Central States VHF Society

Exploring the World Above 50MHz since 1965

  • Digital Communications

    A great number of exciting new digital operating modes have developed, largely because of the availability of personal computers, soundcards, and advanced software. But amateur digital communication began in earnest in the late 1940's (if you don't count Morse as a digital mode!) when hams worked out techniques of connecting mechanical Teletype keyboard/printers to amateur gear using FSK and AFSK modulation. WSJT has become a very popular tool for digital communications. FSK441 mode is in use for meteor scatter contacts and JT65 is popular for terrestrial communications.More Info
  • EME Moonbounce

    Amateur radio (ham) operators utilize EME for two-way communications. EME presents significant challenges to amateur operators interested in working weak signal communications. Currently, EME provides the longest communications path any two stations on Earth can utilize for bi-directional communications. Amateur operations use VHF, UHF and microwave frequencies. All amateur frequency bands from 50 MHz to 47 GHz have been used successfully, but most EME communications are on the 2 meter, 70-centimeter, or 23-centimeter bands. Common modulation modes utilized by amateurs are continuous wave with Morse Code, digital (JT65) and when the link budgets allow, voice..More Info
  • Aurora and Solar Weather

    The interaction between Earth's magnetic field and Solar particles is a complex and mysterious field of science. The storm events involve high electric currents in the ionosphere and vast amounts electric power affecting to great many things. One of the ways to observe what is happening up there, is to detect the effects of these phenomena to non ionizing long wave electromagnetic radiation - radio waves.More Info
  • VHF Contesting and Rover Operations

    Hams have been putting stations in their cars since the Twenties (1920's that is). Today, there is great satisfaction in facing the challenge of installing a transceiver in our small cars and pick-ups, using somewhat inefficient antennas, and still being able to make contacts with hams thousands of miles away while "tooling" down the highway.More Info
  • Annual Technical Conference

    Every year since 1968, during the last weekend in July, the Central States VHF Society hosts an annual technical conference. There are two days of technical presentations, antenna range gain measurements, noise figure measurements, a flea market, and often times a vendor area. It's a great time to learn about weak signal VHF communications and an excellent place to network and catch up with old friends.More Info

2003 Noise Figure (NF) Results

Tested in Tulsa, OK - July 26, 2003


144 MHzCallDesign DeviceNF (dB)Gain (dB)
W5UWBCom'l. LNAATF331430.123
WD5AGOHB Cavity - High IPFSC530.2223
K5GWAGO HelixATF331430.2822
W7QXHB HelixATF541430.5425
K0YWHB- 1969U3101.312
222 MHzCallDesign DeviceNF (dB)Gain (dB)
WD5AGOHB High IP HelixATF331430.2221
K5LLLCom'l ARR 119
432 MHzCall DesignDeviceNF (dB)Gain (dB)
K0YWCavity 0.2219
WD5AGOHB Series L, High IPATF331430.3120
902 MHzCall DesignDeviceNF (dB)Gain (dB)
K5LLLCom'l 4.220
1296 MHzCall DesignDeviceNF (dB)Gain (dB)
WD5AGOHB 2stage-AGONE325-ATF101350.2831
W0LMDWD5AGONE3210 - ATF341430.3832
N6TXMod. DEMI 23-21cm2 stage0.627
WW2RCom'l DEMINE32100.718
K0YWDEMI 0.715
W7QXCNK 0.9420
W0LMDCom'l ICOM 1.717
2304 MHzCall DesignDeviceNF (dB)Gain (dB)
K5VHDEMI 0.419
WD5AGOHB 2stageATF36077-341430.4625
3456 MHzNo Entry
5760 MHzCall DesignDeviceNF (dB)Gain (dB)
10 GHzNo Entry
24 GHzCall DesignDeviceNF (dB)Gain (dB)
W5LUAHB LNA2 X NE32584C1.915
W5LUAAvantekSMW 94-10442.528
47 GHzCall DesignDeviceNF (dB)Gain (dB)
W5LUAHB Rcv converter w/LNA 4.6635

Tested by W5LUA, WA8RJF, and WD5AGO.
Equipment by Agilent Technologies, W5LUA and W9GA.
Compiled by WA8RJF.
HP346A Noise Source, Measurement Accuracy of system according to HP is +/- 0.2 dB!
HP 8970B and Agilent N8975A Noise Figure Analyzer

For 47 GHz: HP342A Noise Figure Meter with 33 - 50 GHz Gas tube Noise head & 10 dB attenuator

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