[Elecraft] HF amp kits

[David Wilburn]

Should have read to the end of the posts.  Thanks for the update.  I 
just remembered it from testing.

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


David Wilburn wrote:
>  From the general class question pool.
> 
> G1F02 (B) [97.315a]
> Without a grant of FCC certification, how many external RF
> amplifiers of a given design capable of operation below 144
> MHz may you build or modify in one calendar year?
> A.   None
> B.   1
> C.   5
> D.   10
> 
> 
> Here is the ARRL link to the question pool.
> http://www.arrl.org/arrlvec/el3-release-12-1-03.txt
> 
> David Wilburn
> dave.wilburn at verizon.net
> K4DGW
> K2 #5982
> 
> 
> Jozef Hand-Boniakowski wrote:
>> I have been a ham for 43 plus years (12/23/63) and up to now have not 
>> heard of any such limitation.
>>
>> Jozef WB2MIC
>>
>> David Wilburn wrote:
>>> 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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