Directive Systems & Engineering DSE3319LYAK User manual

DSE3319LYAK Rev 4/21
Directive Systems & Engineering
2702 Rodgers Terrace
Haymarket, VA 20169-1628
www.directivesystems.com
703-754-3876
33cm Loop Yagi, Model DSE3319LYAK
SPECIFICATIONS
Frequency Range: 910-928 MHz
Number of elements: 19
Boom Length: 72 inches
Boom diameter: 1 inch
Mast diameter: 1 1/2-inch max.
Weight: 4 pounds
Connector: Type N female
Gain: 16.5 dBi
3 dB Beamwidth (E Plane): =30°
F/B ratio: >20 dB
Maximum Power: 550 W. average
Stacking Distance:
H Plane 21 ½ in. vertical
E Plane 24 in. horizontal
PARTS LIST
Note: All hardware is Stainless Steel unless otherwise noted.
Anti-Seize Compound - Apply a small amount of the supplied Anti-Seize Compound to the aluminum joints and
to the threads of the U-Bolts to prevent galling.
BEFORE INSTALLING YOUR NEW ANTENNA, PLEASE BE SURE
TO READ THE ENCLOSED WARNING PAMPHLET.
2 .058" x 1" Drilled boom 19 4-40 x 1 1/4” Screw
2 Reflectors 1 & 2 19 4-40 Lock nut
1 Driven element 28-32 x 1 1/4” Screw
10 Directors 1-10 28-32 x 2” Screw
6 Directors 11-16 4 #8 Hex nut
1Boom to Mast Bracket 4#8 Split lock washer
1Boom to Mast Plate
1 2" U-bolt with nuts & lock washers 1 Anti-Seize Compound
1 Saddle 21" Black End Cap
1Cable assembly w/connector 1 Assembly Manual

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CAUTION: While we strive to remove all burrs from all machined parts, there is always the possibility of
sharp edges. We strongly suggest checking the edges and use a fine file, or 400 grit sandpaper,
to remove any burrs that may have been left.
(Can be up or down) (Can be left or right)
ASSEMBLY INSTRUCTIONS
1) Attach loops to the boom with 4-40 screws and locknuts in proper sequence. Loops go
on the side of the boom marked with an "X". The loops are bagged in similar sized groups
and labeled. Install them in order, being careful not to mix them up on the boom. When
tightening the nuts on the parasitic elements, be careful not to torque them too tightly. Snug
down the nuts, align the elements and use a screwdriver for the final tightening. A 1/4-inch nut
driver is almost mandatory for this job! Attach the driven element with the 5/16 nut provided. If
only a single antenna is being built, it doesn't matter which way the loop is oriented. If
antennas are to be stacked, see "Instructions for Stacking Loop Yagis".
2) Attach the boom to mast plate and bracket (square tubing). Use 8-32 x 2” hardware for
BM bracket, and 8-32 x 1 1/4" hardware for attaching mounting plate to the square BM
bracket. The mounting center is D15. Install U-bolt so that the mast comes up directly under
the boom.
3) Install the cable assembly through the hole in the driven element mounting bolt. Make
sure the connector bracket is correctly oriented, the bend should be forward for center mount
antennas and rear facing for rear mount antennas. Solder the outer shield to the driven loop
first making sure there is no shield sticking above the large hole in the driven loop. After the
shield is soldered, pass the center conductor through the small hole in the driven loop and
bend the center conductor over and solder (See Assembly Tips below).
We have created a You Tube video, the link of which can be found on our website,
documenting the following steps:
https://youtu.be/ojXbsDv5cvU
At this point the connector assembly is facing down, connect a piece of coax and your
SWR bridge or VNA. Pull down on the connector (which will flatten the loop) until you reach
the lowest SWR. If it’s less than 1.5:1 you can stop and make sure the loop doesn’t try to pop

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back up, sometimes you have to squeeze the loop with your fingers to make sure it stays in
the shape that gave the best SWR. If you want to further lower the SWR, from the rear of the
antenna, place both your thumbs on the driven loop on either side and gently push it forward
towards D1, you only need to tilt it maybe 3/16” to ¼” and that should drop the SWR to 1.1:1
or less.
Now, GENTLY bend the UT-141 coax after it exits the boom towards the front or rear,
depending on the mounting. You do not want to bend it so tightly that it crushes where it
extends through the bolt. The connector bracket should line up with either D1 or D2 (or the
hole with the circle around it on rear mount antennas), remove that nut and place the
connector bracket on the screw and re-attach the nut. If the bracket doesn’t line up,
sometimes you have to flip the bracket. Loosen the ¾” nut by holding the connector body with
a 9/16” open end wrench. Remove the connector bracket and flip it.
Connector doesn’t fit Front Mount Connector Rear Mount Connector
4) Attach the feedline and tape it to the mast. Seal all connections with silicone RTV or
equivalent.
5) Attach the two black end caps, and this will complete the assembly of your
DSE3319LYK.
6) The SWR should be 1.5:1 or better. Additional tweaking can be accomplished by
adjusting the distance between the driven element and R1 or by adjusting the shape of the
driven element.
DO NOT, UNDER ANY CIRCUMSTANCES, APPLY ANY TYPE OF SEALANT OR COATING TO THE
DRIVEN ELEMENT, T-ARMS OR CONNECTOR ASSEMBLY, OTHER THAN KRYLON®
CLEAR COAT. ANY OTHER COATING WILL ADVERSELY AFFECT THE SWR AND VOID YOUR
WARRANTY.
ASSEMBLY TIPS:
The boom diameter is 1 inch, and it is drilled for 4-40 hardware (no. 33 drill bit). The driven
element hole is enlarged to 5/16 inch. All elements are 0.032-inch-thick and 0.375 inch wide.
Note that the element spacing from D7 on is 5.115 inches. The feed coaxial cable (0.141-inch

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semi rigid) goes through the mounting bolt and is soldered to the open ends of the element.
For best match, the driven element should be approximately 4 inches high; this makes it wider
than it is tall. This shape can be adjusted for best match. This antenna is based on work done
by G3JVL.
Soldered Driven Element
Note: All dimensions are in inches.

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Directive Systems Warranty Policy
All Directive Systems antennas are built with the finest materials available. We take great pride
in building a quality product that will give years of good service and performance. If there is a defect
in materials or workmanship within 90 days of purchase, Directive Systems will repair or replace
the defective part, free of charge, to the original purchaser. DO NOT RETURN ANYTHING
WITHOUT PRIOR AUTHORIZATION FROM DIRECTIVE SYSTEMS. Please contact us either by
phone or email describing the problem and we will work to resolve it.
If, after examining a new antenna you received, you are not satisfied, contact us immediately
for return authorization and refund. ANY ANTENNA THAT HAS BEEN MODIFIED WILL BE
SUBJECT TO A RESTOCKING CHARGE. IF AN ANTENNA IS SO MODIFIED AS TO MAKE IT
UNUSABLE, DIRECTIVE SYSTEMS RESERVES THE RIGHT TO REFUSE TO ACCEPT THE
ANTENNA FOR RETURN.