![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
SD330 HF Screwdriver Mobile Antenna
SD330 HF Screwdriver Mobile Antenna Specifications: Bands: 3.5 – 30MHz Power Supply voltage & current: DC 12v 100mA Max Power Rating: 200W... Read more
Kojinsha KA1-406 – Yagi Antenna 7 to 28MHz
VERSA BEAM VERSATILE Antenna to cover all the sky in the world ! 100% designed and proof tested in Japan When planning your new antenna syst... Read more
DXplorer system providing facilities for on-air antenna system testing and comparison
DXplorer™ is a unique web-based system providing facilities for on-air antenna system testing and comparison as well as real-time HF propagation analy... Read more
Isotron ISO-8040 – 2 Band HF 80 & 40 Meter Antenna Combination
An Isotron Antenna Solves Virtually Any Restricted Space Problem – For example, a 40 Meter Isotron measures only 22 inches x 16 inches x 15 inch... Read more
Chameleon EmComm III Portable End Fed Antenna Review
The EMCOMM III Portable antenna is a portable High Frequency (HF) antenna specially designed for short to long range portable and man-pack HF comm... Read more
Review
![SMΩRF RF Vector Power Meter by microHAM [ Video ]](https://qrznow.com/wp-content/uploads/2016/12/l_img_smorf_0038-190x122.jpg)
SMΩRF RF Vector Power Meter by microHAM [ Video ]
SMΩRF™ is the vector power meter. Connects to the power RF signal by remote sensor, available in several models for power levels up to 12KW and freque... Read more
MFJ-1263 – MIC / RIG switch, 2 MIC to 2 RIG
MFJ`s new MFJ-1263 Microphone Control Center lets you mix and match any two microphones to any two transceivers. The microphones or transceivers can h... Read more
Yaesu FTDX101D First Look
Hybrid SDR Configuration In addition to the Narrow band SDR receiver, that boasts overwhelming Basic Performance, the Hybrid Configuration Digital Pro... Read more
Installation and Review of the Ameritron RCS-8V Remote Coax Switch
Ameritron’s Remote Coax Switch lets you remotely switch up to five separate antennas using one inexpensive small control line (like standard telephone... Read more
Digital Modes
Digital Mode FT-8 With Light Bulb Antenna 750 Miles!
Jim, W6LG tries FT8 using light bulbs as the antenna and communicates with another ham in Canada. The distance was 750 miles or about 1200km! This is... Read more
FT4 Video presentation by K1JT
See More about New FT4 Here “At about 20 minutes into the presentation, Joe describes FT4 as being asynchronous, meaning that you can start tran... Read more
RASPBERRY PI3 SDR Monitor 40m FT8/JT65/JT9 (RTL-SDR/LINRAD)
Remote Desktop screencapture of my Raspberry Pi3 monitor receiver on 40m amateurradio band with WSJTx and decoding FT8,JT65 and JT9. Receiver hardware... Read more
MFJ-1204 – USB TO RIG SC INTERFACE, W/8-PIN DIN,DATA/ACC PORT
MFJ-1204 Includes radio interface cable (8-PIN DIN) Sign up for the digital revolution and explore a whole new world of amateur radio excitement using... Read more
A New Spin on JT Alert HRD Logbook and WSJT X
WSJT-X for rig control. There’s no need for HRD rig control to be running. Just HRD Logbook, WSJT-X and JT Alert. Read more
Equipment
![ICOM IC-R8600 [ VIDEO ] – Hands on !](https://qrznow.com/wp-content/uploads/2017/04/Icom-IC-R8600-New-Image-With-SP-39-190x122.jpg)
ICOM IC-R8600 [ VIDEO ] – Hands on !
ICOM IC-R8600 Features Ultra-wide frequency coverage (10kHz-3GHz) with RSSI (Received Signal Strength Indication) function Fast moving, real-time spec... Read more
Stryker SR-94 HPC – “Coming Soon”
Stryker SR-94 HPC FULL Featured Radio! 45+ Watts PEP AM / FM 10 & 12 Meters PC Programmable CTCSS / Rep Offsets MIC / RF Gain Controls RF Power Hi... Read more
Automatic Semiconductor Analyser
Connect any way round to automatically identify and measure a wide range of semiconductor devices. The DCA55 will automatically identify the type of t... Read more
TVTR1 630m Transverter – 472-479 kHz
The Monitor Sensors 630m Transverter enables any Amateur Radio Station, equipped with a conventional HF transceiver, immediate, all mode, access to th... Read more
Heil PR 10 Set
Heil PR 10 Set From the amateur radio division of Heil Sound, Ltd., we bring you the Heil PR10 Package. This small but mighty microphone will bring yo... Read more
