[Amps] Amps Digest, Vol 174, Issue 9

[Charles Hedrick]

RE: RF2k SS AMP
I'll stick with Alpha, They've been proven for years to hold up under
grueling pressure.  For the buck they'll do the bang....
Charles, WA4JKW

On Mon, Jun 5, 2017 at 1:10 AM, <amps-request at contesting.com> wrote:

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> Today's Topics:
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>    1. Re: RF2K+ LDMOS linear (Ken K6MR)
>    2. Re: RF2K+ LDMOS linear (Jeff AC0C)
>    3. Re: RF2K+ LDMOS linear (Mark Mumaw)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 5 Jun 2017 04:19:38 +0000
> From: Ken K6MR <k6mr at outlook.com>
> To: "amps at contesting.com" <amps at contesting.com>
> Subject: Re: [Amps] RF2K+ LDMOS linear
> Message-ID:
>         <CY4PR13MB1254CFC7E7978FF740DF4AE29ECA0 at CY4PR13MB1254.
> namprd13.prod.outlook.com>
>
> Content-Type: text/plain; charset="Windows-1252"
>
> ?And you need 2 of them for a serious So2r setup?
>
> It?s pretty simple to switch one amp between the radios, so that?s not
> necessarily true.  But the amp must be able to run pretty much key down for
> the whole contest.
>
> My dual KPA500 setup runs full output continuously on RTTY (switched
> between radios) with only occasional maximum fan activation.  I?m hoping
> the same will be true of the KPA1500.
>
> Ken K6MR
>
> From: Jeff AC0C<mailto:keepwalking188 at ac0c.com>
> Sent: Sunday, June 4, 2017 8:34 PM
> To: amps at contesting.com<mailto:amps at contesting.com>; Kevin Stover,
> AC0H<mailto:kstover at ac0h.net>
> Subject: Re: [Amps] RF2K+ LDMOS linear
>
> Sorry for the confusion.  I was thinking of a pair for So2r.
>
> Each kit is over $3K - not including delivery or local parts sourcing.
> Call
> it $4K as a round number.  And you need 2 of them for a serious So2r setup.
> As amps go, I don't see the price as a primary issue.  Serious runs by
> serious contesters are the issue in my mind.
>
> 73/jeff/ac0c
> www.ac0c.com<http://www.ac0c.com>
> alpha-charlie-zero-charlie
>
> -----Original Message-----
> From: Kevin Stover, AC0H
> Sent: Sunday, June 04, 2017 6:22 PM
> To: amps at contesting.com
> Subject: Re: [Amps] RF2K+ LDMOS linear
>
> All fine and good but where on God's green earth did you get $8K?
> The SPE 2K is $8K but were not talking about that amp (^^^subject
> line^^^). We're talking about the German amp kit which sells for a
> kilobuck LESS than the AL-1500 all in.
>
> Without the auto-tuner the kit sells for about $1K more than that pretty
> Eimac 3CX1500A7 in the AL-1500.
>
> On 6/4/2017 12:19 PM, Jeff AC0C wrote:
> > I'm with Steve here.  The old saw of "build a better mouse trap and the
> > world will beat a path to your door" is almost always false because it's
> > hard to believe the hype surrounding stuff.  If an amp maker wants to
> > crank up the sales in the US of their amps, by far the best way would be
> > to put it in the hands of someone who has a good tech reputation in the
> > community, can give it a serious contest workout and who also has the
> > ability to do a basic IMD test.
> >
> > There are many folks of that description.  Before I shovel what is going
> > to be nearly 8K into a box, I really would feel a lot better if I heard
> > that they lived through a couple of contests over at W3LPL, etc and Frank
> > said they hummed along fine.  I'm using LPL as an example here.  My point
> > is advertising and social media and endorsements from guys in EU are a
> lot
> > less meaningful than a country local here in the US.
> >
> > Made the exact same argument to a Chinese maker when he was trying to get
> > going but he unfortunately just could not wrap their head around the
> > marketing aspect of a product roll out.  The ham universe is pretty
> > small - and an endorsement by someone objective and authoritative carries
> > far more weight in this market than in others, especially given the huge
> > financial investment something like this involves.
> >
> > 73/jeff/ac0c
> > www.ac0c.com<http://www.ac0c.com>
> > alpha-charlie-zero-charlie
> >
> > -----Original Message----- From: Jim Thomson
> > Sent: Sunday, June 04, 2017 11:48 AM
> > To: amps at contesting.com
> > Subject: [Amps] RF2K+ LDMOS linear
> >
> > Date: Sun, 04 Jun 2017 07:58:54 -0600
> > From: Steve London <n2icarrl at gmail.com>
> > To: amps at contesting.com
> > Subject: Re: [Amps] RF2K+ LDMOS linear
> >
> > <I would not declare tube amplifiers dead until a legal limit, SS
> > amplifier repeatedly proves itself in serious contest conditions. I'm
> > not talking about the guy who casually makes 500 search-and-pounce
> > QSO's. I'm talking about the balls-to-the-walls, SO2R, all-band guy/gal
> > who operates close to 48 hours, running stations the entire time.
> > Mistakes happen under these conditions - ooops, forgot to change the
> > tornado tuner on the 80 when moving from 3700 to 3800, etc. Or, RF from
> > one amp gets into the other amp and fools it's microprocessor.
> >
> > The only production SS amp that has come close to proving itself under
> > there conditions is the SPE line. Even they aren't perfect. See
> > http://www.3830scores.com/showrumor.php?arg=leadzTgmmcvix . That was an
> > SPE 2K. In all fairness to SPE, see
> > http://www.3830scores.com/showrumor.php?arg=lua4zPgqvqmsK . A pair of
> > SPE 1.3K's that worked flawlessly. (However, not at the legal limit.)
> >
> > I would love to borrow a pair of these RF-Kit amps and put them to
> > serious use in one of my SO2R contest efforts.
> >
> > 73,
> > Steve, N2IC
> >
> > ##  High swr, so what, amp kicks offline at some pre-set threshold.
> > They are already in use across europe...in rtty contests.  Fans  are
> > pwm controlled, so heat is not an issue.   Eff is high at 65-70%.
> > IMD is typ ?40db pep..using the newer german made LP filters.
> > Mark tells me these amps are 100% duty cycle rated, all modes.
> > If they survive a rtty contest, ssb + cw should be a lollygog.
> >
> > ## You are right though...  send some off to contest sites..and really
> > beat
> > on em for the weekend.   Tube amps  days are numbered, the writing is on
> > the wall.
> >
> > Jim   VE7RF
> >
> > _______________________________________________
> > Amps mailing list
> > Amps at contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> > _______________________________________________
> > Amps mailing list
> > Amps at contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
>
> --
> R. Kevin Stover    AC0H
> FISTS #11993
> SKCC #215
> NAQCC #3441
> ARRL
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>
>
> ------------------------------
>
> Message: 2
> Date: Sun, 4 Jun 2017 23:34:30 -0500
> From: "Jeff AC0C" <keepwalking188 at ac0c.com>
> To: "Ken K6MR" <k6mr at outlook.com>,      <amps at contesting.com>
> Subject: Re: [Amps] RF2K+ LDMOS linear
> Message-ID: <FCF1C02B73004BAB873D4D7E527182F0 at w520>
> Content-Type: text/plain; format=flowed; charset="Windows-1252";
>         reply-type=original
>
> For me, especially with RTTY contesting, the capability of running this amp
> on a So2r basis should not be assumed to be workable until it's actually
> proved.  This gets back to my main point.  The gee-whiz it will be perfect
> buzz on a lot of tech really needs to come with a list of disclaimers to
> cover the exceptions and restrictions.  But they never do; meaning the only
> way to really get a handle on them is for someone to get one and give it a
> hard workout.  That would at least be one solid data point.
>
> And you can't really make a compare to the Elecraft stuff - the same issue
> confronts the KPA1500 (it's an unknown new entity - until it's proven in
> combat).  However they have a proven track record of making a decent
> product
> and improving it when there are issues.  These other various guys who want
> to get into the amp biz are unknown entities by comparison and while they
> may build perfect products and have perfect support, to my thinking until
> that's actually proven it needs to seen with a skeptical eye until proven
> otherwise.
>
> 73/jeff/ac0c
> www.ac0c.com
> alpha-charlie-zero-charlie
>
> -----Original Message-----
> From: Ken K6MR
> Sent: Sunday, June 04, 2017 11:19 PM
> To: amps at contesting.com
> Subject: Re: [Amps] RF2K+ LDMOS linear
>
> ?And you need 2 of them for a serious So2r setup?
>
> It?s pretty simple to switch one amp between the radios, so that?s not
> necessarily true.  But the amp must be able to run pretty much key down for
> the whole contest.
>
> My dual KPA500 setup runs full output continuously on RTTY (switched
> between
> radios) with only occasional maximum fan activation.  I?m hoping the same
> will be true of the KPA1500.
>
> Ken K6MR
>
> From: Jeff AC0C<mailto:keepwalking188 at ac0c.com>
> Sent: Sunday, June 4, 2017 8:34 PM
> To: amps at contesting.com<mailto:amps at contesting.com>; Kevin Stover,
> AC0H<mailto:kstover at ac0h.net>
> Subject: Re: [Amps] RF2K+ LDMOS linear
>
> Sorry for the confusion.  I was thinking of a pair for So2r.
>
> Each kit is over $3K - not including delivery or local parts sourcing.
> Call
> it $4K as a round number.  And you need 2 of them for a serious So2r setup.
> As amps go, I don't see the price as a primary issue.  Serious runs by
> serious contesters are the issue in my mind.
>
> 73/jeff/ac0c
> www.ac0c.com<http://www.ac0c.com>
> alpha-charlie-zero-charlie
>
> -----Original Message-----
> From: Kevin Stover, AC0H
> Sent: Sunday, June 04, 2017 6:22 PM
> To: amps at contesting.com
> Subject: Re: [Amps] RF2K+ LDMOS linear
>
> All fine and good but where on God's green earth did you get $8K?
> The SPE 2K is $8K but were not talking about that amp (^^^subject
> line^^^). We're talking about the German amp kit which sells for a
> kilobuck LESS than the AL-1500 all in.
>
> Without the auto-tuner the kit sells for about $1K more than that pretty
> Eimac 3CX1500A7 in the AL-1500.
>
> On 6/4/2017 12:19 PM, Jeff AC0C wrote:
> > I'm with Steve here.  The old saw of "build a better mouse trap and the
> > world will beat a path to your door" is almost always false because it's
> > hard to believe the hype surrounding stuff.  If an amp maker wants to
> > crank up the sales in the US of their amps, by far the best way would be
> > to put it in the hands of someone who has a good tech reputation in the
> > community, can give it a serious contest workout and who also has the
> > ability to do a basic IMD test.
> >
> > There are many folks of that description.  Before I shovel what is going
> > to be nearly 8K into a box, I really would feel a lot better if I heard
> > that they lived through a couple of contests over at W3LPL, etc and Frank
> > said they hummed along fine.  I'm using LPL as an example here.  My point
> > is advertising and social media and endorsements from guys in EU are a
> lot
> > less meaningful than a country local here in the US.
> >
> > Made the exact same argument to a Chinese maker when he was trying to get
> > going but he unfortunately just could not wrap their head around the
> > marketing aspect of a product roll out.  The ham universe is pretty
> > small - and an endorsement by someone objective and authoritative carries
> > far more weight in this market than in others, especially given the huge
> > financial investment something like this involves.
> >
> > 73/jeff/ac0c
> > www.ac0c.com<http://www.ac0c.com>
> > alpha-charlie-zero-charlie
> >
> > -----Original Message----- From: Jim Thomson
> > Sent: Sunday, June 04, 2017 11:48 AM
> > To: amps at contesting.com
> > Subject: [Amps] RF2K+ LDMOS linear
> >
> > Date: Sun, 04 Jun 2017 07:58:54 -0600
> > From: Steve London <n2icarrl at gmail.com>
> > To: amps at contesting.com
> > Subject: Re: [Amps] RF2K+ LDMOS linear
> >
> > <I would not declare tube amplifiers dead until a legal limit, SS
> > amplifier repeatedly proves itself in serious contest conditions. I'm
> > not talking about the guy who casually makes 500 search-and-pounce
> > QSO's. I'm talking about the balls-to-the-walls, SO2R, all-band guy/gal
> > who operates close to 48 hours, running stations the entire time.
> > Mistakes happen under these conditions - ooops, forgot to change the
> > tornado tuner on the 80 when moving from 3700 to 3800, etc. Or, RF from
> > one amp gets into the other amp and fools it's microprocessor.
> >
> > The only production SS amp that has come close to proving itself under
> > there conditions is the SPE line. Even they aren't perfect. See
> > http://www.3830scores.com/showrumor.php?arg=leadzTgmmcvix . That was an
> > SPE 2K. In all fairness to SPE, see
> > http://www.3830scores.com/showrumor.php?arg=lua4zPgqvqmsK . A pair of
> > SPE 1.3K's that worked flawlessly. (However, not at the legal limit.)
> >
> > I would love to borrow a pair of these RF-Kit amps and put them to
> > serious use in one of my SO2R contest efforts.
> >
> > 73,
> > Steve, N2IC
> >
> > ##  High swr, so what, amp kicks offline at some pre-set threshold.
> > They are already in use across europe...in rtty contests.  Fans  are
> > pwm controlled, so heat is not an issue.   Eff is high at 65-70%.
> > IMD is typ ?40db pep..using the newer german made LP filters.
> > Mark tells me these amps are 100% duty cycle rated, all modes.
> > If they survive a rtty contest, ssb + cw should be a lollygog.
> >
> > ## You are right though...  send some off to contest sites..and really
> > beat
> > on em for the weekend.   Tube amps  days are numbered, the writing is on
> > the wall.
> >
> > Jim   VE7RF
> >
> > _______________________________________________
> > Amps mailing list
> > Amps at contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> > _______________________________________________
> > Amps mailing list
> > Amps at contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
>
> --
> R. Kevin Stover    AC0H
> FISTS #11993
> SKCC #215
> NAQCC #3441
> ARRL
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
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> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> ------------------------------
>
> Message: 3
> Date: Sun, 4 Jun 2017 15:51:15 -0700
> From: Mark Mumaw <nu6x at esedona.net>
> To: amps at contesting.com, WH7W.us at gmail.com, WH7W at arrl.net
> Subject: Re: [Amps] RF2K+ LDMOS linear
> Message-ID: <247f8452-625f-c654-17a8-e4e61902cc6e at esedona.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> I am still_*not*_ getting messages to my email so I hope this goes to
> the proper thread.
>
> I have built several LDMOS linears over the last 5 years. I completed
> one last year using  most of the components that are now in the RF2K+. I
> used the same exact extruded  heat sink (10" x 10" x 3.5") and the same
> 80MM  38 CFM fans used by W6PQL legal limit design used by Mark, WH7W.
> Most recently, I  built the current RF2K+ kit  and have compared the
> two. The RF2K+ heat sink is a more modern (and expensive) design that
> has a significantly greater surface area of serrated cooling fins. The
> C/W/3" thermal rating is over double the extruded heat sink.  The RF2K+
> heat sink is not an extruded and provides a  greater surface area with
> less weight. In addition, the standard 120MM fans are in a push-pull
> arrangement for a total of 150 CFM (vs 114CFM ) at  standard speed and
> 30% more when jumpered to run on 14.7 Vdc.  110 CFM fans (220 CFM
> total)  could also be used at the expense of more noise.  The benefit of
> 120MM fans over 80MM fans is noise. They can move a lot of air with less
> noise. In addition, we benefit from the development on the water cooled
> radiator PC  fan market. It  has resulted is some amazing performance.
>
> In a A/B test clearly the newer RF2K+ heat sink/fan arrangement runs
> cooler and with less noise. In addition, the PWM speed control keeps the
> linear almost silent  during casual operating and speeds up as needed.
>
> BTW, I have a Acom 2000A which is still my most quiet amp.
>
> It also seems everyone is getting a lot more comfortable running the
> LDMOS devices at high temperatures. Where as a few years ago I preferred
> to keep them under 55C, the manufactures are running them up in the 70
> to 80C range. It does not seem to effect there life. With MTTF of well
> over a million hours with junction temps over 170C, I doubt we will see
> many failures due to heat.
>
> To clarify the comment on diplexed filters,  the 3rd harmonic can be
> down as little as 10db (not IMD products). The RF2K+ with its output
> design, run around 13dB which is still 75 watts at legal limit. Pure
> signal will not have any effect on the 3rd harmonics, only the IMD
> products which are down -37dbc PEP or better.  The RF-kit.de has the 0
> dbm RF monitor ready for Pure Signal. This is exciting technology,
> especially if everyone were to use it. Hopefully Flex will develop their
> version soon.
>
> RF-kit.de has experimented with diplex filter design and will probably
> revisit it again.  The same heat is still generated and needs to be
> removed from the cabinet one way or another. It may be of a greater
> benefit on the efficiency of the LDMOS in addition to heat reduction. My
> very first LDMOS linear used diplexed filter design.
>
> The TRX relays on the RF2K+ are mechanical  that will probably be a
> little noisy for the avid  QSK  CW operator. The software is fast enough
> to keep up but a PIN Diode solution or vacuum relay solution would be
> preferred. That is a project I expect RF-Kit to undertake.
>
> The RF2K+ is just now being released for the US kit builder. I would
> expect it will get exercised in some contests later this year. The Flex
> Power Genius has been in development for almost 1 1/2 years and have
> taken 100s of pre-orders but I don't know of any contest experience to
> date. It will come.
>
> It is great all the choices that Ham radio operators will have !!
>
> 73...Mark NU6X  Sedona, AZ
>
>
> ------------------------------
>
> Subject: Digest Footer
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> ------------------------------
>
> End of Amps Digest, Vol 174, Issue 9
> ************************************
>