TH7DXX Manual

by Floyd Koontz, WA2WVL first published in QST (ARRL), February 1995 A New Design One fundamental of directive wire-antenna design is that […]

Just to remember the old (but still good) antenna tricks, here is a brief description of the W3EDP antenna. It is included […]

This description is taken from the Pete’s W2PM posting into Topband reflector.

This antenna is very simple – it’s a mini diamond Flag – with a 660 ohm terminating resistor and a 16:1 transformer. It is the exact size of the so-called magnetic loops, – 5 ft per side, 20 ft total wire, and about 7.1 ft wingspan. It has classic Flag cardiodal pattern and, of course, pretty low output (-50 dB from what I recall). F/B is about 30 dB. I use it with a single preamp with good results. This antenna is quite easily rotatable as you can see (altho the standard 15 X 30 ft Flags have been made rotatable too as most of you know).

This has several advantages over the “mag” loop (for those on small lots) – it’s broadband 1.8 MHz past 30mhz; cardioid pattern with very nice null to rear, decent low angle take off (abt 32 deg) AND is simple – make it in minutes. I used 2 – 330 ohm resistors a binocular 16:1 transformer. I “potted” the resistors and xfrmr in epoxy.

I’ve since cleaned mine up – routing the RG-174 coax from the transformer to the center of the crosses, then connect it to a RG-58 run vertically down the mast.

Thanx loads to Earl K6SE for the design.73 Pete, W2PM

Established theory is timeless, but many amateurs do not have acces to the archives that contain clasical data of present-day interest. Medium […]