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Helical Antenna DIY


chris_bollard

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To Michael Clark / MikeWest / Vin

The scanner worked fine so I emailed the files 'Helical Antenna Design of to you today, let me know if you got them. And on a side note since Vin will be reading this, Congratulations on your sound design award!

VE7KJR (PHIL)

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Phil,

I did get the files, thanks. My reply to your email was kicked back to me. You're not kidding on the math side of things. And a tough build also. Almost worth the $400 to buy one.

BTW, have you ever attempted this build?

Hi Michael, If you consider how much time you would have to put into the project,figuring out the math / getting the materials needed/ and then assembly, I would say several days at least. On the plus side, there is a great deal of satisfaction from building ones own projects and they work. I have not built one myself yet, however I did help a friend build one about 10 years ago for the microwave band (gigahertz) and it worked very well. When I have some more time, I will build one, do the field tests, post the results here with pictures ETC. Don't know why your email got bounced back,I just checked mine and return address works fine.

VE7KJR (Phil)

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Many thanks Phil.

I think the build is not too difficult and with the NZ $ at 50cents  to the US $

a PW antenna is $1000.00 of my money.

To all interested have a look at this:

http://www.rac.ca/tca/2006-01%20Helix%20Design%20Calculator.html

Have found some interesting stuff on the web on helicals.

Construction techniques and materials and stripline design.

Will be having a go next week.

Cheers

mike

www.mikewestgatesound.co.nz

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Many thanks Phil.

I think the build is not too difficult and with the NZ $ at 50cents  to the US $

a PW antenna is $1000.00 of my money.

To all interested have a look at this:

http://www.rac.ca/tca/2006-01%20Helix%20Design%20Calculator.html

Have found some interesting stuff on the web on helicals.

Construction techniques and materials and stripline design.

Will be having a go next week.

Cheers

mike

Hi Mike, There is a lot of information out there for sure but just like everything else on the net you have to weed out the crap, the files I sent were from the ARRL (American Radio Relay League) Antenna Book which is a reference book and very well respected around the world.Although most of the information is related to amateur radio antennas, there is no reason that information would not work or be helpfull to us who use VHF/UHF transmitters/ recievers every day at work.The same principles apply,therefore it is a matter of doing the math to make the dimensions/spacings  work within the frequencies of your radios.The impedance of that design is between 110to180 ohms and will need to be matched to 50 ohms. There are several matching systems designs none of which I have given much though to yet,that will come later.

VE7KJR (PHIL)

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Not only do I have all the info I need but I have a PW unit for evaluation.

I'm surprised at its size but I guess the results are the real measure.

Construction is simple.

Impedance conversion 130 down to 50 is achieved by using a length of wider foil

from the end of the spiral to the BNC connector.

Can't wait to make a start next week

Mike

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Not only do I have all the info I need but I have a PW unit for evaluation.

I'm surprised at its size but I guess the results are the real measure.

Construction is simple.

Impedance conversion 130 down to 50 is achieved by using a length of wider foil

from the end of the spiral to the BNC connector.

Can't wait to make a start next week

Mike

Looks like the RACE in on,, who will be the first out of the gate with a working helical, looks like mike is in the lead followed by ????

I'm so excited for you interest in this project Mike, if you could take some hi res. pics of the PW unit for me that would be great,would like to see some close ups of the matching network. Email them direct if you could .A great bit of detail has to be thought out on the matching strip, size / shape / thickness / angle and distance from the ground plane. Do you have an operating impedance bridge to measure the impedance?

VE7KJR (PHIL)

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Just logged back on after a short holiday (you all must know what that is?) and great to see that there are others on the forum interested in making their own helical.

I'm interested in getting the scanned info. Also in seeing who cracks the prototype first.

Hi Chris, Well you started this thread and I guess I got the ball rolling. I will email you the files later on this afternoon as I am just on the way out the door.

VE7KJR (PHIL)

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