LNR W4OP User manual

SPECIFICATIONS
Coverage 6.9MHz– 29.4MHz
Polarity Low Angle: Vertical
Polarity High Angle: Horizontal
Loop Diameter 45”
Design Z: 50 Ohms
Power Handling: 15W SSB/CW 10W DIGITAL
Weight: 3 lb
Shipping Size 16 X 16 X 3”
Materials: 6061-T6 Aluminum, CPVC,
Hardware: Stainless Steel
Connector: Female gold/teflon BNC
LNR Precision
Asheboro, NC
www.LNRprecision.com
E-Mail: [email protected]
A WORD ABOUT TUNING NARROW BAND ANTENNAS WITH
GRAPHING ANTENNA ANALYZERS.
Analyzers like the Rig Expert series sample only so many points when constructing
a graph. 80 points in the case of the RigExpert series, when not being controlled by
a PC. If you are sweeping say +/- 4MHz,a sample is taken every 100KHz. On an
antenna with a 2.62:1 SWR bandwidth (-3dB points) of 16KHz, the dip may not be
seen or will be quite shallow. Once you find the dip, center it, narrow the Range
and resweep.
Typically, on 40M as an example. I do the final tuning with a sweep range of 40KHz.
This will give a true indication of SWR.
TUNING SMALL LOOPS IN GENERAL
Once you have the SWR centered on your operating frequency, you may wish to
make small adjustments in the coupling loop height to achieve even lower SWR.
Use the same procedure as above– step away from the loop while making your
adjustment.
The unique hybrid matching network makes height adjustments of the coupling
loop less necessary than would be the case with a classic coupling loop.
One might ask why an azimuth motor control was not included. For almost all practi-
cal propagation elevation angles, a small transmitting loop is virtually omnidirection-
al. For close in man made noise sources, you may find that you can rotate the loop
to minimize that noise source. Noise sources above or below the height of the loop
will likely not be diminished much if at all.
SMALL RX/TX HF LOOP
MODEL REMOTE W4OP
40-10M STL
PARTS LIST
PART NO. QTY DESCRIPTION
SUBL1001 1MAIN RADIATOR ASSEMBLY
SUBL1002 1COUPLING LOOP ASSEMBLY
L1003 1COUPLING LOOP THUMB SCREW
SUBL1004 1 3 PIECE SUPPORT MAST
L1005 1 TABLE/RAIL CLAMP
L1006 4 STABILIZER FOOT 1” x 8”
L1007 4RED STABILIZER FOOT THUMB SCREW
L1008 1HOOK&LOOP TIE WRAP 6”
SUBL1010 1REMOTE MAIN TUNING UNIT
L1012 1SMA CONTROL CABLE
SUBL1013 1HANDHELD REMOTE
L1014 1OWNER’S MANUAL
FIG. 1

ASSEMBLY
1. UNPACK THE SUBASSEMBLIES AND LOCATE THE TUNING BOX AND THREE
PIECE SUPPORT MAST.
2. THE LOWEST MAST SECTION HAS A FEMALE 1/4-20 THREAD. FIRMLY SCREW
THIS SECTION INTO THE TUNING BOX.
3. ASSEMBLE THE REMAINING TWO MAST SECTIONS ONTO THE LOWER PIECE IN
ANY ORDER.
4. LOCATE THE COUPLING LOOP AND INSTALL IT ONTO THE UPPER
TUBE. LOWER IT SO THAT THE TOP OF THE LOOP IS BELOW THE TOP OF THE
UPPER TUBE AND LOCK IT IN PLACE BY TIGHTENING THE BLACK THUMB-
SCREW.
5. CAREFULLY EXPAND AND RESHAPE THE RADIATOR INTO A 4’ DIAMETER CIR-
CLE. GRASP THE CABLE WITH BOTH HANDS ABOUT 10” APART AND STRIGHTEN
A BIT– MOVE UP AND DOWN THE CABLE GRADUALLY INCREASING THE RADIUS.
6. LOCATE THE 4 BLACK STABILZING FEET, OR THE BLACK TABLE CLAMP. IF US-
ING THE STABILIZER FEET, ATTACH THEM TO THE TUNING BOX WITH THE 4 RED
THUMBSCREWS. LEAVE THE FEET A LITTLE LOOSE AT THIS TIME.
6. PLACE THE ENCLOSURE ON A LARGE FLAT SURFACE– FLOOR ETC. LAY THE
MAIN RADIATOR ON THE FLOOR AND SCREW THE PL-259’S INTO THE SO-239’S
BY JUST SEVERAL TURNS . DO NOT TIGHTEN THE PL-259’S. MAKE CERTAIN
THEY ARE FREE TO ROTATE
THE RIGHT SIDE HAS TWO SO-239’S. THE FRONT FOR 40-12M AND THE REAR
FOR 10M.
7. LIFT THE RADIATOR UPRIGHT AND PLUG IT INTO THE TOP OF THE UPPER
TUBE. TIGHTEN THE PL-259’S AS TIGHTLY AS POSSIBLE. AS YOU TIGHTEN, MOVE
THE AXIS OF THE CONNECTOR A BIT TO MAKE SURE IT IS ALIGNED WITH THE
SOCKET AND CONTINUE TIGHTENING.
8. THE STABILIZER FEET CAN BE ARRANGED AS NEEDED. IT IS OFTEN EASIER
TO GRASP THE RED THUMBSCREW AND ROTATE THE FEET. IF NOT USING THE
STABILIZER FEET, ATTACH THE CLAMP NOW TO A TABLE OR RAILING TO SE-
CURE THE ANTENNA.
IF USING THE CAMERA TRIPOD OPTION– SEE ITS INSTRUCTIONS.
9. A LOOP & HOOK TIE WRAP IS PROVIDED TO SECURE YOUR FEEDLINE TO THE
SUPPORT TUBE. DEPLOY IT AT THE BASE OF THE SUPPORT TUBE
10. CONNECT THE CONTROL CABLE BETWEEN THE ANTENNA AND THE
HANDHELD REMOTE.
TUNING
1.DEPLOY THE LOOP AS HIGH AS POSSIBLE OFF OF THE GROUND TO REDUCE
GROUND LOSSES.
2. THE TUNING CAPACITOR IS INITIALLY FULLY MESHED (BELOW 40M).
3. INITIAL TUNING MAY BE DONE BY TUNING THE VARIABLE CAPACITOR FOR
MAXIMUM RECEIVER NOISE. FINAL TUNING IS BEST DONE WITH AN SWR
METER OR ANTENNA ANALYZER. THE GRAPHING ANALYZERS MAKE QUICK
WORK OF TUNING. ONE UNIQUE FEATURE OF THIS ANTENNA IS THE CAPA-
BILITY OF PRECISION ADJUSTMENT OF THE COUPLING LOOP WITH RE-
SPECT TO THE MAIN LOOP. THIS FEATURE ALLOWS FOR ADJUSTING THE
SWR TO CLOSE TO 1:1 REGARDLESS OF THE MOUNTING LOCATION– I.E.
PROXIMITY TO GROUND, BUILDINGS ETC.
4. TO TAKE ADVANTAGE OF THIS FEATURE, TUNE THE VARIABLE CAPACI-
TOR TO YOUR OPERATING FREQUENCY. MEASURE THE SWR. RAISE OR
LOWER THE COUPLING LOOP BY 1/4” AND REMEASURE THE SWR. SLIGHT
RETUNING OF THE VARIABLE CAP WILL KEEP THE LOOP ON YOUR FRE-
QUENCY. MAINTAIN THE COUPLING LOOP PARALLEL TO THE MAIN LOOP.
5. IF YOU LEAVE THE COUPLING LOOP ABOUT 1/2” ABOVE THE MAIN RADIA-
TOR, YOU SHOULD BE ABLE TO ACHIEVE SWR ON ANY BAND UNDER 1.5:1.
6. INITIAL TUNING CAN BE DONE BY PRESSING THE TOP SWITCH TO THE
RIGHT (UP) TO BEGIN RAISING THE FREQUENCY WHILE LISTENING FOR
MAX RX NOISE. THERE WILL BE A VERY BRIEF LIGHT BURST FROM THE SE-
LECTED UP OR DOWN LED. WHEN THE CAPACITOR REACHES A FULLY
CLOSED (DOWN) OR FULLY OPEN (UP) STATE, THE CORRESPONDING LED
WILL GLOW, ALERTING THE USER THAT NO FURTHER TRAVEL IN THAT DI-
RECTION IS POSSIBLE
7. FINE TUNING IS THEN DONE BY DEPRESSING THE SLOW MOTION BUT-
TON ALONG WITH THE UP AND DOWN BUTTONS
THERE WILL BE A BIT OF BACKLASH AS THE GEAR REDUCTION GEARS
CATCH UP WHEN DIRECTION OF ROTATION IS REVERSED.
8. REMEMBER, THE NARROWER THE FREQUENCY COVERAGE FOR A GIVEN
LOOP CIRCUMFERENCE, THE MORE EFFICIENT THE ANTENNA. ONE MANU-
FACTURER TOUTS HIS LOOP COVERING ALL OF 40M WITHOUT RETUNING.
ANALYSIS OF THAT ANTENNA REVEALED IT IS OVER 10DB BELOW THE
W4OP LOOP ON 40M.
9. 10M IS COVERED BY SCREWING THE RIGHT SIDE OF THE RADIATOR INTO
THE REAR CONNECTOR. ON THE 10 AND 12M BANDS THE ANTENNA IS NOT
A SMALL TRANSMITTING LOOP BUT RATHER A CAPACITY LOADED CIRCU-
LAR DIPOLE. RADIATION IS AT RIGHT ANGLES TO THE PLANE OF THE LOOP
– JUST THE OPPOSITE OF THE SMALL TX/RX LOOP.
10. IF YOU WILL NOT BE USING THE HANDHELD FOR A WEEK OR MORE,
REMOVE THE 9V BATTERY. THIS HANDHELD HAS THE UNIQUE FEATURE
THAT EVEN AS THE BATTERY VOLTAGE DROPS, A CIRCUIT IN THE RE-
MOTE MAINTAINS THE BATTERY AT A CONSTANT VOLTAGE UNTIL IT IS AL-
MOST FULLY DEPLETED. THIS CIRCUIT HAS A CONSTANT DRAIN ON THE
BATTERY OF A MILLIAMP OR SO.