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Comment by gorkish | Hacker News Reader

I'm quite frankly amazed that this is the first time this guy has had to put a choke on something as a radio amateur. I guess he doesn't use HF that much otherwise he'd probably have opted to buy an entire bag of ferrites.

Maybe his magsafe charger really is bad, but if it's plugged into a computer or a crap charger it's also likely that it's just RFI riding the cable straight out of the computer. USB stuff is the worst offender in my shack -- the majority of USB cables are just a complete joke.

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ha! No doubt - HF user here with a bag of ferrites.

When I'd transmit on 20m, it would sometimes open my old liftmaster garage door. Until I wrapped all of its cables in ferrites.

Can’t wait for his post after he ditches the HT in the car and buys a mobile unit to mount in it. He’ll be in a new world of hell.

where can one buy a bag of ferrites?

There are several options from Amazon, try searching for "Clip-on Ferrite Ring".

I know; i hoped for a site that sells all the types of rings, binocular, clip-on - which are great for choking VHF vertical dipoles with the bottom leg being spokes that are obviously too short for the frequency - i digress.

I'm also just grown weary of amazon.

Check out https://proaudioeng.com/fair-rite-ferrites/. Also dxengineering has them.

Type 31:

> Mix 31 excellent for 1-10 MHz common mode suppression, then about same as 43 up to 250 MHz, NOT recommended for multi-ratio impedance transformers (baluns/ununs) due to material characteristics and power handling capability – ok for ham radio 1:1 feed line choke applications. Curie temperature >130 C

But in looking for concise relevant information i found https://palomar-engineers.com/ferrite-products/ferrite-cores... which i quoted above

edit: also, thank you

Another way to get a lot of ferrite cores for super cheap is to harvest them from cables that included them like VGA and DVI cables. you can cut them out and peel off the overmolding. Most are still split core. The material is often not very good at lower frequencies like HF, but you can use more cores or loop your cable through multiple times to increase the effectiveness of the choke.

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