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Over the past four months I’ve purchased five RTL-SDR BLOG V4 dongles. My idea was to continue adding to the pile, and then to gift all but two of them (one to be a spare as I’m aware these are a limited model) to my friends.

So I’ve put them all through some serious HF performance testing.

I’ve got five wire antennas — a 173 foot NREF (Non-Resonant End-Fed), a 71 foot NREF, plus 20, 40 and 80 meter half-wave dipoles.

I’ve got four radios — an Icom IC-7300, a Yaesu FTDX-10, an Icom IC-718 and a Yaesu FT-840. None of my radios are slouches and they represent a decent spread of design types — dual conversion super heterodyne, direct conversion SDR and of course the hybrid super heterodyne and SDR designs. I also have an AirSpy HF+ Discovery and a Collins 32S-1 transmitter.

My original goal was to use my FT-840, my IC-718 and my Collins 32S-1 as 100 watt transmitters/exciters, along side of the V4 as the receiver.

Over these months I’ve settled on HDSDR as my favorite SDR application as looks and works exactly like a ham radio. It has a stable, non-docking layout with keystroke shortcuts for ALL functions, large calibratable S-meter, squelch, customizable presets from a Frequency Manager, multiple one-click and fully automatic notch filtering, drag-and-drop bandwidth settings and rig control through OmniRig. It works perfectly with all four of my test radios.

All I can say is…WOW. I’m totally amazed, and I emphasize amazed with these SDRs. The are truly spectacular.

Now here comes the honest-to-God truth…the RTL-SDR BLOG V4 performs as well, and in some cases clearly better than any of my radios – flat out – period.

I have directly (but randomly) compared each of these V4’s with all antennas, against all of the four radios on all HF bands (on SSB only) and I am here to tell you [sadly I’ll admit] your SDR’s out performed them all, in all but one instance. And I don’t remember what that was because it was early in my less than than perfect and somewhat subjective testing.

The physical conditions were all the same – in my yard, in the middle of the Michaux State Forest in PA, along the Appalachian Trail, in a 3/4 acre clearing. The antennas are all below 37 feet, the 24/40 meter dipoles are only at 17 sloping down to 12 feet off the ground, the 173 foot NREF is at 37 sloping down to 22 feet and the 80 meter dipole is 34 sloping down to 12 feet high. So nothing special there.

There are few if any higher power AM broadcast stations nearby — only one at 1KW daytime only and one 5KW FM six or seven miles away.

In one case, with only one of the V4s, for some strange reason I was able to see and hear a ham talking to Europe easily at S4 to S5 (calibrated to match the IC-7300’s S-meter with my Rohde & Schwarz CMU200 Communications Test Set), with a noise floor at S3. The spectral display on HDSDR showed the 3.830 MHz signal at 10-12 dB over the noise floor – and get this, that same signal could not be heard nor did it even show up at all on either the DX-10 or the 7300 using the same bandwidth, preamp ON or OFF, and same antenna.

Clearly this V4 was different, and I can’t figure out why.

I repeated this testing over more than an hour, and substituted three of the other V4s and those two radios over and over, several times, using three antennas.

So all I gotta say is…well done.

And oh…one more thing…can you tell me why this one V4 is soooo much more sensitive than the other three?

Obviously I’m not going to gift this one away to anybody, ever.

I didn’t change anything when comparing these. I just stopped the HDSDR app, unplugged and plugged in the next one, and launched HDSDR. No values or ports or cables were different.

Hello, I am the developer of RForAll, an app for scanning and analyzing radio frequencies on MacOS. I always recommend the RTL SDR V3 dongle, and I would like to make my application natively compatible with the V4. Could you please contact me at my email [email protected]? A while ago, I sent an email to admin rtl-sdr.com but didn’t receive a response. I suppose you are very busy, but I need to ask them a few questions. Thank you.