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8 elements quad antenna for 2 meters band, centered on 145 Mhz

HamCalc is a free collection of calculators for radio amateurs include Antenna ERP calculations, Attenuators, Audio Filter design, Coil Winding, Decibels, Great Circles map and calculator, HF Filters, HF Traps, Metric conversions OP Amps QRA Locator to Latitude/Longitude, Radio Horizon calculator, Resonance Satellite orbit calculator Timer calculations (555 timer)Zener Diode calculations Download zip By G4VWL

F6EZX presents a detailed account of constructing a compact, multi-band _Levy antenna_ for portable holiday operations, specifically addressing issues with local QRM from a previous _Deltaloop_ setup. The article outlines the design criteria, including multi-band operation on 40m, 30m, 17m, 15m, 12m, and 10m, a symmetrical configuration to reduce interference, and a low take-off angle for DX. Construction involves 2x 10.3m radiating elements and a 15.3m open-wire feeder (ladder line) with 7cm spacing, made from 1.5mm2 copper wire and foam pipe insulation spacers. Theoretical calculations, referencing F9HJ's "_Les antennes Levy_" book, guide the determination of element lengths and feeder impedance characteristics, aiming for a good match across bands with a commercial antenna tuner. Initial field tests with the _VCI Vectronics VC300DLP_ tuner showed a 1:1 SWR from 80m to 10m, with some difficulty on 17m. The antenna, mounted as a 45-degree slopper with the high point at 12m, successfully facilitated DX contacts to South America, particularly Chile and Argentina, suggesting a lower take-off angle compared to the previous Deltaloop which favored Brazil. The Levy antenna significantly reduced TVI/RFI, attributed to its improved symmetry and greater distance from the QRA. While signal reports on 15m and 20m were 1-2 S-points lower than the Deltaloop, its performance on 40m and 30m was comparable, fulfilling the design goals for a portable, low-cost, multi-band solution.

Radio propagation prediction and simulation tool for VHF-UHF, based on the Irregular Terrain Model, also known as Longley-Rice. Can be used as a repeater site planing tool and radio coverage analysis. Currently it works on Linux and Windows.

The EZ QRA Locator softawre is a simple software for the calculation of QRA locators

Interactive great circles and QRA Locator map

This resource presents over 100 Q-signals, each with its corresponding question and answer format, as standardized by the International Telecommunication Union. The content delineates how these abbreviations can be expanded with additional groups, call signs, place names, or numerical data to provide specific context. It clarifies that a question mark following an abbreviation or its complementary information transforms it into a query. The document highlights that these operating signals, or Op Sigs, are prescribed for international use across all communication types, including military and non-military applications. It references their inclusion in Appendix 9 to the Radio Regulations Annex of the International Telecommunications Convention (Atlantic City) 1947 for QRA to QUZ blocks, and ICAO publications Dec 6100-COM/504/1 for QAA to QNZ blocks. The page specifically marks Q-signals of particular interest to amateur radio operators in red. The utility of Q-signals for concise communication in radiotelegraphy is evident, providing a structured method for conveying complex information efficiently. The resource serves as a practical reference for operators needing to quickly interpret or formulate messages using standardized codes, particularly beneficial for CW operation and international contacts.

This is a Live DX Cluster map powered by google maps diplays a map of ham radio QSOs or contacts based on qra locator and dx-cluster spots information

GitHub reposotory of QradioPredict, a radio propagation prediction tool for VHF-UHF, based on the Irregular Terrain Model, also known as Longley-Rice. Can be used as a repeater site planing tool. Has an internal APRS client which can be used to display stations as a landmark.

QRadioLink is a Linux analog/digital SDR transceiver application with Codec2 digital voice mode support.

This article taken from the IARU Region 1 VHF handbook, is about the history of the original Locator System named QRA-Locator consisted of just five-character code, two capital letters, a two-digit number and a lower-case letter, like inf example CM72j

Demonstrates a cloud-based suite of tools for amateur radio operations, eliminating local software installation. The platform integrates a comprehensive logbook with import/export functionality, an _eMap_ application displaying DX spots, user locations, and grayline data, alongside a dynamic band map derived from DX cluster information. It also provides a _vQSL_ system for QSL management and a mailbox with QSO verification. Users can access a Web DX cluster to monitor spots and _DXCC_ status, or connect via Telnet using external programs like _Logger32_ or Ham Radio Deluxe. The cluster supports advanced spot filtering by QRG, spot call, spot from, and origin, with configurable mail alerts based on IARU zone filters. Additional features include a real-time chat for skeds, azimuth/distance calculations from a user's QTH (with QRA locator), a search engine for spot and logbook databases, a band status matrix, and a propagation tool for MUF calculations, leveraging data from N0NBH.