I've found on two different LDG-tuners (one Z-817 and the other Z-11), that the culprit was the FWD and REV -diodes in the reflection bridge. Perhaps caused by too high RF pulses or something like that. Replaced the originals with 1N5711 schottky RF diodes, and they worked as a charm after the repair. I got this calibration manual from LDG, which must be done after repair. All LDG tuners use an SWR sensor that is close to the original Bruene circuit. The sensor provides a simultaneous forward and reverse power output. A minor change is that since we read the Fwd and Rev power with a microprocessor, it has to be changed to a voltage. The original Bruene circuit provided a current to drive an analog meter. So there is an extra load resistor that you won’t normally see on the Bruene circuit. Unless you are a student of the Bruene circuit, that will not matter to you. Start with the set up. You’ll need a 100 watt radio, a real 100 watt dummy load (not a light bulb) and a voltmeter. For tools, a screwdriver to take the lid off and a tweaker tool for making the adjustments. For QRP tuners you can reduce the RF power to 10 watts. If your tuner has an auto/semi mode, place it in semi. That way the tuner will not tune when you are making adjustments. Check your tuner manual to see if your unit has this and how to change it to Semi. If your tuner has a forward power meter and SWR meter (could be bar graph or analog meter), set the scale to the highest setting. If it only has an indicator LED, skip this part. First, place the tuner in bypass. Again, you may need to check your manual for the directions. For most tuners, it’s a half second press of the tuner button on the tuner. If your antenna tuner has two antenna selection ports, be sure to choose the one with the dummy load on it. If your radio has FM mode choose that. Sometimes RTTY mode can also work. Key the radio and verify two things. One the radio sees a good SWR and two, you have 100 watts coming out of the radio. If one or both of these are off, you cannot continue. You can remove the cover of the tuner now. Be careful not to transmit when you are touching inside with your fingers. Even at 100 watts, it will still give you a nasty RF burn. Find the variable capacitor near the TX SO-239 toward the back of the tuner. Then find the two variable resistors, one for Forward and one for Reverse. If your tuner only has one status LED, you may not have the two variable resistors (which is still fine). Then locate the two test points for Fwd and Rev (some may be F and R). Pre-place the two variable resistor positions in the middle of their travel (if you have these). Now place the DC voltmeter between ground and the Rev test point. Set the meter to 20 volts DC. You could also use an oscilloscope here if you have one. While monitoring the Rev power on the DC meter, adjust the variable capacitor for minimum voltage on the DC meter. The adjustment will completely turn 360 degrees, so find the best spot. If you do not have the variable resistors in your tuner, you are finished. If you have a wattmeter on your tuner, adjust the variable resistor for Fwd to read 100 watts on the tuner’s meter. Then stop transmitting. Lastly, adjust the Rev pot to be in the same physical position as the Fwd pot and that it’s for the calibration. Put the lid back and happy tuning.
That LED flashing like that just looks like voltage fluctuations as the tuner is switching relays. Usually when they say blinking LED it is a very distinct blink, not a flutter.
R and L is the best, definitely the best ham deals from a retail store. They shipped to me free when I was stationed overseas in the military as well. Great guys
Great find TO!. Yeah, lack of witness crease marks on the battery holder foam does look like owner forgot batteries. Oops!. The LDG site does say "zero power tuner" & maybe owner misread that. Maybe store thought it just wasn't worth their shop time to test the repair return being a relatively cheap tuner & waste techs time on a cheapie job. In case its intermittent, I'd note the relay part number down, see coil/contact voltage from its data sheet for possible replacements as usually they have a relay set per band. Thanks for being awesome & wish you a happy Easter
@@temporarilyoffline Happy Easter to you also Steve & hope it's a good one for you!. Greek easter (Pascha) holy week starts today, my time so should be lots of fun!
I bought an AIS A - for under $100.00, online photos of them testing it showed no GPS hooked to the SMA - so I took a chance, guess what, a GPS antenna cured the problem.
@@temporarilyoffline just saw your vid from early August '22 I think on it. yeah. hope its working when it arrives. should be. looks like it might just be an open box situation
Thanks for the vid. What I do not understand is, that you hit the WSJTX tune button and then the tune button on the Auto(!)tuner. From what I read in the manual the Tuner puts the Radio into PSK mode on low power, produces a carrier and measures and tunes for low SWR automatically upon a short (2-3 secs) press on the tune button. No external software or keying required. Why do you do it that way?
It works both ways - Press the button and the tuner puts the radio in a carrier mode, low power and TXs... and tunes. Or it works with /any/ qrp radio by you doing those steps manually FT8 (carrier mode), TX, and then press the button. If there is RF, the tuner tunes.
Very good job. Idea for another video: Could you test a EFHW wire with this tuner ? You have all of the gear for that and I was wondering if this would work. It would be interesting as part of the doomsday radio kit. 73 de VE6DPC
My thought is that its just the changing of the signal with more or less modulation. I was being overly aware compared to my "meh, it works" stance on the old solution.
Still, there's the possibility of an intermittent, or of a flaky relay, so it wouldn't be the only tuner that I packed for a SOTA. At least until it has a longer track record.
![เปิดใจ “ต้นหอม ศกุนตลา” หลังโดนพาดพิงธุรกิจที่เคยทำ และผลกระทบทำถูกปลดฟ้าผ่า! | แฉ 24 ต.ค.67 [2/3]](http://i.ytimg.com/vi/vCi5OIqlxaE/mqdefault.jpg)
I've found on two different LDG-tuners (one Z-817 and the other Z-11), that the culprit was the FWD and REV -diodes in the reflection bridge. Perhaps caused by too high RF pulses or something like that. Replaced the originals with 1N5711 schottky RF diodes, and they worked as a charm after the repair. I got this calibration manual from LDG, which must be done after repair.
All LDG tuners use an SWR sensor that is close to the original Bruene circuit. The
sensor provides a simultaneous forward and reverse power output. A minor
change is that since we read the Fwd and Rev power with a microprocessor, it has
to be changed to a voltage. The original Bruene circuit provided a current to drive
an analog meter. So there is an extra load resistor that you won’t normally see on
the Bruene circuit. Unless you are a student of the Bruene circuit, that will not
matter to you.
Start with the set up. You’ll need a 100 watt radio, a real 100 watt dummy load
(not a light bulb) and a voltmeter. For tools, a screwdriver to take the lid off and a
tweaker tool for making the adjustments. For QRP tuners you can reduce the RF
power to 10 watts.
If your tuner has an auto/semi mode, place it in semi. That way the tuner will not
tune when you are making adjustments. Check your tuner manual to see if your
unit has this and how to change it to Semi.
If your tuner has a forward power meter and SWR meter (could be bar graph or
analog meter), set the scale to the highest setting. If it only has an indicator LED,
skip this part.
First, place the tuner in bypass. Again, you may need to check your manual for the
directions. For most tuners, it’s a half second press of the tuner button on the
tuner. If your antenna tuner has two antenna selection ports, be sure to choose
the one with the dummy load on it.
If your radio has FM mode choose that. Sometimes RTTY mode can also work. Key
the radio and verify two things. One the radio sees a good SWR and two, you have
100 watts coming out of the radio. If one or both of these are off, you cannot
continue.
You can remove the cover of the tuner now. Be careful not to transmit when you
are touching inside with your fingers. Even at 100 watts, it will still give you a
nasty RF burn.
Find the variable capacitor near the TX SO-239 toward the back of the tuner. Then
find the two variable resistors, one for Forward and one for Reverse. If your tuner
only has one status LED, you may not have the two variable resistors (which is still
fine). Then locate the two test points for Fwd and Rev (some may be F and R).
Pre-place the two variable resistor positions in the middle of their travel (if you
have these).
Now place the DC voltmeter between ground and the Rev test point. Set the
meter to 20 volts DC. You could also use an oscilloscope here if you have one.
While monitoring the Rev power on the DC meter, adjust the variable capacitor
for minimum voltage on the DC meter. The adjustment will completely turn 360
degrees, so find the best spot.
If you do not have the variable resistors in your tuner, you are finished.
If you have a wattmeter on your tuner, adjust the variable resistor for Fwd to read
100 watts on the tuner’s meter. Then stop transmitting. Lastly, adjust the Rev pot
to be in the same physical position as the Fwd pot and that it’s for the calibration.
Put the lid back and happy tuning.
Thanks for sharing!
That LED flashing like that just looks like voltage fluctuations as the tuner is switching relays. Usually when they say blinking LED it is a very distinct blink, not a flutter.
I think so too. I was just hyper aware for the test.
R and L is the best, definitely the best ham deals from a retail store. They shipped to me free when I was stationed overseas in the military as well. Great guys
Excellent!
Great find TO!.
Yeah, lack of witness crease marks on the battery holder foam does look like owner forgot batteries. Oops!.
The LDG site does say "zero power tuner" & maybe owner misread that.
Maybe store thought it just wasn't worth their shop time to test the repair return being a relatively cheap tuner & waste techs time on a cheapie job.
In case its intermittent, I'd note the relay part number down, see coil/contact voltage from its data sheet for possible replacements as usually they have a relay set per band.
Thanks for being awesome & wish you a happy Easter
Happy Easter John!
@@temporarilyoffline Happy Easter to you also Steve & hope it's a good one for you!.
Greek easter (Pascha) holy week starts today, my time so should be lots of fun!
You got a fantastic deal! I'd pay $25 for that tuner knowing it definitely didn't work on one band.
Exactly - I don't use all bands that I have access to with a known good tuner... no loss in my book.
There used to be a popular dog food called Lucky Dog. Been munching on some of that, Steve😂?
Most important meal of the day!
I love mine and the batteries last a long time. I pretty much use resonant antennas so it doesn't see a whole lot of use,😅
My antennas are resonant, but it adds a lot of utility and very little weight.
I bought an AIS A - for under $100.00, online photos of them testing it showed no GPS hooked to the SMA - so I took a chance, guess what, a GPS antenna cured the problem.
Nice! They just don't have the time to do the in depth testing (or the ROI isn't there for them)... and we win!
The Radio Gods blessed you! Sweet deal!
I think so! Best not push my luck for a while!
I would say some relay is not up to spec on that band, but for the most, working fine!
So far so good! Let the modifications begin!
Nice job Steve!. practically free 2nd qrp tuner. nice
Can't complain!
@@temporarilyoffline I grabbed a "used, but near new" MFJ-849 swr meter from R&L for about $130. should be here in a few days.
@@dan_in_sd I like that 849.
@@temporarilyoffline just saw your vid from early August '22 I think on it. yeah. hope its working when it arrives. should be. looks like it might just be an open box situation
@@dan_in_sd Its probably fine. I'm sure they turned it on and put some power through it before setting themselves up for trouble with returns.
Thanks for the vid. What I do not understand is, that you hit the WSJTX tune button and then the tune button on the Auto(!)tuner. From what I read in the manual the Tuner puts the Radio into PSK mode on low power, produces a carrier and measures and tunes for low SWR automatically upon a short (2-3 secs) press on the tune button. No external software or keying required. Why do you do it that way?
It works both ways - Press the button and the tuner puts the radio in a carrier mode, low power and TXs... and tunes. Or it works with /any/ qrp radio by you doing those steps manually FT8 (carrier mode), TX, and then press the button. If there is RF, the tuner tunes.
1st buyer...RTFM. 😂
Right!
Cool video tnx bro!
You're welcome!
Very good job. Idea for another video: Could you test a EFHW wire with this tuner ? You have all of the gear for that and I was wondering if this would work. It would be interesting as part of the doomsday radio kit.
73 de VE6DPC
I sure can.
BARGAINER for sure, Steve. Good job 💯🙋♂️
Absolutely
Sometimes mine does that on 12m, but the swr meter shows it has tuned.
My thought is that its just the changing of the signal with more or less modulation. I was being overly aware compared to my "meh, it works" stance on the old solution.
Still, there's the possibility of an intermittent, or of a flaky relay, so it wouldn't be the only tuner that I packed for a SOTA. At least until it has a longer track record.
Right! This is going to be my experiment/mod toy for a while and I'll definitely get my $25's worth out of it!
What are you pinging?
I think I was doing a battery test on a raspberry pi solution... always something going on in the shack!
what a score! LOL
Now it's time for upgrades!
SCORE!
Right!
Better go buy a Power Ball ticket with that sort of luck.
Right!