[Hallicrafters] DD-1 Audio amplifier

[Richard Knoppow]

----- Original Message ----- 
From: "Lloyd Godsey" <kk7iz at cox.net>
To: "'Carl'" <km1h at jeremy.mv.com>; "'rbethman'" 
<rbethman at comcast.net>; <hallicrafters at mailman.qth.net>
Sent: Friday, February 24, 2012 5:13 PM
Subject: Re: [Hallicrafters] DD-1 Audio amplifier


> Not to mention the Hammarlund AN/FRR-12
>
> Thanx
> Lloyd Godsey KK7IZ
> kk7iz at cox.net
> 480-620-7145
> http://www.lloydsdipsydumpster.com/
> http://antiqueradioarchives.com/
>
>
> -----Original Message-----
> From: hallicrafters-bounces at mailman.qth.net
> [mailto:hallicrafters-bounces at mailman.qth.net] On Behalf 
> Of Carl
> Sent: Friday, February 24, 2012 4:09 PM
> To: rbethman; hallicrafters at mailman.qth.net
> Subject: Re: [Hallicrafters] DD-1 Audio amplifier
>
> National had  a diversity model of the NC-183 around 1947 
> and Hallicrafters
> SX-28's were used during WW2.
>
> National also built big racks full of special diversity 
> receivers under some
> FRR-nn contract.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "rbethman" <rbethman at comcast.net>
> To: <hallicrafters at mailman.qth.net>
> Sent: Friday, February 24, 2012 4:21 PM
> Subject: Re: [Hallicrafters] DD-1 Audio amplifier
>
>
>> Long before the SP-600-JX series, there was a Northern 
>> Radio Diversity
>> version of the SP-600 J-11(No X), that was on a Navy '51 
>> contract.  It
>> required two receivers and also the Northern Radio LMO to 
>> keep both
>> receivers in sync frequency wise.
>>
>> I've got one, I've seen a few others.  One could select 
>> either the
>> internal LO or the external LMO.
>>
>> Bob - N0DGN

    Somewhere I've seen pictures of modified Super-Pro 
receivers in double or triple diversity systems. Equipped 
with means for an external LO. All the modifications are 
fairly easy to do.
    My BC-779 had been modified at some time for a crystal 
oscillator. It had been removed when i got the receiver but 
the holes for the knobs over the main tuning dial were still 
there as was a hole in the top cover of the tuning unit just 
over the main tuning capacitor for the LO. Very similar 
arrangement to the SP-600-JX. Mine did not seem to have been 
modified to bring out either the AVC, IF or detector so 
perhaps it was simply a switchable fixed frequency receiver.
     BTW, the Super-Pro has an interesting audio amp, a 
Class-B or near it amp using triode connected 6F6 tubes and, 
like the DD-1 with an interstage transformer. The audio 
quality is very good.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com