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

2001 Antenna Gain Results

Tested in Ft. Worth, TX - July 27, 2001

 

50 MHz CallDesignGain (dBd)
KB0PE3 ele linear loaded Yagi **7.0
WB0TEMReference dipole0
 
144 MHz CallDesignGain (dBd)
WD5AGOHB 7 ele on 8 ft boom *10.0
K5UHFHB 6 ele8.4
W5IU3 ele Arrow4.6
KU4ABHB 1/2' Omni Loop2.3
 
222 MHz CallDesignGain (dBd)
K5UHF8 ele M Squared Modified *11.1
WD5AGOHB 6 ele10.1
 
432 MHz CallDesignGain (dBd)
WA5TKUHB version of the 22 ele K1FO *15.5
K5UHF13 ele M Squared; 8 ft boom12.1
W5IU7 ele 2-Band Arrow10.3
KD4NOQScientific 17 ele Log Periodic8.7
WA5VJB400-500 MHz PCB Log Periodic6.1
WA5VJB7 ele CP Log Periodic5.6 dBiC
WA5VJB400-1000 MHz PCB Log Periodic4.6
WA5VJB9 ele Com'l Log Periodic4.0
WA5VJB418 MHz optimized 4 ele Yagi0
 
902 MHz CallDesignGain (dBi)
K5UHF18 ele M Squared16.9
N5YC18 ele HB Yagi *14.4
K5UHF10 ele M Squared13.9
KD4NOQ8 ele "Cheap Yagi"12.1
KD4NOQ19 ele Scientific Atlanta LP10.3
K5GNA38"x26" grid dish9.1
WA5VJBCushcraft 4 ele Yagi - Ref Antenna7.5
K9FYV3 ele Com'l Yagi6.9
WA5VJB400-1000 MHz PCB LP6.7
WA5VJB3 ele Yagi on PCB6.4
K5GNA22"x17" grid dish3.5
WA5VJBCushcraft CCS8960 vertical3.3
 
1296 MHz CallDesignGain (dBi)
K5UHF22 ele M Squared19.0
K5GNA38"x26" Grid Dish VJB LP Feed *18.8
KO0Z24 ele Loop Yagi18.1
K5UHF15 ele yagi16.5
KD4NOQ11 ele Cheap Yagi13.8
KD4NOQ10 ele Cheap Yagi13.5
WA5VJB10 ele Cheap Yagi - Ref Antenna13.5
K5GNA22"x17" Grid Dish VJB LP Feed *12.9
KD4NOQ19 ele Scientific Atlanta LP8.7
K9FYV3 ele end fire by W9DNT8.6
 
2304 MHz CallDesignGain (dBi)
K5LLL34"x27" Mesh Dish *23.0
K5VH0.9 m dish w/2 band loop feed22.7
K5VH32"x30" mesh dish 7 ele Loop Yagi feed22.4
K5GNA38"x26" Grid Dish20.8
K5GNAAIDC 3733 Dish Feed19.5
K5OE26" Dish w/Helix feed (not CP)18.6H / 15.2V
K5GNA22"x17" w/AIDC 3733 Dish Feed18.3
K5UHF21 ele Loop Yagi17.0
K5GNA17"x22"grid dish w/VJB-LP feed15.0
WA5VJBNarda Std Gain Horn - Reference13.4
K5VH2400 MHz Looper mod'd to 2304 MHz10.3
N5PYK5 Turn Helix (Not CP)8.4V / 5.4H
 
3456 MHz CallDesignGain (dBi)
K5VH0.9 m dish w/2 band loop feed23.3
WA5VJBNarda Std Gain Horn - Reference16.8
 
5760 MHz CallDesignGain (dBi)
WD5AGO2 ft Dish with AGO feed *29.7
K0GCJFXR Horn #H638A20.1
WD5AGOHorn 6.5" x 5" x 6"15.5
WA5VJBNarda Std Gain Horn - Reference15.5
K0GCJHB Horn 3.5" x 2.5" x .5"10.5
 
10.3 GHz CallDesignGain (dBi)
K0GCJ2 ft dish with penny feed *31.9
W0GHZ18" offset dish Feed #230.2
W0GHZ18" offset dish Feed #329.8
W0GHZ18" offset dish Feed #128.7
N5PYK18" dish with pipecap feed27.0
K5UHF5" x 4.75" x 11" horn20.3
WA5VJB2.75" x 2.5" x 12" horn19.2
K0GCJHB horn 5 x 4 x 6.5"18.7
K5UHFARR Gunnplexer horn17.9
WA5VJBReference horn17.7
N5PYK27" flat plate slot array for 9.5 GHz Airborne Radar< 5
 
24 GHz CallDesignGain (dBi)
W0AUSHB 4.25" x 3.25" x 9" horn *24.3
W0AUSHB 3" x 2.5" 5.5" horn23.3
WA5VJBMicrowave Associates Horn Ref.20.3
W0AUSHB 2.3" x 1.75" x 2.5" horn18.5
WA5TKUW5ZN 10/24G feed horn9.7

* Homebrew Winners
** Interference on the range

50 MHz-432 MHz by WB0TEM       Measurements in dBd
902 MHz-24 GHz by WA5VJB       Measurements in dBi


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