around the house. Using simple techniques to find the noise source and then using toroids and snap-ons to reduce or illuminate the noise. A very useful video. “For most of us, RFI is around us all the time. It […]

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 […]

Tracking down interference in the 2m amateur band

This success story is from Andrew, VK3FS. Thanks Andrew… Whether it’s an annoying buzz or hum, radio interference can certainly diminish enjoyment of our hobby. Finding it and getting it fixed can be one of those challenges that can really try us, but it need not be. This is the story of my local QRM […]

List of Tools

Here is a simple list of tools you’ll need to start searching for noise: a small DF loop, like this one for VHF and UHF, a Yagi or other directional antenna. Say something around 8db gain a simple wide band AM receiver or a 2/70 handheld for higher frequency work – two suitable options are […]

LED Down lights – resolving a significant noise problem

Thanks Steve VK5SFA for this article. Sometime in late July 2019, a strong wideband noise appeared across all HF bands at my home QTH in Adelaide. The noise level was S9+20dB (-50dBm) and was making HF reception from my suburban block almost impossible. I started the process of remedying the situation by logging the interference […]

Locating noise in your home

If your noise source is limited to your home (and property) then you’re in luck. You have much greater control over how the noise can be resolved. Follow this simple procedure to locate the noise. Power your receiver with a 12v battery so you’re independent of the mains supply You can start by turning off […]

Locating Power Line Noise

The below videos give a real world example of power line noise suffered by Allan VK2CA. The second video shows first hand how you can use a simple VHF/UHF receiver to narrow down the offending power pole. QRM.guru thanks Allan for providing these videos. This video illustrates first-hand the horrible sounds that […]

Narrowing down the offending noise source

Now you’ve spent some hours playing detective and believe you have a good handle on the location and source of the noise. For example: The two adjacent neighbours are radiating significant broadband noise, indicative of switch-mode power supplies, as well as what may be an auto battery charger. You have also identified some powerline noise […]