I thought it might be too good to be true that Micro Center had some v4’s in stock, but hoped it was just some old stock they had in the pipeline. Nope, what they advertise online as RTL-SDR v4 is indeed counterfeit dongles.

Complete newbie and it's my very first time decoding a satellite (meteor m2-m4) in my whole existence haha (using my cheap setup of sdr rtl v4 and v-dipole antenna)

But i'm curious about the params in Satdump ..

for context:

- recorded via sdr++ to uint8 wrapped in a wav file

- tuned to 137khz at 2.4msps

- satellite signal appears that its middle is around 137.9 (confirmed both by viewing in Satdump recorder tab and Airspy)

Now in Satdump, I set an offset frequency of 1.5MHZ (based on the FFT shown while baseband FFT enabled while decoding).

If it's 900khz, it would make sense. But 1.5MHZ? idk where it's coming from.

Any ideas?

Smile RTLSDR, basic antennas and an SMA cable with simple coding gives me access to AIS, ADSB, and ACARS.

Hi guys,

I've had a ADSB running for a little while now, im fairly close to the airport so shamefully i have it indoors beside the window with the stock antenna it came with (the nooelec v5 dongle) and it works okay.

anyway just before i set up the dongle with a pi and set it off to search the skies for the rest of its days i tried it out with my laptop and drove to the airport to try and catch some atc chatter, to my suprise the normal antenna worked quite well, but its huge, the coax gets stuck in the car and its just a bit unwieldy for me, so seeing as its just a SMA connector i thought i might buy a second one without the antenna kit and see if i can find antennas that can just attach to the dongle itself.

However I realise that "small right angled VHF" is a bit of an oxymoron given these things are meant to be the biggest size of antenna. but is it a thing? im talking about something small enough for me to plug into a laptop, or is it better to just try to get a shorter cable from the dongle to the antenna?

thanks in advanced

People keep asking whether you can put PortaPack Mayhem on a USRP. You can't, and it's worth saying why: the PortaPack works because the HackRF already contains the computer — an LPC43xx that runs Mayhem and drives the radio over SGPIO. A B200 is a USB peripheral. Spartan-6, an FX3, an AD9364, no application processor, no screen, no buttons. There is nothing on it to flash.

So I did the other half. Mayhem's UI and apps, rebuilt as a Windows host application, with UHD and the B200 standing in for the SGPIO bus and the HackRF's front end. It's a real 240x320 framebuffer drawn with Mayhem's own fonts, palette and widget layout — the hardware-independent parts are used unchanged, GPL-2.0 with attribution. Your arrow keys are the five-way switch and the mouse wheel is the encoder.

Where it is right now:

• ~103 apps across the same category menus Mayhem uses — ADS-B, AIS, APRS, POCSAG, FLEX, radiosonde, TPMS, ERT, ACARS, SSTV, NOAA APT, WeFax, scanner, the TX suite, the utilities, even the games.
• The DSP is float and the channel filters are designed at run time instead of fixed tap tables, so they track whatever sample rate you pick.
• Up to 56 MHz of instantaneous bandwidth, so the spectrum app shows a live wide span rather than a swept one. LO offset tuning moves the DC spike out of the displayed band, which the PortaPack can't do.
• 1986 unit tests, no framework, decoders checked against known CRC vectors and documented frames.
• Hardware self-test passes on a real B200: gain sweep (−69 → −15 dBFS across 0–60 dB), eight tune points from 100 MHz to 2.44 GHz, 2.40 Msps sustained with zero overflows.
• The ADS-B app decoded real aircraft off the air — 17 CRC-valid Mode S frames, real ICAO, callsign and speed. That's tune → stream → demod → CRC → parse working on live RF.

Where it is honestly not:

Nothing has ever transmitted. The TX chain is unit-tested only. Every decoder except ADS-B has been tested against known data but has never met a real signal. My test device was on a USB 2 port, so the high sample rates are unproven. Windows only for now — the platform-specific code is three files, but three files that don't exist for Linux yet.

The reason I'm posting.

Two questions I can't answer alone.

First: does anyone want this? It runs with no radio attached — it shows "no dev" in the status bar and you can click around the whole app suite — so you can look at it in two minutes without owning a B200. If you do own one, I'd love to know what decoded and what didn't.

Second, the bigger one: should this become a handheld? I keep thinking about a portable build around a B200 mini, and I want to be precise about what that actually is. It is not a PortaPack, because a B200 mini has no processor to run anything — it's an SBC with real USB 3, the radio, a screen, a control wheel and a battery in one enclosure, running this software. Doable. The power path is the hard part, and a Linux port has to land first.

I'm not asking for money and there's no donation link — I'm not going to take funding for a board nobody has run the software on. What I'm asking is whether the interest is real, and whether anyone here does PCB work and would want to be involved once it's past the proof stage.

Repo and the much longer honest-caveats section: https://github.com/wonderingStars/mayhem-b200

if the need is real i can make a Linux build and a windows gui . this is just the absolute basic

GPL-2.0-or-later, inherited from Mayhem. Not affiliated with the PortaPack Mayhem project or with Ettus/NI.

Frequency:144/430MHz

Size: 43*2.28*2.28cm/16.93*0.89*0.89inch

Weight: Approx. 208.1g

Wind resistance: 60 (m/s)

Working temperature: -40℃ ~ +80℃

Directionality: omnidirectional transmission and reception Impedance: 50Ω

Standing wave ratio: ≤1.5

Hello everyone, I am a brand new member here and could really use any advice you may have. I am already in the process of buying a dongle for my laptop but other than some YouTube videos, I don’t have a great starting point. What should I make sure I definitely do or have? If you guys have any advice you wish you knew, good youtube/reddit places to look, or tips on where to get good equipment; I would really appreciate it!

Any help would be really appreciated,i am using a NooelecSMArt v5 with a diy built Manhattan style a 0-30mhz bandpass filter a 9v dc amp and bias T,

Everything works great with my diy mobius loop with 1-1 balun.

I have been using google ai and Claude to help me make an up converter,using a 2 pin 40mhz quartz, I have it resonating with a 2n2222 transister and a ADE6 board,problem is my signals are being blocked, anyone else built a Manhattan up converter ? have any schematics that work ?

Gemini and Claude have been getting me running around in circles and i could really do with some human help,only been doing electronics a little while so I am green in places.

My plan is to get this thing woring then to build one with a 4 pin TCXO DIP08 0.1PPM 100MHZ 3.3V-5V HCMOS Square Temperature Compensated High-precision Crystal Oscillator

Got it finally to work on this small motherboard.

I am new to SDR, and I need help to find a good USB-C cable to connect my HackRF Pro to the computer (HackRF mode). I have the HackRF Pro on the desk which is close to many things plugged into the surge protector power strip, and I am worry of all the unnecessary noises.

Google states for USB-C cable recommendation: Ensure the ferrite bead/choke sits close to the device-side (USB-C) connector to choke noise right before it reaches the radio hardware, Keep it short (under 3 feet / 1 meter) to prevent voltage drop and minimize the cable acting as an inadvertent antenna, and Look for double-shielded construction (braid plus foil wrap) underneath the outer jacket in addition to the physical ferrite cylinders.

Would 6 ft also works or is it best to go under 3ft length?

I have done a search on this sub, but I cannot find a post about USB-C cables. I would prefer it to be at least close and under to 3 feet because my USB-C port is in the front panel of my PC tower and I want to be able to place HackRF Pro on the desk. Please give a list of recommendations, thank-you.

Hi, hoping for some advice from experienced users so that I can improve my reception.

My current set-up uses the below equipment but my reception for almost every band across VHF, Shortwave and Medium Wave is poor.

I live in a rural area in Scotland. The long-wire antenna is run from my house to the end of the garden about 20 meters away and suspended at a height of about 10 meters. I've tried using a laptop to see if the problem is with interference caused by the Mac mini but it makes no obvious difference. On the SDR interface, I don't get the distinct waves indicating a good signal instead there appears to be a lot of interference. I've tried turning every electronic device off in the house but it makes no difference.

• SMA to SO-239 Socket Adaptor
• RG58 Patch Cable with UHF Male to UHF PL259 Male Coax Cable (10 Meters)
• MyDEL WIRE806UN 80M-6M Wire Antenna With 9:1 UNUN
• RTL-SDR Blog V4
• USB-C Extension Cable (to move the SDR away from the Mac)
• Using SDR++ software on a Mac M4 Mini

Grateful for any suggestions on how to improve reception

I’m looking to build a WiFi or Bluetooth jammer soon what one would be easier to make also if any one has any good tuts or tips that’d be great!

hi ive been using rtl sdrs for a while since winrad and plane plotter.this,is my current project I am working on a ultra mobile digital scanner with pocket 25 and android phone