![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
Aviation (Airband) 118 – 128 MHz J-Pole Antenna
J-Pole Antenna Product Description The airband J-Pole antenna is tuned for the 118 – 128 MHz aircraft aviation band. Aviation fans prefer this antenna... Read more
GigActiv GA3005 Ultra Wideband
GigActiv GA3005 Ultra Wideband Frequenzy range : 9 kHz – 3 GHz Power Supply: 5,5V – 15V Gain: + 3dB Upper Frequency Limit (-1db): 3000 MHz... Read more
Sky Ham Radio End Fed Antenna , Resonant 40 – 20 – 10
Today many Hams encounter big problems when they want to install a good antenna. Many live in an apartment building, or in an area where the rules do... Read more
Inac Antenna AH-2054 (15, 12, 11, 10, 6 m. band)
Inac Antenna AH-2054 antenna is a high performance halo. Supports a high level of radio frequency between 160 and 360W. It covers the HF bands higher,... Read more
Antenna Circular Polarization
“Space communication has forced the use of Circular polarization. The fundamental advantage of circular polarization is that all reflections cha... Read more
Review
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Icom IC-7300 Morse Code and Display Overview [ Video ]
Icom revealed their first Software Defined Radio (SDR) HF transceiver, the IC-7300, on Saturday, August 22nd 2015, at the Tokyo Ham Fair... Read more
Mobile Ham Radio Tips & Tricks Volume #1 by SignalSearch
Photo:Wayne-N0ISV Mobile Ham Radio Tips “A video about mobile ham radio setups by K5ACL & N5CFB. Please join SignalSearch as we dive into ou... Read more
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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
Yaesu FT-991A Unboxing
The FT-991A is the next generation in all mode, all band MF/HF/VHF/UHF transceiver with C4FM (System Fusion) Digital capability. The FT-991A includes... Read more
YouKits HB-1B Transceiver – ARRL Review
HB-1B MK3 2015 is the upgrade version of our HB-1B QRP transceiver. It is a small in size, light weight, lithium battery pack , particularly suitable... Read more
Digital Modes
JS8Call 0.7 Released
J8Call “Howdy Folks, We’ve sure come a long way in the past few weeks. Thanks for sticking with me and enjoying the ride! This release is... Read more
FT8 DXpedition Mode Field Test Attracts Upward of 500 Participants
It was the Fox and the Hounds on the bands March 6, as the WSJT-X development group conducted a field test of the still-beta FT8 DXpedition Mode. A se... Read more
Ultra Portable PSK31/RTTY Digital Modem Ham Radio HF Digital Modem
Digital Modem can encode/decode BPSK31/63, RTTY, QPSK and CWmodes without PC, specially for portable digital communication。With its internal high perf... Read more
Second Test of FT8 DXpedition Mode Set for April 7
The second public test of FT8 DXpedition Mode will take place on April 7, and all radio amateurs are invited to participate. WSJT-X Developer Joe Tayl... Read more
New Digital Modes Gain Traction for Moonbounce, but Occasionally Show Up on HF
In December, Joe Taylor, K1JT, released the latest version (1.7) of his WSJT-X software suite, designed to facilitate basic Amateur Radio communicatio... Read more
Equipment
Heathkit ® Precision RF Meter – HM-1002 – pre-order
Finally, affordable laboratory-grade accuracy. And a whole lot more. For about fifty years, SWR/power meters haven’t really changed at all. Un... Read more
Coax Cable Stripping Tools
Coax Cable Stripping Tools DX Engineering DXE-UT-8213LR Coax Cable Stripping Tools have been designed to properly prepare coaxial cable for use... Read more
UNIDEN UBCD3600XLT DIGITAL SCANNER RECEIVER 25-1300MHz
UNIDEN UBCD3600XLT FEATURES, FUNCTIONS AND SPECIFICATIONS: • Favorites Scan – Allows you to organize your Systems into Favorites Lists. The scanner wi... Read more
Airspy advanced open-source software defined radio receiver
What is Airspy? Airspy is an advanced open-source software defined radio receiver with adequate dynamic range, capable of sampling 10MHz... Read more
SmartLink™ for Remote Access – FlexRadio
Robust, Secure Remote Access to any FLEX-6000 – Operate from Anywhere Simple Click connect. It’s that simple. SmartLinkTM is designed fro... Read more
![IC-9700 Manual – Basic and Advanced Manual [ English ]](https://qrznow.com/wp-content/uploads/2019/03/ic9700-265x168.jpg)
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