![NVIS: Near Vertical Incidence Skywave [ PodCast ]](https://qrznow.com/wp-content/uploads/2017/11/24180150.jpg)
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
Unboxing the MyAntennas EFHW-80-10 End Fed Antenna
EFHW-8010-1K ™ Multi-Band End Fed Half Wave Antenna This is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. Unlike many... Read more
How-To: Splice Wire to NASA Standards
Developed during the heyday of the telegraph, the Lineman’s splice is designed for connections that will be under tension. It is commonly claimed that... Read more
![Antenna Fundamentals 1 Propagation [ Video ]](https://qrznow.com/wp-content/uploads/2016/06/d01645880bc21d293eab203a20ce8adf-190x122.jpg)
New log periodic array from InnovAntennas with parasitic element enhancement
100MHz to 750MHz Log Periodic Array Description InnovAntennas design and build Log Periodic Arrays for any bandwidth and for any purpose. Our LPDA... Read more
20′ DX Flagpole Antenna | OCF HF Vertical Dipole | 3.5 to 50 MHz No Radials, Stealth, Portable
OCF HF Vertical Dipole Higher performance, HF Multiband DX Flagpole Antenna covering 3.5 to 50MHz with NO radials sound like relief for your CC&R... Read more
Review
RM Italy MLA100 Amplifier Demonstration
“Mark, W8BBQ show the RM Italy MLA100 amplifier to get over 100 watts from a QRP rig. 160 meters through 10 meters plus 6 meters. Allows you to... Read more
![Flex 6600 Hamvention 2017 [ Video Demonstration ]](https://qrznow.com/wp-content/uploads/2017/06/Flex-6600M_hamvention-190x122.jpg)
Flex 6600 Hamvention 2017 [ Video Demonstration ]
K5SRD talks about the new Flex 6600 on Amateur Radio Roundtable. FLEX-6600 A Real SDR for Every Operator Both the FLEX-6600™ and FLEX-6600M™ offer the... Read more
SharkRF Openspot3, The Most Advanced Digital Ham Hotspot!
Compatible digital radio protocols and networks DMR (BrandMeister, DMRplus, DMR-MARC, Phoenix, XLX, TGIF) D-STAR® (DCS, REF/DPlus, XRF/DExtra, XLX) Sy... Read more
Digital Modes
New Ham Shack Part 4, Audio Mixer Installation by K7AGE
In this video I show you how I setup an audio mixer for my ham radio station. I am using this mixer to monitor the audio outputs from my Elecraft K3,... Read more
Getting Started on FT-8 by Jim Heath W6LG–Using Holiday Lights
“An amazing new mode for quickly communicating around the world with low power and simple antennas. In this video Jim uses exterior holiday or C... Read more
FT8DMC 3rd Anniversary-Activity Days 2020
To commemorate our 3rd anniversary, special event stations will be on air during the FT8DMC Activity Days from 1. to 31. July 2020. All stations will... Read more
FT4 vs FT8 – A new mode, what’s the difference?
The FT4 Protocol for Digital Contesting by K1JT Read more
Equipment
DX Engineering Radio RF Ground Plane Kits
DX Engineering Radio RF Ground Plane Kits provide an effective method of reducing stray RF pickup by equipment and interconnecting cables. Used under... Read more
A-iPower Portable Generators SUA8250E
Portable Generators Get power where you need it using one of these A-iPower portable generators. They are driven by a compact, high performance, air-c... Read more
ELAD SPF-08 HF PRESELECTOR
Switchable Preselector Filter Board for FDM SDRs ELAD SPF-08 is switchable pre-selector board that allows selection between 8 configurable filters. Us... Read more
Japanese HF KL-1 Kohjinsha PA – 5 KW
The KL-1 consists of a sophisticated and sturdy Main Unit and a Desk Top Controller with five meters (HV, IP, IG, FWD, and REF). The LCD displays BAND... Read more
Kenwood TS-890 – Instruction Manual
The Kenwood® TS-890S transceiver made its world debut at the 2018 Hamvention® in Xenia, Ohio. It features full down conversion receiver with h... Read more
