First class E in France ?

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First class E in France ?

Postby f6bir » Thu Jun 03, 2010 5:16 am

A new Class E AM transmitter is working in France I dont know if it is the first one
Schmematic is the classic Steve described in http://classEradio.com except for driver and mosfet on the PA
Some photos you can wacht on http://f6bir.over-blog.com/

Sorry for my poor english language

Rene F6BIR

http://f6bir.pagesperso-orange.fr/
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Re: First class E in France ?

Postby kf1z » Thu Jun 03, 2010 7:03 am

Very nice looking rig Rene,

Steve had posted the link to your blog at amfone.net as well.


Bruce
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Re: First class E in France ?

Postby Gilly » Fri Jun 04, 2010 3:59 am

Hi Rene

Great work...
I wonder if you had any problems getting it all going...
Is that a low level audio stage at the bottom / front of the case.....where the microphone connects into ?


Wayne

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Re: First class E in France ?

Postby f6bir » Sat Jun 05, 2010 5:53 am

Gilly wrote:Hi Rene

Great work...
I wonder if you had any problems getting it all going...
Is that a low level audio stage at the bottom / front of the case.....where the microphone connects into ?


Wayne

VK3ALK



Hi Wayne

That is true the small dark Hybid module is an audio preamplifier from "KEMO" it works between 9 to 24VDC with input 2<50mV output 200mV<1V
That helps some poor mike
Have a nice day

Rene F6BIR
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Re: First class E in France ?

Postby Gilly » Sat Jun 05, 2010 6:46 am

OK Rene on the KEMO preamp...must be the M40....

Maybe you could comment on my question regarding the Cores you used in the Output filter....on the other posting under " Pictures " I left yesterday...

Is it now finished ? is there anything left that you have to do ?


Wayne
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Re: First class E in France ?

Postby f6bir » Sat Jun 05, 2010 7:52 am

Gilly wrote:OK Rene on the KEMO preamp...must be the M40....

Maybe you could comment on my question regarding the Cores you used in the Output filter....on the other posting under " Pictures " I left yesterday...

Is it now finished ? is there anything left that you have to do ?


Wayne



must be the M40 =.Yes it is
anything left that you have to do = I have to mount the "efficiency meter" and test it

and after I will test the max HV I could use (up to the STP12NM50 mosfet will crash hi!) may be 50VDC 10A the mosfet are low cost in RS regarding the FQA11N90 we cannot find in France. I will expect to grow up near 400w with near 150% modulation ( Steve said I will be limited with only max 500VDS but TO220 is an advantage in a limited space!)).The components (cores filter and self tank) begin to go hot after 2 or 3 minutes I send hi hi

Also i will add the 160m tank and band switsching, but have I enought space in the old PC frame I use ? (did you seen that !)

I did lot of AM QSO with french AM lover they use classic tube transmitter often WWII surplus as I have also (watch my web site)
All said my audio is near broadcast quality !!!. They add the modulation is very "dynamics"

All is subjective but help me to continue in that enthousiat way

I am not sure I wrote in understable english (school level 50 years ago!)
Regards
Rene F6BIR
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Re: First class E in France ?

Postby kf1z » Sat Jun 05, 2010 8:37 pm

You should be able to run 32 volt carrier, modulated to 150% and still be 'ok' with 500 volt devices.
Not much safety margin.

The voltage at the mosfet drains would be about 390 volts at modulation peaks (150%)

Bruce
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Hey Wayne... did you change your callsign?
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Re: First class E in France ?

Postby f6bir » Sun Jun 06, 2010 12:51 am

kf1z wrote:You should be able to run 32 volt carrier, modulated to 150% and still be 'ok' with 500 volt devices.
Not much safety margin.

The voltage at the mosfet drains would be about 390 volts at modulation peaks (150%)



Hi Bruce

Were I have to read" 32volts carrier" at the RF Amp drain ? or at the PDM filter output ? is the referency must be the ground DC

I can test the modulateur with a resistive load (4.7 ohms 200W) rather than the RF Amp is that test can help to do something ?
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Re: First class E in France ?

Postby f6bir » Sun Jun 06, 2010 1:48 am

kf1z wrote:You should be able to run 32 volt carrier, modulated to 150% and still be 'ok' with 500 volt devices.
Not much safety margin.

The voltage at the mosfet drains would be about 390 volts at modulation peaks (150%)
?


I check again and I found

Value of test in safe condition 160w input 32VDC / 5Amp http://image.hpphoto.com/rs/5FEB21E9-FF ... creen-show
http://image.hpphoto.com/rs/B52C4E9E-E7 ... creen-show

output (320vPP/50ohms) =~ 250W PP ? (%?) http://image.hpphoto.com/rs/88621840-96 ... creen-show

Thanks
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Re: First class E in France ?

Postby kf1z » Sun Jun 06, 2010 12:44 pm

f6bir wrote:
kf1z wrote:You should be able to run 32 volt carrier, modulated to 150% and still be 'ok' with 500 volt devices.
Not much safety margin.

The voltage at the mosfet drains would be about 390 volts at modulation peaks (150%)



Hi Bruce

Were I have to read" 32volts carrier" at the RF Amp drain ? or at the PDM filter output ? is the referency must be the ground DC

I can test the modulateur with a resistive load (4.7 ohms 200W) rather than the RF Amp is that test can help to do something ?



The 32volts I referenced came from one of your postts.....

It would be measured at the output of the modulator, or at the input to the RF amplifier.
Assuming this is the voltage at carrier....
Then, at the mosfet drains the voltage should measure about 112 to 128 vdc.

Rule of thumb is to try to adjust the shunt C so that you see 3.5 to 4 times V+ at the drains..... no more...

Then at 100% modulation, your V+ should be 64volts peak, resulting in 224 to 256 volts pk at the drains.

At 150% modulation, you're looking at 96 vdc V+ and 336 to 384 volts peak at the drains.


Make sense?

Bruce
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Re: First class E in France ?

Postby kf1z » Sun Jun 06, 2010 12:47 pm

I think Wayne and I were confused by one of your posts...

You must operate the amplifier so the PWM filter sees the correct impedance from the amplifier..

So, what voltage/current are you normally operating the amplifier at?

What is the design impedance of the PWM filter?

What RF power output are you getting for your power input?

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Re: First class E in France ?

Postby steve_qix » Sun Jun 06, 2010 5:09 pm

I could send some FQA11N90s over to France. I've sent other parts :-)

The FQA is a 900 volt part, and the other MOSFET is a 500 volt part, so to keep the same safety factor, the voltage would have to be reduced to by a factor of .55 which comes out to be 24.75V (25V). The total power supply voltage should be no more than 75 V (71V is better). Do this if you want to keep the same safety factor that you get with the FQA11N90 running at 45V with a total power supply voltage of no more than 135V (130V is better).

The rig looks very good. I have worked France on 75 Meter AM during the winter months. It would be interesting to hear that transmitter over here in the US !

Regards,

Steve
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Re: First class E in France ?

Postby f6bir » Mon Jun 07, 2010 6:45 am

Hi everybody, after one good night of sleep this morning the ideas are clearer

I did again a series of tests

In fact all is moving depending how the PA I tune

Test data # 1(max RF power on dummy load)


Power supply : 63vDC current : 2A

carrier level 20VDC (pwm output filter)

Drain 60v

With 800Hz modulation:

Drain 150v peak , is that means 125% modulation ?

Test data # 2 ( better factor form on the drains)

Power supply : 65vDC current : 1A

carrier level 20VDC (pwm output filter)

Drain 75v

With 800Hz modulation:

Drain 225v peak, is that means 150% modulation ?

My ask :
What is the best carrier level I must adjust (max DC power supply is 70VDC 10A)

Thanks to spend time to help me

73' Rene F6BIR
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Re: First class E in France ?

Postby f6bir » Mon Jun 07, 2010 7:10 am

steve_qix wrote:I could send some FQA11N90s over to France. I've sent other parts :-)

The FQA is a 900 volt part, and the other MOSFET is a 500 volt part, so to keep the same safety factor, the voltage would have to be reduced to by a factor of .55 which comes out to be 24.75V (25V). The total power supply voltage should be no more than 75 V (71V is better). Do this if you want to keep the same safety factor that you get with the FQA11N90 running at 45V with a total power supply voltage of no more than 135V (130V is better).

The rig looks very good. I have worked France on 75 Meter AM during the winter months. It would be interesting to hear that transmitter over here in the US !

Regards,

Steve


Steve
I have an other project for one like yours with band switch 40/80m; this first one was built just to play with mosfet and to see how it works I am convinced now
Some people in France folows what I do ..may be futur Class E fans !

Let me know the frequency you use for AM and when we can expect to contact USA My antenna is an horizontal 84m loop with a 160m trap at center in opposit of the feeder I am located 125m over the sea level
The french Ham AM lovers projects to open an AM network on 7160Kz as soon it will be open free for us (nearly) The power limitation is 500w here !

read you again
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Re: First class E in France ?

Postby steve_qix » Mon Jun 07, 2010 10:14 am

Hi Rene,

During the winter, I've worked Europe on AM on 3730 or near to that frequency. 7160 may be a possiblity once you are allowed to use that frequency. I do have a 1kw 40 meter class E transmitter, but I need to put a 40 meter antenna up.

Let us know when the rules change and you are permitted to use 7160.

Thanks and Regards,

Steve
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