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LZ1AQ using BFU590QX transistors

 

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Hi Bernard,

I changed nothing, both boards had the same components.

Everett

On Oct 30, 2024, at 3:47?AM, Bernard Malet via groups.io <malet-bernard@...> wrote:

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Hello Everett

Between these two versions of transistors, have you changed any component values on your PCB

Best regards

Bernard
 

Hello Everett

Between these two versions of transistors, have you changed any component values on your PCB

Best regards

Bernard
 

Mike,
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With the inputs shorted they both were 105dBm at 1MHz.
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Everett

In a message dated 10/29/2024 10:01:59 AM Central Daylight Time, 3ym3ym@... writes:
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Hi Everett,
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Can you compare the noise level of the 2 variants with the input shorted? Not a true noise figure measurement, but a relative comparison.
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73, Mike AF7KR
 

Sorry about that, yes it is 13.8VDC

In a message dated 10/29/2024 10:04:09 AM Central Daylight Time, groups@... writes:
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Everett,
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Do you mean 13.8VDC? I think there is a typo.
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===================================================================
Mike M
 

Everett,
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Do you mean 13.8VDC? I think there is a typo.
--
===================================================================
Mike M
 

Hi Everett,
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Can you compare the noise level of the 2 variants with the input shorted? Not a true noise figure measurement, but a relative comparison.
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73, Mike AF7KR
 

I just finished building 5 LZ1AQ loop amplifier boards, 4 of which I used? 2SC5551 transistors. The 5th one I used BFU590QX transistors.
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Running sweeps on the 2 looking at both impedance and gain, one with 2SC5551s and the other using BFU590QX, I saw very little difference between the two. Both boards were supplied 3.8VDC, the 2SC5551 board ran at 142mA, the BFU590QX board ran at 130mA.
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I checked both boards with my SA and saw no signs of oscillation on either board.
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Everett N4CY

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