[ARC5] Stupid Question No.5036

[Mike Everette via ARC5]

I stand corrected.  Hallicrafters used the 6CB6 in those receivers.  Still a pretty hot tube, used in Teevy Tuners; and also prone to microphonics.

An SX-96 with good tubes and proper alignment could hear a gnat sneeze in Outer Mongolia on 10 meters, but would also hear a fly land on top of its cabinet.

73

Mike
WA4DLF
--------------------------------------------
On Fri, 7/25/14, Geoff <geoffrey at jeremy.mv.com> wrote:

 Subject: Re: [ARC5] Stupid Question No.5036
 To: "Mike Everette" <radiocompass at yahoo.com>, "WB5WSV Wayne Eleazer" <releazer at earthlink.net>, "ARC-5 Mail List" <arc5 at mailman.qth.net>, "D C _Mac_ Macdonald" <k2gkk at hotmail.com>
 Date: Friday, July 25, 2014, 10:44 AM
 
 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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