Category Archives: Shortwave Radio

New antenna from Bonito: The MegaDipole MD300DX wideband active dipole

Many thanks to Dennis Walter at Bonito for sharing the following product announcement:

MegaDipole MD300DX wideband active dipole

The MegaDipole 300DX is a broadband active dipole with a maximum upper working frequency of 300 MHz. The dipole reacts to the electrical component (E-Field) of the electromagnetic field and will deliver best results regarding signal strength and SNR (signal -to-noise-ratio) at locations with little or no locally generated interference. Nonetheless, the receiver to be coupled to this antenna should have a high enough dynamic range so that it can effectively process the received signals.

In contrast to simple E-field antennas with only one radiating element, the symmetrical construction of the MegaDipole 300DX, will result in almost no negative resonance effects or reflections caused by the coaxial cable.

First choice for DXer

The MegaDipol MD300DX is the ideal antenna for DXers. Particularly in electrically quiet environments, it can really play to its strength in efficiently amplifying weak signals. In practical operations, a maximum signal-to-noise ratio of 110dB was achieved! (see image )

Wideband

With prodigious broadband capability and constant receive characteristics the MegaDipol MD300DX is ideal for wideband receivers, SDR’s and WEB-SDR such as KiwiSDR etc. The MegaDipol MD300DX can of course also be operated on all other receivers, including lower-end SDRs and portable world receivers.

Dual Power Power Supply

The MegaDipol is nominally supplied with 10 – 15V DC (max 40mA), however, it can be operated across a wide variety of supply voltages. The antenna can even be operated with slightly reduced IP values at the same gain with only 5 volts via USB. This offers a significant advantage in that you can supply the MegaDipol on trips away from the radio shack or DX expeditions autonomously, using a low-noise USB power-bank.

The MegaDipol has already attracted a lot of attention with its receive performance at various events such as DX-Camps, field days and in-house exhibitions. In these tests, the MD300DX surpassed the existing antennas usually by 10-15dB in the SNR.

Technical data

Frequency range: 9kHz – 300MHz
IP3: typ. +30dBm (@7.00 & 7.20MHz)
IP2: typ. +78dBm (@7.00 & 7.20MHz)
Size/weight: 98 x 90 x 38mm / 0.12kg

Whats in th Box?

MegaDipol MD300DX
Power Inserter CPI 1000DP
2x 2.5m long radiating elements (PVC-coated, salt-water resistant stainless steel ropes)
2 insulators for installation (weatherproof plastic material with 4.5mm fixing hole)

Available Soon. Price 336,-€ without VAT. Click here to view at Bonito.

Today: W9IMS special event honoring races at the Indianapolis Motor Speedway

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Many thanks to SWLing Post contributor Brian D. Smith (W9IND), who shares this information about SWL-friendly awards offered by his amateur radio club to commemorate the three major auto races at the Indianapolis Motor Speedway:

Indianapolis Motor Speedway special event stations: Act now for your shot at a 2018 certificate!

Attention, paper chasers: Amateur radio station W9IMS has begun another year of special events honoring major auto races at the Indianapolis Motor Speedway. And SWLs are welcome to submit reception reports qualifying them for the same colorful QSL cards and certificates available to the ham radio operators who contact the station.

The certificate and QSLs change every year, with three unique cards offered for the 2018 Grand Prix of Indianapolis, the Indianapolis 500 and the Brickyard 400, so even if you scored the clean sweep in 2017, you’ll find new trophies to pursue this year.

Just one catch: You’ll have to move fast if you want to log W9IMS in the first race, because its final day of operation is Saturday, May 12.

But you’ll have a shot at tuning in the station on any of two and possibly three bands (20, 40 and 80 meters), and since it’s the last day (Race Day), W9IMS will likely stay on the air till as late as 11 p.m. and perhaps beyond.

Here are a couple of hints for tracking down the station during this and the other two special events:

Go to www.w9ims.org, find the “2018 Schedule” heading, and click on the link to the Grand Prix operating schedule (or any other race). Although some W9IMS operators take to the airwaves at unscheduled times, you’ll have your best luck looking for the station during the hours and bands reserved with a name and callsign.

Check DX Summit (www.dxsummit.fi) for spots that identify the current frequency (or frequencies) of W9IMS. If you type “W9IMS” in the search box, you can customize it to list reports for only that station.

The second and third special events will take place from May 21-27 (Indianapolis 500) and September 3-9 (Brickyard 400). Full details can be found on the W9IMS web page; note that QSL cards and certificates are not filled out until after the third race, so you can take your time in submitting your reception reports.

Feel free to submit all of your 2018 QSL and certificate requests in the same envelope. And even if you catch W9IMS for only one or two special events, you can still obtain individual QSL cards for those races.

Ivan performs two tests with the AirSpy HF+

First Brigade Combat Team: Legacy HF comms provide “unlimited range with zero cost or resources”

This weekend: Historic NSS Call Sign reactivated during Armed Forces Day Crossband Test

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100th Anniversary QSL card for NSS

Many thanks to SWLing Post contributor, Brian Smith (W9IND), who shares the following press release regarding the historic U.S. Navy callsign NSS that will be reactivated during the 100th anniversary of the former Naval Radio Station in Annapolis, Maryland:

Historic NSS Call Sign to be Reactivated During its 100th Anniversary

Historic U.S. Navy callsign NSS will be reactivated during the 100th anniversary of the former Naval Radio Station in Annapolis, Maryland. The U.S. Naval Academy Radio Club (W3ADO) and the Potomac Valley Radio Club (W3GRF) will reactivate the historic callsign during the upcoming Armed Forces Day Crossband Military/Amateur Radio Communications Test.

NSS operations from the location of the former Naval Radio Station on Greenbury Point will be from 1300Z Saturday May 12 to 0200Z May 13. CW and SSB transmissions will be on 4038.5, 5330.5, 7533.5, 9447, 14487 and 17545 kHz. NSS will listen for callers on announced frequencies in adjacent amateur bands. Commemorative QSLs will be sent for all QSOs.

NSS began operations in 1918 as the Annapolis High Power Radio Station using a pair of Federal Telegraph Company 500 kilowatt Poulson Arc transmitters and four 600 foot towers operating in the Very Low Frequency (VLF) band. At that time VLF provided the only known capability for trans-oceanic radio communications. NSS began continuous operations in the HF bands about ten years later until 1976 when its HF mission was transferred to Naval Radio Station NAM in Norfolk, Virginia. The 1200 foot central tower and dozens of other towers and masts were demolished in 1999, except for three iconic 600 foot Eiffel towers that remain at the southern tip of Greenbury Point.

A brief video history of NSS is here: