Directional? Ferrite Beads on audio cables?
How to use consoles with RF on modern TVs
cables - Does the position of the Ferrite bead matter? - Electrical Engineering Stack Exchange
Getting Proper Ferrite Beads and Toroids for RFI Suppression?
So I’m not new to HiFi and the world of gimmicky bullshit, more than likely what’s going on here, but I haven’t heard this one before. I bought a pair of RCA cables off Amazon, I wanted something a little nicer than the Best Buy Essentials cables and too poor currently to buy another Audioquest cable, so this supposedly OFC copper cable pair for $25 was going to be a fine middle road for tying in my newly acquired B&K AV1260 12 channel amplifier to my NAD 7150 receiver. Yeah, that’s right, we’re going maybe partially whole house audio!
So anyway, the ferrite bead I’ve seen before, I have my doubts as to whether they do anything at all, but I haven’t seen a unidirectional ferrite bead before. What’s the bullshit behind that concept?
Most consoles from the Atari to the PS2 have RF compatibility, with uses a coaxial port to connect to the TV using Channels 3 and 4. However, most people do not know how to connect a console with RF to a modern TV of today. I'll show you how.
(Note: This requires no expensive adapter or anything like that. I'm trying to help you avoid buy a RF modulator or RF to HDMI of the sorts)
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Connect the RF adapter to your TV's antenna port. You will continue to receive your digital channels if you currently use it for that purpose
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Turn on the console you are connecting
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If you have a console such as the NES or SNES, which don't have a GUI (like the PS2), you must insert a game and turn on the system for this to work
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In your TV's settings, go to the "Broadcast" settings and begin a channel search
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If it asks you if you want to do Digital or Analog, either select both or Analog
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Wait for the channel search to completely end
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Once it is done, turn the TV to channel 3 or 4 and you can now start gaming!
A couple things to note:
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This will not provide stellar picture quality
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I don't know if you can connect another console via the other free channel
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While I have not tested this on tons of devices, I do know this works on Roku TVs
My answer hopefully applies to beads but also ferrite clamps on cables.
If it's preventing susceptibility problems due to interference coming down a cable then its position is not that critical. However, if it's stopping emissions getting out from a device, a better position is as close to the interfering source as possible. There is every chance that interference getting onto a cable (such as from a switched mode power converter) can radiate from the cable so, best to keep the ferrite up as close to the source of noise as much as possible.
The position is important. There's two cases I can imagine. In the first case, a device is radiating through the cable, and this is unwanted. In this case, the bead should be as near to the transmitting device as possible. This reduces the length of the radiating element. In the second case, a device is receiving unwanted signals picked up on a cable. In this case, again, the bead should be as close to the device as possible. The reason we don't use two beads on a cable is that usually it's not required. Either the communication link is unidirectional, only one device is susceptible, or one bead is enough to change the electrical length enough to attenuate the unwanted signal.
I've seen some beads / toroids listed online at Ham radio specific shops, but these always seem to come with an unusually steep markup. On the other hand, Amazon listings often don't list the mix number. Worse, the listings either have a suspiciously high number of "five star reviews" or half the listings say "do not buy these they're crap / not the mix they claim to be." Which of these reviews are accurate, who knows?
What are some good sources for ferrite beads and toroids for RF suppression that aren't excessively marked up? My long coax runs are LMR-400 Flex and my patch cables are RG8X, which sizes work best for these? What about USB cables? Toroids follow the same mix number convention as the ferrite beads, right? What's a good toroid size for wrapping a clothes washing machine's large flat power cable?
Also, is there a rule of thumb for how many beads I'm supposed to put around coax and where? I've read that mix #31 is optimal for HF bands. Is there a mix number that is optimal for 2m/70cm? Thanks!