XX9E Photo Received

Just RX'ed a photo off one the the XX9E team, many thanks lads

New Centre Post Test Day

A break in the WX gave me time to do the first bit of testing for the new air coaxial aluminium centre-post. I first had to lower my mast and remove my original Hexbeam and remove the original centre-post. Few cups of coffee and I was ready to tackle it.

The post is inserted into the original hub for the first time, new flanges are slightly higher and will hide the extra height of the GRP insulator

 Original wire elements are attached to the air coax centre-post.

Coax attaches directly to the coax centre-post, no need to split the coax any more. I may change this to a N-Type socket in the near future. Note the two eyelets, these perform two functions. The first is to hold the top cap in place and the second is to attach the optional ice support cords to them.

A few alterations had to be made to the positions of the cleats that hold the wire elements in place but all in all it was quite an easy task and only took a few hours to compleate. 

SWR test, charts show SWR on band edges, first red line = 1.5

Test equipment Mini VNA

20 Meters

17 Meters

15 Meters

12 Meters

10 Meters

6 Meters

Conclusion

Each element is slightly to short, I can only assume that this is due to the hardware sizes being smaller, EG the nuts and bolts that hold the wire elements on the original centre-post are M6 x 25mm and have two large 10mm nuts on each one. This adds to the length of each element. The new coaxial post only uses M4 machine screws and small 6mm nuts.

When I return from Ramsey Island EU-124 on the 20^th of July I will be cutting some new elements to fine tune the SWR on each band. Very pleased with the results so far.

New Centre-Post design

Been busy designing (the design is not new but this version is round as opposed to other manufactures square versions) a new style centre-post. Have not yet tested the post but hopefully in the next two weeks I will have it on top of my mast!
SO-239 will be changed to an N-Type socket; this is a prototype purely for testing.

Post OD is 35mm and acts as the outer and a 12.5mm Solid rod is placed inside which acts as the centre conductor.

Centre conductor is suspended on specially designed spacers to hold it central to the outer tubing. The correct description for this system is "transmission feed-line"

All isolators are completely bespoke to each centre-post and are produced on site; this ensures a tight fit every time. Stainless steel coach screw is fitted on the top for attaching the support cords and extra eyelets are an optional fitting for ice support cords. I can supply the cords but customer will be responsible for attaching them.

Initial testing on a VNA is showing a 1:01 SWR and 49 Ohms on 13Mhz to 51 Ohms on 54Mhz when terminated on a 50 Ohm dummy load.

Top of post, The top coach screw is for attaching the support cords to and the eyelets are the optional ice support cord fixings.

GRP spacer, this allows the post to sit in the top flange, it also acts as an additional isolator. The hole is intentional and acts as a drain hole for any moisture build up or water ingress.

Isolation rod, this isolates the stub-mast from the centre-post

More information and pictures to follow.

CY9M Hexbeams Leave The Workshop

Wednesday 27 June 2012

After many months of planning by the team the Hexbeams are leaving the workshop. I would like to take this opportunity to thank the team for choosing my version of the G3TXQ Hexbeam antenna and may you all have a safe trip and make many thousands of QSO's!!!!!

73's Ant MW0JZE