[Elecraft] Future of KPA500 & KAT500

[Ken K6MR]

Before the KPA1500 was released, I ran two KPA500s in parallel.  On the high bands, a K3 would not drive both amps to 500 watts.  The NX1P mod enabled a full 1000 W out on all bands.

Ken K6MR

From: Phil Hystad via Elecraft<mailto:elecraft at mailman.qth.net>
Sent: Thursday, June 18, 2020 10:28
To: Gmail - George<mailto:gdanner12 at gmail.com>
Cc: Elecraft at mailman.qth.net<mailto:Elecraft at mailman.qth.net>
Subject: Re: [Elecraft] Future of KPA500 & KAT500

Why would you modify your KPA500 and risk warranty, repair, and clean signals for a mere 1/2 S-Unit at best?



> On Jun 18, 2020, at 9:27 AM, Gmail - George <gdanner12 at gmail.com> wrote:
>
> Paula Keezer NX1P modified a KPA500 to allow it to be driven to about 500
> watts by a KX3.
> She published it - but I can not find it on the web.
> The mod increased the gain by less than 3 db (seems I recall 2.something).
> You would need the 12 to 15 watts to drive it to about 500 watts.
>
> The modification involved removing the input pad and modifying the feed back
> loop to the microprocessor.
> I thought about doing the mod to be able to run a net with my KX3 if my K3
> quit.
> I have a KXPA and decided not to do the modification.
> I can just remove my KX3 & KXPA from my truck if I ever need a backup to
> drive the KPA500. Probably 10 minutes work and find the bag of portable
> cables.
>
> BTW - Ms. Keezer's modification was very detailed and she had many cautions
> regarding doing the modification.
> It defiantly was not a matter of "cutting a jumper" to remove the input pad.
> You need remove the pad parts and change the number of turns in a
> transformer.
>
> Defiantly would void the warranty and make factory repairs iffy depending on
> Elecraft's policies.
> Other manufacturers  I have worked with would restore the amp to factory
> while repairing it.
>
> As a ham you are not limited to the 15 db gain restriction - the
> manufacturer is but not you.
>
> 73
> George AI4VZ
>
> -----Original Message-----
> From: Charlie T
> Sent: Thursday, June 18, 2020 9:06 AM
> To: 'Nr4c'
> Cc: Elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Future of KPA500 & KAT500
>
> Isn't there some sort of "jumper" or ???, that will increase the gain to
> something other than the ridiculous and prohibitive +13 dB figure,  for
> "international" (wink-wink) sales, sorta like the "MARS" mod in almost all
> radios these days?
>
> 99.9% of the chicken band users today are happy with their 5 watt radios.
> However, that restrictive and useless  +13 gain law does NOTHING to stop the
> REALLY big guns on 27.025 who typically run amps using tubes that have
> HANDLES on them!
> (I've personally seen channel 6 mobile set-ups running power in excess of 25
> kilowatts.)
>
> 73, Charlie k3ICH
>
>
>
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On
> Behalf Of Nr4c
> Sent: Wednesday, June 17, 2020 3:14 PM
> To: Paul Gacek <w6png at yahoo.com>
> Cc: Don Putnick <donnieput at gmail.com>; Elecraft Reflector
> <Elecraft at mailman.qth.net>
> Subject: Re: [Elecraft] Future of KPA500 & KAT500
>
> The KAT500 has three antenna out ports. It only needs one In so the KPA500
> needs only one out port.
>
> As for the 10 W in and 500 out idea.  That is prohibited by law. They’re
> only allowed to sell an amp with max gain of 13dB.
>
> Sent from my iPhone
> ...nr4c. bill
>
>
>
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