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

2005 Noise Figure (NF) Results

Tested in Colorado springs, CO - July 30, 2005


144 MHzCallDesign DeviceNF (dB)Gain (dB)
K8EBLNA TechnologiesATF331430.2322.6
K0SMMavcom 2.8820.45
222 MHzCallDesign DeviceNF (dB)Gain (dB)
KL6M*HB LCMGF13020.716.5
432 MHzCall DesignDeviceNF (dB)Gain (dB)
KD9SGARR 1.7318.58
K5QXJHB N6CAMGF14021.812.5
KD9SGICOM AG35 2.7513
902 MHzCall DesignDeviceNF (dB)Gain (dB)
K8EB*DEMI kit 0.7718.6
1296 MHzCall DesignDeviceNF (dB)Gain (dB)
 JL RefATF306770.2118
 AGO RefNE3212-ATF2110.2331
KD5FZXAGO-commNE321 2-stage0.2636
W6ATAGO-commNE321 2-stage0.2732.1
KL6M*DEMI kitATF101360.7617.2
K6KLYHB N6CAMGF13021.6716.8
K6KLYHB 1.829
2304 MHzCall DesignDeviceNF (dB)Gain (dB)
WD5AGO*HB 2-stageNE3212-ATF2110.4822
KL6MHBHEMT 1st stage0.5716.4
WD5AGODEMI xvrtrNE325840.6526.3
5760 MHzCall DesignDeviceNF (dB)Gain (dB)
WD5AGOHB converter 3.822
10 GHzCall DesignDeviceNF (dB)Gain (dB)
W5NZSDB6NT converter

Chairman: WD5AGO
Measurements completed by: WD5AGO, K5TTT & N9KC
Equipment: AIL-2075 & HP346A, Agilent 8975A w/HP346B Noise Source, Accuracy +/- 0.2dB

NOTE: " * " signifies HB winner.

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