[Elecraft] Changes from 100 watts to 10 watts

[N2EY@aol.com]

In a message dated 12/31/02 10:37:26 AM Eastern Standard Time, 
k4wtf@ENTERZONE.NET writes:

> I'm pretty sure that some research went into the 100w "defacto" power
>  level that most of the off-the-shelf HF rigs are capable of.  Otherwise, I
>  can't imagine why everyone would choose around 100w.  It would be
>  interesting to know just what the research was though.
>  
Here's my theory: It all goes back to tubes.

About 1950, RCA developed the 6146 tube, basically as an improvement to the 
prewar 807 and its relatives. 6146 proved very popular with both homebrewers 
and kit manufacturers for a number of reasons, and became probably the most 
popular final amplifier tube in ham gear from about 1951 onwards. Rigs from 
inexpensive Heath and Eico kits to the famous Collins S-line used 6146s. 

6146 was popular because it combined all the needed features of an HF ham 
final tube: low cost, rugged, good power output with low plate voltage and 
low drive, good SSB performance and it could be used from 160-10 in 
conventional circuits. (Some hams used them as high as 2 meters!). 

'50s AM-CW rigs often used either a single 6146 or a pair. When Collins 
produced the S-line in 1958-9, they chose a pair of 6146s in Class AB1, 
resulting in about 100 watts output on CW and 100 watts average on SSB. This 
became the de-facto standard for many rigs, even those which did not use 
6146s.

It became so engrained that the power level break in most contests was set 
around 100 watts RF output. (ARRL uses 150 watts nowadays, which is pretty 
close).

The popularity of grounded-grid linears in ham use just added to the 100 watt 
popularity, because most designs needed 50-100 watts of drive. So a ham could 
start out with a 100 watt class rig, and add the amplifier if/when desired, 
without wasting any RF watts. 

When transistors began replacing tubes in HF ham rigs, the "100 watt" level 
was so engrained that rig designers simply kept the paradigm. This was 
particularly important to hams using amplifiers. 

All because of a bottle from a half century ago.

73 de Jim, N2EY