Victor X-Ray Juliet

Info

I’m a designer, technology enthusiast and licensed radio amateur, operating under the callsign MM7VXJ.

This site serves as a record of my experimentation with radio telegraphy, electronics and other related projects.

I also create CGI animation as silico.studio and my 3D prints are avalable to purchase from physis.shop

Radios

Yaseu FT-857 Yaesu FT-818 Yaseu FT-4X LilyGo T-Echo Heltec LoRa32 RTL-SDR Hack-RF T1000-E

Antennas Diamond VX30N [2m,70cm] DIY V-Dipole [137 MHz] Parabolic [1.7GHz] DIY Random Wire [14 MHz]

29th November 2025
Antenna Rotator
Test 1

This was the first test of a 3D printed antenna rotator, using recyicled componenets from an old 3D printer.

3rd September 2025
Tinkpad T490
Screen Replacement

I was lucky to be gifted a busted ThinkPad T490 laptop with a broken screen. Today I got around to replacing the LCD panel.

Having fixed a number of laptops in the past, I can say the ThinkPad is by far the easiest to service.

I’ll also be installing an NFC (Near Field Communication) board once the parts arrive...

2nd September 2025
Hack-RF One
3D Printing

The HackRF One PortaPack H2 is a small radio device that can send and receive signals across a wide range of frequencies. Which I mostly use it for tracking aircraft ADS-B transponders.

When in the field, I store it in the Pelican 1040 Micro Case. This case is waterproof, dustproof, and crushproof, which makes it ideal for carrying sensitive electronics. The only problem is that, without something to hold the device in place, it can shift around inside and accidentally press the buttons.

To solve this, I designed a simple 3D printable mounting plate that attaches to the lid of the case. It keeps the HackRF One PortaPack H2 securely in place and stops it from moving around. It’s a small tweak, but it makes transporting the device much easier.

You can check out the printable file here.

3rd August 2025
Noaa 19 APT
137.100 MHz
Hack-RF

These weather satellite images from the NOAA-19 satellite show the approach of Storm Floris from the Atlantic Ocean.

The image quality is better than in my previous attempts, thanks to the upgraded HackRF SDR (software-defined radio), which offers a significant improvement over the RTL-SDR, when using the same V-Dipole antenna tuned to 137mhz.

18th July 2025
Seeed Colab
Meshtastic
T1000-E

Over the past few months, I’ve been collaborating with Seeed Studio through their Co-Create program.

Together we are bringing two of my accessory designs for their T1000-E meshtastic device into mass production.

As of today, both the SenseCAP T1000-E Protective Case and the SenseCAP T1000-E Charging Puck are available for purchase directly from Seeed’s online store.

This partnership should simplify access for international buyers, especially those outside the UK, by reducing shipping costs and improving availability.

06th July 2024
Callsign Patch
3D Printing

I created a bespoke callsign patch using the multi-material feature of the Bambu X1 Carbon 3D printer, printing both black and white PLA within the same object.

I included a number of holes around the periphery of the patch so that thread could be used to more securely attach a strip of adhesive hook-and-loop tape to the patch itself.

15th May 2025
L-Band Satallite
Antenna

A while back, I picked up what I believe is the TP-Link TL-ANT2424B directional WiFi antenna. It’s a 2.4GHz grid parabolic antenna.

I bought it used and did not realise it was missing the feed-point reflector - the small assembly where the signal is actually focused.

Rather than write it off, I decided to take a shot at building my own replacement, with the intention of eventually tuning the antenna to recieve transmissions from L-band satellites.

I created a 3D-printed enclosure around the antenna itself and used aluminum plate to make the feed-point reflector.

Right now, it's a bit of a work in progress. I haven’t tested the performance with any proper RF tools yet, but I plan to do some testing to see how well it works in practice.

4th May 2024
Noaa 15 APT
137.000 MHz
RTL-SDR

With the National Oceanic and Atmospheric Administration (NOAA) announcing the de-funding of NOAA Satellites 15, 18, and 19, I set up a new capture of Satellite 15 as it passed overhead, using SatDump, a newly tuned antenna, and an SDR.

25th June 2024
Tracking Weather Satellites
137.000 MHz
RTL-SDR

After building a new V-Dipole using a 3D printed housing and panel mount SMA alongside a SAWbird LNA filter I was able to receive (noisy) APT images from the NOAA weather Satellites.

The amount of noise makes me think that there is alot more work to be done to isolate the radio from background EMF interference.

11th March 2024
Dipole Radiation Pattern
Artwork

Each antenna has a different radiation pattern, the images bellow show the radiation pattern of a dipole antenna. I was interested in creating the toroid of a dipole as there is certain quality to its convergence and symmetry.

These renders are aesthetic illustrations and do not portray any useful information, normally scientific visualizations would show dB levels as graduating hues, for this creation I was only interested in the geometric forms.

10th March 2024
Conversations Part I
Artwork

While visiting the City Art Centre in Edinburgh, I saw the artwork; ‘Conversations Part I’ by Kate Downie which visualises RF signals as bright lines of colour in contrast to a monotone backdrop.

It was my interpretation that the artists was representing the conversations that invisibly intersect the landscape between radio towers as a positive force that connecting people’s lives.

11th Febuary 2024
Logbook
Yaseu FT-4X

I recently aquired my first 2m/70cm handheld transiever, the Yaesu FT-4X.

The first contacts I made eith it were picking up the RSGB news from GB2RS GM3HAM Lothians Radio Society as well as a direct 5,9 contact with GM4DTH on 145.525MHz.

4th Febuary 2024
Meshtastic
868mhz
Lilygo T-Echo

Meshtastic is a software platform which allows LowRa (Low Power, Wide Area) devices to create a mesh network, communicating on 868MHz (in the UK). The information shared includes encrypted text messages as well as GPS locations.

We tested two Lilygo T-Echo devices, sharing telemetry and messages to a range of 2km. The theoretical range of these devices is limited by line of sight, so it is possible to make contacts much further.

I hope to build a custom enclosure for a device using this platform and attach it to the dog's harness so that we can track him on GPS if he ever gets lost.

12th August 2021
Tracking Weather Satellites
137.000 MHz
RTL-SDR

One of the first antennas I built was a simple V-dipole to receive weather satellite data on 137.000 MHz, I was able to track and record the downlink of a Meteor-M N2 satellite. However, there was too much noise to demodulate the imagery from the carrier, pehaps moving the SDR dongle away from the computer would solve this.

29th July 2021
Building a VHF Dipole
144.000 MHz (2m)
RTL-SDR

After experimenting with the antennas that ship with the RTL-SDR I wanted to build an antenna explicitly for the 2m amateur bands which are between 144.000 and 146.000 megahertz in the UK.

I calculated that each ‘leg’ of the dipole should be 49cm in length to give good coverage at 145.000 MHz. I connected the dipole to a length of 50 Ohm coax cable and tied everything else together, clamping the antenna to a fig tree trellis.

I later realised that this antenna is ‘un-balanced’ as it has no balun to correct the impedance of the coax and the antenna itself, but for a first attempt at making a antenna the results were workable.