![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
YouLoop HF loop antenna
HF loop antenna HF Portable & Flexible Receive Loop Antenna Covers HF frequencies (10 kHz to 30 MHz) Usable on VHF up to 300 MHz as a folded Dipol... Read more
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Read on .pdf all information about the famous W3DZZ antenna – Download Here Read more
Topband: Webinar – Waller Flag RX Antenna 101 – How to Construct a WF
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MAX6 -Antenna Analyzers
Antenna Analyzers MAX6 antenna analyzer is not just an ordinary meter for antenna – it’s much more! Built-in radio signal meter allows you to... Read more
Review
3. LDMOS HF AMPLIFIER 100W INPUT 2400W OUTPUT BLF188XR 2 PCS 1.8-54 MHZ
LDMOS HF amplifier 90W input 2400W CW SSB output 1.8-54 MHz This a ready power amplifier. You will need a case and power supply only! Water-cooled h... Read more
Ham Radio Forms a Planet-Sized Space Weather Sensor Network
The article “Ham Radio Forms a Planet-Sized Space Weather Sensor Network,” appeared on February 9 in Eos, Earth & Space Science News — an American... Read more
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Mary Cousins, ex-W1GSC, who was the first woman in Maine to obtain an Amateur Radio license, celebrated her 108th birthday on September 20. Now a resi... Read more
Digital Modes
New “Pre-Release” Version of WSJT-X Includes FT8 Changes
A new “pre-release” version of WSJT-X now is available. This is the Amateur Radio digital software suite developed by Joe Taylor, K1JT, that includes... Read more
FSQCALL – New Digital Mode
A Directed Messaging System for FSQ Introducing FSQCall Sending text using FSQ is generally very reliable, certainly more so than other digital modes... Read more
Video Demonstrates Digital Voice Plus Video “Teleconferencing” Scheme for HF
Rick Peterson, WA6NUT, in Colorado, is promoting FreeDV plus Video, a digital voice-plus-video application for HF. According to Peterson’s QRZ.com pro... Read more
Second Public Test of FT8 DXpedition Mode Demonstrates High Contact Rates Possible
The second public test of FT8 DXpedition Mode has shown that the mock DXpedition stations (“Foxes”) were able to work the pileups of callers (“Hounds”... Read more
Equipment
Ameritron ALS-1306 AMPLIFIER, HF+6M, SOLID STATE, 1200 W PEP, 220 VAC
Ameritron HF+6 1200W Solid State Amplifier 1.5-54 MHz . . . 1200 Watts PEP Output, Instant Automatic band switching, no tuning, no warm-up, SWR protec... Read more
Hambuilder HBR4HF 4 Band HF Transceiver
HBR4HF specification Heterodyne 10MHz Xtal filter exciter based on Hambuilder BritX exciter 300-25000Hz audio band pass active filter using NE5532 4 B... Read more
Compact Power Supply for Elecraft Radios
Description The SS-30DV is designed to supply 25 Amps continuous (up to 5 minutes) and 30 Amps surge at 14.1 VDC. It is the perfect companion s... Read more
How to Build A 130 Watt Dummy Load for HF Ham Radio
In this video I go through the building of a paint can dummy load that a ham radio operator may require for testing and tu... Read more
![PRE-RELEASE INFORMATION – IC 9700 [ ENGLISH ]](https://qrznow.com/wp-content/uploads/2018/09/icom_ic9700-190x122.jpg)
PRE-RELEASE INFORMATION – IC 9700 [ ENGLISH ]
IC 9700 – 144, 430/440, 1200 MHz ALL MODE TRANSCEIVER Read more
