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The intrepid newcomer encounters common mode problems in a mobile environment. Implementing some common mode chokes will be possible to reduce interferences

ARRL members classified ads

Don't neglect one of the most important parts of your station!

W1AW Propagation Bulletins for 2001

Some basic antenna information for the newcomer

The Receiver Test Data resource is a detailed review database focusing on the performance metrics of various radio receivers. The methodology involves rigorous lab measurements, often adhering to standards such as the ARRL RMDR (Reciprocal Mixing Dynamic Range) and BDR (Blocking Dynamic Range). Specific test equipment and protocols are utilized to assess parameters like noise floor (dBm), AGC threshold (uV), and LO noise (dBc/Hz). For example, the _Icom IC-7300_ is evaluated with a noise floor of **-133 dBm** and an LO noise of **-141 dBc/Hz**, providing insights into its performance under different operational conditions. The resource includes a wide range of models, from the _Elecraft K3S_ to the _Yaesu FTdx-101D_, each tested for dynamic range, sensitivity, and selectivity. The data is sorted by key metrics such as third-order dynamic range and phase noise limitations, with RMDR values calculated by subtracting 27 dB from LO noise figures. This structured approach allows users to compare different receivers' capabilities, focusing on technical specifications and performance outcomes in various scenarios. DXZone Focus: Review Database | Lab Measurements | -133 dBm | ARRL RMDR

Telephone EMI, questions and answers on how to solve interference problems to phone lines

Assembling a Code-Practice Oscillator, a PDF by ARRL

A comparison of multiband dipoles, including jumpered dipole versus fan dipole antennas, dipole fed by ladder line, resonant dipoles antennas. ARRL lab notes

The ARRL Foundation is devoted to providing valuable programs to serve the ham community, whether those served are ARRL members or not. Established in 1973 by the American Radio Relay League, Inc. (ARRL) as an independent and separate 501(c)(3) organization, the ARRL Foundation administers programs to support the Amateur Radio community. The ARRL Foundation advances the art, science and societal benefits of the amateur radio service by awarding financial grants and scholarships to individuals and organizations in support of their charitable, educational and scientific efforts. Funded entirely by the generous contributions of radio amateurs and friends, ARRL Foundation administers programs for Amateur Radio award scholarships for higher education, award grants for Amateur Radio projects, and award special Amateur Radio program grants for The Victor C. Clark Youth Incentive Program and The Jesse A. Bieberman Meritorious Membership Program.

MFSK is an easy-to-use chat mode for real-time amateur contacts, nets and bulletin transmissions, but not intended for contesting or Bulletin Board System (BBS) use. It is a half-duplex non-Automatic Repeat ReQuest (ARQ) forward-error-correcting (FEC) mode. It performs well on long-path fading conditions and in the presence of interference

ARES vs RACES FAQ: Two Flavors of Amateur Radio Emergency Operation

Understanding Amateur Radio NVIS Antennas and Propagation, derived from The ARRL Antenna Book and QST Articles

This large, colorful wall map features current geographic detail and labels, grid squares, call sign prefixes, boundaries and more.

Clover technical specifications, digital communications mode that conveys 8-bit digital data over narrow-band high-frequency radio.

Easy to use award tracking software for ARRL, 10-10, CQ, HRN, OMISS, EPC, RAC and more.

Our group is the North East Weak Signal Group. We are an ARRL affiliated regional club dedicated to the interests of "weak signal" work on the bands 50 MHz -

Located in Wynne Arkansas. Repeater 147.375(107.2he Cross County Amateur Radio Club is an ARRL Affiliated Special Services Club. The Club is located in North East Arkansas and is based in Wynne Arkansas which is the County seat for Cross. With members from Cross County and surrounding Counties and communities in Eastern Arkansas the club works to serve our communities as well as the Amateur Radio Community.

Sometimes we need a little more output filtering than traditional designs offer. Look at a new filter that can give you that extra boost. QST article by W3NQN

Radio Frequency Interference To/From touch lamps and dimmers

Recordings of RF noise from personal computers, peripherals and related equipment. If you can match noise at your location to one of these files then you can be confident that you know where your noise is coming from.

An ARRL Special Service Club located in Northeast Nevada. Operates one of the largest linked repeater systems in the State of Nevada.

The RARC is the oldest ARRL affiliated club in Virginia. Founded in 1929 by Ted Mathewson, W4FJ one of the earliest Ham Radio Operators licensed by the FCC.

The reasons for logging your amateur activity fall into three categories: legal, operational and personal. Legally, a log of your transmissions would be invaluable in proving your innocence in an interference complaint. Operationally, having a log of past contacts is a resource when filling out that DX QSL card that may have taken months to arrive

Improving measurement accuracy when low-power analyzers are used.

The NIDXA is an active DX club affiliated with the ARRL. NIDXA runs the W9 Incoming QSL bureau, a DX Packet Cluster, and the world famous W9DXCC convention.

Random Length Multiband Dipoles can be a good solution for field day operations or outdoor activity, read more at ARRL web site

PACTOR-III is a software upgrade for existing PACTOR-II modems that provides a new data transmission mode for improved speed and robustness. PACTOR-III is not a new modem or hardware device. Most current PACTOR-II modems are upgradeable to use PACTOR-III via a software update since PACTOR-II firmware accommodates the new PACTOR-III software

Ham radio on the ISS at ARRL website

CLOVER-2000 is a faster version of CLOVER (about four times faster) that uses eight tone pulses, each of which is 250 Hz wide, spaced at 250-Hz centers, contained within a 2 kHz bandwidth between 500 and 2,500 Hz

Hams have been putting stations in their cars since the Twenties. Today, there is great satisfaction in facing the challenge of installing a transceiver in our small cars and pick-ups, using somewhat inefficient antennas

HSMM Experiments on the 6M Amateur radio Band

Info about operarting permissions in other countries

W1GHZ Palm Software, special-purpose contest logging program for the ARRL 10GHz Cumulative Contest.

QST Magazine, 1991 July, review of the Kenwood TS-850S 160-10 Meter Transceiver

Notes on using the QST propagation charts to determine propagation conditions

The MRAC is one of the oldest amateur radio clubs in the world, having been incorporated in 1917 and affiliated with ARRL

HB9BZA's LoTW users list, originally compiled since 2005 from DX-Cluster and user submissions, now primarily leverages the official ARRL full users list released on July 29th, 2017. This resource details 228,012 calls across 340 current DXCC entities, with the latest update noted on March 2, 2026. It offers various formats, including a full list, text versions, and breakdowns by country, providing valuable insights into LoTW participation for DXers. While the ARRL's official list with "last upload" dates diminished the original list's unique utility, HB9BZA's site continues to offer statistics and user counts by country, which remain of interest. The author, HB9BZA, expresses gratitude to contributors who helped maintain the list's accuracy over many years, achieving an impressive 96.4% match with the ARRL's data before the official release. Knowing which stations are LoTW active encourages more hams to join the system, demonstrating that even rare DXCC entities like Ducie Island or Heard Island can be confirmed quickly. For instance, HB9BZA recounts a 36-minute QSL confirmation for a 3A2MW contact. The list also integrates with the RXCLUS packet radio/telnet client, enhancing DXCC award tracking by identifying LoTW participants and utilizing upload dates for alarms.

The mission of the HDXA is to encourage DX activites in Eastern Nebraska and Western Iowa. The HDXA is a ARRL Affiliated Club with members promoting & sharing DX information and experiences.

Newest ARRL westcoast convention. Features fox hunt, banquet, speakers, VE testing, swapmeet, many prizes.

Progress Report on VHF OFDM Modem submitted by John B. Stephensen, KD6OZH ARRL Pdf file

Pacific Division of the American Radio Relay League

KB22UT Article on how protecting ham radio station and in particular I/O Lines such as AC power, coax cable, control circuits, telephone line.

By Peter Kemp, KZ1Z

Installing mobile radios in your new megabucks car can be a frightening proposition - especially if RF from your rig could damage your shiny new roadster

W5KUB Broadcasting live video and audio from ARRL National Convention (Dayton Hamvention)

Using portable generators during emergencies or at field day site, using batteries and how to recharge them, using solar panels.

The RVARC is a Fredericksburg, VA area 56 year affiliated club with the American Radio Relay League, ARRL.

Domino is the name given by the developers to a family of IFK coded coherent phase single tone MFSK keyed modes, using sequential tone-pairs in two alternate fields arranged as orthogonal but interleaved tone sets.