5 band Cobweb Antenna

5 BAND COBWEB

 

Cobweb Antenna

A BRAND NEW COBWEB ANTENNA TWIN WIRE CUSTOM BUILT 10-12-15-17 AND 20 METERS 

BUILT BY RADIO HAMS FOR RADIO HAMS
 

THIS IS NOT A KIT IT'S A COMPLETE ANTENNA THAT COVERS 14-18-21-24-28 MEG
THE RETAIL PRICE OF THIS ITEM IS OVER £290 BUY DIRECT AND YOU SAVE
please wear gloves when working with fibreglass

NOW WITH HEAVY DUTY CABLE MOUNTING P-CLIPS
OVER ALL SIZE 8'6" SQUARE
MOUNTS TO A 1 1/2 to 2" POLE
weight 6.5 kg
WIND SPEED  WILL TAKE 120 MPH PLUS

A dipole or a CobWeb has a gain of about 5dB over a dipole in free space,

(due to ground reflection) or 7dB over an isotropic radiator (7dBi) and will work equally well over the entire band

.The CobWeb has no lossy components in it, so there are no power limit problems for the 

QRO operators 600 WATTS PLUS.

.The low loss and consequent high radiation efficiency 95% also makes it ideal for QRP! 

THIS COBWEB WAS CUSTOM BUILT BY ME FOLLOWING THE COBWEB REVELED INSTRUCTION
THE ONLY MODIFICATIONS WERE TO THE SUPPORTS THERE ARE NOW FEWER PARTS AND LESS JOINTS
I USE 16MM SOLID ROD NOT 12MM AS THE ORIGINAL HAD
I USED PULTRUDED FIBERGLASS RODS AND TUBES FOR EXTRA STRENGTH
ALL THE OTHER PARTS ARE AS THE INSTRUCTION  I USED TWIN 42 STRAND FIGURE OF 8 CABLE
THE SAME JUNCTION BOX THAT IS SEALED INSIDE AND OUTSIDE AND IT HAS BUILT IN BALUN CHOKE
I USED 6.25MM ALLOY PLATES FOR THE CROSS SUPPORT AND MAST MOUNT
ALL THE U-BOLTS ARE GALVANIZED SO THEY WILL NOT ROT AWAY FITS TO A 2" MAST
THE JUNCTION BOX HAS S0239 SOCKET FITTED SO A STANDARD PL259 PLUG WILL FIT IN
 SO ALL YOU NEED IS TO FEED IT WITH  A RUN OF 50OHM COAX
20 TOP QUALITY CABLE TIES WILL BE SENT TO SECURE THE ELEMENTS TO THE RODS AS IN PICTURE 2
THIS ANTENNA WAS SET ON A 6 FOOT ALLOY TUBE 
  A  LITTLE TUNING WILL BE REQUIRED FOR FULL BAND COVERAGE AN ATU MATBE NEEDED ON SOME BANDS
 YOU MAY NEED A FEW SMALL CABLE TIES FOR FINE TUNING THE ELEMENTS
BUT FULL INSTRUCTION ON HOW TO TUNE WILL BE SENT WITH THE ANTENNA
AS WILL THE CONSTRUCTION INSTRUCTIONS PLEASE WEAR GLOVES WHEN BUILDING ANTENNA
THE OVERALL SIZE IS 8 FOOT 6 SQUARE
ALL THE ELEMENT GAMA MATCHES ARE SEALED WITH HIGH QUALITY HEAT SHRINK TO KEEP THE WEATHER OUT
THE COBWEB IS FULLY OMNI-DIRECTIONAL SO NO EXPENSIVE ROTATORS TO BUY
PURE HORIZONTAL POLARIZATION SO VERY LITTLE CHANCE IF ANY OF E.M.C PROBLEMS
YOU GET 5 FULL SIZED HALF WAVE DIPOLES ONE ON EACH BAND WITHOUT NULLS
IN A SPACE LESS THAN 9 FOOT SQUARE
YOU EVEN GET 2 HEAVY DUTY POLE CLAMPS TO FIX TO YOUR SCAFFOLDING TUBE UP TO
2 INCH FOR FAST ERECTION AND NOW ALL NYLOCK NUTS
NOW WITH SINGLE PIECE BOOMS AT 1.44 METERS  AND 2  REINFORCED TUBES IN THE CENTER HUB
THIS WAS DONE AS A RADIO CLUB PROJECT SO SOME OF THE BEST BRAINS IN HAM RADIO WENT INTO BUILDING THIS ANTENNA
AN A.T.U MAY BE NEEDED DUE TO THE SPREAD OF SOME OF THE BANDS COVERED BY THIS ANTENNA AS WITH ANY DIPOLE
I THINK THAT COVERS IT ALL
THE ANTENNA HAS BEEN TEST ON 800 watts  BUT WILL HAPPILY TAKE MORE
SO THE FULL UK LIMIT IS NO PROBLEM
ITEM WILL BE SENT PARCEL 48 TO MAKE SURE YOU GET IT .
IF COLLECTING PLEASE CASH ON COLLECTION CONTACT ME VIA OR CONTACT PAGE OR CALL ON OUR TEL NUMBER  MONDAY TILL FRIDAY 9 TILL 5

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