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THE AM BULLETIN BOARD => Class E Forum => Topic started by: vk3alk on July 11, 2020, 02:00:48 AM



Title: California Dreamin MK2
Post by: vk3alk on July 11, 2020, 02:00:48 AM
Ok this is only meant to be a bit of fun.....
This is the PWM that Jon may build ( who knows  ;D )

While Jon builds his stuff .... I will build this .....
It will be larger then what I normally do just so things are easier to see .....
Also the circuit may change as I go along depending on how I feel...

Its not a race to finish .... just plod along....



Wayne


Title: Re: California Dreamin MK2
Post by: ka1tdq on July 11, 2020, 02:16:06 PM
Yes Wayne, but if you run over it with a tank will it still run? Huh? ...  ;D

Jon


Title: Re: California Dreamin MK2
Post by: N4LTA on July 11, 2020, 02:24:55 PM
Wayne

Look forward to seeing your new project. I am still a couple of months away from having a shop, but I am collecting stuff for it.

Pat
N4LTA


Title: Re: California Dreamin MK2
Post by: vk3alk on July 12, 2020, 10:28:08 PM
Just a bit of an update....

Have finished building the Inductors for the PWM LPF.....



Wayne


Title: Re: California Dreamin MK2
Post by: N4LTA on July 13, 2020, 04:30:17 PM
Wondered what those were. Looks good. What kind of core?

Pat
N4LTA


Title: Re: California Dreamin MK2
Post by: vk3alk on July 13, 2020, 06:36:39 PM
There IE-33 cores from old Computer Power Supplies....
You can buy them from ebay

https://www.ebay.com/itm/2pcs-PC40-EI33-6-6pins-Ferrite-Cores-bobbin-transformer-core-inductor-coil/151824083630?hash=item23596baaae:g:QSoAAOSwnw5dy4Rh

Would trust the ones from old Power Supplies but have used ones from China and they seem OK.....
I fill them will heat glue to reduce singing etc:
Power handling should be appox 400-500 watts but you would have to test them first.......

RM cores are good and small ...... I use them as well without clips and bobbins .... just wind the coil and push them into the ferrite and fill with heat glue etc:


Wayne



Title: Re: California Dreamin MK2
Post by: KQ6F on July 13, 2020, 06:51:01 PM
Hi Wayne -

I've never played with those cores for use in PWM, but have been tempted.  Their saturation characteristics are primarily governed by gapping.  One needs to be careful to stay away from the sharp drop-off point.  That made me nervous and so I never pursued it.

https://www.mag-inc.com/Design/Design-Guides/Inductor-Cores-Material-and-Shape-Choices?gclid=CjwKCAjwjLD4BRAiEiwAg5NBFo7YTv9kdE6a0bV6Hs3XMrrVPBYEy_oZbb1YMFqJfC5Bd9CgJoryfxoCKU0QAvD_BwE (ftp://https://www.mag-inc.com/Design/Design-Guides/Inductor-Cores-Material-and-Shape-Choices?gclid=CjwKCAjwjLD4BRAiEiwAg5NBFo7YTv9kdE6a0bV6Hs3XMrrVPBYEy_oZbb1YMFqJfC5Bd9CgJoryfxoCKU0QAvD_BwE)

Will be curious to learn how they work out for you.

Rod


Title: Re: California Dreamin MK2
Post by: vk3alk on July 13, 2020, 10:29:17 PM
Hi Rod....

I have used them a few times and they work no problems at all...

Have attached a photo of one from a Power Supply..
A bit messy to take apart but after a while you learn some tricks in how to do it quickly....
They definitely have to be gapped...if not then I would say would blow apart  ;D
If you look at the photo you will see a little piece of PCB which goes between the I and E etc:....

The RM cores come gapped or ungapped .... you need gapped ones....

Have made up the PCB for the PWM and are now on the TX so not far away from building....
It is all on the one PCB.....
Have decided to make it small and cramped ...... don't know why really ... amazing how small this stuff can get....


Wayne


Title: Re: California Dreamin MK2
Post by: vk3alk on July 18, 2020, 01:22:29 AM
Well it's coming along slowly....
Pictures show the partly done board and Triangular waveform at 250Khz.....
Its small but so is Pats board....


Wayne


Title: Re: California Dreamin MK2
Post by: N4LTA on July 18, 2020, 12:59:36 PM
Keep it coming. i'd like to see a schematic of the whole discrete pwm generator.

Pat
N4LTA


Title: Re: California Dreamin MK2
Post by: vk3alk on July 28, 2020, 08:16:02 AM
Better do an update.....

Have been building.....picture1 shows what I wanted to do ..... both PWM & TX on the one board..
But was not happy with the TX and so cut the board in half and used another little test TX Module built sometime ago....

Now that Jon is building a 200watt TX I rewound the output transformer to lower the loading to 10 ohms ... which was not difficult and the efficiency remained the same in the mid 90s....
Using a Mark to Space ratio of 60:40 now my PWM can develop 130 watts into 10 ohms so no problems modulating a 200 watt TX...

The TX module has been tested and works well .... 200 watts is fine and probably the max safe power would be 250 watts...

I now just have to complete and test the modulator which works up to the driver chip....



Wayne




Title: Re: California Dreamin MK2
Post by: ka1tdq on July 30, 2020, 12:31:17 AM
Damn Wayne, better hope I don't change my mind and go with a 300 watt rig!  ;)

Looks pretty darn good! I haven't built anymore but I'm planning the power supply and modulator in my head and ordering parts on eBay. The cat's meow, believe you me.

Off topic, but I just ordered a product from down under. I just purchased the Bitscope https://bitscope.com/#overview (https://bitscope.com/#overview) which is an oscilloscope for the computer. I've decided that I want my California shack to be neat, modern and clean so I don't want clunky oscopes hanging off the desk. I'll be able to monitor my drain waveforms on one of my computer monitors.

One monitor for the scope, one for the SDRplay receiver, and another for web browsing to look up the name of the guy you're talking with while he's rambling on about nothing but you've forgotten his name, dammit. 

I'm totally sure (California talk) that you're going to beat me to the finish line, but standby! ...

Jon


Title: Re: California Dreamin MK2
Post by: vk3alk on July 30, 2020, 05:00:59 AM
Ohhh doesn't matter about coming first ... I'm just chugging along in my favourite room in the house ... my shack...
There is not much activity on AM down here which is a shame as I have these Transmitters and no one to talk too....
Mainly just use them to play music around my house  ;D

But to get serious about things  :D I have one of Steves PWM generator boards with an output board too ..... do you want it  :) :)
If so I will just post it to you.... don't worry about postage or anything its yours if you want....


Wayne






Title: Re: California Dreamin MK2
Post by: ka1tdq on July 30, 2020, 07:03:26 AM
How can I so no to that? I'll take it! It'll greatly reduce the size of the modulator. Thanks, it's greatly appreciated! And in return if you want any Sherman tank parts, I'll post them to you no problem. Just ask, chances are I probably have it.

Jon Rines
12547 Heatherton Ct, Apt 188
San Diego, CA 92128



Title: Re: California Dreamin MK2
Post by: N4LTA on July 30, 2020, 01:15:23 PM
Wayne - Looks good. 

Hoping to get back started soon. Still may be mid to late September. Have been buying lots of replacement parts and bins and cataloging.

Hopefully sooner.

Pat
N4LTA


Title: Re: California Dreamin MK2
Post by: VK3HN on July 31, 2020, 03:29:34 AM
Nice work Wayne.  Did you choose the IE33 cores for the LPF inductors over the RM10s for power handling? At what power would you think the RM10s would get too lossy or too hot?

-- Paul VK3HN.


Title: Re: California Dreamin MK2
Post by: vk3alk on July 31, 2020, 05:56:19 AM
Ohhh boy .... have been caught out here....
I do have friends down in Ozzz really  :D

Pauls a bit of a builder too and has PWM stuff as well....
Just between us Paul ... so I don't have to ring you  ;D .... found a Power Transformer that would be good for you as well as me ....
Jaycar sell them .... a 240:120 isolation stepdown tranformer so that gives you close to 170 volts that would percolate all our stuff very well...

And Jon will post all things very soon.... and Pat times goes bye so quickly you can probably see the finish line with your new Shack....


Wayne



Title: Re: California Dreamin MK2
Post by: vk3alk on August 01, 2020, 08:55:13 AM
Nearly there....
Only a low powered test but its working....
My Bench Power Supply hasn't enough power to run the TX fully modulated at 200 watts so will have to build a supply to handle....
For a DSO the AM waveform displayed by my Siglent 1202X is very nice.....

In time will do a specan test as well...




Wayne


Title: Re: California Dreamin MK2
Post by: vk3alk on August 02, 2020, 12:57:00 AM
Hi Jon....

Have removed the Modules and also 2 of the cores ........
Tried to leave as much lead length as possible too ...

The Modulator worked without any problems and the TX was a 4 FET Class E using 11N90s....and run it at appox 200 Watts...

Will post them soon.....


Wayne


Title: Re: California Dreamin MK2
Post by: ka1tdq on August 02, 2020, 03:30:20 AM
With the filter cores too!? Wayne, you are too nice.

I'm excited to resume building this transmitter again. In the meantime I've ordered all the parts from DigiKey that I'll need (see boxes). The size and weight reduction for the modulator going with PWM can't be overstated. The whole transmitter assembly (RF deck, modulator and power supplies) will fit nicely into my cabinet.

Now I can put just the plate modulated rig I recently built on top of the cabinet. It'll never get used but looks really nice. It'll give the nice, "Ooh, aah" factor for the shack. I've only had a couple QSO's with that rig and that's all it'll probably ever have. It's entirely possible that eventually I'll be the last man standing with RF vacuum tube knowledge. ARRL might even post an article with a picture of me in my 90's, complete with drool seeping out the side of my mouth.

Jon


Title: Re: California Dreamin MK2
Post by: vk3alk on August 06, 2020, 11:05:57 PM
Been a little disrupted here ..... we are on stage 4 of this Covid 19 thing.....
Onto something more interesting....

Have uploaded a triangular waveform .... probably would look better on an analog CRO but the lines are straight....
Will do a specan test soon and look at the IMDs etc:

Ohhh too Jon have the box for your stuff...
Will package real soon....


Wayne


Title: Re: California Dreamin MK2
Post by: vk3alk on August 08, 2020, 06:39:38 AM
I won't do any Posts on IMD testing.... ::)
Ran a single tone ..... one at 3Khz and the other at 6Khz and the IMD product was 35db down....for whatever that means...
I don't trust my 2 tone generator so may do the transmitter some injustice ....

Rod if your around the IE33 cores have very low singing....
Ran the transmitter at 225Watts carrier 100% modulated with a single tone and could only just hear them....

And Jon will upload a picture of your parcel of goods on your post....


Wayne


Title: Re: California Dreamin MK2
Post by: ka1tdq on August 09, 2020, 06:39:59 AM
Sounds good!

Since I have time to sit around and think, quite a dangerous thing, I'm going to do one minor tweak to my plans. I'm still sticking with 200 watts carrier but I'm going to attempt to make this a 40 meter rig. I hate to duplicate capabilities that I already have, and I do have this plate modulated 75 meter rig that I just built. I'm going to buy the Acom 1010 linear to pair with it. The tube is a 4CX800 with cooling from the socket rather than a muffin fan. It'll do well for around 150 watts carrier.

This will give me 40 meter capability and is actually a technical challenge. It's hard to tame the higher frequency and get it stable, but I've got a plan.

Jon



Title: Re: California Dreamin MK2
Post by: vk3alk on August 09, 2020, 07:14:49 AM
Ohhh not a plan....
Well thats good ...... :D

Have gone back to another project that I started a while ago now.....
I don't want to bore people to death but its a 40M H Bridge that seems to work very well....
Have uploaded a photo....

Goes well ... 52 volts @ 3.8 Amps nearly 200 watts input...
The output power is 187 Watts.....
Run it for appox 1 hour ( carrier only ) and the FETs were 33C and the Cores 44C .....

Will need to make another one to tidy up the input area and see if my results can be duplicated....

Total cost appox $50- no more....

Will apply some modulation maybe tomorrow or the next day.....
Should be fine but its still under test.... :)


Wayne


Title: Re: California Dreamin MK2
Post by: KD6VXI on August 09, 2020, 10:36:47 AM
The 4cz800.  If you can read Russian, it's really a 4cx600.

Get a couple spare tubes, Jon. Just to be safe. Rotate them  every year or so.  Again....  Just to be safe

--Shane
KD6VXI


Title: Re: California Dreamin MK2
Post by: ka1tdq on August 09, 2020, 02:09:00 PM
In fact, howís this for design/chill time?

I guess 600 still beats out a 3-500 for plate dissipation. I looked at Ameritron AL-30bís but they just use a side mounted muffin fan with a homemade tube socket. Google it, itís very cheesy.

Jon


Title: Re: California Dreamin MK2
Post by: ua3ral on August 10, 2020, 05:41:34 PM
vk3alk

рад за Вас. Удачи


Title: Re: California Dreamin MK2
Post by: vk3alk on August 10, 2020, 06:24:28 PM
Thank you...


Wayne



Title: Re: California Dreamin MK2
Post by: vk3alk on August 16, 2020, 02:18:57 AM
Since Jon has now decided on a 200 Watt carrier level 40M TX have tested this Module with modulation and are happy with its performance....
Was going to make another module but have changed my mind as have too many things hanging around....
But for 200 Watts will need another power transformer which have ordered and are waiting for delivery...
Although I have a 40M TX its good to have a spare I suppose....
Have just enough aluminium to make a case which is lucky as all stores are closed here due to this Covid19 thing.... 


Wayne


Title: Re: California Dreamin MK2
Post by: ka1tdq on October 16, 2020, 09:35:22 AM
Actually Wayne, things have really gotten way out of hand. I'm now building a hybrid Class E / 4-1000 class C design. Thermionic emissions and drain currents everywhere! And carrier levels to tax the California power grid.

Wreak havoc!

jon


Title: Re: California Dreamin MK2
Post by: vk3alk on October 16, 2020, 05:48:53 PM
Thats Ok I don't mind... :)

Quite excited really should be interesting......

Have you got that parcel yet ?   should be getting closer by now.....

Will also post some pictures of the 40M TX as its near completion....


Wayne


Title: Re: California Dreamin MK2
Post by: ka1tdq on October 16, 2020, 06:19:14 PM
Yes, in fact here is the backyard with the 75 meter dipole installed. Iím at a higher elevation with better soil and a higher antenna here than in Arizona. Iím still putting the shack together right now.

Jon
 


Title: Re: California Dreamin MK2
Post by: vk3alk on November 26, 2020, 12:34:08 AM
Things with this 40M 200 watt carrier level are coming along slowly but getting there....
The picture shows a regulator board and at the rear the PWM....
Testing is only at the 100 watt level with audio applied to the Modulator...

The labelling of the meters has been done with the meter program from http://www.tonnesoftware.com/ ...

The TX module has been tested and works so all should be Ok when installed into the case...

Will post other photos soon...


Wayne


Title: Re: California Dreamin MK2
Post by: N4LTA on November 26, 2020, 08:02:03 PM
Nice looking rig Wayne!

Pat


Title: Re: California Dreamin MK2
Post by: Opcom on November 27, 2020, 12:28:05 PM
In fact, howís this for design/chill time?

I guess 600 still beats out a 3-500 for plate dissipation. I looked at Ameritron AL-30bís but they just use a side mounted muffin fan with a homemade tube socket. Google it, itís very cheesy.

Jon

I don't seem to find the AL-30 model. LOL no amusement for me..


Title: Re: California Dreamin MK2
Post by: vk3alk on November 27, 2020, 11:48:28 PM
Just another boring photo.....

Nearly there .... transmitter working but only testing at appox 100 watts of carrier....
Haven't done any Sinewave or Triangle wave tests as yet just music audio....
Are more then happy with the audio quality....
Been running for appox 1.5 hours and the hottest things are the FB1020-43 type ferrite cores in the TX output at 43 degrees C ...
At 200 watts may need a fan on top  8)
Installed an extra Heat Sink on the PWM assembly .....

The SWR bridge will be the last.....


Wayne


Title: Re: California Dreamin MK2
Post by: vk3alk on December 01, 2020, 05:38:14 AM
I have some good news and not so good news....

The not so good news is that I cannot fully modulate the TX at 200 watts carrier only up to 180 watts unfortunately ...
The reason is too high a load resistance for my power supply and ran out of headroom ....
A slightly lower loading would be great but changing the turns ratio using the FB1020-43 cores creates too bigger jump etc: and efficiency drops....
But the good news is it works great at 180 watts and the audio sounds very nice.....

So I suppose that's a fail... ;D

The only thing left now is aligning the SWR/Power meter and installing....
Had to use a fan above the output transformer and the temperature now seems stable at 35 degrees C....

Actually are very happy with the outcome.... :)

Ohhh the fan is spinning just the camera speed etc:


Wayne



Title: Re: California Dreamin MK2
Post by: vk3alk on December 07, 2020, 07:46:38 AM
California Dreaming MK2 was just a bit of fun with Jon but looks like a new Transmitter has been born...

Its all finished and goes well.....
May put some dial lights behind the meters but most of the time I operate on 40M is during the day...

Labelling of the controls I might do a bit later perhaps... ;D

The Meter labelling is better then what it looks .... the flash lightens it etc:


Wayne


Title: Re: California Dreamin MK2
Post by: vk3alk on December 17, 2020, 10:06:09 PM
If your wondering why there is so much available room in the RF section I have plans to replace that existing module with 2 H Bridge units into a Combiner made as small as possible...
Will experiment also using much smaller cores in the combiner as well....

Will post results as time goes by......


Wayne
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands