[R-390] R-390A s/n improvement 6HA5 mixer, 6GU5 RF amp

[Jacques Fortin]

Hi Renée,
I will appreciate having a copy too.

73,
Jacques, VE2JFE

-----Message d'origine-----
De : R-390 [mailto:r-390-bounces at mailman.qth.net] De la part de Renee K6FSB
Envoyé : 21 avril 2016 02:00
À : Roy Morgan <k1lky68 at gmail.com>
Cc : Jacques Fortin <jacques.f at videotron.ca>; R-390 Forum
<r-390 at mailman.qth.net>
Objet : Re: [R-390] R-390A s/n improvement 6HA5 mixer, 6GU5 RF amp

Hi Roy-
there is one article in ER #26 by Ray Osterwald dealing with rf and
mixers...I have the article and when I return home, scan and hopefully send
to all as a pdf.
Renée, K6FSB


Roy Morgan wrote:
> On Apr 21, 2016, at 12:15 AM, Jacques Fortin <jacques.f at videotron.ca>
wrote:
>
>   
>> Hi Larry,
>> Thank you for having posted the results of your experiments.
>> To my knowledge, this is the first time that someone tries to substitute
the 6C4 mixer tubes of the R-390A for another type of triode.
>>     
>
> Jacques and Larry,
>
> There was a series of articles quite some years ago, I think in Hollow
State News, about replaced tube types in the first RF stage and mixer stages
of the R-390A.  In both places, the new tubes were of the frame grid types,
which were not yet developed when the R-390A was designed.  I don’t remember
if there were any measurements presented to quantify the increased
performance, but I do remember claims of increased sensitivity or lower
noise and increased dynamic range after the changes.
>
> I also remember later articles with the opinion that the improvements did
not warrant the work to implement them, especially considering the fine
performance of the receiver as designed, and the rareness of conditions
where the improvements would make any real difference in actual performance.
>
> I’d be glad to hear if anyone has the references.  Unfortunately I don’t
have access to the articles now.
>
> Roy
>
> Roy Morgan
> k1lky68 at gmail.com
> K1LKY Since 1958
>
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