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Feature Tech AW07A Antenna Analyser – First impressions
18 January 2015 | by Christmas seems such a long time ago and one of my presents was a Feature Tech AW07A HF-VHF-UHF Antenna Analyser which I have finally been able to try it out.
It is about the size of a thick paperback book and is a powder coated steel case similar in style to that used by MFJ equipment, indeed the MFJ-266 analyser appears to be a re-badged version albeit for a lot more money than this unit can be purchased.
It can be powered by batteries fitted internally or by an external supply and is supplied with a power cable for connection to an external supply, mine was white/black rather than the normal red/black cable. It has a N-Type socket for the antenna and comes with two adapters for PL259 and BNC connectors.
It has a power button near the external power socket, two buttons on the top select HF and VHF/UHF operation and two other buttons marked UP and DOWN to select operating mode and/or the frequency band being used. Unfortunately one thing it doesn't come with is a manual but a copy can be downloaded from QSL.net or a slightly different version from the manufacturers website. But I actually downloaded the manual for the MFJ-226 has it is much more detailed.
The front panel decal and manual state it can be run from 10.8-12V, in fact the manual states it should ideally be less than 12.5V and no more than 13V. While doing some research I found the reason for this limitation hidden away on this aliexpress webpage "Avoid higher than 13V power supply circuit for the UV segment may be damaged due to excessive power dissipation." So this would seem to rule out using a standard 13.8V power supply.
It can be fitted internally with eight AA batteries and this is the way most people would use as it offers portability. Removing four screws allows access to the battery compartment and the internals electronics seem well built.
It takes eight AA batteries, in two boxes. The battery boxes have lids secured with a small screws and are fixed to the case using simple sticky pads, while secure at the moment I can imagine in time the adhesive could dry-out and become unstuck leaving the battery boxes loose inside the unit.
The display is a simple two line LCD with an optional bright back light which can be turned on during the power up sequence. The display shows the battery or supply voltage and pressing Down puts the unit into a frequency counter mode. Pressing Up puts into the antenna analyser mode.
In the analyser mode it is a simple case of selecting the HF, VHF or UHF mode. VHF works from 85-185MHz, UHF is 300-390MHz, the HF is split into six overlapping bands A: 1.5-2.7 MHz B: 2.5-4.8 MHz C: 4.6-9.6 MHz D: 8.5-18.7 MHz E: 17.3-39 MHz F: 33.7-71 MHz selected using the Up/Down buttons.
Turning the vernier tuning knob adjusts the generated frequency the antenna is being tested against. I connected the analyser to my 2m YAGI antenna and turned the knob to find the lowest SWR
The manual describes what is being displayed (on UHF just the SWR is shown)
“139.763 MHz” is the frequency
“V “is the band (A,B,C,D,E,F in HF, V in VHF and U in UHF)
The bottom row shows the complex impedance Z = R + jX, so on this screen
“41” represents R = 41 ohms the resistive component
“18:” represents the reactance component value, jX = 18 ohms
“45” is the overall complex impedance magnitude Z = 45 ohms
“1.5” is the SWR value
As you can see for a 2m antenna something isn't quite right! The antennas were down due to last weeks strong winds so I was taking the opportunity to do some maintenance and tweaking of the 2m antenna since I'd seen an increase in the SWR during recent UKAC contests. I had suspected feeder issues, possible water ingress but I tried a dummy load at the antenna end but that read as expected (Z=50ohms) and metering the continuity of the feeder showed no issues, it just seemed to be resonant at too low a frequency.
The analyser confirmed what I'd observed with a normal SWR/Power meter a higher than desired SWR in the middle of the SSB section of the 2m band.
Unfortunately I was unable to get it any lower than 2.5 and most adjustments seemed to increase the SWR. For peace of mind I double checked the analyser by swapping the feeder on to the 2m/70cm collinear and that was spot on
again I double checked the SWR readings back in the shack using the normal meter
While I try to sort out the antenna issue I can say the analyser seems to do its job well. The tuning knob is a little twitchy and has a bit of play which makes setting the frequency accurately a little harder than it should be but hopefully that might improve with use.
The unit also has other functions none of which I have used yet but it is bonus to have some useful test functions available in the shack.
The AW07A can be used as an inductance/capacitance meter by powering it up with the U or D button held down. The inductance or capacitance of a component fitted across the antenna socket is then displayed and this can be done for any test frequency by selecting the band and turning the tuning knob.
As I mentioned earlier the unit can also function as a frequency counter that can measure signals between 1 and 500 MHz and can be used to give an indication of relative RF field strength. A signal source or an external antenna that yields a usable signal level may be connected to the analyser’s antenna jack. The usable signal range is quoted as -20dBm (30mV) to +10dBm (1V). Note that the display reading is a RMS value.
Obviously in the antenna analyser mode the output which is approximately 2V in magnitude can be used as a signal source, with 20dB of second harmonic suppression.
The MFJ manual goes into some detail of how this all works and how to use the analyser for a number of common tasks such as checking baluns, making 1/4wave stubs or measuring velocity factor of coax.
While the AW07A has some obvious shortcomings and may not be a precision device I am impressed with it and what it can seemingly do. It is shame about the lack of a manual but I am not sure getting one is justification for the premium price of the near identical MFJ unit.
Andrew Garratt, MØNRD, is a regular contributor to AmateurRadio.com and writes from East Midlands, England. Contact him at [email protected].It is about the size of a thick paperback book and is a powder coated steel case similar in style to that used by MFJ equipment, indeed the MFJ-266 analyser appears to be a re-badged version albeit for a lot more money than this unit can be purchased.
It can be powered by batteries fitted internally or by an external supply and is supplied with a power cable for connection to an external supply, mine was white/black rather than the normal red/black cable. It has a N-Type socket for the antenna and comes with two adapters for PL259 and BNC connectors.
It has a power button near the external power socket, two buttons on the top select HF and VHF/UHF operation and two other buttons marked UP and DOWN to select operating mode and/or the frequency band being used. Unfortunately one thing it doesn't come with is a manual but a copy can be downloaded from QSL.net or a slightly different version from the manufacturers website. But I actually downloaded the manual for the MFJ-226 has it is much more detailed.
The front panel decal and manual state it can be run from 10.8-12V, in fact the manual states it should ideally be less than 12.5V and no more than 13V. While doing some research I found the reason for this limitation hidden away on this aliexpress webpage "Avoid higher than 13V power supply circuit for the UV segment may be damaged due to excessive power dissipation." So this would seem to rule out using a standard 13.8V power supply.
It can be fitted internally with eight AA batteries and this is the way most people would use as it offers portability. Removing four screws allows access to the battery compartment and the internals electronics seem well built.
It takes eight AA batteries, in two boxes. The battery boxes have lids secured with a small screws and are fixed to the case using simple sticky pads, while secure at the moment I can imagine in time the adhesive could dry-out and become unstuck leaving the battery boxes loose inside the unit.
The display is a simple two line LCD with an optional bright back light which can be turned on during the power up sequence. The display shows the battery or supply voltage and pressing Down puts the unit into a frequency counter mode. Pressing Up puts into the antenna analyser mode.
In the analyser mode it is a simple case of selecting the HF, VHF or UHF mode. VHF works from 85-185MHz, UHF is 300-390MHz, the HF is split into six overlapping bands A: 1.5-2.7 MHz B: 2.5-4.8 MHz C: 4.6-9.6 MHz D: 8.5-18.7 MHz E: 17.3-39 MHz F: 33.7-71 MHz selected using the Up/Down buttons.
Turning the vernier tuning knob adjusts the generated frequency the antenna is being tested against. I connected the analyser to my 2m YAGI antenna and turned the knob to find the lowest SWR
The manual describes what is being displayed (on UHF just the SWR is shown)
“139.763 MHz” is the frequency
“V “is the band (A,B,C,D,E,F in HF, V in VHF and U in UHF)
The bottom row shows the complex impedance Z = R + jX, so on this screen
“41” represents R = 41 ohms the resistive component
“18:” represents the reactance component value, jX = 18 ohms
“45” is the overall complex impedance magnitude Z = 45 ohms
“1.5” is the SWR value
As you can see for a 2m antenna something isn't quite right! The antennas were down due to last weeks strong winds so I was taking the opportunity to do some maintenance and tweaking of the 2m antenna since I'd seen an increase in the SWR during recent UKAC contests. I had suspected feeder issues, possible water ingress but I tried a dummy load at the antenna end but that read as expected (Z=50ohms) and metering the continuity of the feeder showed no issues, it just seemed to be resonant at too low a frequency.
The analyser confirmed what I'd observed with a normal SWR/Power meter a higher than desired SWR in the middle of the SSB section of the 2m band.
Unfortunately I was unable to get it any lower than 2.5 and most adjustments seemed to increase the SWR. For peace of mind I double checked the analyser by swapping the feeder on to the 2m/70cm collinear and that was spot on
again I double checked the SWR readings back in the shack using the normal meter
While I try to sort out the antenna issue I can say the analyser seems to do its job well. The tuning knob is a little twitchy and has a bit of play which makes setting the frequency accurately a little harder than it should be but hopefully that might improve with use.
The unit also has other functions none of which I have used yet but it is bonus to have some useful test functions available in the shack.
The AW07A can be used as an inductance/capacitance meter by powering it up with the U or D button held down. The inductance or capacitance of a component fitted across the antenna socket is then displayed and this can be done for any test frequency by selecting the band and turning the tuning knob.
As I mentioned earlier the unit can also function as a frequency counter that can measure signals between 1 and 500 MHz and can be used to give an indication of relative RF field strength. A signal source or an external antenna that yields a usable signal level may be connected to the analyser’s antenna jack. The usable signal range is quoted as -20dBm (30mV) to +10dBm (1V). Note that the display reading is a RMS value.
Obviously in the antenna analyser mode the output which is approximately 2V in magnitude can be used as a signal source, with 20dB of second harmonic suppression.
The MFJ manual goes into some detail of how this all works and how to use the analyser for a number of common tasks such as checking baluns, making 1/4wave stubs or measuring velocity factor of coax.
While the AW07A has some obvious shortcomings and may not be a precision device I am impressed with it and what it can seemingly do. It is shame about the lack of a manual but I am not sure getting one is justification for the premium price of the near identical MFJ unit.
15 Responses to “Feature Tech AW07A Antenna Analyser – First impressions”
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I’m a little confused.
The display says “Analyzer”, but you spell it “Analyser”.
Please tell me which is correct.
The biggest problem, what does it cost and where do you get one?
Now tell us the REST of the story, did you get it off fleabay?
Yes the Author could have been more forthcoming with price, where to buy etc. But if you take just a few seconds to actually Read the article, the manufacturer’s Web site link is right there in front of you! Here; I will save you the effort so you can get back to your Twitter and Facebook accounts ASAP:
http://www.hamradioinfinity.com
I found it on ebay for between $240 to $267.
Analyser is the British spelling, sorry for the confusion.
Sorry for omitting where to purchase it from, it was a Christmas present but in my previous blog posting (which is syndicated by Amateurradio.com) I mentioned the eBay source (based in the UK) http://www.ebay.co.uk/itm/UK-Stock-DIY-AW07A-HF-VHF-UHF-160M-Impedance-SWR-Antenna-Analyzer-For-Ham-Radio-/191238807689?pt=LH_DefaultDomain_3&hash=item2c86b8a089.
Andrew, NEVER apologize for anything written or omitting anything from ones writings just because someone criticizes it.
A nice little unit, especially at the price of £179 (I got mine from Amazon UK, but described as “SainSonic AW07A” however the artwork on the unit is “FeatureTech”). Laughably it’s shown as about the same price as the MFY sells for but “£100 off”!
It’s generally well made, except that the battery holders are absolute rubbish, with the screws which, on mine, didn’t survive the first battery change (covers don’t line up well and the threads in the plastic break)
Also, the batteries don’t last long at all due to the required minimum voltage of the unit, and I’m looking for a thin (12mm thick) rechargeable battery to replace the packs in the unit. Once the batteries are part-discharged I’m left with 8 AA cells that are fine for running a clock – but I don’t have that many clocks in my house!
Ebay $350AU best test unit in my shack!
Hello I am trying to locate a circuit diagram for the AW07A unit as so far I am very impressed for what you get for your money made all the more pleasing by Andrews observations. any help greatly appreciated.
73 Colline G3PGK
Hi I recently purchased one of these – it arrived without instructions so downloaded one that claimed to be the latest from the web. Mine like yours takes 8xAA batteries, but the 2012 instructions show a more sophisticated one implying a DC to DC converter that takes external power, 4xAA or one 18650 Li-ion. There is a recharging circuit and jumpers to configure for recharging the Li-ion. The PCB is longer and includes the multi-turn variable resister. Some of these budget ones are compared price-wise with the earlier price for this more sophisticated model. To me it is strange that the Chinese produce different models without any change of model – unless these are counterfeit knock-offs of the original model – if one can own intellectual property in a Communist state that is. If they have taken out components on the battery side, have they compromised the stability of the oscillator etc.? Has anyone traced the original manufacture with downloads of the different manuals for the variations of the AW07A?
On december I purchased the AW07A, I bought this the AW07A from Aliexpress, I am agree that product is defected ranges below are my test for the ranges :
Band Frequency refer instruction manual result test
A 1.5Mhz – 2.7Mhz 1.3Mhz – 2.5Mhz
B 2.5Mhz – 4.8Mhz 2.3Mhz – 4.5Mhz
C 4.6Mhz – 9.6Mhz 4.4Mhz – 9.0Mhz
D 8.5Mhz – 18.7Mhz 7.7Mhz – 16.7Mhz
E 17.3Mhz – 39Mhz 17.1Mhz – 34.0Mhz
F 38.7Mhz – 71Mhz 32.5Mhz – 71.5Mhz
V 85Mhz – 185Mhz 97Mhz – 187Mhz
U 300Mhz – 400Mhz Didn’t test.
I am working on band V 85Mhz-185Mhz, I use new battery 8×1.5Volt, I measure it until lower (minimum) potentiometer on scale, I reading the frequency only 97Mhz then I trying to switch and use an external adaptor 12VDC, it’s same reading 97Mhz, then I trying to use 8VDC (I got from D-Link Adaptor), amazing that the reading is less than 85Mhz and the upper frequency is around >180Mhz.
From band A till E I got good measurement more stable, band F less than frequency 34Mhz still stable, but not for up then 34Mhz or band V and U, it’s very hardes to see the Khz digit, mean is always running look like unstable.
I feel…. I got this unstable because of my home very nearly with a BTS Radio Transmitter for cellular, then the oscillator of AW07A picking up a spurious or harmonic from the BTS signal, I trying to use the frequency counter I found some signal around 500-600 Mhz and my AW07A Field Strength Measurement read signal around 3.4 mVolt.
So till now I am difficult to get it a schematic and which company produce this an AW07A.
If someone have a schematic please send to me.
Hello, I am the proud owner of the AW07A. However, in the uhf he goes up to 400 mhz would like to get him to 450 mhz or higher. Can someone help me with this??
DO YOU REPAIR THIS ITEM. IF SO WHERE DO YOU SEEND IT FOR REPAIR. THE TUNING KNOB APPEARS TO BE BROKEN AND THE DEVICE DOES NOT POWER ON/OFF WITH THE BATERIES INSTALLED, CAN YOU ROUGH ESTIMATE THE COST OF REPAIR? ALSO THE POWER CORD HAS JUST PLAIN WIRE ENDS. WHAT DO THEY CONNECT TO TO OPERATE THE DEVICE.
I has purchase a AW07A antenna analyser few years ago and now the Dial knob is broken…
I would like to find it for purchase…
Can somebody help me please???
Thanks in advance and best 73,
Silva – PY8ELO!!!