VK5JST Aerial Analyser

Antenna Analyser

(April 2010)

Today, April 4th 2010, I ordered the VK5JST Aerial Analyser kit via the Internet. The product review on eHam.net shows that the VK5JST analyser works accurately, performs as well as the commercial units, is very easy to operate and for all cheap : AU$150 / 107  (post & package included)*. The modifications I am going to make are : an additional PL(SO-239) or BNC chassis mount for direct coax attachment, a DC connector for external 'juice' and the advised 1N4004 reverse polarity protection diode. The on/off switch probably is going to be moved to the top of the box, next to the coax chassis.

*= Customs could charge you an additional $20, but if you're lucky you pay nothing extra !

VK5JST aerial analyser

Within 5 days (!), a well-wrapped padded package arrived from Seaford Australia. A great job Graham, thanks !

April 25th 2010 : except the RF chokes (inductors), all components have been mounted on the PCB.

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The 5 RF chokes (one for each frequency range) will be located around the center 'band'-switch.

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The actions for the forthcoming days (weeks ?) : assembling the RF-chokes, connecting the external switches, pots and display. When all this is completed, the very exciting stage of the project approaches : setting up and testing the analyser.

April 26th – April 29th 2010 : the five inductors are on board now and all the 'prescribed' holes for the jiffy box have been drilled. As mentioned before, I added some extras : the BNC chassis mount and the DC connector for external 'juice'. Because I'll have to glue some spacer lugs for the display on the lid tonight, unfortunately setting up and testing will have to wait a few days.

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Drilling all the holes was not an easy job : temperatures today exceeded 28 degrees centigrade

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Some extra features …

April 30th 2010 : I put some extra glue on the 4 spacer lugs (3 mm screws) for the display to reinforce it. Attention : use screws with a maximum length of 7 mm otherwise you'll have a major problem with the main PCB later !

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A closer look at the inside part of the lid.

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The location where most of the action takes place …

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I cleared all the mess before taking this picture (hi)

May 1st 2010 : because I was so curious how the analyser finaly would look like, I positioned the display, put the small switches in and closed the box … ready to shoot.

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What a beauty, isn't she 😉

May 2nd 2010 : setup and testing have been completed succesfully : the aerial/antenna analyser works well and is going to be boxed one of these days. I'm a happy guy now, ready to rock and roll 😉

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1st action : the multiturn cermet trimpots have been used to adjust the voltages on the various testpoints.

2nd action : the trimmer on the main tuning capacitor has been used to set the output frequency of the 5th range to 31 MHz : calibration completed.

May 4th 2010 : I connected the analyser via the BNC socket to my FD4 (OCF dipole) which is in the attic. When I switched it on, the analyser showed a lower (11.2 V) voltage for the internal batteries, but it still worked well.

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A perfect result on 40m … that'll cause no problem I assume

Additional information from other HAM's who built this analyser :

PA0FRI's mods