[AMPS] CTI ComTEC, Inc.

[Tom Rauch]

> It prompted me to re-read my technical description of our PLA-800 and
> discover the error that was being discussed.

Actually 4CX250's are among the poorest  tubes for IMD. Was you 
amp ever type accepted? What is the TA number? I did an FCC 
database search, and couldn't find it.

You know of course any amplifier of more than one unit per year for 
use below 144 MHz must be type accepted, can not have gain on 
25-35 MHz, and must not include RF T/R switching. It also has 
gain limits, requiring at least 50 watts of drive whether it is 10 watts 
output or 1500 watts in design.    
 
> The issue of screen current regulation was a typo mistake and we apologize
> for any misrepresentation.  The web page has been corrected to say,
> "screen voltage regulation and plate overload protection".  On the issue
> of IMD, if tetrodes can exhibit more IMD, why did Collins, Westinghouse
> and Gates use TETRODES?

1.) Because they needed the high gain

2.) Because they used tetrodes designed for the service they were 
used in

> I am pleased with the use of this forum however, as it can point out
> mistakes or mis interpretations of product manufactures and can be viewed
> as a useful communications  medium.

All advertising and marketing claims about "clean tetrodes" aside, 
if you look at tetrode amps for amateur service they typically have 
much poorer IMD performance than triodes.

When you tested and submitted your TA papers for the amp you 
sell, did you also do a IMD test even though the IMD test is not 
required? I wonder how many manufacturers check to see how 
clean their PA's are before marketing them, since everyone (even 
those selling parts kits to Hams) is required to file and get TA.


73, Tom W8JI
W8JI@contesting.com 

--
FAQ on WWW:               http://www.contesting.com/FAQ/amps
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com