Tag Archives: amateur radio

Scratch-built 8-band HF SSB/CW transceiver (EI9GQ) – Part 2 – Receiver completion

There’s a reason why most homebrew transceiver kits and scratch-built projects are monoband and single mode — theres a chance you’ll finish it, or at least, get it working for a while. Building a multiband HF transceiver is a big job, as any homebrewer who has attempted it will tell you. It may take years.

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20 meters, 200mW & 12,000 miles: WSPR magic!

Weak Signal Propagation Reporter is a global radio propagation monitoring and reporting network comprised of thousands of low power beacons operating on the amateur radio bands. WSPR beacons can be detected from the lowest of Medium Wave frequencies (137kHz) all the way through the HF spectrum (all the bands from 160m to 10m are popular) to the VHF bands, 50 and 144MHz. WSPR receivers decode the tiny beacon packets and upload them to a central database, at WSPRNet.org, where anyone can literally ‘see’ the propagation paths that are currently open.

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SP-X, a pocket rig for the CW activator in a hurry!

I’ve long been interested in compact and fairly minimal SSB and CW rigs with good performance. I’m not into bells, whistles or menus. Menus are for restaurants! When hiking, walking or bouncing around summits I want to minimise things that are not absolutely necessary, things that can go wrong. Less is more when it comes to a transceiver for portable work.

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SP-8: a homebrew 28MHz SSB transceiver for a UR3LMZ 144MHz transverter

Ten meters or the 28MHz band is showing glimmers of life from sunspot cycle 25. Even so, its not an obvious choice if you want to build a portable SSB monobander and have lots of contacts. But 28MHz is the IF of choice for VHF and UHF transverters. After noticing the 6, 2 and 70cm transverters available on eBay from the workshop of UR3LMZ and the good reports from buyers, I cooked up the idea to build a 28MHz ‘transverter IF’ transceiver, to be paired with one or more VHF or UHF transverters.

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Low-band AM Tx: Chassis and finishing

This post closes off the 160 and 80m ‘Low-band’ AM transmitter series, with a description of the chassis construction, fitting the assemblies into the chassis, and front panel finishing.

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Low-band AM Tx: Power supplies

Complete 500W variable regulated DC power supply assembly.

This post describes the power supplies for a 200 watt AM transmitter. There are four independent DC regulated supplies. The ‘high tension’ (HT) supply delivers 0 to 100 volts at 5 amps steady to the modulator, and is sized for a continuous 200 watt AM carrier (with 800 watts of peak power in the sidebands). Two regular 12 volt linear regulated supplies power the 12 volt circuitry (independent 12 volt supplies is a way of keeping digital and other noise off the modulator and driver stages).

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Low-band AM Tx: Pulse Width Modulator and Preamp

This post describes the modulator section of a 200 watt dual-band (160 and 80m) AM transmitter, built during the COVID-19 first-wave lockdowns in Melbourne. The transmitter is fully solid state, runs cool to luke-warm at 85 to 90% efficiency, and produces high quality AM on the two lower amateur bands.

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Low-band AM Tx: RF Deck

‘RF deck’ is a term that describes the RF power modules in a transmitter or linear amplifier. In this 200 watt 160 and 80m AM transmitter, the RF deck consists of two identical FET RF modules each with its own driver, an RF power combiner, the band switched Low Pass Filter module, a Transmit/Receive switching relay, and an SWR and RF power sampling module.

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Low-band AM Tx: Digital VFO/Controller

Lockdown has made 2020 a year unlike any other. Melburnians were dealt a long and painful period of isolation with a CoronaVirus second wave, from around July to September, still in force, and looking like continuing to (at least partially) keep us housebound for some months yet. Days merge together, work and leisure time is largely indistinguishable. People are rediscovering reading, knitting, and endlessly bingeing TV. Makers are melting solder and stringing wires in the air.

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Mt Ritchie VK3/VC-003 and Mt Toolebewong VK3/VC-033

Paul VK3HN and David VK3KR.

David VK3KR and I made plans for a visit to Mt Ritchie VK3/VC-003, 1255m (8 pts) and Mt Toolebewong VK3/VC-033, 735m (4 pts). This would be our first use of the approach from the north, rather than using the usual 8km round trip via Road 15 (from Acheron Way) then Road 10. While the southern route is a great hike in the Yarra Ranges, it takes up most of a day. But more so, some more skilled cartographers than I have determined that an alternate route in, from the north, has greater clearance from the water catchment area boundary. Two good reasons to choose the new route, from the north.

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Shack of VK2KMI

Ham Radio Blog of VK2KMI

Ham Historian

A passionate amateur looks at Melbourne history

R.IT

My journey of repairing and recycling anything I put my hands on that I believe is still useful. Not just hardware, but including software with relevant content and issues in the field of Cyber Security, Vulnerability Scanning and Penetration Testing.

G4YDM Ham-Radio and SWL news

Radio craft, homebrew, QRP/SOTA, AM

VK1DA.blog

Amateur radio experiences with VK1DA

Tj Lab

信号処理とラジオ

The Microscopic New Yankee Make Shop

Bits of technology and illogic by WA2MZE

Paul Gacek

W6PNG/M0SNA

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