Web Updated;
06/07/2011
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Home Brew "Buddipole" Copy
| I have admired for some time W3FF Budd
L Drummond's "Buddipole" Aerial.
Budd encourages radio operators to construct their own version and in fact publishes details on his web site to provide assistance. Here is the link:- http://www.qsl.net/w3ff/ I have been looking for a portable aerial for use on field days with the ease of packing into my car and being quick and sturdy to construct, I just can't justify the £'s on a buddipole! |
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Photo of the "T" piece insulating connector from "SCATS" |
I previously tried building this
antenna two years ago as an Intermediate licensee, displaying it at Darenth
Valley Radio Club but the construction was made of 22mm PVC pipe and it
was so unstable it actually wobbled!
Although it did radiate and Gary 2E0ULA made a copy to Germany, it was hardly efficient and very ugly! I decided to construct a more rigid, cleaner looking design. After many months of looking I finally found the part in my local SCATS store in Wincheap Nr. Canterbury. www.scatscountrystores.co.uk It is a T piece connector for their "Blue" rigid water hoses. It has three twist locks and a rubber grommet within the joints. |
| The Coils are made by close winding
some 1.5mm Insulated multi-stranded wire around a 55mm Dia PVC waste pipe.
Approx 50 turns are made with a tapping every 5 turns. If you need help on how to make the tapping points, drop me an email and ill explain. The furthest end of the coil is attached to a 10 section telescopic whip. The whip length fully extended is 1310mm. Maplin (Code LB10L) press here for the link. The other end of the coil is connected to a bolt which is insulated from the Main shaft. (shown in this photo on the right of the blue coil windings) |
Detail of close wound Tapped coils. |
| The photo below shows the whip
partially extended and the coil tap positions which I have marked to aid
explanation and ease of tuning.
The 25mm Dia Aluminium hollow section forms the shaft connected from the centre T piece to the coil former. The Aluminium shaft is connected electrically to a "Fly" wire which has a crocodile clip on the end. This allows a secure fixing onto the soldered coil taps. Crocodile clips from Maplin As the coil taps are shorted out the inductance gets greater the further from THE WHIPS. Hence a tapping point of 8 gives more inductance than the tapping point of 1. Not forgetting that the end of the coil closest to the centre T has NO connection to the Aluminium shaft. |
Centre "T" with Choke Balun and (Optional) elastic bands to aid grip when tightening! |
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| The aluminium shafts are Imperial
1" (25.4mm) x 1.6mm Thk It is very important not to use metric 25mm dia as these are too loose within the "T" piece and will not screw up satisfactory. The two dipole arms are 1500mm Each. |
For continuity, mark one of the dipole
arms as +ve and the other arm as -ve. Connect the centre of the coax to the +ve arm and the braid to the -ve. I have water proofed these connections with hot glue. |
| Make a choke balun from 5 or 6 turns
of coax around a 120-150mm Dia form and connect the upright pole into a
tripod base or similar decent support. Guy rope if necessary.
For a guide these are the frequencies and settings for mine. Press here for a settings chart. (this is a starting point)It is advantageous to tune this aerial with an antenna analyser. Check the VSWR before transmitting to ensure the readings are within safe parameters for your equipment! |
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M6NHA - Manchester, M3NHA - Manchester, YT2DDK - Serbia, EA1GGJ - Spain,
G4RUW - Newbury, M3ZAL - Durham,
and HB9S Geneva Switzerland!