Rabu, 29 Februari 2012

Homebrewed Hexbeam, PG3N

This antenna now is mine antenna for the higher HF-bands.
After reading many articles and viewing many sites, I decided to built this antenna.
A fullsize beam for 20 mtr is no option here in my small garden.
In the past I was working with a Single Quad, HF5B Butternut and at last MA5B from Cushcraft.
The MA5B  worked fine, but QRO is a problems for this antenna, Cuschcraft mentioned that beam is capable 1Kw, but
in practice 400 Watts rtty the traps 15/20 mtr were melted.
So looking to an antenna what is suitable here in my garden and can handle QRO with 5 bands, I  find the Hexbeam the best solutions.

Here the baseplate made of 5mm harded aluminium  with sides of 150 mm and a peace of pipe what was available.

Baseplate and pvc tube on top.

For the feedingline I decided to use RG213, instead of the parallel lines what you often see on other sites.
Coax feedlines is according experiences other users, easier to tune then the parallel lines.
Al connections and open ends coax glued with UV resistant 2-component gleu sealer.

Fore the spreaders I use glassfiber rods , these are no fishing rod but are normally in use as landingnet rod.
These rods are a bit robust then the fishing rods, and you can buy them in length of 325 cm, what is nearly the length needed.
On top an aluminium tube piece is fitted with inside some tapped wire.
This tube I use to hold the rope for holding the spreaders in position.
My antennawire is isolated copperwire 1.5 mm  in diameter , this isolation lowers the resonant frequency.
For dimension I used  the length given by DL7IO 5-bands construction, were I use a velocity factor from 0,98 as experiences from DL5ZA

Here the wires ready for installation and papers Dl7IO and K4KIO
In the Netherlands I found 4 stations who are using this antenna.
calls:  PA2JJB,PA0KNW,PE1FJP en PE3AA ,all of these station you can admire pictures.
At Yahoo a user group gives a lot of support and information available.
Here some other parts:

Here constructing:
Hexbeam opbouw PG3NHexbeam opbouw
Fixing rope to spreaders.                                                        XYL is watching.

Hexbeam voedingspunten 10,12 en 15mtr zichtbaar
Baseplate with spreaders and HF-choke.                                       The same but with antenna-wires and feeding-line together.
Coackabel aansluiting bovenkant 20tr HexbeamHexbeam gereed voor aktie
Feeding antenna from top (20mtr).                                                              Ready with constructing.
De hexbeam in bedrijf
Here the hexbeam at 17 mtr high, total weight including pipe above the rotor is 6 kg.
Results are fine,  swr on all bands 1:1,5       F/B 3 a 4 S-point with mine FT1000mp.
20mtr has a swr lower then 1:2 over the full 350 Kc.
As mentioned before, lot of information I got from internet and hours of preparing.
Finding all materials, shaping clamps/cutting feedinglines /creating baseplate/cutting antenna wires etc kept me a few evenings very busy.
But at the end , building the antenna in the garden was without any unpleasant event, a pleasure.
Constructing took a hole Saturday afternoon, and now the HF party can begin.

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