[Moon] [Moon-Net] Agilent 346A and N9069A reading high?


Graham D <graham.d@...>
 

2.When I measure noise figure I see good results on the gain but the
noise figure seems high. For instance my HA8ET Extra 2 LNA reads about
1.4dB whereas I am pretty sure that it is much better than this.
it's all a lot simpler than long convoluted theories....

the pre amp is oscillating

Graham 'MBI 'VHX


Conrad Farlow <conrad@...>
 

I don't think so. That was merely one example of several preamps that I have that have been measured elsewhere by trustworthy individuals to have much better noise figures. I have a 346B noise head I am going to try that as well.

I was hoping that I was being stupid (I certainly have the capacity for it) and missing something basic.

Conrad

2.When I measure noise figure I see good results on the gain but the
noise figure seems high. For instance my HA8ET Extra 2 LNA reads about
1.4dB whereas I am pretty sure that it is much better than this.
it's all a lot simpler than long convoluted theories....

the pre amp is oscillating

Graham 'MBI 'VHX



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Conrad Farlow <conrad@...>
 

Its hooting you were right. I removed the noise head and put a load on it and I can see a descrete frequency that has an 8dB noise figure. This will be the frequency at which it's oscillating.

Do you have anything with a known NF that I can check as a reference. I'll send it straight back to you.

__________________________________________________

73

Conrad G0RUZ IO93FR


North Wakefield Radio Club

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On 19/07/2013 06:38, Graham D wrote:
2.When I measure noise figure I see good results on the gain but the
noise figure seems high. For instance my HA8ET Extra 2 LNA reads about
1.4dB whereas I am pretty sure that it is much better than this.
it's all a lot simpler than long convoluted theories....

the pre amp is oscillating

Graham 'MBI 'VHX



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Conrad Farlow <conrad@...>
 

Ooops should have gone to Graham sorry.

__________________________________________________

73

Conrad G0RUZ IO93FR


North Wakefield Radio Club

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On 19/07/2013 14:10, Conrad Farlow wrote:
Its hooting you were right. I removed the noise head and put a load on
it and I can see a descrete frequency that has an 8dB noise figure. This
will be the frequency at which it's oscillating.

Do you have anything with a known NF that I can check as a reference.
I'll send it straight back to you.

__________________________________________________

73

Conrad G0RUZ IO93FR


North Wakefield Radio Club

__________________________________________________
On 19/07/2013 06:38, Graham D wrote:
2.When I measure noise figure I see good results on the gain but the
noise figure seems high. For instance my HA8ET Extra 2 LNA reads about
1.4dB whereas I am pretty sure that it is much better than this.
it's all a lot simpler than long convoluted theories....

the pre amp is oscillating

Graham 'MBI 'VHX



------------------------------------

Yahoo! Groups Links



------------------------------------

Yahoo! Groups Links



Graham D <graham.d@...>
 

On 19/07/2013 16:10, Conrad Farlow wrote:
 

Its hooting you were right. I removed the noise head and put a load on
it and I can see a descrete frequency that has an 8dB noise figure. This
will be the frequency at which it's oscillating.

Glad you found it Conrad.

if its an ATF then it'll most likely be in the 5 to 6 GHz region.

(the narrow filter will not be helping it because the out of band match will be appalling from everywhere to everywhere else)

and I forgot....if anyone thinks they are going to **consistantly** measure differences of .01 and .03 on anything made by Agilent/HP then it's time to call the men in the white coats.

These things are Production line instruments not Research instruments.

Graham