[Boatanchors] 6146 vs 6146A vs 6146B or 6146W

[Glen Zook]

Now the article may have been edited by others.  However, I can assure you that there have been no changes made by me.  The article is the same as was first written in 2002.

As for commercial two-way equipment:  The 6146 family was definitely the mainstay of all the major manufacturers during the tube days and the hybrid days.  Motorola used the 6146 in the vast majority of tube only transmitters on both lowband and highband starting with the "G" series.  They did use the 5894 as the final amplifier in their 60 watt and higher powered highband but used the 6146, in pairs, for the low band units.  General Electric did the same for many of the Progress Line units.

All of the highband and lowband Motrac units, except for the 100 watt lowband units, had at least one 6883 family of tubes in the transmitter.  Those units sold in the hundreds of thousands of units.

Now if your commercial two-way shop friend used you to modify units then, technically, he was in violation of FCC regulations.  Type acceptance is based on specific designs and any changes from those designs violates type acceptance (now called "certification").  That is why when an amateur radio operator makes component changes to move a unit from commercial frequencies to an amateur radio band removes type acceptance.  However, the vast majority of commercial units that I have ever "moved" to an amateur radio band required only retuning which does not violate type acceptance / certification.

Now as for actually being caught violating FCC design rules:  Today there is virtually no chance of being caught.  But, back until the early 1980s I can assure you that the FCC was very active in monitoring the commercial frequencies for such things as off frequency, improper modulation characteristics, and so forth.  There were numerous monitoring stations set up in all parts of the country.  Today those stations are long gone and FCC monitoring is a mere shell of what it was in the past.

Anyway, I am certain that the vast number of participants in the reflector have long lost interest in the discussion.  In fact, I am sure that a number of them hit the delete button just as soon as they see the topic name.  Therefore I will make this the last post on the subject.

I leave the discussion with the following statements/questions:

In my extensive experience with the 6146 family of tubes I stand by my comments and by what is written in the article.  Over the years I have been associated with well over 50,000 of the 6146 family of tubes (averaging over 100 per week for over 9 years when I owned the Motorola reconditioning center for the south-central U.S. and with decades of experience in the commercial communications market).  Then there is my experience working on well over 1000 amateur radio transmitters using the 6146 family of tubes.

Finally, why did RCA (and a number of the other tube manufacturers) keep on making the earlier versions simultaneously with the later version if the characteristics of the tubes were identical?

Glen, K9STH

Website:  http://k9sth.com