[Boatanchors] Electronic T/R Switch vs Coaxial Type

[Carl]

Thats like saying all motorcycles have 2 wheels so they must perform the 
same!

The 2 tubes arent even close in specs. Johnson used some engineering 
smarts and the ARRL was just being the ARRL.

Carl
KM1H


----- Original Message ----- 
From: "Bob Macklin" <macklinbob at msn.com>
To: "Carl" <km1h at jeremy.mv.com>; <boatanchors at mailman.qth.net>
Sent: Tuesday, November 04, 2008 7:47 PM
Subject: Re: [Boatanchors] Electronic T/R Switch vs Coaxial Type


> The Johnson T/R switch the 2 stages of 6BL7 is very similar to the 2 
> stages
> of 12AU7 in the 62 ARRL handbook.
>
> Bob Macklin
> K5MYJ
> Kent (Seattle), Wa,
> "Real Radios Glow in the Dark"
>
> ----- Original Message ----- 
> From: "Carl" <km1h at jeremy.mv.com>
> To: "Bob Macklin" <macklinbob at msn.com>; <boatanchors at mailman.qth.net>
> Sent: Tuesday, November 04, 2008 4:39 PM
> Subject: Re: [Boatanchors] Electronic T/R Switch vs Coaxial Type
>
>
>> Im not counting the rectifier and I should have said stages.
>>
>> The early Johnson had one RF stage and the 250-39 had two using a 
>> hefty
>> 6BL7.
>>
>> Carl
>> KM1H
>> ----- Original Message ----- 
>> From: "Bob Macklin" <macklinbob at msn.com>
>> To: "Carl" <km1h at jeremy.mv.com>; <boatanchors at mailman.qth.net>
>> Sent: Tuesday, November 04, 2008 6:13 PM
>> Subject: Re: [Boatanchors] Electronic T/R Switch vs Coaxial Type
>>
>>
>> > The Johnson T/R switch documentation on BAMA has two tubes.
>> >
>> > One is a 6BL7 dual triode. The second is a 6X4 rectifier.
>> >
>> > Mine is a 12AU7 dual triode and the 6X4 rectifier is in my HR-10.
>> >
>> > Bob Macklin
>> > K5MYJ
>> > Kent (Seattle), Wa,
>> > "Real Radios Glow in the Dark"
>> >
>> > ----- Original Message ----- 
>> > From: "Carl" <km1h at jeremy.mv.com>
>> > To: "Bob Macklin" <macklinbob at msn.com>; 
>> > <boatanchors at mailman.qth.net>
>> > Sent: Tuesday, November 04, 2008 2:15 PM
>> > Subject: Re: [Boatanchors] Electronic T/R Switch vs Coaxial Type
>> >
>> >
>> >> There are 2 versions of the Johnson. The early one with a single 
>> >> tube
>> >> is
>> >> the TVI generator, the later 2 tube version is usually OK.
>> >>
>> >> Use a LPF with any rig, even a BC-610; the software for balanced 
>> >> and
>> >> unbalanced lines is online.
>> >>
>> >> Carl
>> >> KM1H
>> >>
>> >>
>> >> ----- Original Message ----- 
>> >> From: "Bob Macklin" <macklinbob at msn.com>
>> >> To: "rbethman" <rbethman at comcast.net>; 
>> >> <boatanchors at mailman.qth.net>
>> >> Cc: "Peter Markavage" <manualman at juno.com>
>> >> Sent: Tuesday, November 04, 2008 3:28 PM
>> >> Subject: Re: [Boatanchors] Electronic T/R Switch vs Coaxial Type
>> >>
>> >>
>> >> > Do modern solid state TVs with cable connections have the same 
>> >> > TVI
>> >> > problems
>> >> > the old tube TVs did?
>> >> >
>> >> > I have a 10 year old Sony that gets RF OVERLOAD when I use my 2M 
>> >> > FM
>> >> > RICEBOX
>> >> > that is about 2ft from it with a 19" whip on it. If I turn the 
>> >> > TV
>> >> > sound off
>> >> > there is no problem with the picture. If I tune to cable channel 
>> >> > 18
>> >> > I
>> >> > do see
>> >> > some RF TVI but not much. CH18 is in the 2M band.
>> >> >
>> >> > I need to try it with the new cable DTV converter.
>> >> >
>> >> > Bob Macklin
>> >> > K5MYJ
>> >> > Kent (Seattle), Wa,
>> >> > "Real Radios Glow in the Dark"
>> >> >
>> >> > ----- Original Message ----- 
>> >> > From: "rbethman" <rbethman at comcast.net>
>> >> > To: <boatanchors at mailman.qth.net>
>> >> > Cc: "Peter Markavage" <manualman at juno.com>
>> >> > Sent: Tuesday, November 04, 2008 12:02 PM
>> >> > Subject: Re: [Boatanchors] Electronic T/R Switch vs Coaxial Type
>> >> >
>> >> >
>> >> >> I, like Pete have been running a Johnson TR Switch on the 
>> >> >> output
>> >> >> of a
>> >> >> BC-610.  NO TVI!  I monitor the output of the BC-610 with an
>> >> >> SM-220
>> >> >> w/BP-8.  I also feed my receiver's IF into the SM-220.  I 
>> >> >> observe
>> >> >> NO
>> >> >> TVI.
>> >> >>
>> >> >> I believe that those getting TVI are mistakenly relating the
>> >> >> source
>> >> >> as
>> >> >> the TR Switch.  I only see TVI when over modulating an Apache.
>> >> >>
>> >> >> Bob - N0DGN
>> >> >>
>> >> >> Peter Markavage wrote:
>> >> >> > I've run a Johnson T-R switch on the Johnson Thunderbolt for
>> >> >> > years
>> >> >> > and
>> >> >> > not experienced any TVI related issues. I also have a Dow-Key
>> >> >> > relay
>> >> >> > on
>> >> >> > the back of my Apache that's been there and working since 
>> >> >> > around
>> >> > 1960/61.
>> >> >> > The Dow-Key on the back of my Viking II has been there and
>> >> >> > running
>> >> >> > since
>> >> >> > 1955. These relays were some of my better investments.
>> >> >> >
>> >> >> > Pete, wa2cwa
>> >> >> >
>> >> >> >
>> >> >> > On Tue, 4 Nov 2008 10:36:39 -0800 "BLIMPY" 
>> >> >> > <blimpboy at sonic.net>
>> >> >> > writes:
>> >> >> >
>> >> >> >> Biased vac tube T/R switches have bad reputation as TVI
>> >> >> >> generators.
>> >> >> >> Many
>> >> >> >> in-line filters are not tolerant of impedence mis-matches
>> >> >> >> expecially
>> >> >> >> those
>> >> >> >> with  reactive components.
>> >> >> >>
>> >> >> >> Run of the Mill Dow Key are second rate relays.. compared to
>> >> >> >> Advance
>> >> >> >> Coaxial
>> >> >> >> Relays.. which are available for less money and will give no
>> >> >> >> grief
>> >> >> >> due to
>> >> >> >> unscheduled liberation of smoke.  Some BNC commerical
>> >> >> >> application
>> >> >> >> surplus
>> >> >> >> relays  with dc  may be contradict this generality.
>> >> >> >>
>> >> >> >> a vox type t/r switch might be a workable compromise, but 
>> >> >> >> not
>> >> >> >> true
>> >> >> >> break-in
>> >> >> >>
>> >> >> >> good luck
>> >> >> >>
>> >> >> >>
>> >> >> >> _______________________________________________
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> > _______________________________________________
>> >> >> >
>> >> >> >
>> >> >>
>> >> >> -- 
>> >> >> Bob - NØDGN
>> >> >>
>> >> >> _______________________________________________
>> >> >>
>> >> >
>> >> > _______________________________________________
>> >> >
>> >>
>> >>
>> >
>> >
>>
>>
>
>