New filter more power

[f6bir]

The last photos around the new PWM filter up to 250w now (input 40v 7A)
Cores extracted from old computer power supply
http://idata.over-blog.com/3/89/05/80/a ... C02394.JPG
http://idata.over-blog.com/3/89/05/80/a ... C02393.JPG

the first one (ridiculous!)
http://idata.over-blog.com/3/89/05/80/a ... C02356.JPG

73' Rene F6BIR

[Gilly]

Hi Rene

I was looking at those cores and wondering what percentage of modulation you were running..
At the local Electronic shop they sold Powdered Iron Cores similar in size to yours but could not provide specs on them.. With the TX at 100Watts carrier level they could modulate a little over 100% before saturation....quite good really...
I use the CH777060 cores now.

How high can your positives go now with your new filter ?



Wayne

VK3ALK

[f6bir]

Hi Rene

I was looking at those cores and wondering what percentage of modulation you were running..
At the local Electronic shop they sold Powdered Iron Cores similar in size to yours but could not provide specs on them.. With the TX at 100Watts carrier level they could modulate a little over 100% before saturation....quite good really...
I use the CH777060 cores now.

How high can your positives go now with your new filter ?



Wayne

VK3ALK

With the new filter and a 50ohms dumy load = if I set the carrier level near 100w (on a power meter ) HV is 38VDC 6.5A without modulation

I put a 800hz audio signal to modulate, the power meter read 200w, HV is down to 32VDC 10A (I grow the audio level up just before distorsion begin to appear on oscilloscope)
on the oscillogram the modulation seems be around 80%( négatives peak dont falls to 0, even I change the negativ peak level , but i can reduce modulation with it)
In fact I dont really all understood about the percentage modulation over 100% works could help me ?

73' Rene F6BIR

[Gilly]

Hi Rene

Gee you are really pushing your transmitter.....
250Watts input might be a good maximum point 30volts@8Amps....others on the forum might want to comment....

My question was probably wrong....what I should have asked was .....using those small cores does the filter saturate ?


Wayne

[f6bir]

Hi Wayne

How can I check that .?
In all test I did no limitation was found

with 32VDC/ 10ADC ( 320w power input) RF and modulation folow without saturation( 300w RF peak power) It seems but is that I see is the truth ?

Help me
Rene

[f6bir]

Hi Rene

Gee you are really pushing your transmitter.....
250Watts input might be a good maximum point....others on the forum might want to comment....

My question was probably wrong....what I should have asked was .....using those small cores does the filter saturate ?


Wayne

Hi Wayne watches the photo here from some test I did

http://photosmart.hpphoto.com/FilmStrip ... 514&SKU=HP

[Gilly]

Hi Rene...

To me something does not appear right..
For 100Watts output your input power is 38V @ 6.5A = 247Watts power input...

IS THIS RIGHT ?

On MY TX for 100Watts output my input power is 30V @ 3.7A 111Watts Input.....

If it was my Transmitter .... I would not crank up the power input to the levels you are ( its a nice looking TX )..
Get your efficiency right at 100Watt level first......

These are my Voltage levels:
PWM Drain voltage 135Volts
Carrier level 30Volts

I check that all is working correctly on the PWM Generator board....the negative limiter operates smoothly from no cutoff up to full negative cutoff....you have probably done that though...

There is still a lot to be said though...thats all for now.....


Wayne

[kf1z]

If you are operating 32v @ 10 amps...
And getting 300 watts RF output at carrier... you're doing very well.
I would not expect any greater efficiency!


However, if you are only getting say, 250watts or less for that 320 watts dc input, then you have work to do to correct it.

Bruce
kf1z

[kf1z]

I was looking at your pictures Rene...

What frequency are you operating this rig at?

800khz ?

[kf1z]

I was looking at your pictures Rene...

What frequency are you operating this rig at?

800khz ?

Oh wait... maybe I was seeing an audio tone generator picture at 800,25hz...

That would make more sense!

[f6bir]

I was looking at your pictures Rene...

What frequency are you operating this rig at?

800khz ?

operating frequency is 3600khz

800,85 Hz , 512mV is the audio signal input

[f6bir]

Hi all

Here you find other photos of my Rig (click on each to enlarge)

http://photosmart.hpphoto.com/FilmStrip ... d90&SKU=HP

73' Rene F6BIR