EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: Shaw on July 11, 2013, 02:04:43 am

Title: Identifying and testing unknown antennas
Post by: Shaw on July 11, 2013, 02:04:43 am
Hi all,

I've got a bunch of rubber-duck antennas at home in a box, I know some are 900Mhz and some are 2.4Ghz ones.  Of course they all look the same which is annoying.  Is there any simple way for me to test these?

I don't have a full electronics lab, but I do have a Rigol 100Mhz scope and multimeter... I don't have a signal generator or spectrum analyzer, which I suspect are the two pieces of required kit.

Any suggestions on a quick and easy way to identify these would be great. 
Title: Identifying and testing unknown antennas
Post by: WarSim on July 11, 2013, 02:52:37 am
Without a signal generator or network analyzer, I can't think of anyway at the moment.
Title: Re: Identifying and testing unknown antennas
Post by: Rasz on July 11, 2013, 03:00:26 am
http://pe2er.nl/wifiswr/ (http://pe2er.nl/wifiswr/)

or just get a wifi card and try all the antennas checking signal strength of a known ap
Title: Re: Identifying and testing unknown antennas
Post by: vk6zgo on July 11, 2013, 03:22:30 am
http://pe2er.nl/wifiswr/ (http://pe2er.nl/wifiswr/)

or just get a wifi card and try all the antennas checking signal strength of a known ap

Nice project,but being "rough as guts",I would go with your second suggestion! ;D
Title: Identifying and testing unknown antennas
Post by: WarSim on July 11, 2013, 03:26:41 am
I agree the second suggestion is much better than my no idea option.  :)
Title: Re: Identifying and testing unknown antennas
Post by: olsenn on July 11, 2013, 04:02:30 pm
What are you trying to measure? SWR can be measured with a spectrum analyzer and a bridge or coupler. impedance can be measured with a multimeter or LCR meter, but it's safer if you measure this at the frequency you're operating at. More advanced measurements really call for a network analyzer and more specific equipment
Title: Re: Identifying and testing unknown antennas
Post by: babysitter on July 11, 2013, 07:34:58 pm
Look out for the local ham radio club. You might find that certain guy that loves to do exactly that, there.

I second the method of hooking it up to a Wifi card, and try to get the best estimation of field strength you can get -
with windows, netstumbler is your friend and wl under linux, I think.

Be careful when tightening the connectors.