These photos were sent over to me by a friend, an interesting piece of tech that’s used in the retail industry. This is a BluVision BLE Beacon, which as far as I can tell is used to provide some automated customer assistance. From their website it seems they can also
The other day at the local canal-side waterpoint, this TV was dumped for recycling, along with another later model Colour TV. This is a 1970’s Black & White mains/battery portable made by Thorn. It’s based on a common British Radio Corporation 1590 chassis. Having received a soaking from rain, I
I was recently given a pretty nice LED backlit 1080p LG monitor, with the instruction that it wouldn’t power on correctly. The monitor would power on as far as the standby light, but when fully powered on, would flash the backlight momentarily then shut down. A power supply issue was
Effects of Magnetic Fields on He-Ne Laser Operation If you open the case on a higher power (and longer) He-Ne laser head or one that is designed with an emphasis on precision and stability, you may find a series of magnets or electromagnetic coils in various locations in close proximity
Continue readingMagnets in High Power or Precision He-Ne Laser Heads
Early Versus Modern He-Ne Lasers In the first He-Ne lasers (see the diagram below), exciting the gas atoms to the higher energy level was accomplished by coupling a radio frequency (RF) source (i.e., a radio transmitter) to the tube via external electrodes. Modern He-Ne lasers almost always operate on a
Continue readingHe-Ne Laser Tubes, Heads, Structure, Power Requirements, Lifetime
Instant He-Ne Laser Theory The term laser stands for “Light Amplification by Stimulated Emission of Radiation”. However, lasers as most of us know them, are actually sources of light – oscillators rather than amplifiers. (Although laser amplifiers do exist in applications as diverse as fibre optic communications repeaters and multi-gigawatt
Continue readingTheory of Operation, Modes, Coherence Length
I’m no fan of power inverters. In my experience they’re horrifically inefficient, have power appetites that make engine starter motors look like electric toothbrushes & reduce the life expectancy of lead-acid batteries to no more than a few days. However I have decided to do a little analysis on a
Having now tested the supply I wrote about in my previous post, I can now say that it’s nameplate rating far exceeds it’s actual capability. On running the supply under load, at 6.5A the operating frequency drops into the audible range, a big sign of overload. (It makes an irritating
I recently ordered a PSU to run one of the TVs I converted to 12v operation, and being an older TV, it’s a fairly heavy load at 6.5A. eBay to the rescue again, with a cheap 10A rated supply. Like all similar supplies these days, it’s a SMPS unit, and
Came across this today while scanning through frequencies. Not sure of their exact QTH, but there’s references to the Oldham area in Manchester, about as far away as you can get from any marine or commercial shipping area in the county. I didn’t hear any marine callsigns or vessel names
I think the headline speaks for itself… The usual group, with their Baofengs… Grossly over on the power! After this, they then went up to 446.070MHz, which is in the guard band between channels. All the while admitting they’re using massive high gain antennas as well. Shortly after, they
Continue readingMore PMR Abuse – Tonight’s Menu: Casual Racism
The latest addition to my radio shack is the GY561 frequency & power meter, which has already come in useful for measuring the output power of all my radios. It’s a small device, roughly the same size & weight as a stock UV-5R. Power is provided by 3 AAA cells.
Thanks to Lewis, M3HHY for lending me this one 🙂 Here’s a quick look at a Sainsmart frequency counter module. These are useful little gadgets, showing the locked frequency on a small LCD display. It’s built around an ATMega328 microcontroller (µC), and an MB501L Prescaler IC. The circuit for this
I have recently come across the software the Wouxun factory uses to set the band limits on the KG-UV950P. While the software is in Chinese, it’s functional, and allows setting of all band limits on the radio. Here’s an English version of the interface: Note when using this software: This
Continuing from my previous post where I published an Eagle design layout for AD7C‘s Arduino powered VFO, here is a completed board. I have made some alterations to the design since posting, which are reflected in the artwork download in that post, mainly due to Eagle having a slight psychotic
To accompany the previous two posts about hydraulic generators & their components, here is the actual generator unit itself. Rated at 8.5kVa 230v AC, this will providea mains supply while the narrowboat is away from her home mooring. This unit will be attached to the side of the hull in
Here is a simple 555 timer based flyback transformer driver, with the PCB designed by myself for some HV experiments. Above is the Eagle CAD board layout. The 555 timer is in astable mode, generating a frequency from about 22kHz to 55kHz, depending on the position of the potentiometer. The
This is a small 120W power inverter, intended for small loads such as lights, fans, small TVs & laptop computers. End cover of the unit, 12v DC input cord at the top, power switch & indicator LEDs at the bottom. Opposite end of the unit, with the standard 240v AC
Here is a label maker, bought on offer at Maplin Electronics. Full Qwerty keyboard with 1 line dot matrix LCD display visible here. Power is 4 AAA cells or a 6v DC Adaptor. Rear cover removed. Battery compartment is on the left hand side, space for the tape cartridge on