We hope to have all sorts of application notes posted here as time permits. These notes will be updated and expanded upon as time permits.
T MATCH TUNING NOTES A discussion of the finer points of T Match adjusting.
EFFECT of COAXIAL CABLES at HIGHER FREQUENCIES Tips on interpreting VSWR curves at microwaves.
WATERPROOFING ANTENNAS AND CABLES Good information to know. All about keeping water out of your feedlines and connectors. This is an ongoing project.
HOW TO PLAN THE INSTALLATION OF MULTIPLE VHF ANTENNAS ON ONE MAST Brand new Application note! Plan your next multi-band setup!
SWR to RETURN LOSS CHART What? you do know them all by heart? Bone up on the good numbers here.
50 MHz 4 Yagi Contesting Array 2007 This is a presentation at the Northeast and Southeast VHF Conferences in April, 2008. An update of an older design! (see below)
50 MHz 4 Yagi Antenna Stack, 1989 Packrats VHF Conference presentation outlining details of the first switchable 50 MHz stack system.
This is a conference presentation given at a Pack Rats VHF Conference in 1989. The material is a little old, but there are some good ideas on assembling a multiple yagi array with switching combination diagrams, and a discussion of the benefits of a multiple antenna stack on 50 MHz. The basic idea is the same as is used today in our 50 MHz contest station. The antennas have changed, but the basic switching idea remains.
MAGNETOMETER FOR AURORAL DETECTION (1.2 MB file) This is not antenna related, but is a great way to detect auroras! It is a PDF file.
We had this magnetometer set up in the shipping area of the shop. It worked very well, with the sensor buried out in the garden. The UPS guy thought we were nuts! Everyday he would come in, look at the running chart that was set up in the shipping area, with the Earth's magnetic field displayed, then look at me and shake his head. I'll bet he told stories (at our expense) over at Skip's Bar, on Friday nights!! This is a great project for all you propeller heads who want to detect auroras and then work DX on VHF!!
NEW CONNECTOR ASSEMBLY DETAILS
Information on the updated loop yagi connector system February, 2007. This ties in with the waterproofing article, and also provides some insight into the inner workings of some of our loop yagi products. The connector assembly now has much better VSWR performance, and is an improved waterproof design.
A 28 MHZ AMPLIFIER WINTER PROJECT
I am not sure what this has to do with VHF or UHF, but it was a fun QRO amplifier project for the winter. It utilizes the Eimac YC156 ceramic triode. It has applications for the 50 MHz band as well. I was amazed at the power gain and the efficiency on 28 MHz at amateur power levels.
ARIANE ARRAYS (C3I) REPLACEMENT PARTS