[R-390] 6HA5 vs 6AK5/5654

[Bob Camp]

Hi

The really tricky part of the oscillator output is it’s phase noise. That impacts the
adjacent channel / overload performance of the radio. This is the section that likely 
was in the “missing” engineering report on the radio.

Bob


> On Sep 27, 2016, at 11:36 PM, Larry H <dinlarh at att.net> wrote:
> 
> Hi Russ,  It is important for the osc to produce a certain level of output and the less distorted the output is the better.  The 6ak5 was chosen to produce a very clean osc output.  That minimizes IMDs and noise in the mixer.  If you can't measure a specific improvement, I think you should put the 6ak5 back into service.
> Regards, Larry
> 
>      From: "wb3fau55 at neo.rr.com" <wb3fau55 at neo.rr.com>
> To: r-390 at mailman.qth.net 
> Sent: Tuesday, September 27, 2016 3:25 PM
> Subject: [R-390] 6HA5 vs 6AK5/5654
> 
> Well, I need some input here as to improved performance using a 6HA5.  I put one in the xtal osc section, it works,  but not sure if it is better.  thanks to all.
>   Now working on a '56 contract Motorola, all working except no receive on 28mc. 73s Russ
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