Ham Radio - A look at the EMTECH ZM 2 antenna tuner
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- เผยแพร่เมื่อ 1 ก.ค. 2024
- I also test it against my L-network tuner to compare efficiency.
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Hit me up on the echolink repeater down by my house: W9TE (Node: 519521) - วิทยาศาสตร์และเทคโนโลยี
I recently bought 135 feet of some very small 18 gauge wire, called, " Super Wire " off Amazon !
The idea was to string it up to use with a tiny short wave receiver !
Well after doing that, my mind began to wonder, and I remembered purchasing a QRP Tuner, that I had never used !
Probably been laying around for several years ?
Found an old QRP Transceiver, (4Watts) and with a little ingenuity, I turned my iambic key on it's side, and used one of the paddles for a straight key !
Lol !
But it worked out pretty well !
Propagation report says 40 meters is poor, both Day and Night !
(Damn Sun )
But I didn't let that stop me !
Signals are in the crapper, but I still managed to work a docked Navy Nuclear ship in Maryland, from the Midwest, and Two West Virginia stations !
539 and 559 !
Pretty incredible to me, especially with the band in such shape !
As for the Tuner, it had been so long since I purchased it, I had only a vague idea how it worked ?
Once again, I didn't let that stop me !
Hi ..!
First tuned it so LED was bright, then decided to go the other way, and things began to play !
Funny stuff !
But these Tuners are a breeze to tune !
You can be making contacts in no time !
And to think I let this little Gold Mine set for years ?
But sadly I'm one of those guys that say,
" I might need that someday " ?
Today was my Day, I guess ?
Now if I can get the Sun to cooperate !
🌞((((( 🌎
'73 & Good Dx !
That tuner is a keeper, definitely. The results are amazing!
Excellent! Nice look at the EMTECH ZM 2 Kevin. You answered all my questions about this little tuner. I'll be adding it to my QRP field bag. Thanks!
Amazing how this turned up in my TH-cam feed, 2 days AFTER I ordered the MFJ-9201 Antenna Tuner.
Been using the ZM 2 with my KX3. Always wondered about insertion loss, now I know, thanks.
I really like the ZM-2! Works great. Thanks for the video!
Thanks for the great review kevin, I was planning on buying groceries this week but have considered being a ZM-2 owner
Good video, Kevin. I've used a ZM2 for several years now, and never regretted the purchase. I had never thought about insertion loss, so I learned something today! Well done!
73 de Dick N4BC
A really interesting review - with circuit walk through, manual pages, and testing. Thanks -- I think I would like to buy this one! 🙂
Another useful video. Another benefit of that SWR indicator is that, in tune, you have some protection for your finals. The resistors buffer the impedance so it cannot go wildly high or low. I have a ZM-2 and it is very good. 73, JP, K8AG
I had one but lost it in a house fire 11/2009 along with a lot of other thing, thank God just thing that could be replaced.
Got to pick up another one this December, I need a winter time kit to build.
Thanks for another super video,
73
wd4dda
Interesting and Ironic... I just received my ZM-2 tuner last week and had a chance to try it real quick with a single 30 ft wire semi vertical. It tuned up easily, I was surprised how easy. Appreciate your discussion on the circuit and some info on insertion loss. I tuned it up with a little Pixie-2 transceiver and was glad to see how bright the tuning led lit with 500 mw. Thank you the great overview. Best I have seen on this tuner.
Thanks Kevin, this is great!! I have just acquired an FT817nd, and have been looking for a simple QRP tuner... my mind is made up now! 73, Wayne VK3TWE, Lakes Entrance, AU
Hi Kevin, greetings from the UK!
Great video particularly the comparison you did.
The tuner is really light although a bit on the bulky side only when compared to some very small QRP rigs.
It is still a pleasure to use.
Thanks for sharing.
Thank you for your detailed discussion and excellent video on the ZM 2 antenna tuner. Although I am new to ham radio and do not (yet) understand some of the schematic diagram and all of the terminology (e.g., "insertion loss"), I greatly appreciate your taking the time and effort to both create this video and answer my earlier question. Based on this video, I am giving serious thought to building the ZM 2 antenna tuner kit it as my first major "homebrew" amateur radio project. Again, thank you from a new subscriber. Keep up your great work! 73.
Aduhwan Build a soundcard interface first. You can get a kit for $8.95 on eBay called an Easy-Digi. There is so much you can do with it, then build the tuner.
After watching this video last week, I purchased the EM-2 Kit. I built it last night. Finished it at 0230. Lol. Decided to try it out with my Norcal 40 QRP radio I built in 1994, and my J38 straight key I haven’t used in a decade. That little EM2 tuned (ok transmatched to a 50 ohm load) my 50 foot vertical and its 60 radials no problem. My 3 watts was probably half of that radiated. But, found somebody calling CQ, WA6UYO, Wayne in TX. I need more code practice! and a keyer. We had a nice QSO. I also built a 20,30,40M portable magnetic loop and need a portable radio for it like an FT 817. I enjoyed your Radio Shack HTX-10 video. Worked on mine this week. Its kaput. The transmit audio is crap. I do have voltage after the 404 inductor. No cold solder joints. I dont have the equipment to tune it up or find the problem. I bought it new and its never worked. To cheap to send it out for service. The service would cost more than the radio. Its a paperweight.
Very nice video. Your test for insertion loss was a great idea, Dave. N2SN
Just purchased a kit….really looking forward to building it.
Great vid, thanks for making it! Kit building was easy.... Manual is excellent as you said, just like a Heathkit manual. Operation is easy too. I'm using it on my FT817nd along with a doublet. Have a lightweight OCEF antenna too.
Two others and I are building this at next Tuesday's CW/QRP SIG (special interest group) I moderate for my local club. Should be a fun kit.
I’m finally building my ZM-2 today, taking a break and googling it. I got this in June of 2003, one could say I am little behind on my projects. I had no idea this was still available. -N1XF
It's a great little tuner. Small enough to tuck into a pack along with the radio. You'll enjoy it. Double check against the schematic when wiring, it's easy to get the three way switch wired backwards.
81 foot radiator inverted L + 25 foot counterpoise + ZM-2 ATU =great combination between two 8m fishing poles.
Interesting test on a nice little tuner. Losses do vary with many factors so one data point isn't the entire story. Note that in the ZM-2 Tune mode the resistors swamp the input so the radio won't see more than 2:1 swr (33 to 100 ohms). de w6akb.
Thank you Kevin Nice job
72's Fab F5RLW
Thanks for the info Kevin.
Thanks for the comparison video against your L-network tuner. That was interesting to watch.
I got very interested in tuners after building one of those little eBay kits and having some success with it as an SWL tuner minus the SWR indicator. I left that out but added some binding posts and an SMA connector for added versatility.
I'm building my own T-match QRP tuner utilizing a tapped inductor I'll be winding myself -basically lifting the idea from the ebay kit and scaling it up slightly with a larger ferrite and wire gauge and better grade tuning caps. My goal is my own 10-watt SSB tuner.
I may add my own SWR indicator as my design evolves.
I'm enjoying your practical approach to tuners and your loops as well. I work in a similar fashion.
73 DE N2NLQ
Interesting video, Kevin. Tjanks! I built a higher power version from QST because i hsd open frame tuning caps. All i had to buy was a toroid. I've used it for years and LOVE it! It's tuned everything you can imagine. This Emtech Z match id compact and reasonably priced. Great review!
I would like to build about a 300 watt version. You should do a video of yours.
Jeff ke4fwe
@@jeffdyer2393 OK, that's a cool ideal. Thanks. Darn thing is the handiest tuner.. and you can build it cheap is parts are scrounged up, either from your junk box or ebay. I'll show it in a video maybe later tonight or if not then tomorrow. I just started back up with a 50s era barn style shed restoration. It got so bad that what I'm doing might better be called a 'resurrection'. lol. 73
@@n8nkqrp595 cool thanks. I'll be watching for the video. Good luck on your renovation. This winter I'm going to buy a band saw mill and build a cabin on some land that my dad owns.
@@jeffdyer2393 VERY cool project. Good for you :)
Great video, as usual.
I've gone back through almost all of your videos. Good stuff!
One thing that causes me to wonder. A few times, such as in this video, you've used a nearby field strength meter to measure radiated power. Is it valid to measure the strength of the near field and assume that the far field strength is always proportional? I know that near field and far field are both measured for compliance testing.
Nice demo. Neat little tuner. I wish all radios and accessories that are 200 watts or less used only BNC's. They are better connectors than PL 259's and so much easier to use.
Thanks for posting.
Barry, KU3X/QRP
Thank you for this video.
Hi Kevin,The Z match is a good tuner but wanting to run more power like 25-30 watts,I wanted something that could take the power.I located a vintage MFJ 160-10-S tuner with no meter.
It shows 2/10th of a watt loss with 5 watts.
It's the same size as your network tuner.
I also built a *L* match with a 12 position switch and found it to be just as good as the *Z* match.
Thanks for the great vider BOB AF2DX
Interesting. It appears to me that the Z-Match tuner had a little bit MORE power going to the antenna as measured on the field strength meter. It put the meter up to 84 on the meter and the L-Match tuner only drove it up to about 83 on the meter. Very interesting. Good comparison video. 73 de K7RMJ Frank
Kevin, with C1-B and C3 being on a DPDT switch, and both being in parallel, it seems the switch position to add 500pf is actually adding the 266pf second half of the variable capacitor plus the 500pf fixed capacitor, for a total add-in of 766pf, not 500pf.
Kevin, I noticed that when you tuned w the L Network tuner he did not appear to adjust the Inductance knob?; only adjusting the capacitance so I wonder if that was an oversight or did you do it off video bc perhaps you had to open the box to do it more correctly? Thanks for the good video !
You should sell for Emtech, lol.
I don't believe there is no insertion loss, there has to be some loss no matter how small. One could suppose that both the tuners have about the same amount of loss and thus show approximately the same readings. I like how you explain the circuit and the video is really informative. Good job! 73' KD5INM
I just built a copy from bits in my junk box, and it works a treat .... even better as it cost me nothing to build. One thing though, I've tried several types of antenna, ... LW, dipole, G5RV..... but have never found I needed the extra capacitance switched in. Makes me wonder why such high values of 'C' where included ?,..... good video though ... tnx, de G4FBC
In some situations of extreme mismatch. Like trying to run 80 meters on a short antenna. However, if you find the need to switch in that extra capacitance, you're probably not going to get good performance out of the antenna on that band. The tuner will make the radio happy, but you can't fight the physics of the wire. It will still be an inefficient radiator.
I always thought that the benefit of using tuned feeders is the fact that the antenna is balances (never can get it perfect). Seems like grounding one side of the twinlead would throw the whole system out of whack.
Z-Match, a good efective economic balaced feeder matching device.
do you have any thoughts on the MFJ-9201 vs this?
Im building a fully integrated go box and im thinking about incorporating this type of tuner. I'd also like to incorporate a NanoVNA v2 into the build and I'm wondering if it would be possible to eliminate and replace the LED SWR meter with a connector for the MicroVNA. What do you think?
The LED is basically just indicating a voltage level of reflected power. The nanoVNA is intended to measure complex impedance of an antenna or RF filter circuit. Two very different things.
I would like to see the field strength meter without any tuner to see if there is any loss in tuners generally. Take a frequency that your antenna works well on and then you could compare field strength after the signal is through the tuner or without the tuner.
It's been measured by many. I think there's also a video out there. There is loss. The greater the mismatch the tuner has to deal with, the greater the loss.
@@loughkb that greater loss would be due to feeder as reflected power is rereflected at tuner back to antenna, that's why an antenna system with open wire with high swr is so efficient
Since the three-way switch was in the middle position, why does turning the left-hand capacitor cause the background volume to vary? According to the schematic, the left-hand capacitor is *not* in the circuit when the switch is in the middle position. Thank you.
Referring to the schematic at 3:48, C1 is a dual-ganged variable capacitor. That is to say, two variable capacitors attached to the same shaft. See the dashed line? A and B are independent 266pF variable capacitors that can be used independently or connected as a single variable capacitor (as C2 A and B are). Being attached to the same shaft, A and B will have the same value (typically).
So C1-A is wired directly into the circuit and C1-B can be optionally switched in to increase capacitance (C1-A and C1-B wired in parallel, meaning C1-A + C1-B = 266pF x 2).
Ganged capacitors: th-cam.com/video/fVkRDjrRnc4/w-d-xo.html
Kevin great video👍
I built one of these but my led is brightest on low swr and goes out on high swr
Any ideas what's wrong ?
Ta
You either wound the little pickup torroid backwards, wired it backwards, or ran the pickup wire through it the wrong way.
Kevin Loughin thanx Kevin, il rewire as your suggestions 👍
Very informative video! It is a while ago, but do you remember what the minimum power is? Maximum is 15 Watts, I know...but I wonder if one can use it to match a very low power (~200mW) wspr transmitter. 73 Stephan, DF6PA
There is no minimum, really. It's just transforming the impedance mismatch.
@@loughkb You are absolutly right.I am such a dummy. Used manual tuners 20 years ago...the automatic tuners fried my brain I guess :-) Most automatic tuners need about 1 Watt or 2. 73, Stephan, DF6PA
Good informative video. When do you add capacitance with the 3 way switch?
If you are unable to obtain a match over the range of the two caps, switch in the extra capacitance and try again. It would be in cases of extreme mismatch to the antenna.
@@loughkb Which when adding capacitance, should be increasing insertion loss
Generally the extra capacitance would only be useful on the lower frequencies with certain antenna configurations. Unlikely to be helpful above 80 or 40 meters. Capacitors are pretty efficient so should not lower efficiency much.
12:02
in the worst case it would provide 2:1 swr to the radio
Question from a noob: I'm a sw listener (Tecsun PL-880) and am playing with longwire antennas. Would this ZM2 be useful to me to enable better tuning of the various bands?
PS. Enjoy your videos, thanks for the demo!
It could help. Getting a better impedance match will bring in signals, but also bring up the noise floor. It's another tool in the radio toolbox. It'll act like a preselector for your antenna.
@@loughkb Thanks Kevin, advice much appreciated, when I have some spare $ I'll look at getting one.
Hey Kevin. Is it good for 10m/11m? And how much power does it can get maximum?
Yes, it would work at those frequencies. Its meant to be a low power tuner, no more than about 10 watts.
@@loughkb Thank you. Kevin. 73
What is the purpose of adding 250/500 pf? You did not show that. Thanks!
That shifts the range of impedance matching to compensate for short antennas at lower frequencies. If you can't quite get a match, you can add capacitance and try again.
No need for a 9:1 Unun when using a random wire antenna ? Did the tuner have a build in UNUN?
No need to lower the impedance ahead of the tuner, it could handle the higher impedance on its own.
like the tuner but find toroid coils intimadating
Can you use it with mountain topper?
You can use it with any radio at low power output of about 10 watts or less.
Looks like they only sell pre-builts now -- no more kits. :-(
Is there any easy way to run a bypass switch on the tuner?
Not a lot of room in the case, but maybe you could find space to mount one.
@@loughkb Can you help with the best place to tap into the circuit?
@@dennisschultz1175 At the connectors. DPDT switch. Radio connector to one throw, antenna connector to the other throw. Bridge one set of polls, Run each of the other set of polls to the in and out of the tuner.
When the switch is flipped in one direction, the connectors are bridged. (bypass mode) When the switch is flipped the other way, the connectors are fed through the tuner.
Just got one on ebay £66.00 (87USD) !
WOW,Thats splitting hairs and if you look,you were tuning the knobs before the needle could. settle down. I saw the 4SQROP SOTA tuner, THE MFJ and the tuner from QRP GUYS,are all all the same.. just saying. I have the very old old MFJ-160-10-S and it tunes anything but I am not power restricted BOB AF2DX
Please tell me it Does Not come from China !
No, Tracyton Washington, USA.
good overview... however: ugly construction, while functional, is not warranted at this kit tuner's price point - just my opinion; also the ergonomics of the tuner are awful
Dude, edge your sidewalk...
I'd have to use a shovel or hoe, and with my blown discs, there's no way. Anyway, I like the green plants more than the sterile concrete. :-)