All Vhf

Why does a vhf transmiter desense’s all nearby receivers?

Hi there. Can someone explain to me why does a transceiver desense’s all nearby recievers while transmiting? Does this mean that there some sort of rf power leak from the transmitter? Thank you.

No, it’s not a power leak from the transmitter.

Receiver desense happens when the nearby signal overloads the “front end” – the part before the first IF conversion – of the receiver. Basically the effect of the signal, even if not the signal itself, gets “downstream” in the receiver even though it’s on the wrong frequency. This fools the receiver into thinking “hm, there’s a strong signal coming in” (even though it’s not on the right frequency) and the Automatic Gain Control (AGC) circuit accordingly turns down the RF sensitivity.

KENWOOD TR-751A VHF All Mode Transceiver that NEEDS WORK but Looks Great $200.00

Icom-7000, IC-7000 HF/VHF/UHF All Mode Transceiver $700.00

YAESU FT-100D HF/VHF/UHF ALL MODE TRANSCEIVER MH-36b mic $102.50

ICOM IC-910H VHF/UHF ALL MODE TRANSCIEVER with 1.2 GHz Module $1,775.00

COBRA ELECTRONICS COBRA MRHH 425LI VP MARINE VHF TRANSCEIVER WITH ALL-TERRAIN RA $142.00

New Motorola Style NMO VHF UHF 220 1/4 Wave Antenna ALL Black Ham Police Fire $20.00

ICOM-706 MK II G HF & VHF – UHF ALL MODE TRANSCEIVER! $675.00

Uniden Solara DSC Marine 2-Way VHF Radio 25-Watts, Submersible, All Channels $69.00

Cobra MR HH325 VP, Tri-Watch Handheld VHF w/All Accessories $96.95

Icom IC-211 VHF 2 Meter All Mode AM FM SSB Transceiver $72.00

iCom IC-A23 VHF Air Band Transceiver – NEW as in NEVER USED w/BOX all acc’rys $72.00

Cobra MR HH325 VP, Tri-Watch Handheld VHF w/All Accessories MR HH325VP $105.88

Yaesu FT-817 HF/VHF/UHF ALL mode Transceiver $495.00

Apelco VXL501 marine VHF handheld NIB five watt all channels $74.00

TESTED MOTOROLA CDM750 VHF 45 WATTS 136-174 MHZ 4 CHANNEL CDM + ALL ACCESSORIES $179.99

COBRA MRHH 425LI VP MARINE VHF TRANSCEIVER WITH ALL-TERRAIN RADIO $137.49

Cobra MR HH325 VP, Tri-Watch Handheld VHF w/All Accessories $109.49

Cobra MR HH325 VP, Tri-Watch Handheld VHF w/All Accessories MR HH325VP $112.88

COBRA MRHH 425LI VP Marine VHF Transceiver with All-Terrain Radio $144.51

ICOM IC-746PRO HF/VHF ALL MODE TRANSCEIVER MANUAL $5.95

Cobra MR HH325 VP, Tri-Watch Handheld VHF with All Accessories $107.99

Cobra MR HH325 VP, Tri-Watch Handheld VHF w/All Accessories $110.66

VHF 5/8 WAVE 3dB ANTENNA w/ TRUNK LIP MOUNT COMPLETE ALL BLACK $28.95

VHF 5/8 WAVE 3dB GAIN NMO ANTENNA ALL BLACK $18.99

Yaesu FT-897D ALL-MODE HF-VHF-UHF Tranceiver, FT-897D with DSP!! 100 WATTS!! $1,097.00

COBRA MR HH325VP TRI-WATCH VHF SUBMERSIBLE W/ ALL ACCESSORIES $99.95

Midland Nautico 1 Handheld VHF Radio All Marine Channels Water resistant 18 mile $49.99

Cobra MR HH325 VP, Tri-Watch Handheld VHF w/All Accessories $96.95

Cobra MR HH325 VP, Tri-Watch Handheld VHF w/All Accessories $103.86

Cobra MR HH325 VP, Tri-Watch Handheld VHF w/All Accessories MR HH325VP $96.77

48 ” Inch SS VHF UHF Cb Ham ALL Radio Antenna Whip $19.99

TRAM VHF MARINE ALL-BAND ANTENNA, # 1600-HC $22.98

TRAM VHF MARINE ALL-BAND ANTENNA, # 1610-HC $28.98

TRAM VHF MARINE ALL-BAND ANTENNA, # 1620-HC $37.98

Introduction:
Viral haemorrhagic fevers (VHF) is a disease caused by viruses restricted geographically. Many viruses can cause disease, but four viruses, including Lassa, Marburg, Ebola fever and Crimean-Congo Hemorrhagic Fever (CCHF) has a potential to have in the outbreak and has the potential of the person to person transmission. Among these four viruses, CCHF is endemic in parts of Afghanistan and northern Pakistan.

In September and October of each year, we get the referral of patients with possible diagnosis of CCHF. Since most doctors have little or no experience with these viruses, the uncertainty is often raised the possibility of diagnosis when VHF.

These guidelines for the clinical examination and epidemiological features of CCHF, make recommendations on diagnosis, research and patient care, and suggest measures to prevent secondary transmission.

Crimean-Congo Hemorrhagic fever:
CCHF virus is an enveloped, single stranded Bunyaviridae. Many wild and domestic rabbits act as reservoirs of the virus, including cattle, sheep, goats, y. Ixodid (hard) ticks act as a reservoir and vector of CCHF virus.

CCHF is endemic in eastern Europe, particularly the Union Soviet northwest China, central Asia, India subcontinent, Middle East and Africa.

Transmission: Humans are infected by the bite of ticks or by crushing ticks, often while working with pets or livestock. Contact with blood, secretions or excretions from infected animals or humans also can transmit the infection. In endemic areas, the disease may occur more frequently in the spring or summer.

Nosocomial transmission is well described in the reports from Pakistan, Iraq, Dubai and South Africa. The available evidence suggests that blood and other body fluids are highly infectious, but simple precautions, as barrier nursing, effectively prevent secondary transmission.

Clinical features: The incubation period is approximately 2-9 days. Initial symptoms include fever, headache, myalgia, arthralgia, abdominal pain and vomiting. , Sore throat, conjunctivitis, jaundice, photophobia, and various sensory disturbances and mood can develop. Patechial A rash is common and may precede a bleeding diathesis rampant.

The estimated case mortality rate is 15-70%. Symptoms and signs supporting the diagnosis of VHF are pharyngitis, conjunctivitis, and later the bleeding and shock.

Laboratory Features: Deranged LFTs, leukopenia, thrombocytopenia, and anemia.

Diagnosis: Suspected based on epidemiological risk factors, characteristics clinical and specific laboratory abnormalities. The disease is confirmed by virus isolation by PCR of blood during the first week of illness or by demonstrating IgM antibodies or a fourfold increase in IgG. Antibodies may not appear in the blood until the second week of illness.

Treatment: Ribavirin 30 mg / kg loading dose is 16 mg / kg every 6 hours x 4 days, then 8 mg / kg every 6 hours x 6 days. Supportive care and may require intensive care.

Prophylaxis contacts of high risk is ribavirin 600 mg orally Q6 x 7 days.

About the Author:

Dr. D.S. Merchant is a Gold Medalist in (Anatomy & Histology)
For more information on
Viral Hemorrhagic Fever or visit http://health.update.pk is a popular website that offers information on
VHF – Viral Hemorrhagic Fever, VHF Solutions, and VHF Medications. Please leave the links intact if you wish to reprint this article.

Article Source: ArticlesBase.com – Management of Patients With Viral Hemorrhagic Fever (vhf)