Antenna for SDR

B

balanga

I have just received an antenna for my RTL-SDR dongle and it doesn't seem to do anything.

How can I tell if it has the correct connections?

I can fasten it but I'm not sure about where I was given a cable with the wrong ending.

What ending should the cable have? ie the one that connects to the dongle? I assume all the dongles are the same.
 
tingo said:
All dongles are not the same. Shows us the connectors - on both sides.
Click to expand...
Actually, I have just checked properly and the cable they match up OK. The dongle has a female end and the cable has a male end.

I don't how to tell whether this di-pole antenna is actually giving me anything.

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I just received an antenna kit like this. Did you notice the different telescoping antennas that came with it?
You adjust the antenna length by what frequencies you want to receive.
With the telescoping elements fully extended you will be able to get signals in the lower end of the spectrum.
For the higher end of the RF spectrum you would not want your telescoping antenna fully extended.
Higher frequencies use shorter elements. Lower frequencies need longer elements.

Do a quick check by seeing if dump1090 gives you any output now.
 
It would help to know the exact RTL-SDR model and the antenna you bought. Most RTL-SDR dongles use an SMA female connector, so the antenna cable usually needs an SMA male connector. Some inexpensive antennas come with MCX or other connectors and require an adapter, so it's worth checking that first.

Also, don't expect a dramatic change immediately. Try tuning to a strong local FM broadcast station or a nearby weather or airband frequency to confirm that the antenna is actually working. If you can receive those but nothing else, the issue is more likely antenna placement or frequency selection than the connector itself.
 
I can receive ADS-B with even wrong polarity antenna. It seems to be very receivable.
I think I have issues with some bands because I have large commercial towers 4 & 6 miles away. Maybe need FM filter.

When I received my kit the first thing I did was attach the two longer telescoping elements and mounted that to the suction cup and used 180 degree orientation instead of 120 degrees like V-Dipole.
Mounted it in window.
I wanted to have a baseline to check against my tower antenna setup once finished.

Still nothing on the VHF front but get adjacent Gov Weather station better.
 
SirDice said:
I have the same set.



For ADS-B (aircraft transponders) the dipole needs to be the smallest, point the grounded side down (look at how the cable is attached to the antenna).
Click to expand...
Using the smallest elements seems counter intuitive to someone like me who has no understanding on how to maximise reception.

Does your advice have any advice on radio reception.

What I can't understand is why the FM Radio app on my tiny Samsung Galaxy SIII Mini has better reception than my RTL-SDR dongle when earphones are plugged in.
 
balanga Play with the gain setting(s) on your SDR app. Some programs display them separately as LNA, VGA and Mixer. Others offer a single slider than manages all three. This is, of course, separate from the audio output gain (volume). As gain increases, the noise floor in the waterfall rises. Too much gain will cause intermodulation and severe distorion. What matters isn't the absolute height of the signal peaks but their height relative to the noise floor.
 
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