SI4732

3 Articles

Open HT Surgery Gives Cheap Transceiver All-Band Capabilities

March 22, 2024 by 34 Comments

Watch out, Baofeng; there’s a new kid on the cheap handy talkie market, and judging by this hardware and firmware upgrade to the Quansheng UV-K5, the radio’s hackability is going to keep amateur radio operators busy for quite a while.

Like the ubiquitous Baofeng line of cheap transceivers, the Quansheng UV-K5 is designed to be a dual-band portable for hams to use on the 2-meter VHF and 70-centimeter UHF bands. While certainly a useful capability, these bands are usually quite range-limited, and generally require fixed repeaters to cover a decent geographic area. For long-range comms you want to be on the high-frequency (HF) bands, and you want modulations other than the FM-only offered by most of the cheap HT radios.

Luckily, there’s a fix for both problems, as [Paul (OM0ET)] outlines in the video below. It’s a two-step process that starts with installing a hardware kit to replace the radio’s stock receiver chip with the much more capable Si4732. The kit includes the chip mounted on a small PCB, a new RF choke, and a bunch of nearly invisible capacitors. The mods are straightforward but would certainly benefit from the help of a microscope, and perhaps a little hot air rework. Once the hardware is installed and the new firmware flashed, you have an HT that can receive signals down to the 20-meter band, with AM and SSB modulations, and a completely redesigned display with all kinds of goodies.

It’s important to note that this is a receive-only modification — you won’t be transmitting on the HF bands with this thing. However, it appears that the firmware allows you to switch back and forth between HF receive and VHF/UHF transceive, so the radio’s stock functionality is still there if you need it. But at $30 for the radio and $12 for the kit, who cares? Having a portable HF receiver could be pretty handy in some situations. This looks like yet another fun hack for this radio; we’ve seen a few recently, including a firmware-only band expansion and even a Trojan that adds a waterfall display and a game of Pong. Continue reading “Open HT Surgery Gives Cheap Transceiver All-Band Capabilities” →

Shortwave Radio Picks Up Sideband

September 29, 2021 by 14 Comments

With the push to having most of a radio receiver as part of a PC, it might seem odd to have a standalone communication receiver, but [OM0ET] reviews the latest one he picked up, an ATS25. Inside isn’t much: a battery, a speaker, an encoder, and a Si4732 that provides the RF muscle.

It appears the receiver is pretty broadband which could be a problem. [OM0ET] suggests adding selectivity in the antenna or adding an extra board to use as a bandpass filter.

Continue reading “Shortwave Radio Picks Up Sideband” →

Radio Build Goes Outside The Box

June 3, 2021 by 4 Comments

It’s easy to get caught up in a build and forget that the final version usually needs some sort of enclosure, especially things with sensitive electronics in them. The [Director of Legal Evil] at the LVL1 Louisville Hackerspace notes as much in his recent radio build. It seems as though the case was indeed an afterthought, but rather than throwing it in a nondescript black project enclosure it was decided to turn the idea of a project enclosure itself inside-out.

The radio build is based on an SI4732 radio receiver which is a fairly common radio module and is easily adaptable. It needs a microcontroller to run though, so a Maple STM32 platform was chosen to do all of the heavy lifting. The build includes a screen, some custom analog controls, and a small class D audio amplifier, but this is the point it begins to earn its name: the Chaos Radio. While playing around with the project design in CAD, a normal design seemed too bland so one was chosen which makes the radio look like the parts are exploding outward from what would have been a more traditional-style enclosure.

While the project includes a functioning radio receiver, we have to complement the creator for the interesting display style for this particular set of hardware. It can get boring designing the same project enclosures time after time, so anything to shake things up is often welcomed especially when it puts all of the radio components on display like this. In fact, it’s reminiscent of some of [Dmitry]’s projects, an artist known for deconstructing various common household appliances like this CD Player.

Thanks to [Jose] for the tip!