Hi Jim,
thanks for your KPA500 issue update and returning the thread to its original
point there.
Let us know the results once you gets there.
Ahoj,
Petr
-
73 - Petr, OK1RP
"Apple & Elecraft freak"
B:http://ok1rp.blogspot.com
MeWe: https://bit.ly/2HGPoDx
MeWe: https://bit.ly/2FmwvDt
--
S
craft-boun...@mailman.qth.net on
behalf of K9MA
Sent: 11 February 2020 17:11
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] QRO - KPA500 Failure
That's very high efficiency for a solid-state amplifier. Are they
operating in class C? Are there any IMD specs at those output levels?
That's very high efficiency for a solid-state amplifier. Are they
operating in class C? Are there any IMD specs at those output levels?
73,
Scott K9MA
On 2/11/2020 03:18, Edward R Cole wrote:
I checked the operating specs on two of my QRO amps. Not a KPA500.
2m-1500w PA using a MRF1K50 in
I checked the operating specs on two of my QRO amps. Not a KPA500.
2m-1500w PA using a MRF1K50 in class AB:
945w 1398w dc 67% eff 453w disp
1511w 1888w dc 80% eff 377w disp
2m-1200w PA using a MRFE6VP61K25H in class AB:
566w 1200w dc 47% eff 634w disp
1133w 1542w dc 73% eff 409w disp
les
UPDATE:
Jack/W6FB contacted me directly shortly after posting. I sent him my fault
log to analyze and a detailed description of my equipment setup. Best guess
is a cable or antenna failure causing high SWR sometime in the recent past
that stressed the finals. They gave up the ghost when I was runn
From: elecraft-boun...@mailman.qth.net On
Behalf Of Bob McGraw K4TAX
Sent: Monday 10 February 2020 18:47
To: Andy Durbin
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] QRO - KPA500 Failure
Unless one is concerned about power consumption, the efficiency factor should
be really of no concern.
Sent: Monday 10 February 2020 18:47
To: Andy Durbin
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] QRO - KPA500 Failure
Unless one is concerned about power consumption, the efficiency factor should
be really of no concern. Total heat output will always be greater at maximum
output and
Yes, I was wondering why this was so interesting.
Chuck Jack Hawley
KE9UW
Sent from my iPhone, cjack
> On Feb 10, 2020, at 12:47 PM, Bob McGraw K4TAX wrote:
>
> Unless one is concerned about power consumption, the efficiency factor should
> be really of no concern. Total heat output will
Unless one is concerned about power consumption, the efficiency factor should
be really of no concern. Total heat output will always be greater at maximum
output and less at lower power. Nice for warming the shack on a Winter day.
Bob, K4TAX
Sent from my iPhone
> On Feb 10, 2020, at 12:
: [Elecraft] QRO - KPA500 Failure
"I understand that efficiency decreases as one derates from
the maximum of 1500W output.It surprises me that the power dissipated would
peak at half power output or 750
Watts."
I have no test data for the KPA1500 and will not speculate on the sh
to 600W for RTTY.
73 Doug EI2CNSent from my Samsung Galaxy smartphone.
Original message From: K9MA Date:
10/02/2020 16:29 (GMT+00:00) To: elecraft@mailman.qth.net Subject: Re:
[Elecraft] QRO - KPA500 Failure Several others have posted test data for the
KPA500 here
"I understand that efficiency decreases as one derates from the maximum of
1500W output.It surprises me that the power dissipated would peak at half power
output or 750 Watts."
I have no test data for the KPA1500 and will not speculate on the shape of the
PA dissipation curves. All I have is d
this but maybe some guidance from Elecraft itself would be
helpful for both KPA 500 and 1500.
73 Doug EI2CN
From: Andy Durbin
Sent: Monday 10 February 2020 14:04
To: Doug Turnbull ; elecraft@mailman.qth.net
Subject: Re: [Elecraft] QRO - KPA500 Failure
from Elecraft itself would be
> helpful for both KPA 500 and 1500.
>
> 73 Doug EI2CN
>
>
>
> From: Andy Durbin
> Sent: Monday 10 February 2020 14:04
> To: Doug Turnbull ; elecraft@mailman.qth.net
> Subject: Re: [Elecraft] QRO - KPA500
To: Doug Turnbull ; elecraft@mailman.qth.net
Subject: Re: [Elecraft] QRO - KPA500 Failure
Doug,
"I would like to know if running 2/3, 1/2 or even 1/4 maximum power output
increases reliability and MTBF."
I have no experience of amplifier design but I would expect reliability of
Doug,
"I would like to know if running 2/3, 1/2 or even 1/4 maximum power output
increases reliability and MTBF."
I have no experience of amplifier design but I would expect reliability of the
finals to depend on temperature. Finals temperature will depend on the power
dissipated in the fina
Andy,
Yes, you are right and this applies to both KPA 500 and KPA 1500.The
conditions for maximum efficiency are not necessarily those for minimum
dissipation or reduced stress.I would like to know if running 2/3, 1/2
or even 1/4 maximum power output increases reliability and MTBF.I
John,
You are correct. I am seeing a lot of confusion and erroneous
conclusions based on the terms 'efficiency', 'dissipation' coupled with
'power output'.
As an example, consider that a PA running at 50% efficient at 500 watts
will dissipate 500 watts of heat and 500 watts of power out. Inp
Jim,
maybe it is not your case but check this first:
http://ok1rp.blogspot.com/2017/02/elecraft-kpa500-lpf-tr-switch-rework.html?_sm_au_=iQWn28RMHPpHWSZ6cLpsvK618Vf61
-
73 - Petr, OK1RP
"Apple & Elecraft freak"
B:http://ok1rp.blogspot.com
MeWe: https://bit.ly/2HGPoDx
MeWe: https://bit.ly
There may be reasons for running at less than the amplifier max such
as the US 200 watt 30m band limitation. I have no RF engineering
knowledge but after looking at your data I see less heat with lower
output wattage which seems to me like it would be less stress on finals.
John KK9A
Bob
I run my KPA500 output just below the level I feel I can get away
with...without lighting up the neighborhood. About 350 watts :)
John K7FD
> On Feb 6, 2020, at 2:06 PM, Bob McGraw K4TAX wrote:
>
> I've never seen much if any advantage in running a linear below its rated
> output. I know the
"Basically, based on Bob's measurements, the power dissipated is fairly
independent of drive level. So, running at reduced power really isn't stressing
anything any more that full output."
I have done quite extensive testing of my KPA500 and provided links to my
results. My KPA500 PA dissipati
Basically, based on Bob's measurements, the power dissipated is fairly
independent of drive level. So, running at reduced power really isn't
stressing anything any more that full output. (Unlike an "ideal" class B
amplifier.)
73,
Scott K9MA
On 2/6/2020 16:06, Bob McGraw K4TAX wrote:
I've ne
The advantage I have is that it doesn't set off my fire alarm.
On Thu, 6 Feb 2020, Bob McGraw K4TAX wrote:
I've never seen much if any advantage in running a linear below its
rated output. I know the regulation state never run more power than
needed for adequate communications or terms like t
When I blew the final on my KPA500 Elecraft diagnosed the problem. I had to
make a few meter readings and they figured out the problem. They gave me
the option of removing the transformer for shipping (most of the amp
weight). They gave me instructions to remove and reassemble when it
returned.
As a follow up to my previous message I measured PA voltage and current for
OPER mode not keyed and OPER mode keyed with no RF drive input.
PAI not keyed .0, keyed .2
PAV not keyed 80.9, keyed 77.8
Hi reflected power fault can't happen with no drive so won't influence the
results.
Andy
I've never seen much if any advantage in running a linear below its
rated output. I know the regulation state never run more power than
needed for adequate communications or terms like that. The difference
between 500 watts and 100 watts is 6.9 dB or about 1 S unit.
In fact, most all of th
Elecraft self-insures on outbound shipments (i.e., shipments from Elecraft
to customer). That means they accept the responsibility of carrier loss or
damage because their history of loss/damage has been low.
The fact that they self-insure doesn't cover shipments to them unless the
company is payi
They self-insure OUTbound from Elecraft; it falls on the shipper to
insure, not the recipient.
I had to send in the RF deck (only) of the KPA1500 for factory upgrades
and I asked for Elecraft to cover shipping. I waited a few days.
An hour after I got back from shipping it UPS from Idaho (th
I'm not sure who asked the question first, but check your email from
Elecraft support about shipping. I was told Elecraft self-insures, so my
shipping of my KPA1500 amp from Portland, OR to the mothership was
around $20.
On Thu, 6 Feb 2020, Rick Bates, NK7I wrote:
While also not cheap in shippin
Hi Rick,
I like your call sign! :)
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources
On 2/6/20 1:07 PM, Rick Bates, NK7I wrote:
Since the SWR is still nominal into the amp (as shown on your r
Since the SWR is still nominal into the amp (as shown on your radio),
it's not likely the tuned input circuits (which is confirmed from no
output on all bands).
This points to the high power module. Running low output power from it,
is far less efficient than pushing it hard (compare wattages
Amps making noises like that usually mean you have to take the covers off.
They are easy enough to repair if you are so inclined. If not, then you
will need to contact Elecraft support and odds are you will have to send it
home for a Spa day.
Mike va3mw
On Thu, Feb 6, 2020 at 3:35 PM Jim Brown
On 2/6/2020 12:15 PM, Jim Mullen wrote:
Any pointers of where to start looking?
1) What SWR does the rig see with the amp off?
2) Make notes of any error messages given by the KPA500 display.
3) Call Elecraft Support
73, Jim K9YC
__
E
Guys,
On the other hand, there nothing wrong with trying to characterize the
beastie you have as best you can. If for no other reason to see if
something changes with time and how much.
Also, how does my kit comparing to other kits which presumable have
similar but not identical characteristi
Tony,
All you say is true. and should be heeded by all hams.
I have dummy loads that are known to be flat (within 5%) to 1 GHz, and I
have several more that are flat to within 500 MHz. Others will display
the same characteristics to 60 MHz. I know which ones are which, and I
rely on them to
Guy and all,
You are so correct. This is ham radio, and precision instrumentation
for power output levels is not the norm - a 20% error potential should
always be considered.
Yes, I personally have power instrumentation that is calibrated to the 5
% level up to 30 MHz. That level of precision
> On Tue, Feb 7, 2012 at 3:23 PM, wrote:
>
>>
>> Is your dummy load absolutely a flat 1.0:1 from 1.0MHz to 30MHz?
Suppose that the SWR is 1.2. This means that 0.8% of the power is
reflected (80 milliwatts reflected for 10 forward). If the SWR is 1.1,
the reflected power is 0.2%. A
Hmmm,
Given that ham-affordable components are full of minor and harmless
frequency dependent characteristics, INCLUDING the antennas and dummy loads
used, is there really any good reason to EXPECT 1.8-30 power output
uniformity beyond what is commonly measured? Quite contrary to amps which
were
Is your dummy load absolutely a flat 1.0:1 from 1.0MHz to 30MHz?
73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member
"Only the white eyes would believe they could cut the top
off a blanket, sew it to the bottom and have a longer
blanket."
-- American Indian comment abo
When the KPA100 (the K2's 100w amplifier stage) came out, some of us noted
similar issues.
The gain available from a transistor varies in the opposite direction to
frequency, and
the circuits include feedback mechanisms to try to balance it. The
characteristics of real
components have some ef
Guys,
I'm also curious about this-- especially what's going on on 15M.
My values at 500 W out into a dummy load are:
(amp), [volts], {efficiency}
1.8MHz DC (11.5) [63.1] {70}
3.5MHz (11.2) [63.5] {71}
7MHz(12.2) [62.5] {67}
10.1MHz (not measured)
14MHz (13.4)[61.8] {
Given that the poster is in the UK can probably assume 240Vac.
Regards,
Mike VP8NO
On 04/02/2012 17:31, Jack Berry wrote:
> 120 or 240 volts supply?
>
> On Feb 4, 2012, at 2:27 PM, david park wrote:
>
>> I have recently assembled KPA500 serial number 641. When testing into a
>> dummy load I f
120 or 240 volts supply?
On Feb 4, 2012, at 2:27 PM, david park wrote:
> I have recently assembled KPA500 serial number 641. When testing into a
> dummy load I find that I get a large variation in the DC power input when
> driving for 500W CW when I go from band to band. My worst band is 21MH
Hi Eric,
That is what I hoped to hear. I also had a response off list from a
dedicated tester who "tested" this. It is good to know there is a good
chance of surviving an occasional oops.
73,
Chuck, W5UXH
Eric Swartz - WA6HHQ, Elecraft wrote:
>
> Hi Chuck,
>
> We immediately protect the am
Hi Chuck,
We immediately protect the amp by going into bypass mode. The
microprocessor detects the extreme SWR event and immediately routes the
drive signal around the amp, initially though the diodes, and then
through the bypass relay after it has switched. This happens in a few
milliseconds.
There was a bit of talk on this and hopefully not having to use two y
cables etc. I think Elecraft said that this issue would be addressed
with the new cable.
I hope so.
On 4/24/2011 2:09 PM, AB3EN wrote:
> Will the KPAK3AUX have a provision to tap the CTRL line?? I have the PR6
> Low-Noise 6-
On May 23, 2006, at 4:08 PM, Roland Whitsitt wrote:
A lot of us here will never be able to afford an amp if it's 5k. I
hope elecraft remembers that. I bet most of us wouldn't mind less
bells and whistles just to get a few hundred watts out there.
Maybe a poor-mans amp? to go with my bu
On Tue, 23 May 2006, Ken Alexander wrote:
Same here. At those prices the amps are completely
out of reach.
I understand the amps are of modular construction. I
wonder if Elecraft would consider selling each module
separately? That way you could buy and build one when
you can save the money,
Same here. At those prices the amps are completely
out of reach.
I understand the amps are of modular construction. I
wonder if Elecraft would consider selling each module
separately? That way you could buy and build one when
you can save the money, then buy another one when the
next payday c
Roland (and others),
While I agree with your point, the fact of the matter is that Elecraft was
responding to the needs of a contest amplifier. Yes, the amp is out of my
league financially, but it still fits a marketing niche. More power to them.
Cheap amps can be purchase down the bloc
This coupled with the RF topic seems appropriate because running an amplifier I
have RF no matter what in the world I do, and I tried everything under the sun.
As was mentioned my shack is on the upper floor level with the antenna system
outside and not far away which is the real problem. I hate
You should have seen the look of mischievous delight in his face while
he was telling me this story for the first time. You are having too
much fun.
73's
Bob
N4HY
Eric Swartz - WA6HHQ, Elecraft wrote:
Actually the APT ARF463 is a better device. It has been an excellent,
and rugged, device f
Actually the APT ARF463 is a better device. It has been an excellent,
and rugged, device for use in the KPA800 and KPA1500 amps. It has been
very hard to kill in our destructive testing. The only time I've blown
one up was when I forgot to screw it down to the heat sink! (It made a
great firec
It'll also match a 4:1 SWR at 1000 Watts.
73,
Tom N0SS
At 06:04 PM 5/22/2006, Earl W Cunningham wrote:
Lou wrote:
"...but the Elecraft will only match 3:1 at 1500 watts, not a lot of
room."
==
It means a lot when you consider that the Alpha and Acom amps fault at
2:1.
73, de Earl,
The latter will be my approach for SO2R contesting eventually. Given
the features already leaked, it is clear this amp is aimed at the
contesting crowd as one of the primary potential customers. Anyone
know of any other amp out there at any price with dual inputs and
outputs with auto-bandswit
No, it should be here & I know which one it is and I was hoping for
a better device.
http://www.advancedpower.com/rfdisplay/default.aspx?marketid=13&appid=-1
On May 22, 2006, at 3:18 PM, Bill NY9H wrote:
it an APT device
http://www.advancedpower.com/rfdisplay/default.aspx?
marketid=3:4
Lou wrote:
"...but the Elecraft will only match 3:1 at 1500 watts, not a lot of
room."
==
It means a lot when you consider that the Alpha and Acom amps fault at
2:1.
73, de Earl, K6SE
___
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
Y
One of the Alpha customers allegedly burned down his house by performing a
"stupid antenna trick". (Unmatched antenna in unfortunate proximity to his
deck)
Ed Lambert KD3Y
> ...but at these voltages and currents...
___
Elecraft mailing list
Post to:
True, but the Elecraft will only match 3:1 at 1500 watts, not a lot of
room.
Lou
-Original Message-
From: Ed Lambert [mailto:[EMAIL PROTECTED]
Sent: Monday, May 22, 2006 5:11 PM
To: [EMAIL PROTECTED]; Elecraft@mailman.qth.net
Subject: RE: [Elecraft] QRO
Antenna tuning in addition to
Antenna tuning in addition to auto tuning is a very desirable feature for
me. The Elecraft amps include antenna tuning in addition to auto tuning.
Alpha says they are working on an antenna tuner. So, add the cost of that
unit to the $9100.00. Of course, tube amplifiers are maybe not as sensitive
to
At 02:19 PM 5/22/2006, Lou Laderman wrote:
>Isn't "conventional wisdom" that tube-based amplifiers are inherently
>more rugged and forgiving that transistor amplifiers, easier to work on
>or repair in the field, and that tube amps are the "way to go?"
>Has that changed, and other than price alone,
At 04:19 PM 5/22/2006, Lou Laderman wrote:
and other than price alone, why should I consider the
new Elecraft amp over a tube design featuring auto tuning such as the
Acom or the Alpha (older 87A or the new 9500)?
1. the auto tune in the kpa 800/1500 will be faster, since there are
no induc
Isn't "conventional wisdom" that tube-based amplifiers are inherently
more rugged and forgiving that transistor amplifiers, easier to work on
or repair in the field, and that tube amps are the "way to go?"
Has that changed, and other than price alone, why should I consider the
new Elecraft amp ove
Ten Tec also sells ready made enclosures, steel or aluminum :
http://www.tentec.com/
Rich k2cpe
K2 #1102
---
Brian F. Wruble wrote:
I have always wanted to try building one of those big amplifiers.
One thing
t
Non-K2 owners - take note:
It is not even necessary to have one K2 to drive the Elecraft amp. Of
course, many would also like to have the K2 as one or both transcivers.
Don W3FPR
-Original Message-
I had not yet thought that thru,,, Since the amp take 2 rigs,
elecraft was wise to figure
tom said:
you can actually have two DIFFERENT rigs connected at the same time
and still control the amp with EITHER rig.,,
I had not yet thought that thru,,, Since the amp take 2 rigs,
elecraft was wise to figure the other radio might not be a K2
!!! COOL..
good to see ya To
This means more power splitters and combiners!
Can someone please tell us exactly which mosfets are used in the KPA800?
On May 22, 2006, at 11:00 AM, Ed Lambert wrote:
The big amp uses 16 FET's (not Motorola but I can't remember which
ones)
or <[EMAIL PROTECTED]>
To: elecraft@mailman.qth.net
Sent: Mon, 22 May 2006 11:23:57 -0400
Subject: Re: [Elecraft] QRO
I'm curious, what makes RF amplifiers fairly expensive projects? I
admit I have no experience or exposure to them, but as far as I can
tell the two major building blocks are a pow
Brian F. Wruble wrote:
I have always wanted to try building one of those big amplifiers. One thing
that stops me is that I have no idea where you get or how you build all the
"sheet metal" parts --- complicated pieces of chassis, etc. Anybody out
there who knows how people manage to build or so
Brian,
In the past, there were 3 basic options; I suspect they are the same today:
1. Buy a standard sized box to use as the chassis; use a drill press
to drill small screw holes after your layout is determined and
inked in the box. Use a chassis punch set to cut the larger
hol
hanks. 73 de Brian W3BW
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Vic K2VCO
Sent: Monday, May 22, 2006 12:40
To: michael taylor
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] QRO
michael taylor wrote:
> I'm curious, what makes RF
michael taylor wrote:
I'm curious, what makes RF amplifiers fairly expensive projects?
Tube amplifiers are expensive because high power components (HV variable
capacitors, high power bandswitches, power transformers, tubes, sockets,
etc.) are expensive. In addition, although the basic circu
For me it is the cost of the tube ~$600, the enclosures (I was planning to
purchase new) ~$300 -$400, power supply transformer ~$500 - $600, power
supply capacitor ~$400 -$500, vacuum variable capacitors several hundred
dollars, etc.
I was planning to purchase all new; considerable savings by look
to sell in the
next 7 years?
73 de Jim, N2EY
-Original Message-
From: michael taylor <[EMAIL PROTECTED]>
To: elecraft@mailman.qth.net
Sent: Mon, 22 May 2006 11:23:57 -0400
Subject: Re: [Elecraft] QRO
I'm curious, what makes RF amplifiers fairly expensive projects? I
On 5/22/06, Ed Lambert <[EMAIL PROTECTED]> wrote:
I am no expert on QRO but I am in the process of building the 3CX1500D7 amp
in the 2006 handbook. I am as interested in the engineering aspects of QRO
as in the engineering aspects of QRP.
The economics of my project are getting a little out of h
Hello,
I recently reactivated a Swan linear and an older Hallicrafter HT33A, When
I exceeded about 500 watts on 40 or 80, the GFI breaker in the upstairs
bathroom would trip and the electric bed also upstairs would start
running. (A real No-No if the XYL was in it). I had a lot of bothersom
Bill, K3UJ wrote:
With the possible eminent presentation of a VERY QRO amplifier to the
Elecraft family, there is certain to be a number of us, with only QRP
experience,
jumping in and "playing" with gobs of RF energy for the very first time.
Let's
hear it from those with experience, some d
On Mar 10, 2005, at 1:36 PM, ANNE NORMAN wrote:
From: Pete Norman, g0pks.
I've come across some very neat, physically small, switch mode power
supplies, rated at 23A. Is the general consensus that these are A
Good Thing or To Be Avoided At All Costs?
I'll be needing to equip myself with
On Thu, Mar 10, 2005 at 06:36:21PM -, ANNE NORMAN wrote:
> From: Pete Norman, g0pks.
>
> I've come across some very neat, physically small, switch mode power
> supplies, rated at 23A. Is the general consensus that these are A
> Good Thing or To Be Avoided At All Costs?
>
> I'll be needing
I use a 23A switch-mode Samlex, and I'm very happy with it
de John/W1RT
On Thu, 10 Mar 2005 18:36:21 -, ANNE NORMAN
<[EMAIL PROTECTED]> wrote:
> From: Pete Norman, g0pks.
>
> I've come across some very neat, physically small, switch mode power
> supplies, rated at 23A. Is the general co
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