Thanks, very helpful! I bought some Fair-Rite mix 31 snap-ons recently. My application is trying to suppress some RFI in the 2 to 6 MHz range. Sounds like I made a good choice.
Is there a ferrite material that's considered _"broadband"?_ Someone is selling ferrite beads for power lines supposedly to help filter out *EMP PULSES.* They are similar to your _Snap It Cores_ but no specifications are given, other than being _"broadband"._ I saw a video saying that mil specs require protection from *_10 kHz-10gHz._* Do you have a ferrite material that would cover that range, or would a *combination* of materials (such as 31 and 61) be needed to cover it? I'm sure that you don't *CLAIM* that your devices will actually suppress EMP currents, but I'm just looking for something that will *HELP* (along with a beefy surge suppressor).
A combination of materials would be the most helpful but, it is difficult to truly assess how effective they will be at suppressing an EMP. 75 material covers from around 200kHz into the low MHz range, 44 material covers several MHz to several hundred MHz and 61 goes from several MHz to several GHz. That combination would likely be most effective. How well they work is going to depend on just how high the induced currents are. If they are too great, the cores can saturate and won't provide much attenuation.
Hi guys, i dont have the charts handy at the mo, just wondering what's the best core material for 200-1700 Khz (LW and MW bands) for matching transformers (baluns/ununs etc)
43 material would cover that range with relatively low core losses. At the lower frequencies (say 400kHz and below), a higher permeability MnZn core like 78 material would likely perform better. This would come at the expense of higher frequency performance however.- Mike
@@FairRiteProductsCorpthank you guys.. The whole science behind this is something of a 'dark art' for me at the mo. I do have some toroidals at home that i think are type 77 as i can measure surface resistance across them, as opposed to type 43s which are labelled and measure open circuit. I had used these 43's for matching my flag antennas which measure anything from 200ohm to 1000ohms across the BCband, but decide to replace them with the other unknown ones. I have a nanoVNA and i think this will enable me to identify the characteristics of the unidentified toroidals. Bottom line is, do u think type 77 will offer a noticeable improvement over a type 43 of similar size and turns ratios?
If the 43 cores are already working at low frequency without getting excessively hot, I wouldn't expect a massive improvement. At low power levels, the 77 should provide lower insertion loss due to the higher permeability. At high power, low frequency, the 77 should have lower core losses. Higher frequencies at higher power levels, the 77 may see excessive core heating due to the losses. @@vincentstevens5048
@@FairRiteProductsCorp thank you guys for making an effort to answer my questions. I neglected to mention I'm not transmitting. Its purely for my receive antennas. Im mainly interested in long distance MW reception, but i have the problem of being very close to a BC transmitter, so i am trying various solutions involving different antennas, but matching these to 50ohm is a priority. Thus the use of baluns/ununs etc etc
Thanks, very helpful! I bought some Fair-Rite mix 31 snap-ons recently. My application is trying to suppress some RFI in the 2 to 6 MHz range. Sounds like I made a good choice.
Difficult to follow verbal description, hope for some visual demonstration and illustration. Thank You
Is there a ferrite material that's considered _"broadband"?_ Someone is selling ferrite beads for power lines supposedly to help filter out *EMP PULSES.* They are similar to your _Snap It Cores_ but no specifications are given, other than being _"broadband"._
I saw a video saying that mil specs require protection from *_10 kHz-10gHz._* Do you have a ferrite material that would cover that range, or would a *combination* of materials (such as 31 and 61) be needed to cover it?
I'm sure that you don't *CLAIM* that your devices will actually suppress EMP currents, but I'm just looking for something that will *HELP* (along with a beefy surge suppressor).
A combination of materials would be the most helpful but, it is difficult to truly assess how effective they will be at suppressing an EMP. 75 material covers from around 200kHz into the low MHz range, 44 material covers several MHz to several hundred MHz and 61 goes from several MHz to several GHz. That combination would likely be most effective. How well they work is going to depend on just how high the induced currents are. If they are too great, the cores can saturate and won't provide much attenuation.
Hi guys, i dont have the charts handy at the mo, just wondering what's the best core material for 200-1700 Khz (LW and MW bands) for matching transformers (baluns/ununs etc)
43 material would cover that range with relatively low core losses. At the lower frequencies (say 400kHz and below), a higher permeability MnZn core like 78 material would likely perform better. This would come at the expense of higher frequency performance however.- Mike
@@FairRiteProductsCorpthank you guys.. The whole science behind this is something of a 'dark art' for me at the mo. I do have some toroidals at home that i think are type 77 as i can measure surface resistance across them, as opposed to type 43s which are labelled and measure open circuit. I had used these 43's for matching my flag antennas which measure anything from 200ohm to 1000ohms across the BCband, but decide to replace them with the other unknown ones. I have a nanoVNA and i think this will enable me to identify the characteristics of the unidentified toroidals. Bottom line is, do u think type 77 will offer a noticeable improvement over a type 43 of similar size and turns ratios?
If the 43 cores are already working at low frequency without getting excessively hot, I wouldn't expect a massive improvement. At low power levels, the 77 should provide lower insertion loss due to the higher permeability. At high power, low frequency, the 77 should have lower core losses. Higher frequencies at higher power levels, the 77 may see excessive core heating due to the losses. @@vincentstevens5048
@@FairRiteProductsCorp thank you guys for making an effort to answer my questions. I neglected to mention I'm not transmitting. Its purely for my receive antennas. Im mainly interested in long distance MW reception, but i have the problem of being very close to a BC transmitter, so i am trying various solutions involving different antennas, but matching these to 50ohm is a priority. Thus the use of baluns/ununs etc etc