[Hammarlund] NuvistaPlug & more

[jeremy-ca]

When did you ever know me to be organized Gene? Ive done a few on the fly 
and probably scratched some calculations down somplace.

Devices have improved since those days and Im itching to do some testing 
again.

Keep tuned.

Carl
KM1H


----- Original Message ----- 
From: "Eugene Balinski" <eugeneb at nni.com>
To: "jeremy-ca" <km1h at jeremy.mv.com>; <rrkrr at comcast.net>; "ChasW3KC" 
<w3kc at verizon.net>; "hammarlund" <hammarlund at mailman.qth.net>
Cc: <glowbugs at piobaire.mines.uidaho.edu>; "ChasW3KC" <w3kc at verizon.net>
Sent: Friday, November 09, 2007 4:27 PM
Subject: Re: [Hammarlund] NuvistaPlug & more


> Carl,
>
>  Do you happen to have a schematic and parts list
> available ?   Could come in handy in a few radios.
>
> 73,
> Gene K1NR
>
> On Fri, 9 Nov 2007 12:43:58 -0500
> "jeremy-ca" <km1h at jeremy.mv.com> wrote:
>> The 6BA6 was later followed by the 6BZ6 and Collins liked
>> the 6DC6. All provided improvements over the 6BA6.
>>
>> For ultimate NF improvement a FET with associated
>> circuitry can be mounted on an adaptaplug or similar and
>> require no receiver changes.
>>
>> Carl
>> KM1H
>> ----- Original Message ----- From: <rrkrr at comcast.net>
>> To: "ChasW3KC" <w3kc at verizon.net>; "hammarlund"
>> <hammarlund at mailman.qth.net>
>> Cc: <glowbugs at piobaire.mines.uidaho.edu>; "ChasW3KC"
>> <w3kc at verizon.net>
>> Sent: Friday, November 09, 2007 11:00 AM
>> Subject: Re: [Hammarlund] NuvistaPlug & more
>>
>>
>> > The stock 1st RF amplifier tube in the SP-600 was a
>> 6BA6 - a remote cutoff
>> > pentode.  The 6BA6 has a relatively high noise figure
>> which becomes a very
>> > significant limitation to receiver MDS above 20 MHz or
>> so.  The
>> > "Nuvistaplug" used two 6DS4 remote cutoff Nuvistor
>> triodes connected in
>> > cascode, which gave good gain, much improved noise
>> figure, and high
>> > reverse isolation for the 1st RF amplifier.  The
>> Nuvistaplug was sold as a
>> > tube socket plug-in replacement for a number of 7 pin
>> tubes.  The tube
>> > socket connections of the Nuvistaplug must have been
>> adaptable to the
>> > particular device to be replaced.
>> >
>> > The British companies Racal and Eddystone liked to use
>> cascoded triodes
>> > for 1st RF stages in their receivers.  They used the
>> ECC189 (American type
>> > 6ES8) which is a single 9-pin miniature tube containing
>> two triodes that
>> > are designed to be connected in cascode.  In order to
>> use this tube in an
>> > SP-600, the 7-pin 1st RF amp tube socket would have to
>> be replaced with a
>> > 9-pin, and the resulting noise figure would probably
>> not be as good as
>> > that for the Nuvistor.
>> >
>> > The 2nd RF amp in the SP-600 is also a 6BA6, but with
>> the gain of the 1st
>> > RF amp in front of it, the noise of the 1st RF amp
>> dominates, so it's not
>> > worth replacing the 2nd RF amp with a lower noise
>> device.
>> >
>> > Bob K4ERR
>> >
>> >
>> > -------------- Original message ----------------------
>> > From: "ChasW3KC" <w3kc at verizon.net>
>> >> For the SP-600, what tube type did the NuvistaPlug
>> replace?
>> >> Was it ever used in radios other than the SP-600?
>> >> As I recall,  Ameco used to make a preamp that used
>> >> nuvistors
>> >> (the Ameco preamp I have is solid state and I think it
>> came
>> >> out later).
>> >> TNX/73 de Chas W3KC
>> >>
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