[ARC5] Stupid Question No.5036

[Geoff]

The 6BK7, BQ7, and BZ7 were used in VHF TV tuners but certainly not in those 
receivers mentioned.

You might find the oddball radio that used them here but since they are 
sharp cutoff triodes there would be minimal useful AGC action without a 
specifically designed loop just for it.
The 6GM6 is a step above and the 6EH7 is the ultimate for a common 
production tube but it is a 9 pin miniature. Ameco used it in one of their 
pre nuvistor preamps.

Carl


----- Original Message ----- 
From: "Mike Everette via ARC5" <arc5 at mailman.qth.net>
To: "WB5WSV Wayne Eleazer" <releazer at earthlink.net>; "ARC-5 Mail List" 
<arc5 at mailman.qth.net>; "D C _Mac_ Macdonald" <k2gkk at hotmail.com>
Sent: Friday, July 25, 2014 9:54 AM
Subject: Re: [ARC5] Stupid Question No.5036


The 6BQ7 was used in a lot of Teevy Tuners as the RF stage, and I believe 
Hallicrafters used it in the SX-96 and SX-100 receivers if my memory's 
correct.  Only problem, is that it has a tendency to develop microphonics.

As for the 6BZ6, it's a good tube at VHF.  I doubt you'll be able to improve 
on it to any great degree.

73

Mike
WA4DLF

--------------------------------------------
On Thu, 7/24/14, D C _Mac_ Macdonald <k2gkk at hotmail.com> wrote:

 Subject: Re: [ARC5] Stupid Question No.5036
 To: "WB5WSV Wayne Eleazer" <releazer at earthlink.net>, "ARC-5 Mail List" 
<arc5 at mailman.qth.net>
 Date: Thursday, July 24, 2014, 6:27 PM

 Hi, Wayne.

 You'll likely get a good
 response to your question if you ask it on either the
 National or Boatanchors mail list.

 KM1H is the former head of National's
 service department and has written on several occasions
 regarding "hottening up" old tube receivers. I
 don't remember off-hand his recommendations, but use of
 a remote cut-off tube for the RF amp is definitely a major
 concern IIRC.

 * * * * * *
 * * * * *
 * 73 - Mac, K2GKK/5 *
 * (Since 30 Nov 53) *
 * k2gkk
 hotmail com *
 * Oklahoma City, OK *
 * USAF & FAA (Ret.) *
 * *
 * * * * * * * * *



 > From: releazer at earthlink.net
 > To: arc5 at mailman.qth.net
 > Date: Thu, 24 Jul 2014 14:00:43 -0400
 > Subject: [ARC5] Stupid Question No.5036
 >
 > I have a stupid
 question.
 >
 > Where
 in the usual tube data is the frequency response for the
 tube?
 >
 > I am
 considering replacing the 6BZ6 RF amp tube on a National
 NC-270 with a tube that will give better performance on 6
 Meters. The 6GM6/6EW6 looks like a possibility but how do
 I know that the performance on 6 Meters will be better? It
 is a tube used in the IF's of TV sets, and that sounds
 good, but I see no data that tells what the frequency
 capabilities of tubes are. The old ARRL handbook had the
 max usable frequency for triode transmitting tubes but I do
 not see similar data for other tubes anywhere.
 >
 > Thanks,
 >
 > Wayne
 > WB5WSV


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