[AMRadio] Mfg date for 4-400 series

[Barrie Smith]

I have an HB-3 here that shows a data sheet for the 4-400A dated 9-62.

I also have an Eimac catalog from the early 1950s that shows the 4-400.

73, Barrie, W7ALW


----- Original Message ----- 
From: "John Lawson" <jpl15 at panix.com>
To: "Discussion of AM Radio in the Amateur Service"
<amradio at mailman.qth.net>
Sent: Friday, March 23, 2007 9:32 AM
Subject: Re: [AMRadio] Mfg date for 4-400 series


>
>
> On Fri, 23 Mar 2007, Bob wrote:
>
> > According to the info that I have, they were in production in 1950.
They
> > were not listed in the 1948 data sheets.  So it could be between 1948
and
> > 1950.
> >
> > Hope this helps.
>
>    Actually, this deepens the Mystery - both my HB3s reach from the late
> 30s to the early 60s... they were updated by subscription, so it depended
> on who had them as to exactly which updates got posted.
>
>    I have a 1962 TT5 that goes directly from 4-250A to 4-1000, as do the
> HB-3 sets.
>
>    I am lacking RCA transmitting tube data from 1963 - 1971.
>
>    The 4-400 does appear in the 1972 TT5 manual.
>
>    So: if they were made starting in 1950 - why are they not in the data
> books until nearly 15 years later..?
>
>    I'm sure there's a fine answer out there, somewhere.... just one of
> those trivial pusuits to distract one from the day's Business..  ;}
>
>
>   Cheers
>
> John
> KB6SCO
> DM09fg
>
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