The kit includes:
- 1 x 61mm ferrite core
- 1 x 50mm ferrite core
- 5 x large ferrite snap-ons
- 5 x medium ferrite snap-ons
- Application notes on the effective use of ferrite filters
This kit will help you reduce QRM from your transmitter, as well as reducing or even eliminating local QRM affecting your receiver. These will be particularly effective is you are suffering common-mode noise, where interference enters your radio via the coax shielding.
If you suffer the following, a combination of these ferrites may help:
- computer rebooting when you transmit
- RF hot microphone or Morse code key
- RF feedback affecting your own transmission
- RF interfering with your computer screen
- losing data control to/from your computer when you transmit
- resetting or impacting your ADSL or NBN modem
- interference to devices such as TVs, broadcast radios, garage door openers etc.
- noise being radiated from LED lights and other consumer electrical products
- noise travelling along your mains power
If your local QRM is persistent you may need to track it down and take remedial action at its source (e.g. LED lamps, garage door openers, wall-warts, switch-mode power supplies).
The ferrites in these kits exhibit very similar RF suppression characteristics as Mix 43 products.
A good RF earth is also recommended.
Our first batch of kits sold very quickly. We now have a second batch ready to ship. During the period of Covid-19 restrictions we’re shipping the kits to any Australian address for $40 each plus $10 P&P. We can ship up to 3 kits for the one fixed price with Australia post – this will reduce the cost per kit. If you’d like to buy more than 3 kits, please email us at feedback@qrm.guru
If you are ordering from outside Australia, please email us first and we will send you a PayPal invoice with the additional postage costs: $25 to USA and $31 to EU. You may well be able to source cheaper parts locally… postage is expensive!
If you’d prefer to pay by direct bank transfer please visit this page.
Once it’s safe to get out and about, we’ll bring them to club meetings and Hamfests.
Order here

Complimentary membership to RASA is included in your purchase.
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