Getting started – an introduction to antennas
So you’re considering an SDR receiver or already have one. With any of the RSP family you have the possibility of receiving signals anywhere from 1kHz all the way up to 2GHz. That’s a lot of spectrum and no single antenna will give good performance over the entire frequency range. However it is possible to cover most of it with just 2 or 3 antennas.
The picture above shows the four most popular choices of antenna for covering the bulk of the spectrum offered by wideband SDR receivers like the SDRplay RSP family. The “long wire” (more correctly named as the “random wire” antenna) and the whip antennas are the lowest cost options but have some limitations which is why the more expensive active magnetic loop and discone options have become popular. The key pros and cons are shown in the table below:
For HF there is a lot of scope for experimentation as illustrated in the following attempt to summarise some of the considerations. Trial and error can play a big role in getting the best signals and the least locally generated electrical noise:
For dedicated reception of a narrow band of specific frequencies there’s a whole host of specialist options (e.g. ADSB antennas for 1090MHz, Inmarsat antennas for 1.6GHz, special 137MHz antennas for NOAA satellite reception and so on as well as the traditional yagi antennas with directional properties.
However for now, just looking at the most common choices, here are links to wiki pages each of the popular antennas types mentioned above:
The long wire antenna: https://en.wikipedia.org/wiki/Random_wire_antenna
The active magnetic loop antenna (need a better link) : https://en.wikipedia.org/wiki/Loop_antenna
VHF/UHF whip antenna: https://en.wikipedia.org/wiki/Whip_antenna
Discone antenna: https://en.wikipedia.org/wiki/Discone_antenna
Here are a few examples:
SDRplay has informally mentioned several suppliers of antennas (e.g. Bonito, Moonraker, SDR-Kits and so on). However we plan to more formally recommend some specific makes of antennas which we here at SDRplay have checked out and are confident to recommend as “Approved for use with SDRplay”