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Are these ferrite cores any good?


#1

Not strictly an antenna so hopefully this category is alright.

I found these two ferrite cores at work today. Same size, seemingly the same model although there may be internal differences I can’t see. But the magnets look the same.

Two different colours too, but the two model numbers may just reflect that and not any other differences. The manufacturer appears to be “TODAISU” but there’s not much I can find online about them.

Is anyone familiar with them? Would they do alright at reducing any interference I may be getting on 2m or 70cm? And if so, where exactly on my coax do I clip them?


#2

Uses for this would be outside use with a HT for SOTA and also RTL-SDR dongle use with my range of antennas.


#3

Maybe. Or possibly not. Maybe you could describe the interference then people can give a more detailed reply.
Also the radio model and antenna would help.


#4

Ah, fair dos.

I think I’m conflating two different things. I often get spurious signal readings on my Kenwood F7E, but it happens outside too. It may be the radio, they’re pretty bad for that.

The dongle interference is probably internally generated by other appliances in the home? I can sometimes see lines on maybe SDR software display that appear to be nothing.

Maybe I should have come in with screenshots and the like too, but I just found them and excitedly wondered if they were any good :slight_smile:


#5

They’re very good for what they are designed for. But as you have yet to describe in a meaningful way what the setup is and what the problem is, then it’s hard to offer help.


#6

Okay. I’ll see if I can get some better info this weekend and bump this then.

Just thought someone would recognise the cores themselves and tell me what they may be designed for. I assume that they’ve been designed for specific pieces of equipment so it may have jogged someone’s memory.


#7

Google said https://www.google.com/url?sa=i&source=undefined&cd=&ved=0ahUKEwjSouDw16zfAhUS1xoKHesADV0QzPwBCAM&url=https%3A%2F%2Fm.bukalapak.com%2Fp%2Felektronik%2Fkomponen-elektronik%2Ftcgfg-jual-todaisu-ferrite-cores-models-ht2629s-brand-new&psig=AOvVaw3seMAOG3A8xqK0HeYrAleb&ust=1545336144428373


#8

Your google-fu is better than mine. I’ve tried lots of combinations. Thank you.


#9

So I tried them myself and took some measurements and they are very good. Just putting on one core on with two loops drops the noise floor by a good 10-15 db. That was listening to the local ATIS at Edinburgh Airport on my SDR dongle. The noise floor drop on FM seemed lower (local repeater). No appreciable drop in signal level received, seemingly. I get better performance with 2, then not much more with 3.

Not sure if they will help with any of the local sources of noise I’m getting, so time to investigate that now.

No need for anymore on this, just providing closure :slight_smile: