[Hackrf-dev] How to tell if antenna is faulty

[Jonathan Guthrie]

Your multimeter is probably using DC to determine what the resistance 
is.  At DC an antenna's resistance is...unknown.  It could be anything 
from zero to infinite, depending on how the antenna is expected to work.

Mr. Vanhorn's response is pretty good, but allow me to expand upon it.  
The antennas that come with the HackRF One are honestly not very good, 
so you should probably expect to acquire (either purchase or construct) 
better ones, and the ones you want depend on what you expect to do with 
the device.  They were enough for me to get started and to verify that 
the device works, but I've already constructed others that I'm going to 
use for my actual purposes.  So, the first question you need to answer 
is:  What do you want to do with your HackRF One?  I don't want to 
speculate and give you a bunch of advice that's wrong.

To answer the question that you actually asked, you determine that an 
antenna is working by connecting a signal generator to it and looking at 
the signal radiated from it (if any) using a field strength meter or by 
using it to receive a radio signal of known strength.  You can also 
often determine some useful things by hooking an antenna analyzer to it 
and seeing how it responds to signals of various frequencies.  Antenna 
design and analysis is a very complicated subject with lots of 
deeply-held opinions masquerading as fact, but that's the basics.

On 1/30/2019 4:15 PM, cliff palmer wrote:
> I have a Hackrf One with an Ant500 Antenna and I am having no luck 
> with multiple tutorials found on YouTube, including the ones at Great 
> Scott Gadgets.  I measured the resistance on the (disconnected but 
> fully extended) Ant500 Antenna using a multimeter (one lead on the 
> metal part of the antenna and the other on the male lead in the 
> connector.  The multi-meter measured up to 75 Ohm resistance.
> I'm really new to SDR and so I don't know if resistance should concern 
> me, but it seems like an antenna should not have resistance.
> I would appreciate some advice about how to determine if this is 
> really a problem (and the antenna is faulty) or if I am making a 
> typical new-to-SDR mistake.
> Thanks
>
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> HackRF-dev at greatscottgadgets.com
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