[MLB-WIRELESS] Antenna link

[Andrew Wagstaff]

I've bought one of those dipole antennas and had it tested on the spectrum
analyser. It has around 2-3dB gain, mainly because of the long length (75cm)
of poor quality coax.

Regards

Andrew Wagstaff

----- Original Message -----
From: "Alan" <gone_4wding at bigpond.com>
To: "Horace Pinker" <horacepinker at hotmail.com>
Cc: <melbwireless at wireless.org.au>
Sent: Tuesday, May 17, 2005 10:08 PM
Subject: Re: [MLB-WIRELESS] Antenna link


> 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
> >>>
> >>>
> >>>
> >>> To unsubscribe: send mail to majordomo at wireless.org.au
> >>> with "unsubscribe melbwireless" in the body of the message
> >>>
> >>>
> >>
> >>
> >> To unsubscribe: send mail to majordomo at wireless.org.au
> >> with "unsubscribe melbwireless" in the body of the message
> >>
> >
> >
> >
>
>
> To unsubscribe: send mail to majordomo at wireless.org.au
> with "unsubscribe melbwireless" in the body of the message
>
>

To unsubscribe: send mail to majordomo at wireless.org.au
with "unsubscribe melbwireless" in the body of the message


To unsubscribe: send mail to majordomo at wireless.org.au
with "unsubscribe melbwireless" in the body of the message