HCDX Antenna Special, 1 August 2004
This is an antenna specially calculated for the tropical 60 meter band, with instructions for those who do not possess a lot of space at their locations.
This antenna is a short dipole made up of inductores (L1 /L2) in half of each arm, based with the concept of inductive load.
The dimensions are shown in the figure. The L1/L2 can be built on tubes of PVC; the feeding slope to the radio can be either coax of 50 or 75 ohms.
Construction
Antenna: A total of 12 meters of wire, with a diameter of about 2 mm, divided into four sections. Insulators cn be of porcelain or PVC. To fasten the antenna one can use, thread of clothes for the anchorage.
L1/L2: Two tubes of PVC of 5 cm (2 inches) of diameter and approximately 20 cm of longitude. Roll 60 turns of wire of 1.5 mm on each tube, closely wound. A length of 10 meters of wire should be sufficient for each inductor.
The diagram above show the disposition of the antenna with its respective inductors L1/L2.
By Enrique A. Wembagher, Argentina
Looks like a good idea. Would only take elements about 37 feet long to have a rotatable dipole if designed to have the antenna strapped to bottom of lightweight PVC material for the support needed. HI You would neet a "truss" support at the center to help keep the PVC from sagging badly. May do this during upcoming Spring/Summer better weather.
ReplyDeleteSan,
ReplyDeletethank You a lot for comment my friend. Yes if it will be mounted enough high then it can be good solution. Only the problem can be with big coils losses. On-air test results will be interesting.
73 - Petr, OK1RP
This comment has been removed by the author.
ReplyDeleteL1/L2: 50 or 40 mm?
ReplyDeleteI think that: 50 mm for 4 MHz and 40 mm for 5 MHz.
¡Aprox!
73 from Spain.
www.ea7hfg.com.es
Hello friend,
ReplyDeleteaccording to the original source here:
http://www.hard-core-dx.com/nordicdx/antenna/wire/60mtrapdipole.html
the L1/L2 coils diammeter should be 50mm.
In my opinion it is not so critical. The inductive load will extend the electrical lenght and depends to actual coils inductance (and antenna location) the resonance must be adjusted by changing the lenght of both legs...
73 - Petr, OK1RP
Hi ive only got the white pvc but its 40mm will that be ok to use...? guess the legs dipole may be a bit longer?
ReplyDeletecheers
paul
Paul if the inductance will be lower because of the smaller diameter of coils then the legs will need to be a bit longer in order to put antenna into resonance.
DeleteHi Petr, Thanks for the 60m plan, i have made one following the details and i can't get it to resonate on 60m 5mhz
ReplyDelete, it is resonant on 15m 21mhz but i can't get it to work on 60m. I used 50mm x 200mm tube and 1.5 magnet wire 60 turns. The only difference is i used 1.5mm not 2mm for the 3m sections, can anybody help me figure it out. Many Thanks Rob.
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ReplyDeleteThe best solution for all the antennas ..MANY THANKS TO mr Claude,,, VE2DPE .https://www.hamradiosecrets.com/short-ham-antennas.html.
ReplyDelete.. Divide 99.8 / f= length in meters... and you have the total length of the antenna ,,, So 99.8 / 5.300 = 18.83 meters of wire ... BUT....the total wire of the ladder line is>> 18,83+18,83=37,66meters....THIS means...a little more than 5/8λ.((33.60m)).of the normal length λ= 53,77m
I make these antennas using current balun 1:1..and coaxial,,,tv cable 75 ohm!!!!!
....if you need to reduce the length for better tuning ,, we can cut from the top of the double line, bit by bit, If we want to lengthen the antenna, we can add at the end of each short-circuited edge ,, just a piece of wire..
...what performance does it have ??? if not better .... at least the same with a dipole λ/2 .. THAT'S ALL
....in the same philosophy, is the linear loaded antenna of K4VX http://www.arrl.org/files/file/Technology/tis/info/pdf/0207040.pdf GOOD LUCK..
73' SV2FNN