RTL-SDR Blog V4, listen again


That's right, I'm going back to listening in times of social network chicken coops where nobody seems to practice it much.

And I'm back with an SDR (software defined radio) that the kings gave me and that has arrived a while ago because I missed a lot the gadgetry.

The SDR chosen was an 8-bit RTL-SDR Blog V4. It is the latest model developed by the creators of the https://www.rtl-sdr.com website. It is very cheap (about 30 euros) and for its features and performance is the best you can find as an entry-level device to get started in the fiddling if you do not have much in your pocket and / or just want to find out exactly what this is before making the leap to a better quality SDR (All of them from about 150 euros to more than 1500).


There is nothing new here. These things have been with us for over three decades. The origins of RTL-SDR go back to mass-produced DVB-T TV tuner dongles based on the RTL2832U chipset developed by Realtek.

In 2008, Eric Fry released the first software for using this chip in SDR applications, and since then, the ham radio community and hobbyists have continued to improve the software and hardware required for the RTL2832U chip to work in a number of SDR applications.

Between Antti Palosaari, Eric Fry and Osmocom (in particular Steve Markgraf) they discovered that the raw I/Q data of the RTL2832U chipset could be accessed directly, allowing the DVB-T TV tuner to be converted into a wideband software defined radio via a custom software driver developed by Steve Markgraf.

No single person or company owns the RTL-SDR name and its software and hardware in its entirety. Osmocom was the community that developed the first RTL-SDR driver that was released as open source.

Since then RTL-SDR has become an evolving phenomenon based on contributions from the community behind all open source software. Certain manufacturers market different RTL-SDR dongles to which they add a model name.

In order not to write a long-winded rant, in this first entry I'll just review this "Blog V4", which is sold with two options: just the dongle and a package with a modest kit consisting of a dipole and some accessories.

Beware of clones

Many clones of this popular model have been produced. Most of them are very poor, although they can still look good because the replicas are becoming more and more accurate (only aesthetically). All these clones usually mount cheap or bad components on poor materials. This results in a very bad experience, such as shifted frequencies, excessive noise and general poor performance and/or overheating because, to make it cheaper, they are poorly cooled and don't even include a sad thermal pad (as in the case of the original V4).

If you don't want to fall into the clone trap, make sure you buy it from the official RTL-SDR Blog shops. In this image, the brand provides identification of some of the clones and details of the components that are not used and other differences.

Originals can be found at different prices. On Ebay (~30 dollars), Aliexpress (~35 euros), Astroradio (~45 euros) Amazon (~50 euros). List of official shops.

Today I am only writing this as an impromptu unboxing and in the following posts I will review its installation, set up, use and tinkering and my experience with some of the software that can be used to tune the ear in the radio spectrum and I will also review what will be the antenna of choice when I have it ready.

I opted for the kit (for about ~15 euros more) knowing that the supplied antenna is very minimal, but as there is some fiddling to be done to mount the replacement so in the meantime I could try the thing out to get used to it.

The kit

It arrived from the Far East in an anti-static bubble bag.

All the tools go inside this other bag.

Above, the four arms of the two telescopic antennas (the long one from 23cm to 1m and the short one from 5cm to 13cm) inside a tube with two plastic caps.

From left to right: tripod with flexible legs with 1/4 male screw, 3m RG174 coaxial cable with male and female SMA connectors, the dongle, the dipole with 60cm of cable (also RG174), a suction cup with articulated head with 1/4 male screw and a very short paper manual.

The V4 works between 500Khz and 1766 Mhz. To know in depth its specifications and applications, nothing better than to go to the official website where they do a very good job explaining even the smallest details about the receiver.

This version, released in August 2023, comes in a black aluminium body to aid heat dissipation (one of the problems with the V3, which heated up like a toaster). It looks sturdy and well finished, although some screws don't seem to go all the way in.

Another thing that caught my eye straight away was that the USB connector is offset or bent upwards and is noticeable to the naked eye. I thought it had arrived faulty or bent from a knock, but there's no slack in it. It's holding firm, so I don't know if it's arranged this way by design or for some other reason that escapes me. In other reviews I also found that this deviation is pointed out

Another roll is the width. Its 2.70 cm makes it impossible to plug it into a common HUB or into computers with several busy connectors on the sides if they are not further apart than usual.

The small tripod with foam-covered legs included in the kit looks flimsy at first glance, but it is not. It behaves quite well and allows you to mould its legs so that you can even hook it up by hugging a ledge or shelf of a bookcase.

It should be noted that the whole thing is rather more minuscule than it looks in the photos.

The suction cup with ball-jointed head also performs decently on glass or other smooth, clean surfaces and supports the weight of the horizontally arranged dipole well with its longer arms unfolded.

However, it is not suitable for attaching to the roof of a vehicle if you intend to drive on the road

As for the antennas, the smaller one looks like a toy antenna and they are clearly insufficient unless you are in a prime location, but, yes, when placed in a V-shape they do give a very cool retro TV horn antenna look.

The cable is also weak, the RG214 coaxial is not exactly the best you can put in a rig that is intended to listen to and filter out weak signals.

The dipole, which is not intended for permanent outdoor use, is not a marvel of science either, and its plastic finish indicates as much. The arms fall off from time to time, especially in a horizontal position, and you have to keep tightening the screws that hold them in place.

Here you can read everything the manufacturer advises about the use and adjustment of the antenna.

I have already had time to put the antenna in almost all possible positions and sizes and although all the accessories seem weak, with use you don't get the feeling that they are going to break right away.

The suction cup is surprisingly strong enough to grip and hold the (little) weight of the antenna.

On the whole it is acceptable. A fun, inexpensive device and, if you are new to ham radio, it may surprise you and even infect you with the vice of wanting to listen to infinity and beyond.

Next installments:

Installation and use of SDR# Sharp software.

First tests of the MLA 30 active loop antenna

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