Just got a dongle? Want to extend range, hear more, or simply try out something new?
Handpicked choices below.
Before shelling out 20-100 dollars, learn to use software and educate yourself on how radio works.
Do 5 easy mods to your dongle first, then if money is still burning your pocket, you won't go wrong with a discone antenna.
Cost: around $50
There are lots of signals below 30 MHz (called High Frequency) from shortwave broadcasts to amateur radio operators, from Morse code to listening to the same world events from the major superpowers. Radio America / Russia / China sounds different and are quite revealing for the whole picture.
To get a taster how shortwave sounds like, you can try direct sampling, which is a no-cost method, possible with most generic $10 dongles and a piece of wire. The process is well documented here with images, but an upconverter will be much, much better.
A wide selection of upconverters are available, personally, I use Nooelec's Ham It Up for years.
A metal case is compulsory, read my review here.
Balun One Nine
A really tiny device, used to make HF reception better with one or two wires.
Broadcast FM filters
These will either eliminate all signals except their designated frequency range (bandpass filters), or get rid of interference from strong local stations like commercial FM (bandstop filters).
Filtering makes a huge difference, so I highly recommend rtl-sdr.com's BCFM filter for general use, or any bandpass filter for a given frequency.
Prices: from $20.
Radio signal amplification has several benefits; however, lower quality $10 preamps e.g. for TV use will be useless, because they generate and add a lot of noise to the signal.
Low Noise Amplifiers (LNAs) are the answer in radio, can be built into the dongle (orange Pro Stick in the image) or connect separately (bottom row).
Filters can be integrated with a preamp (top left):
In the 20-30 dollar range, bare boards, such as the LNA4ALL, is the staple preamp of the community, eBay seller's novakx5 LNA has bias-T or power pads, Janilab's LNA tested earlier (and in daily use since) covers dongle tuning range and can be easily powered with a smartphone charger.
Uputronic offers several filtered and a wideband preamp in metal cases with bias-T or external power.
Personally, I've bought a Pro Stick and LNA4ALL and been extremely happy with both, but ever since I had the pleasure of using Upotronics equipment, I wholeheartedly recommend their preamps for $45-60 plus shipping due to build quality and no-hassle convenience.
Pigtails and adapters
Cost: 3-6 dollars, or around $20 for a bundle covering most types.
What type you need depends on standard used on dongle, antenna or accessories, most common are:
I use and abuse Nooelec pigtails for years, never had to worry about reliability.
Just one more dongle. Then one more. Then...
In certain jurisdictions, listening to emergency services (police, firefighters, ambulance etc) is legal, but the process requires two dongles.
If emergency services are not legal where you live, don't go near those frequencies.
Or if you've just got a Nooelec SMArt, buy an rtl-sdr.com v.3, or vica versa - dongles only are available for around $20.
If yearning for something new and a rewarding challenge, a Nooelec XTR+ comes with 2-year warranty and has superb performance on airband and for upconverter use.
Ordering a cheap generic opens up possibilities for experimentation such as cooling - immersing $8 into sunflower oil is less stressful than possibly sacrificing a more expensive dongle if something goes wrong.
Explore satellites with Outernet and L-band
If you have a v.3 at hand, you'll only need to spend $20 on an Outernet preamp and $10 on a CHIP microcomputer (or use a Pi 3 if you have one), then home build a suitable antenna to receive signals from space.
Outernet also sells a complete kit for a hundred dollars with top-notch components (review) for a plug-n-enjoy experience.
Aircraft also transmit on this band, the service is called ACARS.
Raspberry Pi 3
Not strictly an accessory, more like a standalone computer system which can be used for RTL-SDR purposes, such as a remote server with rtl_tcp, or as an ADS-B station.
Plus many more, Internet of Things, home automation, or retro gaming is all for the takin'. The list is endless.
Where do we go now?
If you're a beginner, do yourself and your credit card a favor, and please learn about radio first. Buying stuff can wait, ordering equipment you'll just turn around in your hand is a waste of money.
Browse this blog, or visit rtl-sdr.com and click on interesting tags below posts, google away and watch Youtube videos.
For paid knowledge, I recommend my book (what a surprise) or the excellent book from rtl-sdr.com's author, or any ARRL book.
Join the RTL-SDR Facebook group, share your success and failures on Reddit, and so on, the point is:
Read, ask, have fun.