Digital HF/VHF/UHF Scanning Direction Finder R&S DDF 0xA

HF , VHF , and UHF Systems and Technology

A wide variety of unique systems and components inhabits the HF, VHF, and UHF bands. Many communication systems (ionospheric, meteor-burst, and troposcatter) provide beyond-line-of-sight coverage and operate independently of external infrastructure. Broadcasting and over-the-horizon radar also operate in these bands. Magnetic-resonance imaging uses HF/VHF signals to see the interior of a human ...

Fiber-Optic Propagation Effects in Long-Haul HF/VHF/UHF Analog Photonic Links

Heart rate variability (HRV) analysis in radio and TV broadcasting stations workers.

OBJECTIVES The aim of the study was to assess the mechanism of cardiovascular impairments in workers exposed to UHF-VHF radio frequency electromagnetic fields (EMF). MATERIALS AND METHODS Heart rate variability (HRV) was analysed using 512 normal heart beats registered at rest. The analysis concerned time-domain (STD R-R) and frequency-domain (VLF, LF, HF) parameters of HRV. Fifty nine worker...

A Doppler Radio-Direction Finder

adio-direction finding has gained a lot of interest in recent years especially on the VHF and UHF bands. There are many different approaches to determining the origin of a radio transmission. Each approach has its advantages and disadvantages. An experienced RDFer learns to make use of several methods to master the art. Directional antennas with good front-to-back ratios (such as a Yagi or quad...

Evaluation of the Recommendation ITU-R P.1546-2 for UHF Field-Strength Prediction over Fresh-Water Mixed Paths

In this paper, the principal objective is to validate a new approach for the field-strength estimate in VHF and UHF radio links partially over water. The method is compared with measurements conducted in the cities of Belo Horizonte, MG, and Braslia, DF, Brazil. The approach is based on physical insights applied in the Recommendation ITU-R P.1546-2 mixed path treatment. The results show good ag...