NEW Project - 6146B Plate modulated by Hammond 1628SEA and 85W SS Amp

[K1JJ]

**  3/7/2022 UPDATE **

About 95% of parts mounted.  I added the muffin fan on rubber mounts, vibration free, Variac controlled.  Added the panel gold pin striping.   Made a computer printed temporary nameplate. (Commando)  I want to get a brass one engraved later on.  I added HUGE rubber feet for better ventilation below. They're from an air compressor.  They are mounted on 4" plates which also reinforces the chassis.  

Frank/GFZ suggested I drop the big plate RF choke and move a smaller one to the plate side of the tank for less stray pickup.  RF connections will be very short now. Cleaned up the iron transformers with black paint to make them more presentable.  Fixed a few panel flaws.   Still need to design up panel lettering.

Awaiting some heavy duty terminal strips to start the wiring - new old stock from a 1940s command set.   All the drilled holes are now filled with parts.

I still want to mount the screen current meter on standoffs or Plexiglas in case there is a plate to screen dropping resistor crap out of any kind.

Anyone have more suggestions before I start the wiring?

Are you not entertained?    

T

Pic 1: A proud Commando standing at attention:

Pic 2: I may add a small coil  between  the C1 tuning cap  and L1 tank coil to tap 10-20M.

[K1JJ]

More:

Notice the muffin fan in pic 3.  I tested it and found there is a good flow through the audio chip's heatsink as well as residual air finding its way past the 6146Bs.  I may keep the 6146B viewing window open for the best airflow. There will be a Plexiglas cabinet covering the sides and top, just like my other rigs.

It's difficult to get all of the gold pin striping to shine by the lighting.  In fact the camera is very brutal on every little imperfection. It's a great acid test to take a shot and then look for flaws. This rig looks so good in person until it gets on the silver screen.  I don't have the patience for detail any more than this.  [sigh]   Yeah, yeah, I know the meters don't match. I used to buy them at flea markets for $1 and loaded up. But I'm out now and they want $30+ on eBay...

[K1JJ]

Pic 1: That RF choke is very similar to a Valiant's choke.  I've had poor luck with them for QRO rigs, but it may work OK for 550VDC plus modulation. Any opinions?

Pic 1: Notice the "cool" heatsink. It uses heat sinking paste to sink to the chassis. The TDA audio 85 watt chip is mounted directly beneath it.  Muffin air flow through it ca be adjusted. It will be dissipating maybe 40-50 watts under operation according to the datasheet, so we should be FB.

Pic 2:  There is a nice space, 6"X 8"X 6" next to the blue filter caps. This would fit the big Hammond 1642SE transformer if the three 6146Bs stress the smaller 1628SEA.

Pic 2: Check out the rubber to the road feet!  The green caps at the top are part of the compact TDA chip module.  Heatsink on top.

[K1JJ]

More:

Pic 1: The freq counter/ DDS gold pin-striping is lit up.

Pic 2: Notice the heatsink fins point upwards for best heat flow and in direct line of the air flow. And the muffin fan splits its air between the fins and the 6146Bs towards the front. 6146s usually don't need air; and especially considering how easy they will be run in this rig.

Pic 3: Notice the bandswitch has been flipped 180 so that the connections will be be shorter and more direct.  Its panel shaft is missing the 1/4" sleeve.

Pic 3: Notice the wide berth given to the tank coil for best Q and least interactions.  The muffin fan is plastic near the tank coil.

Pic 3:  The switch under the meter is the 160M loading cap padder to add a 1000 pF fixed cap to the C2 loading variable cap.

[K1JJ]

3-9-2022, Wednesday update:

This is the fun part... assembling the plate tank circuit!  

The straps are soldered to the bandswitch, but not to the coil until I have it running and optimized. They are in approximate positions for now.  I plan to cold silver plate all the copper once it's  finalized.

This rig will be operated mainly on 160-40M. But I added a 10M tank coil based on the pi-network calculator. The bandswitch is configured for 160M to 10M. We will have to see if this rig will tune up on the higher bands based on minimum C1 and overall stray capacitance to ground.

The 160M C2  .001 uF padder cap is installed with an on-off switch.

I mounted the screen current meter on standoffs and placed a fake meter bezel on the panel.  When using a plate-to-screen dropping resistor, there are failure scenarios where there could be HV on the meter.  All about safety.

Added a safety RF choke from C2 loading cap to ground.  This will short HV and pop fuse in case plate coupling cap shorts and puts HV on the antenna circuit.

I added the three parasitic suppressors to the 6146Bs.

Next comes the power, control and 6146B socket wiring. That can be drudgery, so I'll just do a little bit each day.  

T

[K1JJ]

Pic 1: Notice the second meter from the right, rear view, is on standoffs. (screen current)  And notice the front panel shot, second meter from left - there is a bezel that I cut out from a bad meter. It looks almost "normal."

[K1JJ]

I tried my best to use low inductance straps and reasonable lead lengths thruout the tank circuit for both efficiency and stability.  The 6146Bs are hopefully happy.  Next, the grid and screen circuits need good treatment underneath with good bypassing and the L-C input matching, etc..

The copper straps will attach to the FRONT of the tank coil for shorter length. I left them long just in case.

Pic 1: A look at the fan mounting feet.  These are standard rubber chair leg pads found at any Home Depot, etc.  No fan vibration.

Pic 2:  A good look at the floating screen meter and fake bezel.

[K1JJ]

A big goal crossed off - the wiring for Commando is completed with Teflon wiring.  The wire routing and harnesses still need to be dressed up and cleaned up with tie wraps and clamp-on guides, but I always keep it loose and messy for the testing phase in case there are some changes. I will keep wiring far away from the 6146B finals and input tuning circuitry.

I added in a 1500 ohm 45 watt non-inductive resistor chip from grid to ground for better stability.  The 85W audio module is installed and all hooked up. Theoretically, if everything is wired correctly, it would work FB on the air right now.  But this is never the case.  Human error and bad parts are part of the game.

So far I have tested the filaments, PTT circuits, HV step start sequencing and coax in/out  relay switching. I added in an adjustable time delay on the rear panel for the HV step start.  I found an antenna relay connection wrong.   I usually check all the wiring against the schematic before turning on anything else.  The Hamond spark gaps are installed as well as the HV fine wire fuse posts.

I decided to remove the 10-20M coil and will use Commando from 40-160M only.  These are my favorite bands and if I want to get on the higher bands I will use the modified hi-fi FT-1000D and several linear amps in service.  I could always add 10-20M easily later if desired.

I used ball park grid leak and screen dropping resistors until I can test it for optimization later on.  The screen clamper 6AQ5 and OA2 circuit is wired and ready.

Next comes the fun part; testing and optimizing the rig for power, stability and the highest audio peaks I can get.  

Hmmm...  was wondering if adding a Heising reactor to this specialized  Hammond single ended xfmr would help to increase its saturation capability?    The point being it is rated at 130 mA of DC current and a single 6146B is around 120mA.  IE, to take the DC off its core for handling 2-3 tubes.  Just thinking out loud.

One thang I keep reminding myself of; it takes just as long to build and test a little rig as it does for a big rig. Except for more panels and metalwork, there are just as many parts to mount, to wire up and then test.  eBay takes just as long for parts and the UPS truck takes just as long to get here...  

T

[K1JJ]

These old buzzard rigs take a lot of wires to work...

Pic 1:  at the top is the 85W audio module -  heatsink on top of chassis.

Pic 2 : Two Variacs - one for muffin fan and other one at bottom for HV, 0-800VDC.

I am reminded that at one point I thought I had too much room in that 15" X 17" X 6"  chassis. But like everything, space gets filled up based on how much is available.

All solder connections are double and tripled checked for strength and durability.  All crimp-on lugs have molten solder poured down their holes.  Solder connection failure is a rare event with these rigs.  Internal solder connection failure can be some of the hardest problems to find so it pays to make sure in the early stages of construction.
T

[KD1SH]

Audio amp module snuggled up next to the Air-Dux - no fear of RF getting into the audio? I was thinking of putting mine in its own little cage; maybe I'm being overly cautious.

[K1JJ]

Audio amp module snuggled up next to the Air-Dux - no fear of RF getting into the audio? I was thinking of putting mine in its own little cage; maybe I'm being overly cautious.

Hi Bill,

The same thought occurred to me too.  In fact, I got the input tank circuit (Air Dux) optimized for 50 Ohms 160-40M last night and the coil is twice as big as it needs to be.  So I could either cut it in half and move it away from the TDA7294 -  or put a shield between them.  It's not easy to locate things when there are big parts on the top and parts on the bottom.

All of the wiring needs to be tied off and bundled - neatly away from the underside components anyway.

I added the parts labels (in the pics below) which makes it easier for troubleshooting and optimizing in the future.  I will send the panel labels lettering design to my local friend Bob/ W1RKW  so he can print them out for me.  We are getting closer to switching on the HV and seeing if Commando works at all.

T

Teflon wire, baby!

[K1JJ]

More Details:

[K1JJ]

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[W1RKW]

Tom,  I really like the "Tom & Yaz 3/20/22" signature label. Like an artist that signs their paintings.  Nice touch OM!  BTW, the rig looks excellent.

[KD1SH]

Yes indeed, a great big virgin chassis seems plenty big until you start putting stuff into it, just like an empty storage shelf seems big until you start loading piling stuff on.
I don't think I could ever cram stuff efficiently into a small space nearly as well as a commercial manufacturer. Looking at something like an SP600 or R390, or even a Ranger, it's really quite impressive when you imagine trying to accomplish that yourself.
Love the idea of labeling everything: when I'm building my stuff, and for the first few months afterward, it all looks so comfortable and familiar, but revisit it a couple of years later and it's all a big bowl of colored spaghetti.

[K1JJ]

Hi Bill,

Yep, those Rangers and Valiants really pack in the parts.  The drawback is when you have to replace a Chernobyl resistor or equivalent. I watched the procedure on YouTube and decided I could do a better job building a low power rig; especially the reliability later.

The inside labels really do help to refresh the memory later on.  I have eight homebrew rigs now - and  five (including Commando) use Plexiglass clear cabinet covers. I'm just a building fool!  I get a real thrill looking in at the rig's inner workings as I walk by. The labels help to get back in sync.  The biggest problem is not being into a rig for a few years and it craps out. The labels help a lot.

Well, I'm glad you mentioned the input coil being kinda close to the TDA7294 chip.  I cut the coil in half and mounted it away from the chip and closer to the bandswitch and tuning cap. Much cleaner looking arrangement.  I will try it like that - and if there are any problems I'll add some shielding.   BTW, that L/C input circuit is so simple and gives close to a 1:1  50 ohm SWR every time.

Bob/RKW:  Thanks much for the comments!  I think once the wires and harnesses are all laced up and neat, it will be one of my better looking rigs of the harem here...      I'll be sending out the panel label info to you soon.  That will be the final touch.    Yep, I wonder what someone might think if they come across an "antique" K1JJ & Yaz signature rig 100 years from now at a hamfest.

The current phase for Commando is the refinement phase. Redoing the JS'es and testing, optimizing.  I cleaned up the shack of building debris and back to a clean environment for the refinement. It's all a mental game now. A matter of attitude to file off the rough edges.


T

[W1RKW]

Tom,
Just something to ponder before you put the big power to everything. Regarding the audio module and RF shielding.  I noticed when I play with my 2m handheld that it's RF will affect some of the audio devices here and from several feet away. Things like computer speakers and some other things. Granted these consumer devices aren't the best when it comes to RFI but maybe it could be used to test your audio module before applying the power to Commando. I'm wondering if you can power up just the audio module and put a scope on the output and do a 2m test to see how it would behave at 2m RF. Would it be an indicator at HF??  Not sure. Thinking out loud.

OK on the labels.  Whenever you're ready, I can support.

bw

[K1JJ]

** Commando 3-23-2022 UPDATE **

Made some good troubleshooting and testing progress.... so far no fuses popped or loud bangs.

The HV filter cap circuit had a 50K  to ground measurement.   That shows something is wrong. I found a wiring error on the screen clamper circuit. Fixed it and turned on the high voltage.   The high voltage worked FB from 0-800VDC using the Variac.   The power transformer is actually 600-0-600V  CT.    So, using a fullwave CT, I get about 850VDC max, no load.  I plan to run no more than 550V under load since there are 3 tubes and plenty of carrier available.  The Variac was set for boost; I reduced it to normal.

I didn't have a reading on the 0-1000V  panel meter. Turned out that a ground connection for the meter was floating on a plastic cable guide. Connected it to metal and it worked... however, it was off by 20% from my calculations.  I changed the divider resistor and HV now reads exactly as my VOM.

Using the MFJ-259 I  tuned the taps on the input coil for 50 ohms for ~1:1 swr on 160, 75 and 40M and soldered them. The 6146Bs use a 1500 ohm, 45 watt chip resistor to ground, so the load is stable. I don't expect the extra 10 mA grid current to effect it more than 10K of load, which is minor.

I turned on the +- 35VAC TDA7294 power transformer with no problems. The chip was hooked up and stayed cool. I didn't go any further until I test out the 6146B finals. I might even use a power resistor as an audio load at first.  I found there is 50VDC on the chip. That is about the maximum it can be run, so my plans for a boosting transformer are not needed.  50V should be plenty.


The HV stepstart delay was acting flaky and would not hold a delay setting. Turns out that the rheostat was intermittent. I replaced it with a 5K pot and now have a stable step start delay from instant to about 1 second.   I test cycled the PTT by keying the power supply at 800V with no problems.

I turned on the fan, 6146B fils and OB2/6AQ5 clamper circuit fils.  No problems, though I still need to put some real RF drive into the grid circuit to test the screen clamper.  It should light up the OB2 when enuff current is detected at the gridleak DC point.   No grid current and the OB2 should go off as it is now, killing any screen current.

I notice that the 50K off the screen to ground (part of the screen clamper circuit) is showing 10 mA of screen meter current. This is something I need to think about, but may just live with it.

I may increase the step start resistor from 20 ohms to 50 ohms since it presently does not give enough "jump" when it comes on.  I want say, 400VDC on key up and then 600V when the step start shorts out the limiting resistor.

My PTT pilot lamp was hot as a pistol. Turned out it was a 14V bulb on a 24V circuit. I found a 13V tap and all is well wit that.

So next I plan to put some 1 watt RF into the rig from my station DDS and tune it up on 160M and see how much carrier power it will do. I still need to determine the tank bandswitch connections and solder them permanently.  Then I'll back it way down to a few hundred volts and carefully add some audio to the TDA7294 to see how it likes it. I'm still not sure if a 1 volt line audio signal is enough. I want to add an input audio gain pot to the front panel once I determine if I will need another gain stage or not. I am having trouble determining just how much audio signal is needed to drive that module. I read that it is good for 36 dB? gain, but it is not clear.   My guess is 1 volt will be enuff drive.

So it looks like all is going very well with no big surprises yet.   The RF power and audio tests will really tell the story next.

Bob/RKW:  FB on the suggestions for the TDA7294.  I suspect if anywhere, it will act up on 40M and higher, but it is easy enuff to add a shield around it if it has a bad spell...


T

[WD5JKO]

** Commando 3-23-2022 UPDATE **


I turned on the fan, 6146B fils and OB2/6AQ5 clamper circuit fils.  No problems, though I still need to put some real RF drive into the grid circuit to test the screen clamper.  It should light up the OB2 when enuff current is detected at the gridleak DC point.   No grid current and the OB2 should go off as it is now, killing any screen current.

I notice that the 50K off the screen to ground (part of the screen clamper circuit) is showing 10 mA of screen meter current. This is something I need to think about, but may just live with it.


T

    Tom,

   That 50K should not pull any current when the VR tube is not lit. You may be seeing the 6aQ5 plate current. Kind of depends on where you are measuring that screen current.

The clamp circuit might be on the edge of capability with three 6146's. Data sheet screen current for a plate modulated 6146B is around 9-10ma / tube..That OB2 is rated for 30ma..

Was thinking that an OC3 (VR105) Octal would give you more margin. Then there is that 6AQ5....might be fine if it clamps hard enough, but if not something like a 6W6...

Looks like fun!!

Jim
Wd5JKO

[K1JJ]

** Commando 3-23-2022 UPDATE **


I turned on the fan, 6146B fils and OB2/6AQ5 clamper circuit fils.  No problems, though I still need to put some real RF drive into the grid circuit to test the screen clamper.  It should light up the OB2 when enuff current is detected at the gridleak DC point.   No grid current and the OB2 should go off as it is now, killing any screen current.

I notice that the 50K off the screen to ground (part of the screen clamper circuit) is showing 10 mA of screen meter current. This is something I need to think about, but may just live with it.


T

    Tom,

   That 50K should not pull any current when the VR tube is not lit. You may be seeing the 6aQ5 plate current. Kind of depends on where you are measuring that screen current.

The clamp circuit might be on the edge of capability with three 6146's. Data sheet screen current for a plate modulated 6146B is around 9-10ma / tube..That OB2 is rated for 30ma..

Was thinking that an OC3 (VR105) Octal would give you more margin. Then there is that 6AQ5....might be fine if it clamps hard enough, but if not something like a 6W6...

Looks like fun!!

Jim
Wd5JKO

Thanks for the input Jim.

Yes, that current is likely the 6AQ5 plate current doing its job to shunt the screen current.  It is conducting heavily when there is no grid drive. It appears to be working FB so far.  The screen current meter is connected between the modulated B+ and the pin 5/ pin 5 connection of the 6AQ5 and OB2, so it makes sense to see the 6AQ5 plate current there with no RF drive.

A friend suggested I try a 6AH5 in place of the 6AQ5.  Three 6146Bs are probably at the limit for this clamper circuit.  

Question about the 50K from screen to ground...  Lets say that normally without a screen clamper, the screen dropping resistor is 47K.  By adding the additional 50K to ground from the screen, how will that affect the screen modulation swing and will I need to reoptimize the screen dropping resistor to compensate?  It appears to be also acting like a voltage divider, thus reducing the screen modulation?

I'll run some tests and see how the OB2 and 6AQ5 act today under full drive and let ya know.  I don't want to cut new octal socket holes if I can help it...

T

[K1JJ]

Update 3-23-2020:

Today I fired up Commando into a dummyload for the first time.  For a good hour there was no output at all.  I slowly eked out 10 watts, barely.  Something was obviously wrong.  I disconnected and tested every circuit I could think of and all worked FB.


So then it dawned on me... maybe the tubes are bad!  The obvious is possible but unlikely. I went to my questionable used 6146 stash and started testing the tubes one by one.  I was also considering ripping the 6146 tubes out and going with a single 4D32. But I already have a single 4D32 rig so that is the only reason I stuck wid the 6146s.

As luck would have it the set of three I had in the rig were all barely working. Some arced over. But little by little I was able to get each good tube to put out 50 watts at 600 volts and 90 watts at the maximum  voltage around 750V.

Now I have a box full of bad 6146s.  The three good ones were very strong, however. I put the three into the rig together. After playing around I was able to get a very stable output on 75M of about 75 watts at 550 volts. At 600 volts I was up to about 90 watts and at  700 volts the Bird kissed 150 watts out.  This is comparable to a Valiant that also runs three 6146s.

I think that 550V at 75W out will be a good goal for this rig considering the Hammond xfmr. (Unless I spring for a Hammond 1642SE big mofo then its 125W)

Earlier on the screen clamper 0A2 tube was working but sometimes flashing like crazy at 600V and above. I disconnected it for now. It seems that with the HV step start doesn't really need the clamper cuz the HV bleeds off quickly. But I will try to get it working as another backup.

The input circuit tunes FB at 1.3:1 or better swr on the bands.  

So next comes some audio. I like the HV Variac feature. I can easily change the carrier power out from 25W up to 150W. The Hammond and TDA7294 will be a good independent match-up for the adjustable carrier, for whatever audio I can put out.  The Variac will also give me versatility to drive the 4-1000A linear at the proper RF level.

I notice my 250 mA plate current meter gets pinned at full 150W power output.  It was planned for one tube. Gotta find a 500 mA meter I guess.

So after some more repair changes, I'll try some audio.

T

[K1JJ]

I am testing the TDA7294.   With a 50 watt carrier, the module starts to modulate the carrier well up to about 10%, then falls apart and the audio folds back and collapses.  The rig is staying solid on all parameters, so it must be the module.  The heatsink gets luke warm, so it is working.  I tried shielding and cap bypassing, but no luck.

To make the story short, I turned the transmitter completely off and ran the TDA7294 by itself. I put an 8 ohm 20 watt resistor across its output as a load.  Looking at the scope when the audio input is applied, the 45V VCC is solid and the input 1 volt audio waveform is clean. The resistor is warming up to about 10 watts and is clean. But as I cross the 10 watt level output it falls apart.  When the scope is across the 8 ohm load resistor, the collapse takes place in the form of flat topping and a general fold back distortion look.  It is definitely in the module since everything is disconnected except for it. The VCC stays rock solid at about 45V.

Any ideas how to proceed?

Here's the module datasheet:

https://www.st.com/resource/en/datasheet/tda7294.pdf

T


Here is the eBay module:

https://www.ebay.com/itm/143464647535?_trkparms=ispr%3D1&hash=item216728cb6f:g:LxkAAOSwu5thoqKs&amdata=enc%3AAQAGAAAA4H3LEDT9X5xyUJzlSVX0ybAeNUa5aSKJKyUrv0oR3UO8%2FxHdOjRzwMN3Rf5Q43u%2Fp9%2BA8nmo%2BHaVHJb%2BwzhILu3RSZYfkK0DyCvf9OvTDyQgnES2zkGNbdmeKXawl3rKFx7XRxJCSNqVSUT7EcjLsJJwuBmoJR1veDFUACEykIe90XHOUbB4CIiDGwpKWVQsGYz97Rw2XK8pxLhz4ylI059M687dMazzmVicSiUeYgP3%2FEpWVRIR36Sn6uswX1oLGnbVEd6EMHcjxcRfP8QCtAjbHducyYsSzQ3sltgwM3wI%7Ctkp%3ABFBMjNGiqvdf

*** UPDATE:  I notice that the required input AC voltage on this eBay module shows +- 23V maximum.  This is a new change. It used to say +- 35.     +- 35VAC is what I am feeding it.  I wonder if the VCC is on the hairy edge and the module is shutting down a protection circuit?   They talk about 50V DC max in the datasheet  so it is confusing when we have a X1.4 factor after being rectified.  I'll try a lower voltage and see what happens tmw.  The audio looks quite nice when running under 10 W.

[K8DI]

The data sheet test conditions are +/- 35v.  The power supply range (where they say it works) is +/- 10 to 40v.  The it’s going to explode absolute max is +/- 50v.  The AC input is not nearly as important as the actual DC at the chip…so measure that, and make AC changes based on the DC voltages…    Remember that solid state data sheet maximums don’t have anything like the wiggle room of a transmitting tube data sheet maximum…

That said, although I don’t like being the bearer of bad news, a $15 module from China that should cost $50 most likely has a counterfeit chip…they work ok at low levels then either shut down or blow up at high levels.  In repairing amps with this sort of chip, unless I can get it from a real supplier/it’s still in production, I’ve resorted to buying used pulls with old date codes, because all the new ones on places like eBay are fake and don’t work right.

If it were me, I’d hook up an external, known good, audio amp to the transformer and get on with the testing, and circle back to the module. Then I’d get the DC voltage right, and buy a new chip from a reputable supplier (Digikey has them in stock for $6.87).

Ed

[W1RKW]

Tom,
The rail supply voltages +Vs (pin13) and -Vs (pin15) should not exceed 50Vdc which is also what the 2 large filter caps are rated at.  So you'll  need to determine what the AC side would be for bridge rectified for whatever rail supply you want to drive +Vs and -Vs at.  

EDIT: Ed brings up a good point about counterfeit components.  I have the exact same module and looking at the chip, I am suspect of it because the ST trademark is absent. In fact, there's no trademark of any kind on it at all.

The ST Micro datasheet states +/-50VDC absolute maximum. So about 35VAC would be the absolute max AC input for the module (using a real TDA7294).

[K1JJ]

Bob and Ed,

Thanks for the valuable info. You are likely correct about bad fake chips.   A search for  "counterfeit TDA7294" brings up a rat's nest of comments.   I would order a new chip from DigiKey, but I don't think I can unsolder and solder that tiny package without destroying the circuit board. Or maybe I will order a proper chip from Digi-Key and give it a go anyway.  

Or,  I might think about a different module.  Anyone have a suggestion for something similar and reliable?  

Yes, I could use an external 150W Dayton amp, but I'd still like to do it self contained here as planned.

I'll take your suggestion, Ed, and continue testing with an external amp for now.

In the meantime, I read where one guy tried decoupling the board using bypass caps. I notice it broke into parasitics when folding back, so maybe I'll try some cap bypass experiments.


What a PIA.


Fake chips:

https://www.google.com/search?q=tda7294+counterfit&rlz=1C1GCEA_enUS908US908&oq=tda7294+counterfit&aqs=chrome..69i57j33i10i160l2.11259j0j15&sourceid=chrome&ie=UTF-8


T