The latest from Clip Lead Alley !

[steve_qix]

Clip Lead Alley strikes again  

This is a low power (about 80 watts in this example), simple class E transmitter using a class H modulator.

The design is easily extensible to 225 watts by adding MOSFETs to the modulator and RF amplifier.  The transmitter will function well at as low as 10 watts output, if this is needed for a linear amplifier.

The class H modulator is capable of 200% positive modulation, and includes a negative peak limiter.  The RF amplifier features a single tuned circuit (drive is digital), and covers 160 through 40 meters.  Much smaller RF components may be used - these are what I had lying around the shack, so I used them.

Here is the modulator schematic:


The overall modulator, as built:


A closeup of the modulator itself:


And, the RF amplifier:

[w1vtp]

Steve

DON'T SNEEZE!   

[W1JS]

      

[W2VW]

It sounds much better than it looks.

I have had bad luck with those clip leads. They look like Radio Shack ones. The crimp connections cannot be trusted.

Great idea coming up with a power level where the xmtr can directly substitute for a ricebox.

[steve_qix]

It sounds much better than it looks.

I have had bad luck with those clip leads. They look like Radio Shack ones. The crimp connections cannot be trusted.

Great idea coming up with a power level where the xmtr can directly substitute for a ricebox.

The Radio Shack clip leads have morphed over the years.  The old ones were crimped, and in order to use them successfully, had to be soldered (which I did every time I bought a pack).  But, recently, RatShack has been using a different clip lead supplier... and they ARE (or were) soldered!  But, I do always check - because like your experience, I've had bad connections in clip leads cause problems.

[KF1Z]

Great!

JUST what I've been looking for.   

Thanks for posting it Steve.

[K1JJ]

Good gawd, man!  Have you no shame?...    


(I want the finished circuit to build as my next project)


Can the exisiting H-modulator board be used for this without much trouble?  I understand the RF section will need to be point-point based on our conversation?

T

[W1AEX]

Steve, I'm speechless...

As Dave said, it certainly does sound excellent. Hey, I was only kidding yesterday when I said to have those plans on my desk by today. Hope you didn't stay up all night taking pictures and drawing up the schematic!

That does look like a very slick way for someone without a lot of solid state experience (who has been procrastinating) to give the FET design a try. A board kit would make it a done deal! I love the fact that it will do 160m - 40m too!

73,

Rob

[steve_qix]

Good gawd, man!  Have you no shame?...    


(I want the finished circuit to build as my next project)


Can the exisiting H-modulator board be used for this without much trouble?  I understand the RF section will need to be point-point based on our conversation?

T

Hi Tom,

The existing class H implementation is *completely* different, from soup to nuts. 

I need to add a couple more "features" to this one for completion.  One important feature is an overload detect, but I want a no-brain variant of my existing overload shutdown, with a low parts count and an easy adjustment to set up.

The idea of the project is simplicity.  Whether I can keep it that way is the challenge 

[W3GMS]

Steve,
Your clip lead specials amaze me! 

Have you thought about a PDM version?  As your well aware, they are not that complex. 

It would be a great starter kit for those that have never built much before. 

Joe, GMS

[WD8BIL]

Looks like I'll need more clip leads!

[steve_qix]

Steve,
Your clip lead specials amaze me! 

Have you thought about a PDM version?  As your well aware, they are not that complex. 

It would be a great starter kit for those that have never built much before. 

Joe, GMS

Hi Joe,

Well, there were several reasons I went with analog for this simple kit 

The biggest reason is the wide range of power.  With this setup, one can load the RF amplifier from less than 1 amp, to up to 3 amperes (with one MOSFET in each portion of the modulator), and the modulator is perfectly content.

The circuit is very simple.  A lot of components required for a PWM implementation are not necessary (such as an input filter).

This one is very easy to debug with DC instruments.

And since the circuitry is all analog, it is very forgiving with respect to construction techniques.

Of course the advantage of PWM is a lower weight, no power transformer (if an off-line design is used), and greater efficiency     This is the only analog transmitter I've got at the moment.  Everything else I use is PWM, but of course all of those other transmitters run a lot more power, so PWM is really the only way to go.

And of course, analog signals travel over clip leads much better than do digital signals 

Regards,

Steve

[k3zrf]

Those clip leads are making me hungry looking like tri-colored pasta 

How do you remember what you are clipped to?

[N0WVA]

And here I was thinking that my bench was too messy and I should clean it off ( amounting to sweeping it into a cardboard box with my forearm). Welp. Guess I wont now!

[flintstone mop]

Steve ,
That conglomeration hasn't changed very much. Maybe 15 more clip leads.
And on your thread about sub-woofers........While we have you here.........Why do you need to hear or feel audio down to 10hz?..........HUH?

Fred

[WA1GFZ]

clip leads are an art. You really have to understand current loops to get away with it.

[K9ACT]

My wife got a bigger kick out of these pics than I did.

My stuff does not look so bad anymore and I had to tell her that you are smarter than I.

I keep telling her that the amount spaghetti is directly proportional to genius.

js

[K5UJ]

Steve, I gather you are getting ready to win the clip lead category in the Feb. 6 rally.  Congratulations I think the award should be given now--why wait hi hi.

Can't wait to hear the new rig and if there were ever a RIG, this is IT 

73

Rob

[WBear2GCR]

STEVE!!!

Please please please don't design anything with quad TL074 chips!!

At least go with a 5532/5534 family??  Singles or duals??
Many many potential subs vs. almost none??

Not to mention the new ultra ultra low distortion chips from National and LT??

Please?



               _-_-bear

[steve_qix]

I've got a pretty nice overload shutdown circuit going.  Although this adds some parts, it is a very important feature.  I'll document the changes when I'm not so tired 

I built this whole thing point to point, clip leads and dead bug.  But, I think a PC board is in order to facilitate construction.

It would be reasonable to make the board accept up to 3 MOSFETs in each class H bank, for up to 225 watts of power input.  Configuring the board with 2 MOSFETs in each bank will give you 150 watts in, and a single in each will give you up to 75 watts dc input to the final.

Makes a nice DX100/Apache/Valiant power level transmitter.

Above 225 watts? Use PWM 

Regards,

Steve

[K6IC]

Hey Steve,

Great idea,  and nice implementation,  as usual.  Am buying more 'Cliplead Futures" !

73  Vic

[WA1GFZ]

Steve,
I put a LED in series with the NPL transistor collector so it flashes when the npl is turned on. I mounted the LED on the front panel of the modulator as a monitor.
It could also go in the base circuit if you need more than 10 ma of NPL current.

[W1UX]

Steve ,
That conglomeration hasn't changed very much. Maybe 15 more clip leads.
And on your thread about sub-woofers........While we have you here.........Why do you need to hear or feel audio down to 10hz?..........HUH?

==============================================================================
 
Well, like the girl said in the hifi store sitting on the subwoofer, "could you play that organ recording again?"

 

[WA4JK]

Steve do you think one could stuff one of your overload shutdown circuit cards into a K7dyy box? Thaht might be the answer to the class D issues.

[KF1Z]

Steve do you think one could stuff one of your overload shutdown circuit cards into a K7dyy box? Thaht might be the answer to the class D issues.

It would work....

Of course you'd have to have a power supply... That's isolated from the rest of the DYY circuitry. Not even a ground...

And find the right traces on the DYY board to cut, to route the Modulated DC through the overload board..
Maybe there is already a jumper? going from the modulator section to the final FETs?

May be a little tricky, since almost all the circuitry in the DYY is floating.. (which is probably the root cause of some failures)

But I bet it can be done