[Elecraft] HF amp kits

[David Wilburn]

Just working from memory here, but wasn't there also a limit that the 
amateur could only build one such amp a year?

David Wilburn
dave.wilburn at verizon.net
K4DGW
K2 #5982


Jim Wiley wrote:
> The 15 db rule applies only to manufactured for sale amplifiers.  It 
> does not apply to amplifiers that an individual ham builds for him or 
> herself, particularly when a a kit is not involved..  Section 97.317 of 
> the rules, which is where the 15  db rule appears, applies to the 
> certification of external RF power amplifiers that a manufacturer offers 
> for sale.  Home-made amplifiers do not require certification.  They must 
> still meet some standards, such as those involving purity of emissions 
> (harmonics, for example) and of course must not be operated above 1500 
> watts PEP, but that's pretty much it.
> 
> I am unsure of how the rule applies to kits, but I think they would be 
> considered a "manufactured product" if all the parts needed to complete 
> the amplifier are contained, in the kit.  If, however, a "kit" contained 
> only some of the parts, and could not in itself be assembled into a 
> working amplifier without adding extra parts, then the certification 
> rule probably  would not apply.
> 
> It would be perfectly legal for a ham to build a home-brew grid-driven 
> amplifier that  could take  the 10 watt signal from his K2 and boost it  
> to 1500 watts output.  Such an amplifier would have (roughly) 22 db of 
> gain.   A pair of 4CX800 tubes could accomplish this, I think.   
> Remember also that the old Johnson Thunderbolt could be operated in 
> grid-driven mode, and it had (still has, if you can find one) similar 
> performance, using a pair of 4-400 tubes.
> 
> 
> - Jim, KL7CC
> 
> 
> 
> 
>>
>>> Chris Kantarjiev wrote:
>>>
>>>>
>>>> The Linear Amp kits seem to need a fair amount of drive. I've been
>>>> idly thinking about a linear that would allow me to drive it with
>>>> my barefoot K2 and get 600-800 watts out for CW.
>>>
>>
>> The limit is 15 dB and is still in the requirements despite the  
>> recent loosening of Part 97.  That should give something over 400  
>> watts when driven by a K2. I don't recall whether the "easily- 
>> modifiable" rule is still there, so it may be possible to have an amp  
>> with an attenuator on the front-end (I heard that one of the Tokyo  
>> High Power amps does this, but haven't verified that).
>>
>> 73, Bob N7XY
>>
>>
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