Welcome to Issue #010 of Radio Waves Weekly! A landmark tenth issue, and the news matches the milestone. KP5/NP3VI has just gone QRT from Desecheo Island after 104,000 QSOs on solar power alone — a first in DXpedition history. TX9W heads to the Marquesas in three weeks. WSJT-X Improved 3.1.0 brings FT2 into the open-source world. iDigi 2.2.2 puts eight digital modes into one native macOS app. SP DX Contest opens Saturday, POTA Spring Weekend is April 18-19, and two unusual wire antennas from vu3dxr.in await your weekend.
1. KP5 Desecheo Island — 104,000 QSOs, Solar-Only Power, History Made DX RETROSPECTIVE
KP5/NP3VI went QRT on March 3 after 50 days of fully unattended operation using solar-powered Remote Deployment Units — no generator, no fuel, no operator on the island at any point during the activation. The team logged over 104,000 QSOs with 20,000 unique callsigns from Desecheo (#14 Most Wanted, dormant since K5D in 2009). It is the first rare-entity DXpedition to reach 100,000 QSOs running exclusively low power on 100% solar energy, and also conducted the first-ever FT2 mode contacts from a DXpedition. OQRS for direct QSLs is open at M0OXO. The DX-World log covers the full operational history.
Complete expedition log & QRT notice → dx-world.net/kp5-np3vi-desecheo-dxpedition/
2. TX9W — Marquesas Islands (IOTA OC-027) on the Air April 19–30 DX ALERT
A six-operator team from the Oklahoma DX Association and France activates TX9W from Hiva Oa, Marquesas, April 19–30. Six amplified stations cover 160–6m on CW, SSB, FT8, FT4 and RTTY simultaneously, with deliberate emphasis on CW and SSB contacts rather than FT8-only running. Planned CW frequencies include 7007, 14007, 21007 and 28007 kHz. Daily log uploads to ClubLog Livestream; LoTW after return. Goal is 100,000 QSOs. For VU stations, 15m afternoon grey-line and 20m morning openings are the most reliable windows to the Central Pacific.
Band plan, team list and log → k5we.com/tx9w/
3. WSJT-X Improved 3.1.0 — Open-Source FT2 Lands in a Mainstream Decoder DIGITAL SOFTWARE
DG2YCB’s WSJT-X Improved 3.1.0, released February 26, is the most significant build yet: it introduces a fully open-source FT2 implementation — a 77-bit mode with 3.75-second TR periods, compatible with IU8LMC’s Decodium 3 builds but carrying no proprietary code. It also adds compound and non-standard callsign support across all 77-bit modes (FT8, FT4, FT2, MSK144, Q65), and an improved multithreaded FT8 decoder. Available for Windows 64-bit, macOS and Linux. Developer notes that FT2 is still experimental — he hasn’t committed to keeping it permanently.
Installers and full changelog → sourceforge.net/projects/wsjt-x-improved/files/WSJT-X_v3.1.0/
4. iDigi 2.2.2 for macOS — PSK31, RTTY, FT8, SSTV and WEFAX in One Native App DIGITAL SOFTWARE
Released March 23 by HB9ZHK, iDigi 2.2.2 updates the macOS-native digital mode suite with the ability to call any FT8 or FT4 station directly from the waterfall, automatic FTP-upload of received SSTV and WEFAX images, Hamlib 5 support, and a light/dark theme toggle. The app covers PSK31/63/125, RTTY, CW, WSPR, WEFAX, FT4, FT8 and over 100 SSTV modes in a single binary — no extra sound card software, no Wine layer. Trial period available free from the Mac App Store; full licence is $9.95.
Release notes → machamradio.com/blog/2026/03/23/idigi-version-2-2-2-has-been-released/
5. Elecraft KH1 Firmware v1.27 — Off-Grid FT8 Self-Spotting via SOTAmat QRP NEWS
Firmware 1.27, released January 12, adds FT8 transmit capability to the KH1 specifically for SOTAmat self-spotting in the field without mobile data. Additional changes include Morse audio feedback for visually impaired operators, adjustable QSK delay up to 2.5 seconds, and ATU and monitor level settings that now survive power cycles. The KH1 is Elecraft’s 200g palm-sized 5W CW transceiver covering 40–15m with a built-in ATU. The QRPer report details all six firmware changes with practical field context.
6. Half Rhombic Antenna with Counterpoise — Directional Gain Without a Full Rhombic ANTENNA BUILD
Originally published in RSGB Radio Communication, December 1996, the Half Rhombic is a terminated travelling-wave wire antenna: one sloped leg runs from a high feedpoint down to ground level where a terminating resistor and a quarter-wave counterpoise sit. The terminating resistor suppresses the reverse lobe, delivering a clean unidirectional pattern toward the far end of the slope. Resistive loss is around 3 dB compared to a lossless antenna, but the directional advantage toward a chosen continent often more than compensates. An underrated option for anyone with a long sloped run available in one direction.
Dimensions and circuit → vu3dxr.in/half-rhombic-antenna-with-counterpoise/
7. Rockloop — Indoor HF Loop for 10, 15 and 20 Metres, No ATU, No Radials ANTENNA BUILD
The Rockloop is a compact air-cored loop tuned by a twin-gang polyvaricon capacitor salvaged from an old AM transistor radio. It tunes to 15m at 15–20 pF, 20m at approximately 30 pF, and 30m at around 60 pF, covering three bands with one coil on a tabletop or balcony railing. Based on a SPRAT design by DL1HCU, the build requires no ATU, no counterpoise and no outdoor installation — making it a practical first antenna for licensed operators in flats or apartments running QRP. Tuning chart and winding instructions are on vu3dxr.in.
Full build guide → vu3dxr.in/antenna-rockloop-compact-hf-antenna-for-101520-metre-ham-bands/
8. SP DX Contest — Opens Saturday April 4, Running Since 1933 UPCOMING CONTEST
The SP DX Contest runs 1500 UTC Saturday April 4 to 1459 UTC Sunday April 5, 2026 on 80, 40, 20, 15 and 10m — SSB and CW scored separately. Polish stations send RST plus province abbreviation; everyone else sends RST plus serial number. Polish callsigns are the valuable multipliers, making VU stations welcome callers who boost SP scores. With 15m and 20m performing strongly at Solar Cycle 25 peak, SP stations should be audible across South Asia during early UTC evening on both bands. Log submission is online at the contest site.
Rules and online log submission → spdxcontest.pzk.org.pl
9. POTA Spring Weekend — April 18–19, Parks Worldwide Active Simultaneously PORTABLE OPS
Parks on the Air runs its annual Spring Weekend on April 18–19, 2026 — the third full weekend of April each year. Operators activate parks worldwide simultaneously, producing an unusually dense cluster of spots on the POTA map and better-than-average hunter pileups. It is also World Amateur Radio Day on April 18, adding significance to field activations this year. Any POTA-listed national or state park qualifies; VU operators can activate Indian national parks and wildlife sanctuaries listed in the POTA database. No pre-registration needed — just activate and upload your log.
Event guide and park finder → docs.pota.app/docs/events.html
10. “Your First Pileup” — Practical Techniques for Working Both Sides of the Pile DX RESOURCE
A solid, practical guide published on OnAllBands.com covering pileup management from both ends — as the DX station running a pile, and as the hunter trying to break through one. Covers when to go split, how to keep a rhythm, why calling while the DX is still in QSO is the single most common mistake, and how to pace yourself during a long activation. Written for operators at every level, from first POTA activation to rare DXpedition. Timely reading ahead of TX9W’s Marquesas pileup on April 19 and the run of Pacific activations through April and May.
Full guide → onallbands.com/your-first-pileup-techniques-for-success/
11. 425 DX News — Free Weekly DX Bulletin, Every Saturday Morning DX RESOURCE
Published every Saturday by 425DXN.org, the 425 DX News bulletin is the most consistently comprehensive weekly DX summary available in English — covering active and upcoming DXpeditions, contest reminders, QSL information and propagation notes. Issue #1418 (March 28) covers CY0S final log status, T31TTT on Kanton, TX9W preparations and C5B Bijol Islands in April. The bulletin arrives by email subscription or is downloadable as a text file directly from the website. An essential Saturday morning read for any active DXer and a useful companion to this newsletter.
Subscribe or download latest issue → 425dxn.org
12. DXpeditioning Basics — Wayne Mills N7NG’s ARRL Guide, Free PDF Download DX RESOURCE
Wayne Mills N7NG’s authoritative guide, hosted permanently by ARRL, covers the complete mechanics of running a DXpedition pileup: split frequency structure, listening window management, CW speed discipline, QSY signalling, and the specific habits that separate a smooth-running pileup from a chaotic one. Written from decades of expedition experience across rare entities. Distinct from hunter-side advice — this is the operating manual from the island end of the QSO. A 20-page free PDF, directly downloadable, no registration needed.
Free PDF → arrl.org/files/file/DXCC/dx-basics.pdf
Want to contribute? Found an interesting circuit, a new SDR software, a helpful radio blog, or breaking ham radio news? Email me or leave a comment below. Your link might be featured in next Sunday’s digest!
