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Reviews Categories | Antenna Analyzers | VK5JST Aerial Analyzer Help


Reviews Summary for VK5JST Aerial Analyzer
VK5JST Aerial Analyzer Reviews: 36 Average rating: 4.7/5 MSRP: $95 +post
Description: This is a design from Australia and put out as a kit by one of the Amateur Clubs there. It covers 1.3 to 31 Mhz
Product is in production.
More info: http://www.users.on.net/~endsodds/analsr.htm
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VE1HAO Rating: 5/5 Jan 13, 2014 10:23 Send this review to a friend
Excellent!   Time owned: more than 12 months
The VK5JST Aerial Analyser is excellent value and very useful. The kit cost less than the MFJ-207 my wife gave me years ago, which only indicates SWR and has an inaccurate analogue frequency indicator. The MFJ has proven unreliable to boot. The VK5JST is more reliable, gives much more information, and is far and away more accurate.

I second the advice to read the material on the net, e.g.,http://pa0fri.home.xs4all.nl/Diversen/VK5JST/Ant%20analyzereng.htm

The mechanical work cutting out the enclosure takes a little time and care, but doing it yourself keeps the price down.

The actual build is fairly straightforward for any technically competent ham, but do pay attention to the instructions and take your time. In particular, pay attention to the cautions regarding spacing of some components from the board. A scope makes calibration much easier. Try to borrow one if you don't have one. A good soldering station and some magnifiers -- for those of a certain age -- make life easier, of course. Component spacing isn't that tight, but it's tight enough.


It works fine and seems accurate enough when checked against several counters and precise resistors, certainly beating the whole MFJ line for value for money. In addition, there is the satisfaction of feeling that you are a real ham. Of course, if you build it you can fix it, but mine has been reliable so far. The neighbouring hams love it too. Build one and become popular!
 
G4YVM Rating: 5/5 May 22, 2013 09:43 Send this review to a friend
Excellent build, works first time, great fun  Time owned: 0 to 3 months
It took me about a week of just a few hours each day to get the analyser sorted. The only hair pulling snag was fitting the flexi wires to the LCD screen...aghhh!!!! I should have used ribbon cable and they should have supplied plugs and sockets, but neither was the case so I did it the way they suggest which is with 16 separate wires. It worked its just fiddly.

The analyser cost me less than a hundred fine British pounds and its excellent.

After I have used it for a while I'll add to the review.

 
M0STO Rating: 5/5 Apr 15, 2013 17:29 Send this review to a friend
YES YES and YES again as it's great and a wonderful build.   Time owned: 3 to 6 months
Has to be 5/5 all the way. Would sell built for more than it is in parts..You wouldn't leave home without your credit card ...WOULD YOU.

Just prior to Christmas 2012 I thought I needed some project to keep me busy over winter. Since I own a Cushcraft A3S and was flummoxed by terrible SWR until I took a tape measure to it and done all the adjustments to the millimetre (was still out though on my tuned points). I needed an antenna analyser to help me nip this in the bud and VK5JST was my first choice. It is fantastic and was a joy to build. I opted to make all from scratch (PCB, Box.. etc.). Even though the website does not point out component locations it is still easy to build and I honestly took 2 and a half months to assemble it as I hate the anti climax after finishing a project. It was cheap to build (around £55 or $85 USD) and probably the best money I spent in ages on ham radio equipment. I opted for the 4 slot 16Mhz crystal version utilising the PICAXE 28x2 which was very easy indeed to program and get to operate (other options are 28x1 and a single block code for 4Mhz crystals and can also use the 28x2. Calibration is a breeze too with test pins and other contributors have included a comprehensive tune and calibration word document. After taking it to my A3S I can now fiddle about getting it all nicely tuned for phone,CW or band centre without putting my back out. This little analyser uses or at least needs a good 12v supply as the programming says no way to 12v or lower and shuts-down right after displaying the voltage and callsign however this is easily modded in the code to shut down at lower voltages but not recommended as much of the calibration is done keeping 4.5v at test pin 2 ADC input of the PICAXE and variations here will ultimately lead to inaccuracy and I think now is a good point to point out that I was dry on a joint and after fixing the joint the voltage at test pin 2 exceeded 5.5v at the ADC input and this blew the PICAXE @ a cost of £8 so be very careful of your voltages and check, check and check again before you put the PICAXE in the slot.

I personally used 10 x 1.2v 1000ma NiMH battery's and they hold just a little over 12.8v (I use a diode inline and this drops by 0.7v)_ when fully charged which in turn is supposed to give about 4 hours usage but I doubt this as after just 30 minutes I was down .4v but I am using a LCD display with an LED back-light which is not part of the standard build. I would like to add Mr Tregellas VK5JST is very helpful if you get stuck but I would advise you check everything thoroughly before emailing him as only user mistakes or bad components would be to blame for a non working unit. There has also been some code changes to implement serial data out for logging which I have in my possession and hope to perhaps add Bluetooth to the mix and log direct to my PC over Bluetooth. Also if you do choose to do a self build (I would recommend the kit if your unsure at all) then double check the IN34 diodes as I opted for the OA91 equivalent as my local stockist had no stock of the IN34 and also be aware that there are some dodgy fakes masquerading as IN34's !! they are simple silicon diodes and not germanium (glass envelope and cats whisker type is the difference).
I had tin plated my board with a tin and with an oversized drill took away material that would cause shorting on the ground-plane side. Getting back to the actual operation the 4 slot version has 4 digit mode fast gate, 5 digit slow gate, component mode and angle mode. Quickly getting back to the battery situation, I have also built the little charging circuit which is on the VK5JST analyser website and also added an LED board based on the 12F683 which flashes red, solid red, green and flashing amber for various voltage ranges so keeping an eye on charging and discharging as a visual indicator away from the battery voltage on screen as you may wonder why your analyser has gone dead. The documentation says use 160pf variable capacitor which are like hens teeth but a 147pf will do fine as the overlap between switching is enough to cover the upper and lower of the previous selection. This kit is also capable of 200khz with just a few modifications which I am yet to do. STOP PRESS have done which swaps out 6 caps in the envelope detector and adds more inductors for continuous coverage down to 200khz STOP PRESS If I did have a whine then it would be the accuracy of the display compared to my very accurate frequency counter but this can be rectified in the code and apparently this is down to circuit conditions for which the crystal was made. I also see the stability can be a bit up and down until it's all boxed up but it's like any simple VFO and a puff of breath is enough to send it off by a few kilohertz. Others have reported instability of the 5v so adding an ALC and 5v regulator modification to the oscillation circuit keeps the whole lot more accurate and less prone to drift. Also a 10pf trimmer over the 16mhz crystal too which sorts out the crystal being off . So in summary YES YES and YES again as it's great and a wonderful build.
In Summary
Pros: Cheap, Accurate, Moderate to easy build and a novice with guidance could do it, out performs more expensive analysers, configurable firmware with Basic and easy to program, good level of battery life, serial data out to Bluetooth enabled PC if your that adventurous and countless modifications for performance.
Cons: Uses expensive PICAXE IC's, Instructions need some advanced technical understanding to make sense of the actual operational fundamentals , prone to drifting, PCB is not ABS box friendly to standard EU sizes (a personal gripe). No 2m and 70cm coverage that does not need extensive modification beyond the scope of a total rebuild (for accuracy anyway)
Easy to use and pretty accurate if you set it up correct. Will tune as good if not better than some of the other analysers on the market but you would really want to have 2 meter and 70cm coverage should you wish to fork out 6 times the amount for a commercially available analyser. Just look about on the web for people who have built the analyser and you will see...anyone can do it. Many thanks to VK5JST Jim, Stan VA3SMM and Jeff ZL1BIV and anyone else who worked on this analyser. In a last statement "it's a top notch analyser with simple to learn basic code and has the scope for expansion. Like a multimeter or wave-meter...every shack should have one"

PS: I blew mine up 3 times but fixed easily. Battery packed shorted out the switch and killed an inductor in tank circuit and took out D1 and D2 (wow loads and loads of smoke). Blew up a PICAXE because of AD pin over current (fix is use a resistor to current limit) and shorted out one of the 2N2222 transistors. Mostly because blob of solder and battery pack insecure but lessons learned.
 
PE7GL Rating: 4/5 Mar 16, 2013 04:21 Send this review to a friend
Experiment and improvements  Time owned: 0 to 3 months
After building these kit I saw that the out put of HF power amplifier was not constant so after measuring I found that Q10 was the reason of this problem.
I have remove Q10 and placed a jumper between emitter and collector pads.
After the modification the output is now far better and constant.
The analyzer is now good running at 8Volt supply voltage.
I has also replace the 7805KC by a 78L05 voltage regulator.
The supply current decreases from 70 mA to 30 mA. So we have a longer battery live.
For batteries I use now 8 NIH cells and de analyzer can run 30 Hours at one charge loading.
Gerard PE7GL
 
G3EJS Rating: 4/5 Oct 14, 2012 05:49 Send this review to a friend
Very useful  Time owned: 3 to 6 months
Easy to build and setup. I just bought the PCB (in fact I am waiting for the third one to arrive) which makes it a very inexpensive piece of equipment.

I have to agree with previous comments about the tuning rates.
The second one I built with a 10 turn pot for the main tuning, and no fine tune was needed.

It can easily be built in a day, and a greater part of that would be the case and finding components on the board.

That is really my only "complaint", the components are not numbered in the circuit diagram, nor on the board overlay, so you are left tracing tracks to identify one of several 47k resistors in one area of the board. A very minor complaint, but one that does use more time than anything else on the board build.

It is accurate enough for building and setting up aerials, at least as good as the MFJ, probably better.
It works OK up to 55-60MHz.

Certainly strongly recommended, anyone who builds, sets up or checks antennas should have one.

Photos at http://www.g3ejs.com/construction.htm
 
KF7UJM Rating: 4/5 Sep 10, 2012 19:21 Send this review to a friend
Economical, Useful, and Fun to Build  Time owned: 3 to 6 months
I have recently completed the VK5JST "Arial Analyser" kit. This relatively simple device displays the measured frequency of its oscillator, plus resistance, reactance, and SWR at that frequency. It has three tuning controls – a band select knob plus coarse and fine tuning knobs. It also includes a switch that gives you an extra bit of frequency resolution at the expense of a slower update speed. It’s just enough information for most hams but doesn't include loss information, a graphical display, etc. that more expensive devices have.

First of all, I'd like to say that this kit is about the most economical antenna analyzer available. For the complete kit, mine cost $145 AUS (which is very close to par with the US dollar) including shipping from Australia. The quality of the kit is good enough that one is tempted to compare it with something made by a for-profit venture, but such a comparison wouldn't quite be fair. As a more appropriate point of reference, this device was actually designed by a regular guy and sold by a club, the Adelaide Hills Amateur Radio Society, for barely the cost of the parts. Although the end result is pretty good for the money, this kit is fairly “rough” and I wouldn’t recommend it for beginners. The package arrived in about two weeks, and included the plastic enclosure and a set of printed documentation. Inside the plastic enclosure was a great unsorted heap of parts that weren’t organized in any way.

I spent some time with documentation first. The theory of operation was quite good and gave a pretty thorough explanation of both the overall theory and the specifics. More documentation is available online, including a troubleshooting guide that goes into even more detail about the nuts and bolts of operation. Unfortunately, the actual instructions are very brief and in paragraph (rather than step-by-step) form. They are adequate, though, if you read the whole thing a couple of times before starting and pay close attention to details that aren’t obvious at first. My biggest complaint is that most components did not have part numbers. This makes it difficult to correlate a part on the schematic to its location on the layout. Because of this it is very hard to build the circuit sequentially, making sure each stage works before continuing, and also hampers troubleshooting in general. In one case there are 17 identical capacitors placed through the board with no identifiers on any of them.

The first thing one must do before picking up the soldering iron is to place the bare PCB against the inside of top cover and mark off the precise locations of all the holes to drill. One thing that surprised me about this kit is that I would eventually spend more time working on the mechanical aspects of it than on the electronics. The only holes provided in the enclosure are on the four corners of the top cover for the screws that hold it on. I had to figure out for myself exactly where each hole went, what diameter it should be, what kind of clearance I needed from surrounding objects, etc. In addition, I had to figure out how to hack a big rectangle in the middle of the top cover for the display, file a gap in the side for the coarse tuning knob, and saw off ends of switches and pots that were way too long, all without plans. Fortunately, they give you a very nice engraved faceplate that will hide many of your mistakes. My biggest mechanical issue was caused by the only missing part in the kit, the lock nut on the fine-tune pot. Because this nut was a rare metric size I was unable to find a suitable replacement locally. I wound up buying an electrically equivalent Radio Shack pot that was physically much larger, forcing me to move it to a different location after I had already drilled the hole for the first one.

The PCB is a low-cost two-layer design with unplated holes and no soldermask, but very well laid-out. The entire component side is a ground plane. One idiosyncrasy of its design is that any ground connections on the component side are done without using a hole; in other words you must solder the lead directly to the ground plane after bending it appropriately. This really slowed down my soldering at first but eventually I got the hang of bending the leads efficiently. Construction of the big rotary switch in the middle for band selection is a complicated issue, because they can’t guarantee the supply of a particular one and so they change over time. Because of this they don’t give specific instructions on exactly where to put the stop and which inductors to wire to which terminals – you have to work that all out yourself. Mine was a 12-position switch of which only five were needed, but because the analyzer can be modified to work at higher or lower than specified frequencies extra positions are nice to have. In my case I turned the switch fully clockwise, put the stop in Position 8, and installed the knob so that it pointed in a non-standard position, but others will have different solutions.

I had relatively few problems with the circuit itself. I recommend checking off all the parts as you solder them on to make sure all of them wind up in the right place. They give a nice little turn-on and alignment procedure that you can do with basic instruments, although an oscilloscope is quite helpful. Fortunately sockets are provided for all ICs, and the turn-on procedure has you install them sequentially as you verify each part of the circuit. As my soldering skills are somewhat average, I did fry a couple of parts from overheating them with my soldering iron, notably the CPU crystal, and I shattered a germanium diode. So, I had to buy a couple of things from DigiKey to get going again. The documentation was good enough to allow me to quickly isolate faults.

A number of mods to the device are common. First of all, you can install a serial port you can use to load your own code into the PICAxe processor. Different versions of source code are available for free online, and the development tools are free from the manufacturer. If you do this you might as well install a newer version of the PICAxe with more Flash ROM for bigger programs. People have also extended the frequency range at both the high and low ends. The standard version goes up to 31 MHz, but it can be made to work up to 55 MHz for your 6m antenna. You can also add rechargeable batteries and/or an AC adapter. Because it uses binding posts instead of a BNC or UHF connector, and worse yet the binding posts are not the US standard ¾” apart (making it impossible to use the double-banana to BNC adapters we all have), some people install coax connectors on the box. I currently use a custom-made adapter with an SO-259 soldered to copper lugs.

After completion, I tested it with a frequency counter and highly accurate 50, 75, and 100 ohm resistors. Keep in mind that its accuracy depends largely on how nit-picky you are when you calibrate it, and how good your instrumentation and cabling setup are. I found that the measured frequency is accurate to within about 1 or 2% across the spectrum. I found that the resistance and SWR were quite accurate below about 15 MHz and decreased somewhat above that, although still certainly within limits acceptable to your average amateur. I also tried measurig the impedance with several capacitors and it always read within the component's stated tolerance.

Although I found this kit to be challenging at times in ways I didn’t expect, overcoming those difficulties only added to my sense of accomplishment in completing it. In the end I now have a useful analyzer for very little money that I understand the workings of and can modify and repair if needed. Although there are smaller ones and fancier ones, this one is great in terms of frugality, simplicity, and the DIY ethos.
 
KJ6QLD Rating: 4/5 Dec 29, 2011 22:15 Send this review to a friend
Pleased with result  Time owned: 0 to 3 months
Bear in mind that I am not a seasoned builder of electronic equipment, (this is the first project I've ever build) nor have I ever used a different antenna analyzer, but overall I'm quite happy with this kit. There was nothing missing from the package, every last piece was there. The instructions were clear and accurate, although I would have certainly appreciated a bit more detail. This is my primary gripe, I had to rely heavily on google and youtube at a few points. Likely, somebody with more expertise can breeze through this build, but a few photos at different stages and a few more step-by-step comments would have made a big difference for me. The troubleshooting document posted online was excellent and valuable in helping me track down my mistakes. I also added an external power jack and stereo port for programming - the newer programs available online seem to result in a more stable device than the one that came loaded on the chip. Overall, it seems to work very well. One point of interest: I mounted an SO-239 fitting directly to the enclosure, in parallel with the banana sockets (contrary to the instructions). This seemed to cause some erratic readings, so I gave up on the enclosure-mounted SO-239 and instead made an external SO-239 adapter as the instructions suggested, which mitigated this problem.
 
K6JBG Rating: 5/5 Feb 14, 2011 22:16 Send this review to a friend
Excellent Contrivance  Time owned: 3 to 6 months
Ingenuity was required to build the unit. I taped the face plate to the case cover and cut out the display window going back and forth with a large needle clamped with vice grips. I added a 10 turn 10k linear pot for frequency trim. I extended the Polyvaricon shaft with an M2.6x0.45x25 screw and a #4IDx.25ODx7/8" spacer & carefully hand drilling a .3125 hole through the panel and cover. Looking to add a planetary reduction drive perhaps. Although as large a knob as you can fit [1-1/8" dia.] acts as a reduction. Occasionally had to move a soldered in component. Used an old trick -> heat up solder; pull out; use a numbered drill in a pin vice to drill out the solder; hole ready to go at it again. On occasion I made my own holes to make a few mods. Upgraded to the latest PICAXE 28X2 chip with 4 memory banks. Jim Tregellas, the principle designer, has been a tremendous help with technical issues. Frequencies are very accurate against my KENWOOD TS-570DG w/TXO installed and a 0 to 50MHz freq meter. Buy one and have someone who has built one be your mentor. Over 5,000 units in the field -> that says a lot.
 
ZS1JHG Rating: 5/5 Feb 3, 2011 06:36 Send this review to a friend
A great piece of test equipment  Time owned: more than 12 months
Still very happy with my VK5JST Aerial analyser.
The build instructions are clear and include a detailed component overlay,the assembly sequence is detailed in the instructions and additional help is available from a number of posters websites.
You need a temperature controlled soldering iron with suitable tips to make a neat job. I am still on my first set of batteries - Lithium - as I use a power supply for all indoor testing.This is an excellent piece of test equipment that works first time if you read and follow the instructions.
 
W3SEH Rating: 0/5 Jan 20, 2011 18:31 Send this review to a friend
Unsuccessful Experience  Time owned: 3 to 6 months
I don't get it. Based on all those glowing reviews I expected a successful experience with this device, but no, quite the opposite. The instructions are really poor and do not correctly sequence your component installation which leads you to have to uninstall things to get others in. There is no solder mask on the board which causes unwanted bridges. The instructions cite that as an advantage - not! I've built literally dozens of HeathKits and my own designs over the years - I'm not at all new to building. The device didn't work when finally assembled and no way to discover why due to poor component placement. I can't recommend this to any one. I trashed it.
 
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