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Helical filters design

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pinuccio48

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helical filter

Is an helical filters design tool available?

Thanks
 

niki

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helical filter design

Difficult topic, needs a lot of experience.

One of the best information source:

Anatol I. Zverev, "Handbook of Filter
Synthesis", chapter 9: helical filters
 

vanderspunk

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helical resonator design

Have not seen any really good program for helical filter design, but I can recommend the book Filters With Helical and Folded Helical Resonators by Peter Vizmuller, Artech House, ISBN 0890062447.
 

Pim

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helical resonator filter

I once managed to assemble a very high performance notch-filter for about 230 MHz by using a helix resonator with top-tuning (by adjusting the distance of a grounded plate closer or further from the top of the helix). I used it for a simple cable-tv descrambler as they just put on an interference signal on the RF for the channel.

I recall that I found some useful info regarding helix-based designs in the ARRL handbook (don't remember the year of the book, but it was at least 10 years old). The most work was not in calculating things but done by trial-and-error. I would strongly recommend a good book on the subject before trying anything like I did, i.e. trial-and-error as it was a very time-consuming task to get it all perfect.
Also, my design was sensitive for temperature (the dimensions of the helix, which was made of about 1,5 mm dia copper wire), changed sligthly with the temperature. So one had to fine-tune it now and then. But correctly tuned it had a superior performance indeed.

/Pim
 

filterman

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helix filters

Hi
I am impressed the good advice elektoda member can provide.
I met once a Dos program for helical bandpass filter design,it was part if the old SCOPE suite(before it become serenade), it was part of the old RF design filters that accompanied supercompact and harmonica,maybe the present Ansoft team would be kind to give it to you for free as they didn't incorporate it in their new filter design tools.
 

Rostfrei

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helical resonator

Pim said:
I once managed to assemble a very high performance notch-filter for about 230 MHz by using a helix resonator with top-tuning (by adjusting the distance of a grounded plate closer or further from the top of the helix). I used it for a simple cable-tv descrambler as they just put on an interference signal on the RF for the channel.

I recall that I found some useful info regarding helix-based designs in the ARRL handbook (don't remember the year of the book, but it was at least 10 years old). The most work was not in calculating things but done by trial-and-error. I would strongly recommend a good book on the subject before trying anything like I did, i.e. trial-and-error as it was a very time-consuming task to get it all perfect.
Also, my design was sensitive for temperature (the dimensions of the helix, which was made of about 1,5 mm dia copper wire), changed sligthly with the temperature. So one had to fine-tune it now and then. But correctly tuned it had a superior performance indeed.

/Pim

Hello Pim :lol:

I need to build notch filter with helical resonator for exactly the same thing as you deed. Can you please give me some guides on building it. Maybe you could send me your design so I could see how you did it ? I would need to build it for channel S9 (PAL) witch is on frequency 161.25 MHz.

Thanx in advance for all your help.

Regards,
 

7rots51

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helix resonator

any new info on helical filter design?pdf? article? soft?
 

Harry Bilgewater

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Some links of interest

http://www.jlab.org/accel/inj_group/docs/Coaxial_Resonators.pdf

The above is pretty much the beginning of Helical Resonators.

A monograph by Peter Vizmuller titled Filters with Helical & Folded Helical Resonators is probably the most concise work that a filter designer familiar with more traditional lumped element designs can have. Check AbeBooks Official Site - New & Used Books, New & Used Textbooks, Rare & Out of Print Books for older copies at a reasonable price. I found mine there for $15.00 as opposed to the current price of the new editions.

Also if you find a copy of Anatol I Zverev's work titled Handbook of Filter Synthesis for less than $50.00 grab it. It is worth its weight in gold in my humble opinion. Zverev's book kind of requires a stiff math base but there is good stuff even for those not steeped in Math. Zverev's book is really a lab notebook in many respects but he does cover just about every filter structure one could imagine.

Another great buy is Microwave Filters, Impedance Matching Networks and Coupling Structures by G. Matthaei, L. Young, and E.M.T. Jones. This has a lot baseline material. If you love Math then you will be right at home with the above books. Again check AbeBooks Official Site - New & Used Books, New & Used Textbooks, Rare & Out of Print Books as often I find older tech references there either no longer in print or so dang expensive that George screeches. I bought my last copy of Handbook of Filter Synthesis (my first one was worn slam out, falling apart, and just in tatters) on abebooks for $35.00 and it was in new condition. It was a library copy which appeared to never have been checked out as the card in the back was virgin and there were no signs of wear.

Hope this helps.

Harry
 

shown

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Capital Tool Industries

Capital tool industries produces Form Milling Tools for all types of applications based on customers specifications
 

pme@airtelmail.in

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Can you please let me know how to find the length of a helical filter? is it lambda/4?
 

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