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Cobweb Antenna


· Tape Measure Yagis
· Add bands to a Hustler 5BTV (8BTV?)
· Simple Mods for your xBTV antenna
· Simple 144MHz/440MHz ground plane twins

Tape Measure Yagi style #3 with choke for 70cm

PVC cut and temporarily assembled to check measurements of boom length and element spacing adjusted for 440 MHz use.

Tolerances are tighter at the frequency so be sure to take into account the actual depth of the T's in your boom section measurements (about .75").

Yagi Dimensions for 440 MHz
Reflector (REF) Length13.78
Driven (DRI) Element Length11.83
1/2 Driven Element Length5.91
Director (DIR) Length11.70
REF to DRI element center-to-center length2.66
REF PVC length1.66
DRI to DIR element center-to-center length4.16
DIR PVC length3.16
"U" hairpin total length1.67
The critical measurements are the element center to center spacings.

REMEMBER: At this frequency, use 1/2" wide tape, not the 1" wide used for 220 and below.

Close up of the balun, screws, and feed line

Holes were drilled for routing the RG-58 coax through the PVC, wrapped approximately 4 turns, then back into the boom and out the back end. BNC connector was installed after the coax was routed. Lugs were soldered to the ends of the feed line for attaching to the driven elements. The driven elements were sanded clean under the screws,and every thing was assembled as shown. Note the additional set of screws on the driven elements to keep them from twisting.

While the calculations call for a 1.67" hairpin matching wire, this yagi was built without one. The testing continues to determine real world impedences using 1/2" tape and the necessity for a hairpin match at this frequency.

The finished antenna

Another view of the completed antenna.

Assembled and photographed by Glenn McFarlin, W4ULB

Close up view of the handle

Holes were drilled in the PVC to allow the handle to rotate for vertical horizontal polarization, inserting a pin to lock it in place

Assembled and photographed by Glenn McFarlin, W4ULB

Yagi Dimensions for 432 MHz
Reflector (REF) Length14.04
Driven (DRI) Element Length12.04
1/2 Driven Element Length6.02
Director (DIR) Length11.92
REF to DRI element center-to-center length2.71
REF PVC length1.71
DRI to DIR element center-to-center length4.24
DIR PVC length3.24
"U" hairpin total length1.70
In case someone wants to use one of these for SATCOM work

Yagi Dimensions for 224 MHz
Reflector (REF) Length27.07
Driven (DRI) Element Length23.23
1/2 Driven Element Length11.61
Director (DIR) Length22.98
REF to DRI element center-to-center length5.23
REF PVC length4.23
DRI to DIR element center-to-center length8.18
DIR PVC length7.18
"U" hairpin total length3.27
Measurements for 224 MHz


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