Times Technologies Vector Impedance Analyzer Review
T100 Antenna Analyser
The Times Technologies T100 Vector Impedance Antenna Analyser is being made available by Mr. Morris Chang of Times Technologies in Hong Kong who has a Web Site at http://timestechnology.com.hk.
Recently I was in the market for an antenna analyser which covered the VHF and UHF Ham Bands and was surprised that all of the commercial units targeting the amateur market would not display signed impedance at UHF. Most would only display VSWR and impedance magnitude at UHF even though they did signed impedance and other complex functions on lower frequencies.
Then I found the T100, which appeared to do a lot more. The unit was very reasonably priced, so I thought it was worth a try. Here's a summary of my experience with the unit.
Friday 12th Nov, 2010 14:00
Operating the T100
I purchased the T100 on eBay and was very impressed when it arrived four days later from Hong Kong. Normally it takes three to five days for items to arrive from the other side of Australia, so for an item to take the same or less time from Hong Kong is impressive.
I powered the unit on and found that I didn't need to consult the manual to operate the unit. The menu configuration and operation is intuitive and simple.
Within a few minutes I was testing antennas and I must admit that it was very pleasing to see how quickly and easily I was able to visualise how my antennas were operating across their operating band without having to manually tune across and try to picture their performance curve.
The graphical display on the T100 is simple but more than adequate and can be used to display the entire VHF or UHF spectrum, or to zoom into a particular portion of the spectrum in smaller steps.
By Ben Crnojacki VK3KBC
Testing the T100
The T100 has a simple menu consisting of:
| Single Frequency
|| Displays Frequency, Impedance and SWR
| Sweep Frequency Plot
|| SWR Plot
|| Impedance (Z) Plot
|| Resistance (R) Plot
|| Reactance (X) Plot
|| Return Loss (S11) Plot
|| Phase Angle Plot
| PC Mode
To begin testing antennas, you only need to use the first two main menu items.
The single frequency screen displays a large SWR reading along with the frequency being tested and the impedance of the antenna currently under test.
The Sweep Frequency Plot displays a graph of one of the functional parameters for either the VHF or UHF ranges.
The unit operates between 100 - 170 Mhz on VHF and 400 - 470 Mhz on UHF.
On Air Testing
The first thing that I did with the T100 was to test an antenna which I've been using for many years. It is a 2m 1/4 wave vertical with four radials at 45 degrees to the horizontal. This was erected about 20 years ago as a temporary antenna but ended up becoming a permanent fixture.
I use the antenna with a FT8900 on 2m and 70cm. I has always performed well and I've never bothered to re-assess its performance since it was first commissioned. I have used 2m 1/4 wave antennas as 3/4 wave antennas on 70cm in the past and didn't bother to check the performance of this particular unit with a SWR meter on UHF, assuming that it would work as well as others had in the past.
As the above screen captures show, the antenna has its lowest SWR on 431.900 Mhz but is not resonant there, showing 53 ohms and 6 ohms inductive there with it's phase shift zero-crossing somewhat higher, indicating that its true resonant point is higher in frequency. (Note: I have not yet removed the protective plastic from the antenna analyser display, so it looks a bit rough.)
At an operating frequency of 434.200 Mhz, which is near where I often operate, it has a SWR of 2.25 and has an impedance of 70 ohms - very poor for what is supposed to be a 50 ohm antenna!
At that frequency, the antenna has a resistive component of 55 ohms with a capacitive reactance of 43 ohms.
Clearly, I could do with a better antenna; one which has more inductance at this frequency. (That's my next project!)
What about other antennas?
If my trusty old 1/4 wave was so poor on UHF, I wondered how my other 'trusted' antennas actually performed.
I have a number of handheld transceivers, so my next test was to see how the commercial 'handie talkie' antennas performed. Many are sold as multiband antennas, claiming that they are suitable for say 2m and 70cm combined,
so I tried a random selection of antennas that were nearby.
The first antenna I tried was a 2m rubber ducky antenna from an old ICOM IC-2A transceiver.
"Wow, not bad", I thought. This antenna was nicely resonant in the centre of the 2m band and had a SWR of less than 1.5:1 with a reasonable bandspread, reaching 1.8:1 at the band edges. Touching the antenna along its length made the trace worse, which was expected. Handling the base of the antenna or changing the grip on the T100 had little effect. This meant that the antenna was working as expected and that the T100 was acting a bit like a handheld transceiver to the antenna.
All good so far.
I then tried an antenna which I often used with my Standard C528 dual band transceiver. This was a Maldol Model Mal-440 with a BNC connector.
"Hmmm.. not bad, but not great", I thought. This antenna displayed its best SWR of 2.56:1 at 440 Mhz. It was still just OK at where I wanted to operate, with a SWR of 2.88:1 at 435.000 Mhz.
This antenna was a lot more sensitive to its groundplane and did not like being operated away from the body or when the antenna analyser was placed on an insulated surface like a table. The SWR jumped up dramatically. Not great, but still within expectations....
Operation on 2m was fine, with a broad, almost flat trace and a SWR of 1.5:1 across the 2m band.
The next test antenna was the original Standard C528 2m/70cm rubber ducky antenna.
Performance was reasonable with 2m coming in at 1.25:1 at 144.300Mhz and rising quite steeply either side from that and reaching almost 3:1 at 148.000 Mhz and 70cm showing a SWR of 3.34:1 at 434.000 Mhz and rising slightly either side of that to the band edges.
Again, less than 2.5:1 band edge to band edge on both bands would have been acceptable but not great. This antenna was just acceptable on 2m but not on 70cm. It was also sensitive to movement away from the body and liked having a groundplane.
The next antenna tested was an old, and well used, Diamond Brand RH77B 2m / 70cm flexible whip antenna.
This antenna performed poorly on 2m, showing a minimum SWR of 1.17:1 at 162.000 Mhz with a SWR of 3.32:1 in the middle of the 2m Band.
At UHF it was great, displaying a minimum SWR of 1.3:1 at 434.000 Mhz and a reasonably flat characteristic across the 430 - 440 Mhz Band.
The Times Technologies T100 Antenna Analyser is, in my opinion, worth every cent of the AU$220 price that I paid including delivery from Hong Kong.
It displayed repeatable and unambiguous outputs and was simple to operate. It is firmware upgradeable and I can't wait to see what future versions of firmware will be capable of.
The construction quality is good, but not Fluke Multimeter quality. The case is not indestructible; more like a calculator case.
The keypad does not have a tactile feel so when you press it you're not sure if you've pressed hard enough but it seems to work reliably.
The front face plate (and mylar keypad) assembly seems to be glued to the front of the unit but there is no solid plastic between the glass display and the plastic membrane covering the display. This means that you have to be careful not to put the unit in amongst other tools which may let something sharp poke or prod the display cover as it would probably put a hole in the membrane.
The display cover quality is very similar to the remote head cover on the Codan 8528 HF radios available here in VK.
(Note that the display in my photos still has the protective shipping plastic stuck to it, so the display actually looks better than what's shown in the photos)
I would personally like to recommend a solid plastic display cover be considered for future models but apart from that minor consideration, I think it's a great unit. Congratulations Mr Chang and thanks for a great analyser!
Now it's time to start building some antennas! :-)