[MLB-WIRELESS] Antenna link

[Alan]

Horace,
I tend to agree, I pulled out all of my old electronics books and found 
the formula for calculating the wave lenght. Even using a velocity 
factor of 0.8 which is about the best you could expect from a coat 
hanger I calculated a wave length of exactly 100mm. Using 1/2 
wavelengths the straight sections should be 50mm, or perhaps a bit 
longer if you were using copper wire.
How often is the anayser at the meetings? any idea who owns it?

Just for interests sake, the formula I used for the wavelength is
         
Speed of light
--------------  x 0.8(velocity factor of wire)
2.4 Ghz

this works out like
300,000,000 metres/second
----------------------------- x  0.8    = 0.100 metres
2400000000 Cycles/second

My other problem was the connector on the bottom was a PL259 which is 
not exactly rated at 2.4 Ghz. I look in the latest Jaycar catalogue and 
find that they are advertising a ready made 5dB dipole antenna for 
$19.95. Why am I wasting my time!. Mind you they will not be in stock 
until 4th July.

Alan Barrow



Horace Pinker wrote:

> Hi actually i had very limited success with it, it is good for around 
> the house and it picks up a few things on the roof but nothing over 
> 1Km unless it was amplified to start with(local libraries). So I 
> brought it in to the second last meet and it was put onto the analyser 
> and ..... it bombed out badly, it would seem that it was designed for 
> a totally different frequency or someone didnt do the calcs properly. 
> I have had a look for a formula for calculating the proper lengths  
> and i didnt get too far, as there is a lot of clutter from commercial 
> manufacturers who worked this out and now want to get their dividends 
> to pay up :(
>
>> From: Alan <gone_4wding at bigpond.com>
>> To: Horace Pinker <horacepinker at hotmail.com>
>> CC: melbwireless at wireless.org.au
>> Subject: Re: [MLB-WIRELESS] Antenna link
>> Date: Sat, 14 May 2005 21:58:37 +1000
>>
>> Has anyone had any success with this antenna?
>> I have just made one, well  three actually, the first two wern't 
>> accurate enough so I threw them away.
>> I have installed it on the roof and I can hardly pick it up from a 
>> room in the house.
>> The lead I used was the original antenna system of a Belkin card, I 
>> cut the original antenna off and connected it to theis new one.
>> I made the high gain version with the 4 coils.
>>
>>
>>
>> Alan
>>
>>
>>
>>
>>
>>
>> Horace Pinker wrote:
>>
>>> Some of you were interested in the antenna i brought to the meeting, 
>>> tho its not new some of you asked for the link, so here it is.
>>>
>>> http://www.frars.org.uk/cgi-bin/render.pl?pageid=1071
>>>
>>> I have made a template for this antenna and if anyone wants me to 
>>> make them the wire element let me know and i can bring it in for you 
>>> next meeting
>>> Cheers
>>>
>>>
>>>
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>>>
>>
>>
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>
>
>


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