[Boatanchors] 6146 question

[Gary Schafer]

Hi Jim,
I have installed B and W tubes in all three, 32S1, kWM2 and KWM1 and I had to add capacitance to the neutralizing circuit to all. Maybe the HealthKit sb transmitters to but I don’t remember for sure on the HealthKits.
By the way the “B” has more plate disipation than the A and the screen voltage is a little different if I remember correctly.

73
Gary K4FMX

Gary Schafer


> On Jan 28, 2024, at 4:37 PM, w5jo at brightok.net wrote:
> 
> And as I recall the  Collins 32S1 had to be neutralized as did the KWM-1 and 2 when the B tube was installed.  One of those three required a modification to the neutralizing cap, I forget which.   Some of the Japanese radios had to have  neutralizing caps modified too.
> 
> That story all started from the same source, a person who did repair and refurbishment of Motorola gear and worked on a lot of Collins gear.
> 
> I have swapped an A tube and one with no suffix to a W tube without problems.  Also the 6293 (I believe that is the number) will work.  It is a pulse rated 6146.
> 
> Jim
> W5JO
> 
> -----Original Message-----
> 
> Finally some sanity about the nonsense 6146  'white paper' posted at least 63 gazillion times on every single forum on this earth.
> Thanks Darrell.
> 
> The back line story is.....Motorola VHF/UHF FM radios were used in taxicab, garbage truck and other commercial services for decades.
> Each design was FCC type accepted after much testing to ensure the design would work as certified.
> This means that certain ckts were not adjustable....such as the PA neutralization.
> Fixed components were used in the neutralization so when changing 6146 PA tubes, there was no adjustment to be made.
> When the 6146 tubes had a slight design change, the PA was no longer neutralized causing components to burn up.
> Much of this was on UHF 450mhz etc.
> But....that paper will not mention the above...why this was perpetuated for decades is another mystery (well, not really).....most everyone just ignored it.
> As Darrell mentioned....fiction and myths.
> 
> 
> Dave Harmon
> K6XYZ
> Sperry, OK.
> 
> -----Original Message-----
> 
> 
> Don't be spooked by the fiction concerning this tube. I'm thinking of one article on the internet in particular that's be circulating myths about it for decades. Any of them will work fine.
> 
> 73,
> Darrell
> 
> 
> 
> 
>> On 1/28/2024 2:25 PM, Richard Knoppow wrote:
>>     The A and B are essentially similar. I think the A has controlled
>> heater warm up for mobile use. Not a significant difference. The B was
>> redesigned, I think by Sylvania, it is physically larger and may not
>> fit in some equipment designed for the A. It also has different
>> interelectrode capacitances and may be difficult to neutralize in some
>> gear not designed for it. A W in a tube type means it was sold to a
>> government contractor. W tubes sometimes have tighter tolerances on
>> specs. Otherwise they are the same as the A version.
>>     The Ranger has a very good reputation. Worth restoring.
>> 
>>> On 1/28/2024 10:55 AM, corner five wrote:
>>> hi group.
>>> I am the new owner of a viking ranger 1, ver2. fully restored, and
>>> soon to be on the air.  I'm new to the world of tube rigs and wish to
>>> learn as well as do right by my new treasure, so looking for your
>>> thoughts related to the single 6146 final.
>>> .
>>> I have read that there are four variants of the 6146.
>>> => 6146, 6146A, 6146B, 6146W.
>>> My ranger currently has the 6146A installed.  Somewhere down the line
>>> I may need to replace this tube.  From what I read the 6146 and 6146A
>>> are essentially identical and both will work fine in this transmitter.
>>> .
>>> Question: Can I safely use the 6146B?  If so, will I need to change
>>> anything from the current (6146A) setup to accommodate this different
>>> final?  I ask because the "ok" use of the 6146B seems to be yes or no
>>> depending upon what transmitter you are using.
>>> .
>>> Same question for the 6146W.
>>> .
>>> .thanks.
> 
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