[OZAPRS] Newb HF questions ;)

[David and Justine Olsen]

No but I did think to myself, that is a short dipole for 120 MHz- I  
am a pilot.



On 24 May 2009, at 08:10, Ray Wells wrote:

> 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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