[Elecraft] HF amp kits

[Sandy W5TVW]

I built an HF amplifier kit a couple of years ago.  The HF Packer amplifier. 
It was around $125.  All the parts were there and some things have to be 
done by the builder that normally are "pre fabbed".  Drilling and tapping 
holes, placing parts in enclosures accurately.

The amplifier is fairly small and uses two low priced MOS Power FET 
transistors.  With about 2-3 watts of drive it will produce 35-40 watts of 
output.  Very nice filtering arrangement on the output, switchable froom 
160-10 meters.  Has an RF actuated changeover relay system and it is linear 
for SSB use.  My K1 drives it easily and quite well.

73,

Sandy W5TVW

Google "HF packer" for website and details.
----- Original Message ----- 
From: "David Wilburn" <dave.wilburn at verizon.net>
To: "Elecraft Reflector" <elecraft at mailman.qth.net>
Sent: Thursday, April 05, 2007 4:57 PM
Subject: Re: [Elecraft] HF amp kits


> 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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