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 Post subject: Is there a ferrite rod/material for use on HF frequencies?
PostPosted: Apr Fri 19, 2019 5:00 pm 
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Joined: Aug Mon 17, 2009 9:14 pm
Posts: 84
Location: martville ny
Hello

I would like to build a receiving ferrite rod antenna for use up to @ 30Mc.
I have googled the question and their many who say that ferrite (in general) cannot be used above @ 2Mc.
But their are some who allude to the existence of a certain "Mix" that will allow for HF reception.
Can anyone shed some light on this?

Thanks
Dave


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 Post subject: Re: Is there a ferrite rod/material for use on HF frequencie
PostPosted: Apr Fri 19, 2019 5:29 pm 
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Location: Maryland 20709, USA
oldlongwave wrote:
I have googled the question and their many who say that ferrite (in general) cannot be used above @ 2Mc.
Hi Dave,

The Amidon catalog lists ferrite mixes (#43 and #64) for use up to 1000 MHz.

For 2-30 MHz, probably the #75/J material is appropriate.

- Leigh

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 Post subject: Re: Is there a ferrite rod/material for use on HF frequencie
PostPosted: Apr Fri 19, 2019 7:07 pm 
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Joined: May Tue 30, 2006 4:46 pm
Posts: 10009
Location: Santa Rosa, CA
Ferrites usually get used in switch-mode power supplies below 1 MHz, but there are ferrites that can be used in the VHF/UHF ranges.

https://www.researchgate.net/figure/Rel ... _224694532

Image

Rich


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 Post subject: Re: Is there a ferrite rod/material for use on HF frequencie
PostPosted: Apr Fri 19, 2019 8:01 pm 
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Joined: Nov Mon 06, 2017 2:35 pm
Posts: 119
Location: Texas, U.S.A.
Dave,

Yes.

Possibility:

https://www.cwsbytemark.com/index.php?m ... tjtc3uegh3

https://www.cwsbytemark.com/images/R-050750-61.pdf

http://www.bytemark.com/products/rod_new.html

http://www.amidoncorp.com/product_image ... terial.pdf

WB5HDF


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 Post subject: Re: Is there a ferrite rod/material for use on HF frequencie
PostPosted: Apr Sat 20, 2019 12:47 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 2334
Location: Saskatoon
Ferrites generally have two frequency ratings:
1. For tuned circuit use.
2. For broadband transformer use.

The frequency rating for broadband transformer use is normally much higher than the frequency rating for tuned circuit use. You'll need to use the tuned circuit frequency rating for a ferrite rod antenna.


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 Post subject: Re: Is there a ferrite rod/material for use on HF frequencie
PostPosted: May Sun 12, 2019 11:10 pm 
Member

Joined: Aug Mon 17, 2009 9:14 pm
Posts: 84
Location: martville ny
Hello

Thanks very much for all your replies! Sorry, I dont get on this forum often enough. Looks like #61 material is my best bet for use on the shortwaves.
Have a question though... Bytemark lists the #61 as having a usable frequency range of .1-25Mc.
Found this other site Stormwise, that sells a 125u rod (they dont specify the material number) and they say it is good to only 10Mc.
What could be the difference?

Thanks
Dave


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 Post subject: Re: Is there a ferrite rod/material for use on HF frequencie
PostPosted: May Mon 13, 2019 12:39 am 
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Joined: Sep Mon 16, 2013 2:42 am
Posts: 3547
Location: Tucson, Arizona U.S.A.
Another difference between ferrite materials, is it made to have low loss or high loss at its designated frequency? Low loss materials are used for antennas, transformers, and other signal applications. High loss materials are designed to absorb the frequency they are made for. They are used in the ferrite beads used for suppressing interference.

You shouldn't have any trouble finding the right material for your application. The real problem will be, is it available in the shape you need?

Also note that each manufacturer has their own numbering system for the mixes they make, even though they may be equivalent to some other company's product under a different number. Always check the performance curves to be sure.

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Jim Mueller


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