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

1997 Noise Figure (NF) Results

Tested in Hot Springs, Arkansas - 25 July 1997


50 MHzCallDesign DeviceInput NetworkNF (dB)Gain (dB)
WA5VJBHB CavityMGF-1801 0.1522.2
N2CEITransverterATF-10136 0.6320.2
144 MHzCallDesign DeviceInput NetworkNF (dB)Gain (dB)
WA8WZGMCMATF-10136 0.2324.39
KA0RYTHomebrew CavityFSC-11LFCavity0.2521.3
WD5AGO FLC-053 0.3424.29
WA0RDX NE334LC0.3623.33
WQ0PHomebew 1/4waveCavityMGF-1302Cavity0.4518.26
WQ0P MGF-1302LC0.5218.41
WQ0P MGF-1302LC0.5616.35
W5UNDEM Hi dynamic range convATF-10136 0.9916.82
222 MHzCallDesign DeviceInput NetworkNF (dB)Gain (dB)
N2CEIDown East Microwave  0.6718.83
K6MYCDown East MicrowaveATF-10136 0.7719.14
432 MHzCall DesignDeviceInput NetworkNF (dB)Gain (dB)
KA0RYTHomebrew Cavity #3ATF-10135Cavity0.219.74
KA0RYTHomebrew Cavity #5FHX-35LGCavity0.2219.9
KA0RYTHomebrew Cavity #4FHX-35LGCavity0.2521.76
KA0RYTHomebrew Cavity #1FHX-35LGCavity0.2721.35
WD5AGOHomebrew CavityFHC-30Cavity0.319.4
W7QXHomebrew"ATF-36077,ATF-10136"Helical Resonator0.3141.8
KA0RYTHomebrew Cavity #2FSC-11LGCavity0.3421.36
W7QXHomebrew"ATF-36077,ATF-10136"Helical Resonator0.3536.2
K5GWW7QX Homebrew"ATF-35176,ATF-10136"Helical Resonator0.3641.26
WW2RKB2AH CavityMGF-1302Cavity0.3716.06
K5GWWD5AGOATF-101361 stage0.3818.03
K5GWWD5AGOATF-101362 stage0.4227.83
W7QXHomebrew"ATF-35176,ATF-10136"Helical Resonator0.4936.37
WA8WZGDown East MicrowaveATF-10136 0.4919.6
N2CEIDown East Microwave  0.6417.76
KB5ZUDARRMGF-1302 0.9217.33
N0GXAAmpire Antenna Mounted Preamp  2.2314.66
902 MHzCall DesignDeviceInput NetworkNF (dB)Gain (dB)
WA0RDXHomebrewNE334 0.2621.3
WA0RDXHomebrewMGF-4918D 0.3524.8
WA0RDXHomebrewMGF-1302 0.4817.19
1296 MHzCall DesignDeviceInput NetworkNF (dB)Gain (dB)
WA8WZGAGO"ATF-36077, ATF-10136" 0.2632
WD5AGOAGO"NE325, ATF-10136" 0.2931
K6MYCAGONE321 0.3115
KA0RYTKB2AHFHX-35 0.3619.6
WB5LUALUA HomebrewATF-36077 0.3922
K5GWAGO"NE325, ATF-10136" 0.3926
VE4MAHomebrewATF-10135 0.534.5
KA0RYTHomebrew 1/2 Wave CavityFHX-35 0.5514
WA8WZGKB2AHFHX-35 0.5928
K5JLHomebrewFHX-35 0.7511
WQ0PLUA HomebrewATF-10135 0.8513.6
W8ULCMCMMGF-1302 0.8814.2
WA5VJBPARAMP (Sam Harris)1961 Vintage 2.426
WV0KDEM Converter  1.314
KA2KQMKK7B Homebrew Converter  422
KG0MWDEM Homebrew Converter  6.813.6
2304 MHzCall DesignDeviceInput NetworkNF (dB)Gain (dB)
DEMLUAATF-36077 0.5219.04
N4EQT MGF-1402 1.2817.27
WB5LUACONVERTER MGA-86576  2.1727.76
3456 MHzCall DesignDeviceInput NetworkNF (dB)Gain (dB)
WB5LUALUAATF-36077 0.7512.5
WA0BWELUAATF-36077 0.813
5760 MHzCall DesignDeviceInput NetworkNF (dB)Gain (dB)
W5ZNLUAATF-36077 0.711.95
N2CEILUAATF-36077 0.7211.8
WA0BWELUAATF-36077 0.7410.9
WB5LUALUAATF-36077 0.7811.93
WA8WZGLUAATF-10136 1.9619.6
10368 MHzCall DesignDeviceInput NetworkNF (dB)Gain (dB)
W5ZNLUAATF-36077 0.711.95
N2CEILUAATF-36077 0.7211.8
WA0BWELUAATF-36077 0.7410.9
WB5LUALUAATF-36077 0.7811.93
WA8WZGLUAATF-10136 1.9619.6
24192 MHzCall DesignDeviceInput NetworkNF (dB)Gain (dB)
W5ZNDMC  4.5817.67
WB5LUAHB Converter + t/r switchHMMC-5023 5.5825.58
WB5LUAWJ 466-6 TWT  19.629

HP346A Noise Source, Measurement Accuracy of system according to HP is +/- 0.2 dB!

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