[Elecraft] KPA-1500: Gain Mod when FCC Lifts 15db Rule

[Ken K6MR]

“any non-USA ham can bypass the input to enable lower drive
requirements.”

Legal for US hams also. Restriction is just on the manufacturer. You are responsible for your equipment.
My KPA500s are modified for lower drive (thanks to NX1P who did the hard work) so that I can drive two in parallel.

Ken K6MR

From: Edward R Cole<mailto:kl7uw at acsalaska.net>
Sent: Friday, April 21, 2017 5:03 PM
To: Elecraft Reflector<mailto:elecraft at mailman.qth.net>
Subject: Re: [Elecraft] KPA-1500: Gain Mod when FCC Lifts 15db Rule

A little more background for the FCC (USA) gain restriction for HF amplifiers:

I believe that was a result of wanting to stymie CB use of ham
amplifiers using 5-15w drive.  15-dB for 1500w implies 47w min drive.

The LDMOS being used for 1200w on 2m only require 3-4w drive; that is
26-dB gain!  Likely the devices chosen by Elecraft for their KPA1500
have similar gain so they install attenuation into the drive path or
change bias to lower gain (or both).  My guess once the schematic is
available any non-USA ham can bypass the input to enable lower drive
requirements.  A KX2 or KX3 ought to suffice.

Of course this would violate warrantee.

On a similar thought process, now that the KX3 is capable of 15w, I'm
wondering if driving the KXPA100 harder than 8w will result in higher
output?  Would it be safe to do?
I'm thinking 10w/100w.  The KXPA100 I have drives easily to 110w
saturated with about 4-5w on 80-15m, but requires 8w to achieve 70-80w at 6m.

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
   dubususa at gmail.com

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