Recently we sent document author “D. B. Gain” a sample RTL-SDR V3, so that he could write a review and guide on it. The guide is now available at http://www.udxf.nl/ute-info.
The larger the antenna system, the greater the gain – usually. It doesn’t take too much RF to overload the V3 dongle, so a 20ft piece of wire will do better than say a 430ft wire loop atop some phone poles. Use an attenuator if you have one. Remember the issue with AMBC swamping where AM stations pop up in various parts of the HF spectrum and use a preselector and/or attenuator if you can. Shortwave broadcast stations can also create spurs in the V3. Some radio parts houses carry a variable attenuator meant for cable TV or VCR player use that can be employed at HF with the use of some F to UHF or whatever connector your antenna system employs adaptor, this can be installed in the antenna system and adjusted to result in least usable signal getting to the V3, which assures best dynamic range. Then one would adjust the FFT Spectrum gain in your SDR control app of choice to best level on a quiet band, say 14MHz. This will ensure you don’t have to mess with adjusting the gain on lower frequency bands just to keep the band noise baseline above the bottom of the FFT window.
Mr. “Gain” has also uploaded several other screenshots of the V3 in action on HF in this gallery.
Mikael Dagman (SA6BSS) also wrote in to let us know about how he’s been using the V3 to receive WSPR. He writes:
For an experiment I have set up a SDR play and a RTL blog v3 dongle fed from the same antenna (butternut hf9) through an antenna splitter, grabbing Qrss signals on 40m, on the v3 I added a bpf. The v3 is run from SDR sharp q-branch RTL AGC on and both radios feeding separete instances of spectrum labs, doing wspr as the same time on both radios, there I hardly any difference, maby one spot out of ten the rsp get 1 db more in sn . Without the filter on the v3 its completely falling apart but with the filter inline I am more then impressed!!
I will stay on 40m for a couple of days trying to catch a ZL station tx:ing with 1.1W Qrss with the v3, (that’s 16000 km away) I will then qsy to 30m with the v3 where there is more signals to look at.
Spectrum available here http://www.qsl.net/sa6bss/
You see that bottom spectrum have the name RTL upper left corner.
Over on YouTube Leif (SM5BSZ) has also uploaded a video where he compares the performance of the RTL-SDR V3 with the Airspy+SpyVerter. Of course the V3 cannot compete with the higher end Airspy, but still performs decently enough for a beginner. If you are strapped for time, the results are concluded at about 28 minutes.