N4EKV.COM - Antennas

Amateur Radio Station N4EKV
Antennas

Home | Op | QTH | Rig | Keys | Ant | QSL | /QRP | /P | /M | Logbook (3755) | Guestbook (201) | Links

	From right to left: Home brew 40m ground plane. 160m ladder-fed doublet. 2m/440 vertical. The 40m ground plane uses a DK9SQ 33ft telescoping fiberglass pole sitting atop a 10ft piece of 1-1/2" PVC conduit which in turn is supported by a 2" steel fence post sunk in cement. Guys at the 15ft (GP's base) and 25 ft (top of 3rd DK9SQ section) levels keep it aloft! Four down-sloping 33ft radials make the SWR <1.5:1 across the entire 40m and 15m bands. This is an excellent DX antenna, pulling in distant sigs that my 160m doublet couldn't even detect. EZNEC says it has a take-off angle of just 22-degrees. 660K image of the guying system and hub here. The white piece is a 1-1/2" PVC repair junction that mates the 10ft PVC support mast with the base of the DK9SQ (requires filing the raised ridge from the bottom of the DK9SQ.. a 5-min task). A flange mount SO-239 acts as the hub for the antenna and a simple U-bolt holds the feedline's PL-259 connector to the repair junction as well as anchoring the first tier of 3/32" Dacron guy lines. A 2.5mH RF choke wrapped in coax seal shorts the radiator to the coax shield to drain static build up (important!) The house was undergoing a re-siding project when the above photo was taken which necessitated the removal of my rotary EDZ (seen below) from the chimney.
	Rotary extended double zepp (EDZ) for 10-40 meters. Homebrew contruction, 44ft tip to tip. Fed by 450-ohm ladder line and balanced L antenna tuner. This design by L.B. Cebik provides nice bidirectional gain with low take-off angles. It performs exceptionally well on 20m! Elk Antennas 2m/440 5-element log periodic beam seen above the EDZ. WARNING: Perhaps due to the fiberglass poles, this antenna collects large amounts of static electricity which gets carried down the ladder line to my shack. RF chokes to ground on each side of the ladder line drain the static.
	Detail of the EDZ hub assembly. 4x12x3/8 inch 6061 aluminum stock from Metal Supermarkets. 22ft telescopic fiberglass poles from The Mast Company. Radio Support Blocks from DX Engineering. The 22ft wire elements were quickly relocated to run inside the poles when the wires started slapping in the wind during ground-level testing. Elastic shock cords tied to the ends of the wires and extending through the pole tip fittings keep the wires fully extended and rattle-free. Electric fence insulator acts as strain relief for dangling ladder line.
	Elk Antennas 2m/440 log periodic beam. Mounted on 1" PVC mast to avoid interaction with elements. Coax is deliberately routed in a perpendicular path from the element plane per manufacturer's recommendation. Update: This $39 TV rotator did not have nearly enough capacity for this antenna! Not only couldn't it turn the antenna into any wind above 20mph, but the unit completely failed after only three months in service. I've procured a rebuilt CDE CD-44 rotator that will be replacing it.
	160m ladder-fed doublet. Two 10ft Radio Shack TV masts clamped to a handy fence post support the center of the doublet. The legs are 135ft each and they slope downwards to similar supports at the end points. Due to the curvature of the hill, the wire is only 6-7ft from the ground at some points, despite heavy weights stretching it via pulleys from the ends. Old fashioned ladder line feeds the antenna.
	This is a high-gain 2m/440 vertical. it delivers 6db gain on 2m and 8.2db on 440. Fed by RG-9913, the ground plane is close to the 1000ft elevation mark. Ladder line leading to the doublet is visible in the foreground. OOS March 2003 to install EDZ and 2m/440 beam. That's one steep roof for climbing! Note the red and black rope I have in place to make the job safer. Still, it's like repelling on my way down!
	How to keep the feed line tidy? Electric fence insulators! The XYL still hates it..

Home | Op | QTH | Rig | Keys | Ant | QSL | /QRP | /P | /M | Logbook (3755) | Guestbook (201) | Links