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

2002 Noise Figure (NF) Results

Tested in Milwaukee, WI - July 26, 2002


50 MHzCallDesign DeviceNF (dB)Gain (dB)
144 MHzCallDesign DeviceNF (dB)Gain (dB)
KA0RYTCavity2 parallel NE334S010.1429.65
KA0RYTTapped LCMGF18010.2021.55
KA0RYTTapped LCATF331430.23 21.58
K5DYYARR P144VDG 0.3923.84
WB9OWNDemi 144LNAATF211360.4921.22
K5DYYARR P144VDG 0.5021.88
KO2RDemi 144LNAATF211860.5821.20
WA5VJBTapped LMGF18010.6016.80
K9CAARR P144VDGGaAsFet0.6322.19
W7XUARR SP144VDGMGF13020.9720.98
N8KWXDB6NT MKU 24NEC??1.0126.53
K0VSVRFC 2-117 1.2517.01
K0TLMARR SP144VDA?1.3512.90
222 MHzCallDesign DeviceNF (dB)Gain (dB)
WA5VJBTapped LMGF18010.1921.50
432 MHzCall DesignDeviceNF (dB)Gain (dB)
KA0RYTTapped CavityFHC40LG0.1528.44
KA0RYTSSB LNA435?0.4220.87
KA0RYTL MatchATF101360.5917.30
N4SCDEMI 70 LNAWPATF211860.7018.87
K5DYYARR P432VDG 0.7518.36
NS7NDEMI 1.8215.24
K0VSVTE 4412G 3.0911.80
902 MHzCall DesignDeviceNF (dB)Gain (dB)
N4SCDEMI 33 LNAWPATF101360.6818.57
1296 MHzCall DesignDeviceNF (dB)Gain (dB)
N0ISHB W6POMGF14020.4817.40
WA9FWDDEMI 23LNAHATF101360.5018.55
K5LLLSeries LATF101360.5414.70
W7VXSurplus Amp?2.1419.01
2304 MHzCall DesignDeviceNF (dB)Gain (dB)
WA5VJBHB DB6NTNE3260.6413.94
W7VXSurplus Amp?2.2621.20
3456 MHzNo Entry
5760 MHzCall DesignDeviceNF (dB)Gain (dB)
10368 MHzCall DesignDeviceNF (dB)Gain (dB)
WB0LJCLau Dec 92 QEXATF 360770.9912.20
N2CEIDEMIATF 360771.0912.44
N2CEIDEMIATF 360771.1612.11
WB0LJCLau Dec 92 QEXATF 360771.189.74
WA2VOIDSS LNA?1.5919.84
WA2VOIDSS LNA?1.5919.90
WA2VOIDSS LNA?1.7322.58
WA2VOIDSS LNA?1.8320.01
N0UKCom'l LNA?3.548.91
WB0LJCLJCMGA 865767.100.4**
N0UKCom'l PA?12.008.50
24192 MHzCall DesignDeviceNF (dB)Gain (dB)
W5LUALNAAvantek SMW 94-10442.5527.08
VE4MAHB DB6NTNE32584C2.7022.93
W5LUAW0EOM LNA?4.0519.00
W5LUAW5LUA HB?4.0911.08
VE4MARX converter w/DB6NT LNANE32584C2.4450.22
W5LUARX converter w/Avantek LNA2 x ATF360773.3738.42
47 GHzCall DesignDeviceNF (dB)Gain (dB)
VE4MAHB Rcv converter w/LNA 5.0*****
W5LUAHB Rcv converter w/LNA 5.7*****

For 47 GHz: HP342A Noise Figure Meter with 33 - 50 GHz Gas tube Noise head & 10 dB attenuator
** Not a typo
*****Not measured

Tested by W5LUA, WA8WZG, KA0RYT, VE4MA, W5ZN, WA8RJF and N2CEI.
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 346C Noise Source on 24 GHz & up

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