Rochester VHF Group 09 February 2007 “Cheap” Yagis Rochester VHF Group 09 February 2007

“Cheap” Yagis Presenters: Mark Adams, K2QO Bill Rogers, K2TER 11/23/2018 Rochester VHF Group

Introduction “This year, I just scraped together enough ‘bottle and can’ money to buy my VHF radio equipment. Do I have to wait till next year for the antennas I need to put a decent signal on the air?” 11/23/2018 Rochester VHF Group

Introduction “Having never homebrewed an antenna other than a HF dipole, I don’t think I have the skills or experience to replicate the NBS yagis in the ARRL Antenna handbook. Now what?” 11/23/2018 Rochester VHF Group

Introduction “I’d like to try roving on the bottom 6 bands but I don’t want to spend an arm and a leg on another set of antennas that are 6 feet or less in length. What’s an avid VHFer to do?” 11/23/2018 Rochester VHF Group

Introduction The Answer… You need “Cheap” yagis. Cheap yagis were originally conceived by Kent Britain, WA5VJB, in an effort to assist Cuban operators in getting on the VHF bands. Cheap yagi construction plans are readily available for all bands from 144 MHz to 1296 MHz. These designs are scalable for use at other frequencies, as well. 11/23/2018 Rochester VHF Group

Why “Cheap” Yagis? Simplicity – Mechanical construction and Feed point impedance matching. Availability – Common materials can be obtained with one stop to a hardware store. No special tools needed. Plans are in public domain. Repeatability – It’s hard to mess these up. Time efficiency – You could build a set of these antennas in a Saturday afternoon. Affordability – Less than $10/antenna at retail rates. 11/23/2018 Rochester VHF Group

The “Cheap” Yagi Driven Element No balun req’d 11/23/2018 Rochester VHF Group

144-1296 Cheap Yagi Stack 11/23/2018 Rochester VHF Group

144 MHz Yagi dimensions 11/23/2018 Rochester VHF Group 144 MHz Driven El. = 38.5" and H = 1.0" - All 1/8" dia. elements Reflector Driven Director 1 Director 2 Director 3 Director 4 3 Element  Length 41   37 3 Element Spacing 8.5 20 4 Element 42 37.5 33 19.25 40.5 6 Element 36.5 32.75 7.5 16.5 34 52 70 11/23/2018 Rochester VHF Group

222 MHz Yagi dimensions 11/23/2018 Rochester VHF Group 222 MHz Driven El. = 24.5" and H = 1" - All 3/16" dia. Elements Reflector Driven Director 1 Director 2 Director 3 Director 4 3 Element  Length 26   23.75 3 Element Spacing 5.5 13.5 4 Element 26.25 24.1 22 5 11.75 23.5 6 Element 21 10.75 33.75 45.5 144 MHz Driven El. = 38.5" and H = 1.0" - All 1/8" dia. elements Reflector Driven Director 1 Director 2 Director 3 Director 4 3 Element  Length 41   37 3 Element Spacing 8.5 20 4 Element 42 37.5 33 19.25 40.5 6 Element 36.5 32.75 7.5 16.5 34 52 70 11/23/2018 Rochester VHF Group

432 MHz Yagi dimensions 11/23/2018 Rochester VHF Group 432 MHz Driven El. = 13.0" and H = 3/8" - all 1/8" dia. Elements Reflector Driven Dir 1 Dir 2 Dir 3 Dir 4 Dir 5 Dir 6 Dir 7 Dir 8 Dir 9 6 Element  Length 13.5   12.5 12 11 6 Element Spacing 2.5 5.5 11.25 17.5 24 8 Element  12.00 30.75 38 11 Element 11.75 45.5 53 59.5 11/23/2018 Rochester VHF Group

903 MHz Yagi dimensions 11/23/2018 Rochester VHF Group 902/903 MHz Reflector Driven Director 1 Director 2 Director 3 Director 4 Director 5 Director 6 Director 7 Director 8 Length 6.2    * 5.6 5.5 5.4 5.3 5.2 5.1 Spacing 2.4 3.9 5.8 9 12.4 17.4 22.4 27.6 33 11/23/2018 Rochester VHF Group

1296 MHz Yagi dimensions Measured gain: 12.5 dBd The driven element is small enough to allow 0.141 semi-rigid coax to be used instead of RG-58. Silicon Bronze welding rod was used for the elements but any material can be used. Driven element dimensions are L = 4.0" and H = 1/2" Elements are 1/8" diameter. Measured gain: 12.5 dBd  1296 MHz Reflector Driven Dir 1 Dir 2 Dir 3 Dir 4 Dir 5 Dir 6 Dir 7 Dir 8 10 Element Length 4.3   3.9 3.8 3.75 3.65 3.6 3.5 Spacing 1.7 2.8 4 6.4 8.7 12.2 15.6 19.3 23 11/23/2018 Rochester VHF Group

K2QO/R Antenna Setup 11/23/2018 Rochester VHF Group

K2QO Rover We use Cheap Yagis on 2, 222, 432 and 903! 1296 is a Quagi from the Handbook. This is an easy to make antenna too. Performance of 6-el 2M Yagi same as driven section of my FO-12. 11/23/2018 Rochester VHF Group

Construction Notes: Start with the exact dimensions as published by Kent Use a file to remove any sharp edges Consider plastic caps for element tips 11/23/2018 Rochester VHF Group

More Tips Consider surplus patch cables. Cut off one end and attach to feed. Best if connection at antenna is a female. Use $2.99/Gal Redwood stain. Radio Shack mast clamps are FB. Wind loads are virtually nil. 11/23/2018 Rochester VHF Group

Closing 11/23/2018 Rochester VHF Group