[Amps] FCC Denies Expert Linears’ Request for Waiver of 15 dB Rule

[Roger (K8RI)]

I think what most posters are missing is the FCC has not ruled on the 15 
db gain limitation.  They simply refused to grant a WAVIER to one 
specific company. The FCC will rule on the 15 db limit for "ALL" 
commercial amps. I believe the commenters to the FCC who were worried 
about the general power level creeping up, the sellers of "legacy" amps 
being limited, or hams exceeding the legal limit are misplaced.   Sure 
there are already hams running far more than the legal limit.  OTOH  
when I run 1500 watts to a 10db gain antenna the ERP is 15 KW in one 
direction.

We have been able to purchase amps that exceed the 15 db limit and far 
exceed the legal limit for years.  They just had to either be imported, 
or home built. IE Tetrode amps from Australia or China. When tuned and 
driven properly, these amps have a very clean signal.

A high gain amp, would have to run 3 KW out for a 3 db advantage. Even 
imported amps capable of that are not cheap!

Also, there is the issue of required overhead in amps capable of running 
the legal limit on any mode, no time limit.  There are really just three 
options. The very expensive auto tune amps, imported amps (neglecting 
those with attenuators on the input), or home brew.  A manual tune amp 
that has enough overhead to run 1.5 KW, any mode with no time limit does 
push the price up a bit.  The biggest problem with Tetrode amps is 
mistuning and driving rigs with ALC controlled output running at reduced 
power. With a Tetrode the screen current is peaked rather than peaking 
the output. It's a minor difference but it makes a noticeable difference 
in the quality of the signal.  Check any of the ARRL handbooks for the 
last 5 years or so.

73

Roger (K8RI)

On 12/28/2016 4:05 AM, Morel Grunberg wrote:
>  From ARRL Bulletin:
>
> FCC Denies Expert Linears’ Request for Waiver of 15 dB Rule, Petition
> Pending
>
> 12/27/2016