mzac Posted July 1, 2014 Share Posted July 1, 2014 So I was trying to find a good place to put my stock antenna that came with my R820T SDR dongle, and the only place I found at my kitchen table was on my ceiling light above the table. I have a feeling that the way I have set it up it is quite close to being a reverse j-pole as my lamp is all metal and is grounded to my electrical panel. This said, with this configuration I am getting ADS-B signals up to 200km away and I am about 30 meters above sea level. Can anyone else confirm if this could be the cause or am I just lucky? Quote Link to comment Share on other sites More sharing options...
KD6W Posted August 1, 2014 Share Posted August 1, 2014 Nice picture. The stock antenna is actually pretty good for ADS-B operation and best when stuck on something metallic like your light fixture or the top of your refrigerator. J pole antennas are easy to make, omnidirection folded dipoles designed to easily match the impedance at a specific frequency to a transmitter. That said, a half wave length hunk of wire sticking straight up in the air will have the same receive gain compared to a j pole. For really good gain, you need a really good gain antenna like a YAGI but those are directional and why most folks simply use co-linear antennas including high power broadcasters. The simple vertical antenna gain can be greatly improved by simply putting a back plate ground plane behind it but then the pattern would become cardioid in shape. 200km readings are fairly common when the aircraft are at cruising altitude. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.