We can’t remember ever seeing a late-night TV ad for oscilloscopes before but, for some reason, Tektronix did produce a video ad in 1987. You can see it below and enjoy the glorious music and video production standards of the 1980s.
We assume this was made to show at some trade show or the like. Even if there was a Home Shopping Network in 1987, we doubt many of these would have been sold despite the assertion they were “low cost” — clearly a relative term in this case.
You’ve got to wonder if the narrator understood what he was saying or if he was just reading from a script. Pretty impressive either way. We loved these old scopes, although we also like having very capable scopes that don’t strain our backs to lift.
On the bright side, these scopes today are pretty affordable on the used market if you can find one that doesn’t need a repair with an exotic part. For example, we found several 2221s or 2221As for under $200 without looking hard. The shipping, of course, could potentially almost double the price.
While you can get a modern scope for $200, it probably isn’t the same quality as a Tektronix. Then again, the new scope won’t have CRTs and exotic Tektronix parts to wear out, either. Picking a scope is a pretty personal affair, though, so one person’s great scope might be another person’s piece of junk.
More fallout for SpaceX this week after their Starship launch attempt, but of the legal kind rather than concrete and rebar. A handful of environmental groups filed the suit, alleging that the launch generated “intense heat, noise, and light that adversely affects surrounding habitat areas and communities, which included designated critical habitat for federally protected species as well as National Wildlife Refuge and State Park lands,” in addition to “scatter[ing] debris and ash over a large area.”
Specifics of this energetic launch aside, we always wondered about the choice of Boca Chica for a launch facility. Yes, it has all the obvious advantages, like a large body of water directly to the east and being at a relatively low latitude. But the whole area is a wildlife sanctuary, and from what we understand there are still people living pretty close to the launch facility. Then again, you could pretty much say the same thing about the Cape Canaveral and Cape Kennedy complex, which probably couldn’t be built today. Amazing how a Space Race will grease the wheels of progress.
[Shahriar] of The Signal Path is back with another fascinating video teardown and analysis for your viewing pleasure. (Embedded below.) This time the target is an Agilent E5052A 7 GHz signal Source/Analyser which is an expensive piece of kit not many of us are fortunate enough to have on the bench. This particular unit is reported as faulty, with a signal power measurement that is completely off-the-rails wrong, which leads one to not trust anything the instrument reports.
After digging into the service manual of the related E5052B unit, [Shahriar] notes that the phase noise measurement part of the instrument is totally separate from the power measurement, only connected via some internal resistive power splitters, and this simplifies debugging a lot. But first, a short segue into that first measurement subsystem, because it’s really neat.
Cross-correlating time-gated FFT (TG-FFT) subsystem at the top, dodgy power detector at the bottom
A traditional swept-mode instrument works by mixing the input signal with a locally-sourced low-noise oscillator, which when low-pass filtered, is fed into a power meter or digitizer. This simply put, down-converts the signal to something easy to measure. It then presents power or noise as a function of the local oscillator (LO) frequency, giving us the spectral view we require. All good, but this scheme has a big flaw. The noise of the LO is essentially added to that of the signal, producing a spectral noise floor below which signals cannot be resolved.
The E5052 instrument uses a cunning cross-correlation technique enabling it to measure phase noise levels below that of its own internal signal source. The instrument houses an Oven-Compensated Crystal Oscillator (OCXO) for high stability, in fact, two from two different vendors, one for each LO, and mounted perpendicular to each other. The technique splits the input signal in half with a power splitter, then feeds both halves into identical (apart from the LOs) down-converters, the outputs of which are fed into a DSP via a pair of ADCs. Having identical input signals, but different LOs (with different phase noise spectra) turns the two signals from a correlated pair to an uncorrelated pair, with the effects of chassis vibration and gravity effects also rolled in.
The DSP subtracts the uncorrelated signal from the correlated signal, therefore removing the effect of the individual LO’s effect on the phase noise spectrum. This clever technique results in a phase noise spectrum below that of the LOs themselves, and a good representation of the input signal being measured.
This is what a DC-7GHz resistive power divider looks like. Notice the inductive matching section before each resistor branch.
Handily for [Shahriar] this complex subsystem is totally separate from the dodgy power measurement. This second system is much simpler, being fed with another copy of the input signal, via the main resistive power splitter. This second feed is then split again with a custom power divider, which upon visual inspection of the input SMA connector was clearly defective. It should not wobble. The root cause of the issue was a cold solder joint of a single SMA footprint, which worked loose over time. A little reflow and reassembly and the unit was fit for recalibration, and back into service.
[Kevin] wanted to emulate the look and feel of the original TX816 aesthetic, developing a custom PCB handling the user interface for four of the eight channels, and a second acting as an interface to the Raspberry Pi using a Pico. Also sitting on this PCB is the GY-PCM5102 I2S DAC, and the MIDI connectors needed to connect to the system controller. Both PCBs, including a PCB-based front panel, were developed with KiCAD. The firmware for the Pico part of the system can be found on the firmware GitHub. The video demo (embedded below) shows off the system running a very 80s-sounding rendition of Holst’s famous ‘Jupiter’ from the planet series, and we all agree it sounds pretty sweet. For a complete rundown of the build, here are the links for the blog series for ease of access: Intro, PCBs, Panel, Build Guide, Mechanical, Pico/TX816 IO code, and finally usage. Phew!
With only two space stations in orbit around Earth today in the form of the International Space Station and the Chinese Tiangong (‘Sky Palace’) station, it’s easy to forget how many space stations were launched in the previous century. And the Soviet Union launched by far the most, as part of the Salyut (Russian for ‘salute’ or ‘fireworks’) program. Although the program entailed both military (Orbital Piloted Station, or OPS) and civilian (Durable Orbital Station, or DOS) stations, it was the civilian stations that saw the most success, as well as the most daring rescue attempt with the recovering of the Salyut 7 space station.
Salyut 7 (DOS-6) was set to repeat Salyut 6’s success after its launch on April 19th 1982, until disaster struck in February 1985. Due to a series of electrical and other faults ground communication with the space station was cut off, and the at the time unmanned space station began to gradually tumble towards the Earth’s atmosphere. This left those in charge with two options: leave the station to burn up in the atmosphere, or stage a rescue mission.
Ultimately, on June 6th, 1985, Soyuz T-13 launched to rendezvous with Salyut 7. On board were cosmonauts Vladimir Dzhanibekov – who had previously manually docked with Salyut 7 – and Viktor Savinykh. Both men had done all they could to perform a manual docking and attempt to revive the stricken space station. Ultimately they managed to revive the station using what little charge was left in its batteries and the Soyuz’s thrusters, all the while braving freezing temperatures in the dead station’s interior.
Salyut 7 would continue to perform its duties until February 1991, with Mir (DOS-7, launched 1986) as the first modular space station taking over. The final DOS module (DOS-8) that directly traces its lineage to this era is still in orbit today as the ISS’ Zvezda module, keeping the Salyut legacy and the bravery of Dzhanibekov and Savinykh alive.
Hackaday Editors Elliot Williams and Tom Nardi definitely didn’t plan on devoting most of this episode to 3D printing and space stories, but let’s be honest, it was bound to happen sooner or later. After an update on the Hackaday Prize, the discussion moves on to a pair of troubled spacecraft and the challenges of exploring the final frontier. From there you’ll hear about a chocolate 3D printer we’ve had our eyes on for years, the tools you should have next to your own (non-chocolate) 3D printer, and a bit of contemplation of what it really means to design for 3D printing versus traditional manufacturing methods. But it’s not all plastic fantastic — by the end of the episode you’ll also hear about some particularly bold high-altitude aviators and the surprisingly short time we have left with the humble barcode.
Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Beep. We’ve come a long way since June 26, 1974 when the first bar code was scanned at a grocery store in Troy, Ohio. That legendary pack of Juicy Fruit proved that even the smallest of items could now carry numbers associated with inventory and price.
By now, we’re all too familiar with this sound as self-checkouts have become the norm. Whereas you yourself could at one time literally check out during the transaction, you must now be on your toes and play find the bar code on every item.
Pico. Also sitting on this PCB is the 
