NVIS: Near Vertical Incidence Skywave [ PodCast ]

Sometimes the best direction to send your signal is straight up!

Near vertical incidence skywave, or NVIS, is a skywave radio-wave propagation path that provides usable signals in the range between groundwave and conventional skywave distances—usually 30–400 miles (50–650 km). It is used for military and paramilitary communications, broadcasting,[1] especially in the tropics, and by radio amateurs. The radio waves travel near-vertically upwards into the ionosphere, where they are refracted back down and can be received within a circular region up to 650 km from the transmitter.[2] If the frequency is too high (that is, above the critical frequency of the ionospheric F layer), refraction fails to occur and if it is too low, absorption in the ionospheric D layer may reduce the signal strength.

There is no fundamental difference between NVIS and conventional skywave propagation; the practical distinction arises solely from different desirable radiation patterns of the antennas (near vertical for NVIS, near horizontal for conventional long-range skywave propagation).

Antenna

Buddipole vs AlexLoop Walkham

November 03, 2015 No comments

Buddipole vs AlexLoop Walkham    “Tried to do the most objective analysis on a comparison between the Buddipole and a AlexLoop Walkham ante... Read more

New ! SteppIR SARK-110 Antenna Analyzer

December 28, 2014 No comments

  The SARK-110 is a completely new design concept for an Antenna Analyzer. This is a truly pocket size device, so you can take it anywhere. It of... Read more

4-Band OCF Antenna 40, 20, 10, and 6 meters

March 05, 2015 No comments

  4-Band antennas cover 40, 20, 10, and 6 meters, with no tuner required! 12 meters may also work on the 4-Band 300 watt model. The 4-Band antenn... Read more

500 mW on 7 MHz with the Wadetenna

December 29, 2014 No comments

Testing the Wadetenna on 7 MHz SSB. Only 500 milliwatts was used instead of the usual 5 watts. Contacts up to about 500km, mostly to portable stations... Read more

FX771 MetroPWR Overview

September 14, 2017 No comments

 Technical Features METER METROPWR FX771  Coverage 1.8/55 MHz 160/6mt + VHF/UHF (optional)  Measure Power AVG, PeP, dBm, R, Z, X , SWR, ReturnLoss  Po... Read more

Review

Exploring the Yagi, Log Periodic, and Phased Array [ Video ]

September 07, 2017 No comments

Discusses the difference between Yagi antennas, log periodic antennas, and phased array antennas.   Read more

What makes a good portable CW paddle?

September 28, 2016 No comments

Richard G3CWI of SOTABEAMS has released a 3 minute video looking at the differences between a paddle designed for portable use and a fixed-station pad... Read more

First Impressions of the Icom IC-7300 HF + 6M Transceiver

February 16, 2016 No comments

Icom IC-7300 by AB4BJ “I have been having a great time at Orlando Hamcation that this year features the ARRL National Convention.  One of the hi... Read more

QRP Labs at the 2019 Dayton Hamvention®

May 22, 2019 No comments

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Beta Testing of MFJ-1234 RigPi Station Server

December 18, 2018 No comments

MFJ-1234 Read more

Digital Modes

Decoding Ham Datamodes From WebSDR

September 29, 2015 No comments

WebSDR Alex Csete OZ9AEC is showing you how you can listen to and decode digital ham radio traffic without having any receiver or antenna. All you nee... Read more

FT8Call 0.5 Released – New features, a MacOS build, APRS.fi spotting, and more!

September 02, 2018 No comments

“Howdy Folks,   I’m excited to bring you the next development version of FT8Call, version 0.5, and boy do I have some fun stuff included i... Read more

Release: WSJT-X Version 1.8.0

July 11, 2017 No comments

WSJT-X Version 1.8.0  ” 1. New mode called FT8: sensitivity down to -20 dB on the AWGN channel; QSOs 4 times faster than JT65 or JT9; auto-seque... Read more

World Wide Digi DX Contest

June 29, 2019 No comments

The World Wide Radio Operators Foundation (“WWROF”), in collaboration with the Slovenia Contest Club (“SCC”), is pleased to announce the first annual... Read more

New Digital Mode FT-8 Ham Radio Digital Mode for the Fast & Furious!

July 17, 2017 No comments

Here’s a short demonstration on the new digital mode FT-8 developed by K1JT & K9AN. Part of the WSJT-X software suite. We’ll go over h... Read more

Equipment

Icom AIR. LAND. SEA. [ Brochure ]

September 12, 2016 No comments

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Anytone AT-6666 All-Mode 10 Meter Mobile

September 10, 2015 No comments

  Anytone AT-6666 All-Mode 10 Meter Mobile 60 watts SSB – 360 Memories CTCSS / DCS Option Included Programming Cable Included General Speci... Read more

ADALM-PLUTO: A NEW $149 TX CAPABLE SDR WITH 325 – 3800 MHZ RANGE, 12-BIT ADC AND 20 MHZ BANDWIDTH

February 15, 2017 No comments

The easy to use ADALM-PLUTO active learning module (PlutoSDR) helps introduce electrical engineering students to the fundamentals of software-defined... Read more

VTR1100 Tactical Radio Communication

February 06, 2016 No comments

DESCRIPTION The LANDSEC ™ VTR1100 is a 1.6 MHz to 30 MHz, 125 W or 25 W selectable HF transceiver for co-located communications in vehicle installatio... Read more

Codan 2110M – HF Transceiver – Military

March 05, 2015 No comments

    Frequency rangeTransmit: 1.6 to 30 MHz, 10 Hz steps Receive: 0.25 to 30 MHz, 10 Hz steps Frequency Stability: ±0.5 ppm from –30°C to +60... Read more