[OZAPRS] Newb HF questions ;)

[Ray Wells]

Ben,

Nope, not a knitter, but my wife is.

Didn't anybody spot my "mistake"?

If one needle when used as a quarter wave, and the frequency is 240MHz, 
two of them used as a dipole will still be 240MHz, and not 120MHz.

Ray vk2tv

Ben Lindner-VK5JFK wrote:
> Well done Ray. Were you a knitter from way back ? having those needles 
> hanging around. Not that there is any thing wrong with that, a lot of 
> men knit :-)
>
> Ben vk5jfk
>
> Ray Wells wrote:
>> Looks like it's time to get technical, heaven forbid!
>>
>> I've just measured a typical aluminium knitting needle at 300mm. If 
>> we assume it is a quarter wavelength and the length to diameter ratio 
>> is 0.96 we can divide 300000 by (1200/0.96) to arrive at 240Mhz. This 
>> is a reasonably thin needle so an appropriate adjustment needs to be 
>> made for fatter needles. The metal end-cap would add slight 
>> capacitance to slightly lower the resonant frequency.
>>
>> Since knitting needles are usually used in pairs, a dipole would be 
>> resonant at about 120Mhz which is great for the aircraft band.
>>
>> Ray vk2tv
>>
>>
>> Tony King wrote:
>>> I had to ask.... What band are knitting needles resonant on??
>>>                                        Regards Tony VK3API
>>>
>>> Ben Lindner-VK5JFK wrote:
>>>> "Have you thought about trading in your radios for knitting needles 
>>>> :-) "
>>>>
>>>>
>>>> Ray,  I believe that Scrap Booking and Quilting have taken over 
>>>> from knitting now. :-)
>>>>
>>>> Ben
>>>> VK5JFK
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