Fw: [HEATH-TEMPE] OFF TOPIC QUESTION.

[Peter A Markavage]

416's are all over the place and can be had cheaply in comparsion to some
of the other WECo tubes. Design operating frequency for the 416 series
was around 3950 MHz. As you moved down in frequency, gain dropped off 
and generated tube noise increased. You also needed a KS-14134 tube
socket which were not easily found.

Good 417A front end designs can get the noise figure down to 2db or a
hair under. Transconductance for the 417A was typically 24,000 micromhos.
Compare that to some of the other front end tubes of that day.

Pete, wa2cwa

On Mon, 3 Nov 2008 12:51:21 -0800 Bob Groh WA2CKY <rgroh at SWBELL.NET>
writes:
> Don't know about the gold grid but they were real. That would have 
> been back in the 1950's and early 1960's as I remember.  They were 
> good for a noise figure (and, boy, this is just off the top of my 
> head) for 2-1/2 or 3 dB noise figure. The 416A was even hotter and 
> more unavailable and I believe it might have been good for NF's down 
> to 2 dB. Both were used in Bell Tel microwave systems. By the early 
> 70's, transistors started to be easily available with NFs much less 
> that that and the day of the tubes was over. Nowadays NFs run down 
> into the 1 dB or better area with low cost transistors. Sigh.
> 
> 73
> Bob Groh, WA2CKY
> 
> 
> 
> 
> ________________________________
> From: Wilson Lamb <infomet at EMBARQMAIL.COM>
> To: HEATH at LISTS.TEMPE.GOV
> Sent: Monday, November 3, 2008 1:31:35 PM
> Subject: Re: [HEATH-TEMPE] OFF TOPIC QUESTION.
> 
> Back when Earth was young, everyone wanted WE 417As for vhf preamps. 
>  Does 
> anyone know how they compare to a modern SS front end??  Had a gold 
> grid, I 
> think.  Was that snake oil?
> Wilson
> W4BOH
> ----- Original Message ----- 
> From: "Peter A Markavage" <pmarkavage at JUNO.COM>
> To: <HEATH at LISTS.TEMPE.GOV>
> Sent: Monday, November 03, 2008 12:20 PM
> Subject: Re: OFF TOPIC QUESTION.
> 
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