31-Mix Snap-On Ferrite

31-Mix Snap-On Ferrite
31-Mix Snap-On Ferrite 31-Mix Snap-On Ferrite
Brand: Ham Goodies
Product Code: HG-31PRBSLVR
Availability: 4
Price: £14.50

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This snap-on ferrite is a serious item - It's a 31-mix ferrite that is ideal for use as a mains filter and/or HF choke for the whole of HF.  With increased amounts of domestic "QRM" such as switch-mode power-supplies, televisions, cable routers and LED lighting making HF reception in some situations a non-starter - how do you go about taming it?

Known as the Problem Solver in GM3SEK's In Practice articles (and a live demo in this RSGB "Clean Up Your Shack" video) the snap-on design enables you to wind several turns of cable in a non-invasive manner.  31-mix is perfect for use across HF and especially on the lower bands - and at 3x thicker than a typical FT240-31 toroid, it's a bit of an animal.

  • Fair-Rite part # 0431177081
  • 56mm length, 43mm width
  • Internal diameter: 25.6mm

How to Use - For a mains choke/filter, see the picture above - it uses the conductors of 2.5mm twin&earth with 5 turns in total and is best used for your radio's PSU only so that anything else is behind the filter.  As an RF coaxial choke, 8 turns should be sufficient across the HF bands.  We also sell 31-mix ferrites in FT240 (2.4") diameter for Baluns, Chokes etc.  Smaller 5mm snap-on and 9mm snap-on ferrites for USB cables are also available.

It's also wise to test your house without mains power - Switch-off the main circuit-breaker and run your radio off a battery: How is the noise-floor now?  If it has dropped, then that's good news - it means that you can switch things back on one at a time to discover what is causing the interference.  With some time and a little patience, you may get a few S-points back and possibly a much improved HF experience!

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