On 6 Mar 2004 11:38:50 -0800, (Anna) wrote:

Hello!
Does anyone know where I can find an antenna for this device
advertised on eBay?

http://cgi.ebay.co.uk/ws/eBayISAPI.d...ategory=46 68

I really dont want to bid on it and find I cannot use the thing in the
end. The advert does not indicate if a standard antenna will fit. I
dont really care if the antenna is a stick antenna or magnetically
mounted.

How easy would it be to construct one from simple components.. I mean
is it like using a coat hanger as a car radio aerial?

Thanx!
Anna

Hi Anna,

The antenna looks like it connects to an SMA connector located at the
left of the picture. Your mission is to find a suitably connectored
antenna. You could as easily just stick a wire of the proper
thickness (what ever it takes) that is a few cm long into the center
of that jack and see what happens. If nothing happens, you trim or
add wire. If nothing persists, you need an antenna amplifier. If
something does happen, it becomes a matter of optimization. It
doesn't get much more complex than that.

However, given your presumptions of car radio aerial, coat hanger,
etc., I would suspect you may have more issues with the output
connector on the right. This represents the issues of powering and
the data protocol which are the greater challenge. For the majority
of us here, the opening bid cost is of no consequence (especially when
it is on par with shipping charges) and if you have any interest, it
should be approached as a tutorial. In other words, if the total is
not seen as disposable income, you should pass as the cost is
certainly going to rise with the learning curve: do you have the
mating interface connector, its cabling, a source of power, a
computer, software? Are you going to put it into a chassis/box? Will
it always be in the same spot or portable (antenna needs vary here)?
Doesn't make much sense in not being portable which suggests, do you
have a laptop?

If you are adding this to an embedded processor design (free standing
display of the data), then most of these questions are moot and your
greatest risk is needing an antenna amplifier. Beyond that, it is
only the necessity of cosmetics for the antenna itself.

73's
Richard Clark, KB7QHC