LA2YUA ⁽⁷⁴⁾

The Racal Acoustics RA5000 "Raptor" is a military-grade hearing protection/headset, in this article we'll be looking closer at the RA5000/1/1025 model.

Red Hat Enterprise Linux and the closely associated CentOS Stream 9 remove a lot of legacy kernel modules from their kernels. This seems to also include removing sources from their distributed kernels.

I wanted to add the scsi/bfa driver to support Brocade Fibre Channel adapters, this is mainlined but not part of the RHEL kernel sources.

This is a followup to the previous ADF antenna system article, and details performance measurement of the BFU550X based cascoded TIA.

The King KA-42B ADF antenna is a neat little 3-in-1 antenna-pod for aircraft. With some minor^[0] effort it can be used as a pretty good HF reception antenna.

^[0] for certain definitions of "minor"

A followup to the previous NAGRAFAX article, this details how I fixed the automatic phasing circuitry, and has some detail pictures of the electronics boards.

The NAGRAFAX is an early 1980's weather-fax printer, sold as a kit along with a weather-fax FM receiver and intended for marine use. I picked up this unit for $10 at a local auction (first and only offer, surprisingly).

The RF Section or 1st Converter consists of the pre-amplifier, first mixer, and first IF filter in the receiver signal chain. This is typically the most important part of the radio since it determines the sensitivity and selectivity of the radio.

This card was finished in late 2022, at the time of initial publication it has not been integrated yet.

The 3021N Synthesizer is a very complex part of the original radio. It's almost sad to replace it, but I needed the room to fit new power supplies. The synth was designed in the fall of 2020.

This is part of a series covering the 3021N communications receiver. This part covers the Demodulator, and was the third part of the receiver that I replaced with a modern expansion. The demodulator card was finished in the middle of 2020 (I wasn't too busy).

This is part of a series covering the 3021N communications receiver. This part covers the DSP, and was the second part of the receiver that I replaced with a modern expansion. It replaces the Audio Amplifier PCA. This card was designed in late 2018.

This is part of a series covering the 3021N communications receiver. This part covers the Scan Tune Logic PCA, and was the first part of the receiver that I replaced with a modern equivalent, in the middle of 2018.

This is part two of a series covering my extensively modified ITT Mackay Marine 3021N communications receiver.

This article covers various details on the chassis and the signal path. More details of the various cards are given in later articles covering their replacements. The work covered in this section took place between 2017 and 2021.

The ITT Mackay Marine 3021N is a mid 70's communications receiver, designed for merchant marine and military use. I've basically built it again using modern electronics, which will be covered in detail in this series.

This is part 1, covering the basic overview of the receiver and its role in the original marine communications system. I acquired the 3021N some time the middle 2010's, and started serious work on it in 2018. The series has its own tag: 3021N

This one's pretty simple.

Someone gave me two of these couplers, couldn't find too much about them online.

This is a basic teardown of my old cable modem.

The EPC3010 was the basic modem supplied by Get.no, a former cable internet/TV supplier that was bought out by Swedish telecom giant Telia.

I found a late 90's GPS receiver made by Raytheon, let's take a look.

The Wide Band RoF System works quite well, but some practical issues were identified after almost a year in operation.

This article documents a pole mounted dual band radio modem, suitable for use with 9600 baud data, 4800 baud PSK, 1200 baud AFSK, and voice.

After some hard drive failures I decided to up my backup game, and ended up buying two LTO-5 tape drives.

Radio over Fiber is a well established concept by now, this is a look at a wide band multi-antenna receiver system with radio over fiber distribution.

This is a collection of what is required to put a HP Z420 and (probably) Z620 motherboard in a new case.

The Symmetricom X72 is a very compact high quality Rb oscillator, I bought a broken one hoping the physics package wasn't broken.

The C-MAC STP 2373LF is a 2x2x1" OCXO used in e.g. the Epsilon EC2S GPS clocks. Since a number of these clocks were broken in obvious or subtle ways, I decided to reuse the OCXO's and other useful components from these.

Continuing even further along the military radio thread, I previously discussed military handsets here.

In this post I will show how I built a basic interface-box/intercom for interfacing a generic military handset to mobile radios such as the Motorola GM360 and the Hytera MD785.