Recently, I have been fascinated with software defined radio (SDR.) There are a number of cheap
USB dongles which fall into the RTLSDR camp. I believe most of the USB dongles use Realtek (RTL) chipsets, hence the name.
RTLSDRs are interesting because they allow you to scan a wide frequency and cost maybe $20 on Amazon of eBay. After getting a few, however, I started to wonder how limiting the stock antenna might be. The stock antennas which come with most RTL-SDR USB dongles are meant to pick up digital TV in Europe and are pitifully small.
I wondered – would a proper antenna make a difference? The answer, in short, is yes.
I decided to perform an SDR antenna comparison, using the stock antenna against a discone antenna. After some research, I settled on a discone because they are generally well-suited to receive on a wide spectrum of frequencies. In this case, I purchased a Diamond D130NJ as it had decent reviews and was available nearby. Here is the antenna fully assembled.
I have had limited time to test the two; I was so excited with my initial results I had to share. My discone is still on the ground; here’s a comparison of reception for a local NPR radio station between the stock antenna and the discone.
As you can see, there’s a notable difference in the signal. Once I mount the antenna I am going to run some tests to generate meaningful data. Based on a quick test, however, a proper antenna makes a world of difference… at least if you want to listen to the commercial radio band.