10 Meter US Yagi Stack - Design Modifications

6 May 2004

Old Configuration:

Top 53 ft, Box 45 ft, Bottom 34 ft. This is only 19 feet of spacing between the antennas. 

New Configuration: Top 53 ft, Box 45 ft, Bottom 20 ft. this gives the desired 33 foot spacing, which should provide stacking gain of about 3 dB.


Feedlines should be equal lengths from the Stackmatch box and an odd number of quarter waves (per W0UN).

Coax is Belden 8214, Vf = .78.

246(.78) / 28.200 = 6.80 ft per quarter wavelength.

6.80 * 5 = 34 ft 3 in. (This is the odd number of quarter wavelengths.)

Required length from box to bottom is 25 + 4 foot at antenna + 3 ft top loop = 32 ft.

Decision: fabricate two 10 meter pigtails of 40 ft 10 in each, trimmed to exact electrical length of 1.5 wavelengths at 28.200 with the MFJ-259B.

26 July 2013

In connection with addition of the triplexer, feed was converted to always stack, StackMatch moved to shack, and cabling redone. On this date fabricated a matching harness using two sections of RG-11/U coax to drive the stack. Click here for the calculations sheet. The harness was designed to match the antenna center frequency of 28.200. Fabrication by W0CG in Idaho.

Now, op will be able to select "US/JA Stack", "Europe (Yard)", or "Europe (Ridge)". THis is for the former.