Re: [Elecraft] KPA500 troubles

[Eric Swartz - WA6HHQ, Elecraft]

Probably best to change the topic of this, as it has drifted into a different 
area.

Eric
/elecraft.com/

On 11/13/2015 9:01 PM, Jim Brown wrote:

On Fri,11/13/2015 1:30 PM, Wes (N7WS) wrote:
Note, there is no mention of any directivity, or lack thereof, so I would 
take it that this is a theoretical free-space value.


One could do that, of course, but your original post brought ground 
conductivity into the computation, which is, IMO, entirely appropriate.


FWIW, I've done some extensive modeling studies of horizontal and vertical 
antennas at various mounting heights; horizontal antennas don't care much 
about soil but care a lot about height; vertical antennas care a bit about 
height and a lot about soil. That work is on my website.


I think I would use average gain of the antenna as installed as the basis for 
compliance with the Rules, but the question remains, what height for the 
dipole? :)


This is, for me, purely academic. My soil being terrible, a vertical is a poor 
choice for 60M, and I have a bunch of high horizontal dipoles, so I'd use one 
of them. :)


BTW -- there's a 2-part piece on this topic by Rudy Severns in QEX this past 
summer, specifically addressing very short verticals for the 630m band.


73, Jim K9YC
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Re: [Elecraft] KPA500 troubles

[Wes (N7WS)]

Why would one filter, that like just like all of the others is switched into the 
circuit by a relay on each end, fail while none of the others do not?


On 11/11/2015 1:32 PM, Jim Brown wrote:


The LPF is on the output of the amplifier. One possible cause of failure could 
be lightning.


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Re: [Elecraft] KPA500 troubles

[Wes (N7WS)]

Then I guess I could just "vaguely" follow the rules, sort of like the 
President, his cabinet, the heads of the alphabet soup agencies, IRS, EPA, FBI, 
NSA, VA, ICE, DHS,... do.


That said, I think you're making this too complicated.  The rule states:

   "For the purpose of computing ERP, the transmitter PEP will be multiplied by
   the antenna gain relative to a half-wave dipole antenna. A half-wave dipole
   antenna will be presumed to have a gain of 1 (0 dBd). Licensees using other
   antennas must maintain in their station records either the antenna
   manufacturer's data on the antenna gain or calculations of the antenna gain."


Note, there is no mention of any directivity, or lack thereof, so I would take 
it that this is a theoretical free-space value.  Zero dBd is equal to 2.15 dBi 
so modelling another antenna and calculating its gain in dBi, which is the 
normal modelling outcome, then subtracting 2.15 from that number yields the gain 
relative to an ideal dipole, i.e the FCC reference.


Right away this gives a significant advantage to an actual horizontal dipole 
that has ground gain, assuming that the dipole is rotatable and the elevation 
angle is favorable for the path. Absent that, and considering the physical size 
one would probably use a vertical and bump up the power to account for the 
inevitable losses.


Wes  N7WS


On 11/12/2015 3:12 PM, Jim Brown wrote:
Your point is, of course, well taken, Wes. BUT -- there's a certain vagueness 
to the FCC definition, in that it does not specify mounting height of the 
reference dipole, making comparisons to a vertical antenna, which relates to 
mounting height quite differently, at least a bit squishy.


73, Jim K9YC



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Re: [Elecraft] KPA500 troubles

[Jim Brown]

On Fri,11/13/2015 1:30 PM, Wes (N7WS) wrote:
Note, there is no mention of any directivity, or lack thereof, so I 
would take it that this is a theoretical free-space value.


One could do that, of course, but your original post brought ground 
conductivity into the computation, which is, IMO, entirely appropriate.


FWIW, I've done some extensive modeling studies of horizontal and 
vertical antennas at various mounting heights; horizontal antennas don't 
care much about soil but care a lot about height; vertical antennas care 
a bit about height and a lot about soil. That work is on my website.


I think I would use average gain of the antenna as installed as the 
basis for compliance with the Rules, but the question remains, what 
height for the dipole? :)


This is, for me, purely academic. My soil being terrible, a vertical is 
a poor choice for 60M, and I have a bunch of high horizontal dipoles, so 
I'd use one of them. :)


BTW -- there's a 2-part piece on this topic by Rudy Severns in QEX this 
past summer, specifically addressing very short verticals for the 630m 
band.


73, Jim K9YC
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Re: [Elecraft] KPA500 troubles

[Walter Underwood]

Eric Swartz was very clear about this in a message to this group yesterday:

"Component failure like this can occur in any manufacturer's radio or amplifier 
for many reasons, such as power line surges, nearby lightning strikes, 
operating with excessive SWR, transmitting into a wrong antenna etc. You do not 
need to be operating on a particular band, or even have the amp or radio on to 
incur lightning damage. This can also cause partial damage to components that 
then shows up as a failure later after additional operation.”

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Nov 13, 2015, at 9:57 PM, Vic Rosenthal  wrote:
> 
> But why would a filter for a band that the operator had never used fail?
> 
> Vic 4X6GP/K2VCO 
> 
>> On 13 Nov 2015, at 11:52 PM, Wes (N7WS)  wrote:
>> 
>> Why would one filter, that like just like all of the others is switched into 
>> the circuit by a relay on each end, fail while none of the others do not?
>> 
>>> On 11/11/2015 1:32 PM, Jim Brown wrote:
>>> 
>>> The LPF is on the output of the amplifier. One possible cause of failure 
>>> could be lightning.
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Re: [Elecraft] KPA500 troubles

[Vic Rosenthal]

But why would a filter for a band that the operator had never used fail?

Vic 4X6GP/K2VCO 

> On 13 Nov 2015, at 11:52 PM, Wes (N7WS)  wrote:
> 
> Why would one filter, that like just like all of the others is switched into 
> the circuit by a relay on each end, fail while none of the others do not?
> 
>> On 11/11/2015 1:32 PM, Jim Brown wrote:
>> 
>> The LPF is on the output of the amplifier. One possible cause of failure 
>> could be lightning.
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Re: [Elecraft] KPA500 troubles

[Wes (N7WS)]

I guess I'll have to repeat myself.

There is no requirement to have a "measured" antenna; calculated gain (loss) is 
permitted.  It's kind of like high school algebra, you just have to show your 
work.  With modern analysis tools such as Eznec, it is almost trivial to do so, 
if you know what you are doing.


Soapbox mode on: When I was first licensed, we were relegated to using the DC 
input (Vp x Ip) as our power limit because it was assumed that we did not have 
the ability to measure RF power accurately.  As technology improved and this was 
no longer the case, the power limit(s) was changed to transmitter output power. 
Now we have been given a band, where like every other service, we get to use 
ERP, since the FCC, giving us the measure of the doubt, assumes that we know how 
to determine it.*  We should, it's a requirement of *§97.13*:


   "(c) Before causing or allowing an amateur station to transmit from any
   place where the operation of the station could cause human exposure to RF
   electromagnetic field levels in excess of those allowed under §1.1310 of
   this chapter, the licensee is required to take certain actions.

   (1) The licensee must perform the routine RF environmental evaluation
   prescribed by §1.1307(b) of this chapter, if the power of the licensee's
   station exceeds the limits given in the following table:"

* Also see 
https://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65.pdf 
where on page 16 it says:


   "Many antenna-modeling programs are based on NEC or MININEC analysis. These
   programs often yield very accurate results. An amateur enters his or her
   antenna dimensions and ground characteristics into the antenna model, and
   the program is then executed to calculate electric and magnetic field
   strengths near the antenna. These programs do require some amount of user
   skill, but the average amateur should not experience too much difficulty in
   using them. The ARRL Web page maintains a list of software vendors who sell
   antenna modeling software (http://www.arrl.org/news/rfsafety)"

Soapbox mode off.

N7WS

On 11/12/2015 1:05 AM, Guy Olinger K2AV wrote:

Kpa500 on 60 is illegal unless you have a *measured and
documented* VERY lossy antenna that would reduce the effective radiated
power to the same as 100 watts on a dipole. The simple 99 percent answer is
that on 60m SHUT OFF the Kpa500 and run 100 watts barefoot.

73, Guy K2AV




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Re: [Elecraft] KPA500 troubles

[Jim Brown]

On Wed,11/11/2015 1:30 PM, Wes (N7WS) wrote:
If I use an inductively-loaded vertical monopole with a minimal ground 
screen over Arizona ground my "dBd gain" might well be several dB 
negative. In which case, I'm allowed to compensate for that, and line 
loss, in determining amplifier output power.  In that, and many other 
events, a 100W transceiver is inadequate, ergo, a KPA500 is not out of 
the question. 


Your point is, of course, well taken, Wes. BUT -- there's a certain 
vagueness to the FCC definition, in that it does not specify mounting 
height of the reference dipole, making comparisons to a vertical 
antenna, which relates to mounting height quite differently, at least a 
bit squishy.


73, Jim K9YC


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Re: [Elecraft] KPA500 troubles

[Guy Olinger K2AV]

Kpa500 on 60 is illegal unless you have a *measured and
documented* VERY lossy antenna that would reduce the effective radiated
power to the same as 100 watts on a dipole. The simple 99 percent answer is
that on 60m SHUT OFF the Kpa500 and run 100 watts barefoot.

73, Guy K2AV

On Thursday, November 12, 2015, W4GRJ  wrote:

> Since I have never operated on 60m ever... You figure it out
> Jack
> W4GRJ
>
> On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via Elecraft] <
> ml-node+s365791n7610243...@n2.nabble.com > wrote:
>
> On Wed,11/11/2015 12:10 PM, W4GRJ wrote:
> > Got the KPA500 back from Elecraft.
> > Problem found: L22 and other components in the 60M low pass filter
> circuit
> > burnt through the LPF PCB.
>
> 60M LPF??? Last I looked, the US power limit on 60M is 100W relative to
> a half wave dipole.
>
>
>
> > Repair $650 later: Replaced low pass filter module and installed QSK mod.
> >
> > On the phone I asked what caused the failure, answer was no idea other
> than
> > component failure. I understand stuff fails but I thought I would get
> more than 2 years before a major expensive failure.
>
> The LPF is on the output of the amplifier. One possible cause of failure
> could be lightning.
>
> > Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it
> to
> > purchase the KPA500.
> >
> > Sometimes the grass is not greener.
>
> My only experience with an ALS-600 was at a contest station in PJ4
> several years ago. I found it to be a really inferior amp - most of the
> time, I was lucky to get 300W out if it. No comparison to a KPA500.
>
> 73, Jim K9YC
>
>
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Re: [Elecraft] KPA500 troubles

[w4grj]

I need to correct the information on the repair cost

It was $615 with shipping not $650 as I previously reported.

 

Jack W4GRJ

 

 


On Thursday, November 12, 2015, W4GRJ  wrote:

Since I have never operated on 60m ever... You figure it out
Jack
W4GRJ

On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via Elecraft] 
 > wrote:

On Wed,11/11/2015 12:10 PM, W4GRJ wrote:
> Got the KPA500 back from Elecraft.
> Problem found: L22 and other components in the 60M low pass filter circuit
> burnt through the LPF PCB.

60M LPF??? Last I looked, the US power limit on 60M is 100W relative to
a half wave dipole.



> Repair $650 later: Replaced low pass filter module and installed QSK mod.
>
> On the phone I asked what caused the failure, answer was no idea other than
> component failure. I understand stuff fails but I thought I would get more 
> than 2 years before a major expensive failure.

The LPF is on the output of the amplifier. One possible cause of failure
could be lightning.

> Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it to
> purchase the KPA500.
>
> Sometimes the grass is not greener.

My only experience with an ALS-600 was at a contest station in PJ4
several years ago. I found it to be a really inferior amp - most of the
time, I was lucky to get 300W out if it. No comparison to a KPA500.

73, Jim K9YC


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Re: [Elecraft] KPA500 troubles

[w4grj]

Don’t need any more responses on the legalities of 60M since the amp was never 
used on 60M

as stated in several other replies.

Jack W4GRJ

 

From: guyk...@gmail.com [mailto:guyk...@gmail.com] On Behalf Of Guy Olinger K2AV
Sent: Thursday, November 12, 2015 3:05 AM
To: W4GRJ
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA500 troubles

 

Kpa500 on 60 is illegal unless you have a *measured and documented* VERY lossy 
antenna that would reduce the effective radiated power to the same as 100 watts 
on a dipole. The simple 99 percent answer is that on 60m SHUT OFF the Kpa500 
and run 100 watts barefoot. 

 

73, Guy K2AV 

On Thursday, November 12, 2015, W4GRJ <w4...@satterfield.org> wrote:

Since I have never operated on 60m ever... You figure it out
Jack
W4GRJ

On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via Elecraft] 
<ml-node+s365791n7610243...@n2.nabble.com <javascript:;> > wrote:

On Wed,11/11/2015 12:10 PM, W4GRJ wrote:
> Got the KPA500 back from Elecraft.
> Problem found: L22 and other components in the 60M low pass filter circuit
> burnt through the LPF PCB.

60M LPF??? Last I looked, the US power limit on 60M is 100W relative to
a half wave dipole.



> Repair $650 later: Replaced low pass filter module and installed QSK mod.
>
> On the phone I asked what caused the failure, answer was no idea other than
> component failure. I understand stuff fails but I thought I would get more 
> than 2 years before a major expensive failure.

The LPF is on the output of the amplifier. One possible cause of failure
could be lightning.

> Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it to
> purchase the KPA500.
>
> Sometimes the grass is not greener.

My only experience with an ALS-600 was at a contest station in PJ4
several years ago. I found it to be a really inferior amp - most of the
time, I was lucky to get 300W out if it. No comparison to a KPA500.

73, Jim K9YC


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Re: [Elecraft] KPA500 troubles

[Charlie T, K3ICH]

That seems like a helluva lot to fix the bandpass
filter for a band that you never used.

Very UN-Elecraft sounding to me.

73, Charlie k3ICH



-Original Message-
From: Elecraft
[mailto:elecraft-boun...@mailman.qth.net] On
Behalf Of w4grj
Sent: Thursday, November 12, 2015 7:14 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA500 troubles

I need to correct the information on the repair
cost

It was $615 with shipping not $650 as I previously
reported.

 

Jack W4GRJ

 

 


On Thursday, November 12, 2015, W4GRJ
<w4...@satterfield.org> wrote:

Since I have never operated on 60m ever... You
figure it out Jack W4GRJ

On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via
Elecraft]
<ml-node+s365791n7610243...@n2.nabble.com
<javascript:;> > wrote:

On Wed,11/11/2015 12:10 PM, W4GRJ wrote:
> Got the KPA500 back from Elecraft.
> Problem found: L22 and other components in the
60M low pass filter 
> circuit burnt through the LPF PCB.

60M LPF??? Last I looked, the US power limit on
60M is 100W relative to a half wave dipole.



> Repair $650 later: Replaced low pass filter
module and installed QSK mod.
>
> On the phone I asked what caused the failure,
answer was no idea other 
> than component failure. I understand stuff fails
but I thought I would get more than 2 years before
a major expensive failure.

The LPF is on the output of the amplifier. One
possible cause of failure could be lightning.

> Previously had a Ameritron ALS-600 for 5+ years
never a problem, sold 
> it to purchase the KPA500.
>
> Sometimes the grass is not greener.

My only experience with an ALS-600 was at a
contest station in PJ4 several years ago. I found
it to be a really inferior amp - most of the time,
I was lucky to get 300W out if it. No comparison
to a KPA500.

73, Jim K9YC


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Re: [Elecraft] KPA500 troubles

[W4GRJ]

Yes, I agree and complained, they said the repair was discounted by $200.

The amp is 2 years old.

I am seriously thinking about selling while there is a bit of a warranty and
buying the SPE 1.2KA amp.

Jack W4GRJ

 

 

From: Charlie T, K3ICH [via Elecraft]
[mailto:ml-node+s365791n7610272...@n2.nabble.com] 
Sent: Thursday, November 12, 2015 7:34 AM
To: W4GRJ
Subject: Re: KPA500 troubles

 

That seems like a helluva lot to fix the bandpass 
filter for a band that you never used. 

Very UN-Elecraft sounding to me. 

73, Charlie k3ICH 



-Original Message- 
From: Elecraft 
[mailto:[hidden email]] On 
Behalf Of w4grj 
Sent: Thursday, November 12, 2015 7:14 AM 
To: [hidden email] 
Subject: Re: [Elecraft] KPA500 troubles 

I need to correct the information on the repair 
cost 

It was $615 with shipping not $650 as I previously 
reported. 

  

Jack W4GRJ 

  

  


On Thursday, November 12, 2015, W4GRJ 
<[hidden email]> wrote: 

Since I have never operated on 60m ever... You 
figure it out Jack W4GRJ 

On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via 
Elecraft] 
<[hidden email] 
<javascript:;> > wrote: 

On Wed,11/11/2015 12:10 PM, W4GRJ wrote: 
> Got the KPA500 back from Elecraft. 
> Problem found: L22 and other components in the 
60M low pass filter 
> circuit burnt through the LPF PCB. 

60M LPF??? Last I looked, the US power limit on 
60M is 100W relative to a half wave dipole. 



> Repair $650 later: Replaced low pass filter 
module and installed QSK mod. 
> 
> On the phone I asked what caused the failure, 
answer was no idea other 
> than component failure. I understand stuff fails 
but I thought I would get more than 2 years before 
a major expensive failure. 

The LPF is on the output of the amplifier. One 
possible cause of failure could be lightning. 

> Previously had a Ameritron ALS-600 for 5+ years 
never a problem, sold 
> it to purchase the KPA500. 
> 
> Sometimes the grass is not greener. 

My only experience with an ALS-600 was at a 
contest station in PJ4 several years ago. I found 
it to be a really inferior amp - most of the time, 
I was lucky to get 300W out if it. No comparison 
to a KPA500. 

73, Jim K9YC 


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Re: [Elecraft] KPA500 troubles

[Eric Swartz - WA6HHQ, Elecraft]

Hi Jack,

I apologize for any consternation this has caused you. 

Since multiple components burned through the LPF  PC board, that is major 
damage and would require replacement of the whole LPF board, which is a major 
cost component of the amp. (Taking out this board and replacing it requires 
disassembly and reassembly of a major portion off the amp.)  The repair cost 
also includes the tech time to diagnose, disassemble, repair, reassemble, 
retest and do full production TX burn-in of the amp on all bands.

Component failure like this can occur in any manufacturer's radio or amplifier 
for many reasons, such as power line surges, nearby lightning strikes, 
operating with excessive SWR, transmitting into a wrong antenna etc. You do not 
need to be operating on a particular band, or even have the amp or radio on to 
incur lightning damage. This can also cause partial damage to components that 
then shows up as a failure later after additional operation. 

As a side note, every year during lightning season we see a significant 
increase in all sorts of 'interesting' repairs sent in to us on all of our 
products. Many times the user is not even aware that a strike occurred 
somewhere nearby while they still had their antennas connected.

I'll review your repair report with our techs to make sure we didn't over 
charge for anything. I'll also check to see if they mis-identified which band 
the destroyed LPF components were from.

73,
Eric
elecraft.com
_..._

> -Original Message-
> From: Elecraft
> [mailto:elecraft-boun...@mailman.qth.net] On
> Behalf Of w4grj
> Sent: Thursday, November 12, 2015 7:14 AM
> To: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] KPA500 troubles
> 
> I need to correct the information on the repair
> cost
> 
> It was $615 with shipping not $650 as I previously
> reported.
> 
> Jack W4GRJ
> 
>> On Wed,11/11/2015 12:10 PM, W4GRJ wrote:
>> Got the KPA500 back from Elecraft.
>> Problem found: L22 and other components in the
> 60M low pass filter 
>> circuit burnt through the LPF PCB.
> 
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Re: [Elecraft] KPA500 troubles

[W4GRJ]

Eric,

Thank you for your response. I did send a message to Wayne for his review,
so I don't want to cause

double efforts on this..I appreciate the review.

 

Since I do live in a active lightning area, I have a well grounded station
and polyphaser surge protection.

Coax is grounded when not in use.. possible but I don't think it was
lightning related.

In 15 years at this QTH I have never had a lightning issue with my station
or anything in the house.

 

Thanks Again,

Jack

 

From: Eric Swartz - WA6HHQ, Elecraft [via Elecraft]
[mailto:ml-node+s365791n761027...@n2.nabble.com] 
Sent: Thursday, November 12, 2015 10:46 AM
To: W4GRJ
Subject: Re: KPA500 troubles

 

Hi Jack, 

I apologize for any consternation this has caused you. 

Since multiple components burned through the LPF  PC board, that is major
damage and would require replacement of the whole LPF board, which is a
major cost component of the amp. (Taking out this board and replacing it
requires disassembly and reassembly of a major portion off the amp.)  The
repair cost also includes the tech time to diagnose, disassemble, repair,
reassemble, retest and do full production TX burn-in of the amp on all
bands. 

Component failure like this can occur in any manufacturer's radio or
amplifier for many reasons, such as power line surges, nearby lightning
strikes, operating with excessive SWR, transmitting into a wrong antenna
etc. You do not need to be operating on a particular band, or even have the
amp or radio on to incur lightning damage. This can also cause partial
damage to components that then shows up as a failure later after additional
operation. 

As a side note, every year during lightning season we see a significant
increase in all sorts of 'interesting' repairs sent in to us on all of our
products. Many times the user is not even aware that a strike occurred
somewhere nearby while they still had their antennas connected. 

I'll review your repair report with our techs to make sure we didn't over
charge for anything. I'll also check to see if they mis-identified which
band the destroyed LPF components were from. 

73, 
Eric 
elecraft.com 
_..._ 


> -Original Message- 
> From: Elecraft 
> [mailto:[hidden email]] On 
> Behalf Of w4grj 
> Sent: Thursday, November 12, 2015 7:14 AM 
> To: [hidden email] 
> Subject: Re: [Elecraft] KPA500 troubles 
> 
> I need to correct the information on the repair 
> cost 
> 
> It was $615 with shipping not $650 as I previously 
> reported. 
> 
> Jack W4GRJ 
> 
>> On Wed,11/11/2015 12:10 PM, W4GRJ wrote: 
>> Got the KPA500 back from Elecraft. 
>> Problem found: L22 and other components in the 
> 60M low pass filter 
>> circuit burnt through the LPF PCB. 
> 

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Re: [Elecraft] KPA500 troubles

[W4GRJ]

Like I said, never ever  operated on 60M, I mean never without the amp.
When discussed with Craig at Elecraft he could not explain the failure, just 
referred to a component failure.
Jack
W4GRJ


On Nov 11, 2015, at 3:59 PM, David Pratt [via Elecraft] 
 wrote:

Same in the UK, Jim.  Operation on 60m does not require the use of a 
KPA500 unless one wants to contravene the terms of one's license. 

73 de David G4DMP 

In a recent message, Jim Brown <[hidden email]> writes 
>On Wed,11/11/2015 12:10 PM, W4GRJ wrote: 
>> Got the KPA500 back from Elecraft. 
>> Repair $650 later: Replaced low pass filter module and installed QSK mod. 
>> Problem found: L22 and other components in the 60M low pass filter circuit 
>> burnt through the LPF PCB. 
> 
>60M LPF??? Last I looked, the US power limit on 60M is 100W relative to 
>a half wave dipole. 
> 

-- 
  + - - - - - - - - - - - - - - - - + 
  | David M Pratt, Kippax, Leeds.   | 
  | Website: http://www.g4dmp.co.uk | 
  + - - - - - - - - - - - - - - - - + 

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Re: [Elecraft] KPA500 troubles

[W4GRJ]

Got the KPA500 back from Elecraft.
Problem found: L22 and other components in the 60M low pass filter circuit
burnt through the LPF PCB.
Repair $650 later: Replaced low pass filter module and installed QSK mod.

On the phone I asked what caused the failure, answer was no idea other than
component failure.
I understand stuff fails but I thought I would get more than 2 years before
a major expensive failure.

Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it to
purchase the KPA500.

Sometimes the grass is not greener.

Jack
W4GRJ




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Re: [Elecraft] KPA500 troubles

[W4GRJ]

Since I have never operated on 60m ever... You figure it out
Jack 
W4GRJ

On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via Elecraft] 
 wrote:

On Wed,11/11/2015 12:10 PM, W4GRJ wrote: 
> Got the KPA500 back from Elecraft. 
> Problem found: L22 and other components in the 60M low pass filter circuit 
> burnt through the LPF PCB. 

60M LPF??? Last I looked, the US power limit on 60M is 100W relative to 
a half wave dipole. 



> Repair $650 later: Replaced low pass filter module and installed QSK mod. 
> 
> On the phone I asked what caused the failure, answer was no idea other than 
> component failure. I understand stuff fails but I thought I would get more 
> than 2 years before a major expensive failure. 

The LPF is on the output of the amplifier. One possible cause of failure 
could be lightning. 

> Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it to 
> purchase the KPA500. 
> 
> Sometimes the grass is not greener. 

My only experience with an ALS-600 was at a contest station in PJ4 
several years ago. I found it to be a really inferior amp - most of the 
time, I was lucky to get 300W out if it. No comparison to a KPA500. 

73, Jim K9YC 


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Re: [Elecraft] KPA500 troubles

[David G4DMP]

Same in the UK, Jim.  Operation on 60m does not require the use of a 
KPA500 unless one wants to contravene the terms of one's license.


73 de David G4DMP

In a recent message, Jim Brown  writes

On Wed,11/11/2015 12:10 PM, W4GRJ wrote:

Got the KPA500 back from Elecraft.
Repair $650 later: Replaced low pass filter module and installed QSK mod.
Problem found: L22 and other components in the 60M low pass filter circuit
burnt through the LPF PCB.


60M LPF??? Last I looked, the US power limit on 60M is 100W relative to 
a half wave dipole.




--
 + - - - - - - - - - - - - - - - - +
 | David M Pratt, Kippax, Leeds.   |
 | Website: http://www.g4dmp.co.uk |
 + - - - - - - - - - - - - - - - - +

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Re: [Elecraft] KPA500 troubles

[Wes (N7WS)]

*§ 97.313 Transmitter power standards*.

"(i) No station may transmit with an effective radiated power (ERP) exceeding 
100 W PEP on the 60 m
band. For the purpose of computing ERP, the transmitter PEP will be multiplied 
by the antenna gain
relative to a half-wave dipole antenna. A half-wave dipole antenna will be 
presumed to have a gain
of 1 (0 dBd). Licensees using other antennas must maintain in their station 
records either the antenna

manufacturer’s data on the antenna gain or calculations of the antenna gain."

If I use an inductively-loaded vertical monopole with a minimal ground screen 
over Arizona ground my "dBd gain" might well be several dB negative. In which 
case, I'm allowed to compensate for that, and line loss, in determining 
amplifier output power.  In that, and many other events, a 100W transceiver is 
inadequate, ergo, a KPA500 is not out of the question.


Wes, N7WS

On 11/11/2015 1:32 PM, Jim Brown wrote:

On Wed,11/11/2015 12:10 PM, W4GRJ wrote:

Got the KPA500 back from Elecraft.
Problem found: L22 and other components in the 60M low pass filter circuit
burnt through the LPF PCB.


60M LPF??? Last I looked, the US power limit on 60M is 100W relative to a half 
wave dipole.





"(i) No station may transmit with an effective radiated power (ERP) exceeding 
100 W PEP on the 60 m
band. For the purpose of computing ERP, the transmitter PEP will be multiplied 
by the antenna gain
relative to a half-wave dipole antenna. A half-wave dipole antenna will be 
presumed to have a gain
of 1 (0 dBd). Licensees using other antennas must maintain in their station 
records either the antenna

manufacturer’s data on the antenna gain or calculations of the antenna gain."

If I use an inductively-loaded vertical monopole with a minimal ground screen 
over Arizona ground my "dBd gain" might well be several dB negative.  In which 
case, I'm allowed to compensate for that, and line loss, in determining 
amplifier output power.  In that, and many other events, a 100W transceiver is 
inadequate, ergo, a KPA500 is not out of the question.

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Re: [Elecraft] KPA500 troubles

[Fred Smith]

The KPA500 is a good small amp I use mine with an IC-9100 most of the time and 
have not had any real issues with it in 4 yrs. now. For the K3's and K2 I use 
Alpha amps an 87A and a newer 9500 for HF use. All I can say the brick on the 
key with forever in the ads they run does say a lot. But it's not till you open 
up a quality amp like Elecraft or Alpha go you see the real difference.

You can have problems with any product no matter who makes it but at times we 
bear part of the fault ourselves or like Jim said even lighting might have 
played a part.

73,
Fred/N0AZZ

Sent from my iPad

> On Nov 11, 2015, at 2:32 PM, Jim Brown  wrote:
> 
>> On Wed,11/11/2015 12:10 PM, W4GRJ wrote:
>> Got the KPA500 back from Elecraft.
>> Problem found: L22 and other components in the 60M low pass filter circuit
>> burnt through the LPF PCB.
> 
> 60M LPF??? Last I looked, the US power limit on 60M is 100W relative to a 
> half wave dipole.
> 
> 
> 
>> Repair $650 later: Replaced low pass filter module and installed QSK mod.
>> 
>> On the phone I asked what caused the failure, answer was no idea other than
>> component failure. I understand stuff fails but I thought I would get more 
>> than 2 years before a major expensive failure.
> 
> The LPF is on the output of the amplifier. One possible cause of failure 
> could be lightning.
> 
>> Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it to
>> purchase the KPA500.
>> 
>> Sometimes the grass is not greener.
> 
> My only experience with an ALS-600 was at a contest station in PJ4 several 
> years ago. I found it to be a really inferior amp - most of the time, I was 
> lucky to get 300W out if it. No comparison to a KPA500.
> 
> 73, Jim K9YC
> 
> 
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Re: [Elecraft] KPA500 troubles

[Jim Brown]

On Wed,11/11/2015 12:10 PM, W4GRJ wrote:

Got the KPA500 back from Elecraft.
Problem found: L22 and other components in the 60M low pass filter circuit
burnt through the LPF PCB.


60M LPF??? Last I looked, the US power limit on 60M is 100W relative to 
a half wave dipole.





Repair $650 later: Replaced low pass filter module and installed QSK mod.

On the phone I asked what caused the failure, answer was no idea other than
component failure. I understand stuff fails but I thought I would get more than 
2 years before a major expensive failure.


The LPF is on the output of the amplifier. One possible cause of failure 
could be lightning.



Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it to
purchase the KPA500.

Sometimes the grass is not greener.


My only experience with an ALS-600 was at a contest station in PJ4 
several years ago. I found it to be a really inferior amp - most of the 
time, I was lucky to get 300W out if it. No comparison to a KPA500.


73, Jim K9YC


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Re: [Elecraft] KPA500 troubles

[Gary]

Interesting. As a field tester I tried darned hard to break mine, 
unsuccessfully, guess I failed again.

Sadly, some components do fail, you just have to take it on the chin.

My experience with several MFJ products has not been good, I successfully broke 
all of them at least once.

It's sometimes just a case of luck, or that chap, what's his name?, oh yeah, 
Murphy.

73
Gary 

-Original Message-
From: "David G4DMP" <da...@g4dmp.fsnet.co.uk>
Sent: ‎12/‎11/‎2015 6:58 AM
To: "j...@audiosystemsgroup.com" <j...@audiosystemsgroup.com>
Cc: "elecraft@mailman.qth.net" <elecraft@mailman.qth.net>; 
"w4...@satterfield.org" <w4...@satterfield.org>
Subject: Re: [Elecraft] KPA500 troubles

Same in the UK, Jim.  Operation on 60m does not require the use of a 
KPA500 unless one wants to contravene the terms of one's license.

73 de David G4DMP

In a recent message, Jim Brown <j...@audiosystemsgroup.com> writes
>On Wed,11/11/2015 12:10 PM, W4GRJ wrote:
>> Got the KPA500 back from Elecraft.
>> Repair $650 later: Replaced low pass filter module and installed QSK mod.
>> Problem found: L22 and other components in the 60M low pass filter circuit
>> burnt through the LPF PCB.
>
>60M LPF??? Last I looked, the US power limit on 60M is 100W relative to 
>a half wave dipole.
>

-- 
  + - - - - - - - - - - - - - - - - +
  | David M Pratt, Kippax, Leeds.   |
  | Website: http://www.g4dmp.co.uk |
  + - - - - - - - - - - - - - - - - +

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Re: [Elecraft] KPA500 troubles

[mcduffie]

On Tue, 20 Oct 2015 08:58:17 -0700 (MST), ok1rp wrote:

> if your KPA500 has LPF board rev. D or earlier then You will need to make
> LPF TR Switch Rework REV5 modification, Elecraft parts kit: E850607. But
> maybe there is another issue in your case.

Apparently, I missed the OP on this.  What is it about?  What vintage amp (SN?),
and what does this modification do?

Gary AG0N
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Re: [Elecraft] KPA500 troubles

[W4GRJ]

It has been sent to Elecraft.will advise results when I get it back

SN 1767

 

From: mcduffie [via Elecraft]
[mailto:ml-node+s365791n7609384...@n2.nabble.com] 
Sent: Wednesday, October 21, 2015 10:05 AM
To: W4GRJ
Subject: Re: KPA500 troubles

 

On Tue, 20 Oct 2015 08:58:17 -0700 (MST), ok1rp wrote: 

> if your KPA500 has LPF board rev. D or earlier then You will need to make 
> LPF TR Switch Rework REV5 modification, Elecraft parts kit: E850607. But 
> maybe there is another issue in your case. 

Apparently, I missed the OP on this.  What is it about?  What vintage amp
(SN?), 
and what does this modification do? 

Gary AG0N 
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Re: [Elecraft] KPA500 troubles

[Stewart]

Hi Petr,
I can't find this mod for the KPA500 on the Elecraft site. In fact, I can't 
find 
any KPA500 mods.

Where is it on the web site, please?  I must be looking in the wrong place...

73
Stewart G3RXQ

On Tue, 20 Oct 2015 08:58:17 -0700 (MST), ok1rp wrote:
> Hi Jack,
>
> if your KPA500 has LPF board rev. D or earlier then You will need to make
> LPF TR Switch Rework REV5 modification, Elecraft parts kit: E850607. But
> maybe there is another issue in your case.
>
> Try to read first then decide. If you want and you have SMD tools then You
> can try to make this mods first and test if it was the case. If not then you
> can send to Elecraft service. If you have no SMD tools and experiences then
> it is better to send it to them now. The people at Elecraft service are
> great and professional so no worry about.
>
> It is not complicated just a bit tight on the board and not so much space
> around the parts to remove the old one. Must be done very carefully. I made
> this mod on KPA500 for two friends already and in both cases amps worked
> well after that.
>
> Hope it helps.
>
> 73 - Petr, OK1RP
>
>
> -
> http://ok1rp.blogspot.com
> --
> View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7609332.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> __
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Re: [Elecraft] KPA500 troubles

[W4GRJ]

Peter, thanksamp on it's way to Elecraft.
I will report results when I get it back.
Jack
W4GRJ

On Oct 20, 2015, at 11:58 AM, ok1rp [via Elecraft] 
 wrote:

Hi Jack, 

if your KPA500 has LPF board rev. D or earlier then You will need to make LPF 
TR Switch Rework REV5 modification, Elecraft parts kit: E850607. But maybe 
there is another issue in your case. 

Try to read first then decide. If you want and you have SMD tools then You can 
try to make this mods first and test if it was the case. If not then you can 
send to Elecraft service. If you have no SMD tools and experiences then it is 
better to send it to them now. The people at Elecraft service are great and 
professional so no worry about. 

It is not complicated just a bit tight on the board and not so much space 
around the parts to remove the old one. Must be done very carefully. I made 
this mod on KPA500 for two friends already and in both cases amps worked well 
after that. 

Hope it helps. 

73 - Petr, OK1RP
http://ok1rp.blogspot.com


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Re: [Elecraft] KPA500 troubles

[ok1rp]

Hi Jack,

if your KPA500 has LPF board rev. D or earlier then You will need to make
LPF TR Switch Rework REV5 modification, Elecraft parts kit: E850607. But
maybe there is another issue in your case.

Try to read first then decide. If you want and you have SMD tools then You
can try to make this mods first and test if it was the case. If not then you
can send to Elecraft service. If you have no SMD tools and experiences then
it is better to send it to them now. The people at Elecraft service are
great and professional so no worry about.

It is not complicated just a bit tight on the board and not so much space
around the parts to remove the old one. Must be done very carefully. I made
this mod on KPA500 for two friends already and in both cases amps worked
well after that.

Hope it helps.

73 - Petr, OK1RP



-
http://ok1rp.blogspot.com
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Re: [Elecraft] KPA500 troubles

[K4ia via Elecraft]

Does anyone have a serial number for the changeover?  I don't see 
anything on the Elecraft wab page.


Buck
k4ia  K3 #101
Honor Roll 333
8B DXCC

On 10/20/2015 11:58 AM, ok1rp wrote:

Hi Jack,

if your KPA500 has LPF board rev. D or earlier then You will need to make
LPF TR Switch Rework REV5 modification, Elecraft parts kit: E850607. But
maybe there is another issue in your case.

Try to read first then decide. If you want and you have SMD tools then You
can try to make this mods first and test if it was the case. If not then you
can send to Elecraft service. If you have no SMD tools and experiences then
it is better to send it to them now. The people at Elecraft service are
great and professional so no worry about.

It is not complicated just a bit tight on the board and not so much space
around the parts to remove the old one. Must be done very carefully. I made
this mod on KPA500 for two friends already and in both cases amps worked
well after that.

Hope it helps.

73 - Petr, OK1RP



-
http://ok1rp.blogspot.com
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Re: [Elecraft] KPA500 troubles

[efortner]

Test it one more time with a 50 ohm dummy load on the output to make sure
you don't have a problem between your antenna and KPA 500 SO239 output
connector.

73, Earl K4KAY

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of W4GRJ
Sent: Monday, October 19, 2015 8:20 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 troubles

All of a sudden my KPA500 is misbehaving. It sounds like it is arcing inside
and smells the classic something is burning smell. SWR LED's are dancing
upwards as it arcs.
KAT500 tuner has the SWR around 1.3:1

I will probably send it off to Elecraft but thought I would ask here for
suggestions to look at before I send it off.

Thanks, Jack
W4GRJ



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Re: [Elecraft] KPA500 troubles

[w4grj]

Good suggestion...I will do that 
However, I am running barefoot 100 watts thru the KAT500 with no issues.
Tnx,
Jack
W4GRJ

-Original Message-
From: efortner [mailto:efort...@ctc.net] 
Sent: Monday, October 19, 2015 8:53 AM
To: 'W4GRJ'; elecraft@mailman.qth.net
Subject: RE: [Elecraft] KPA500 troubles

Test it one more time with a 50 ohm dummy load on the output to make sure
you don't have a problem between your antenna and KPA 500 SO239 output
connector.

73, Earl K4KAY

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of W4GRJ
Sent: Monday, October 19, 2015 8:20 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 troubles

All of a sudden my KPA500 is misbehaving. It sounds like it is arcing inside
and smells the classic something is burning smell. SWR LED's are dancing
upwards as it arcs.
KAT500 tuner has the SWR around 1.3:1

I will probably send it off to Elecraft but thought I would ask here for
suggestions to look at before I send it off.

Thanks, Jack
W4GRJ



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Re: [Elecraft] KPA500 troubles

[George K5KG via Elecraft]

Yes, but but but if it is arching and burning, be careful!

73, George, K5KG

On 10/19/2015 8:53 AM, efortner wrote:

Test it one more time with a 50 ohm dummy load on the output to make sure
you don't have a problem between your antenna and KPA 500 SO239 output
connector.

73, Earl K4KAY

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of W4GRJ
Sent: Monday, October 19, 2015 8:20 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 troubles

All of a sudden my KPA500 is misbehaving. It sounds like it is arcing inside
and smells the classic something is burning smell. SWR LED's are dancing
upwards as it arcs.
KAT500 tuner has the SWR around 1.3:1

I will probably send it off to Elecraft but thought I would ask here for
suggestions to look at before I send it off.

Thanks, Jack
W4GRJ



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--
George Wagner, K5KG
Sarasota, FL
941-400-1960

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Re: [Elecraft] KPA500 troubles

[jim]

Power corrupts...

Jim

W6AIM



.

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of w4grj
Sent: Monday, October 19, 2015 6:07 AM
To: 'efortner'; elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA500 troubles

Good suggestion...I will do that
However, I am running barefoot 100 watts thru the KAT500 with no issues.
Tnx,
Jack
W4GRJ

-Original Message-
From: efortner [mailto:efort...@ctc.net]
Sent: Monday, October 19, 2015 8:53 AM
To: 'W4GRJ'; elecraft@mailman.qth.net
Subject: RE: [Elecraft] KPA500 troubles

Test it one more time with a 50 ohm dummy load on the output to make sure
you don't have a problem between your antenna and KPA 500 SO239 output
connector.

73, Earl K4KAY

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of W4GRJ
Sent: Monday, October 19, 2015 8:20 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 troubles

All of a sudden my KPA500 is misbehaving. It sounds like it is arcing inside
and smells the classic something is burning smell. SWR LED's are dancing
upwards as it arcs.
KAT500 tuner has the SWR around 1.3:1

I will probably send it off to Elecraft but thought I would ask here for
suggestions to look at before I send it off.

Thanks, Jack
W4GRJ



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Re: [Elecraft] KPA500 troubles

[Jack]

The amp was factory built, about two years old and has worked fine till 
yesterday.
Anyway talked with Elecraft, the amp is going back. They said there are some 
updates needed in addition to the repair. I will post the fix when I get it 
back.
Thanks to all the other replies.
Jack
W4GRJ

On Oct 19, 2015, at 12:27 PM, Ron D'Eau Claire  wrote:

Jack, did you build the KPA500 yourself? In any case, one point that can
cause trouble is where the hot (center conductor) lead goes to the RF Output
connector. See Figure 40 on page 28 in the kit assembly manual (if you
bought yours built, you can download the manual from the Elecraft web site
(http://www.elecraft.com/manual/E740149%20KPA500%20Kit%20Assembly%20Manual%2
0Rev%20F4.pdf). That lead needs to be dressed away from the sharp edge of a
shield as shown in the figure to avoid the possibility of an RF arc. 

If that's the problem, just move the wire away as described in the manual. 

What the KAT500 does not tell you is the SWR on the line between the amp and
the ATU. If it's fairly high you can build up some substantial RF voltages
there. 

73, Ron AC7AC 

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of W4GRJ
Sent: Monday, October 19, 2015 5:20 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 troubles

All of a sudden my KPA500 is misbehaving. It sounds like it is arcing inside
and smells the classic something is burning smell. SWR LED's are dancing
upwards as it arcs.
KAT500 tuner has the SWR around 1.3:1

I will probably send it off to Elecraft but thought I would ask here for
suggestions to look at before I send it off.

Thanks, Jack
W4GRJ



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Re: [Elecraft] KPA500 troubles

[Ron D'Eau Claire]

Jack, did you build the KPA500 yourself? In any case, one point that can
cause trouble is where the hot (center conductor) lead goes to the RF Output
connector. See Figure 40 on page 28 in the kit assembly manual (if you
bought yours built, you can download the manual from the Elecraft web site
(http://www.elecraft.com/manual/E740149%20KPA500%20Kit%20Assembly%20Manual%2
0Rev%20F4.pdf). That lead needs to be dressed away from the sharp edge of a
shield as shown in the figure to avoid the possibility of an RF arc. 

If that's the problem, just move the wire away as described in the manual. 

What the KAT500 does not tell you is the SWR on the line between the amp and
the ATU. If it's fairly high you can build up some substantial RF voltages
there. 

73, Ron AC7AC 

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of W4GRJ
Sent: Monday, October 19, 2015 5:20 AM
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA500 troubles

All of a sudden my KPA500 is misbehaving. It sounds like it is arcing inside
and smells the classic something is burning smell. SWR LED's are dancing
upwards as it arcs.
KAT500 tuner has the SWR around 1.3:1

I will probably send it off to Elecraft but thought I would ask here for
suggestions to look at before I send it off.

Thanks, Jack
W4GRJ



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Re: [Elecraft] KPA500 troubles

[Arie Kleingeld PA3A]

Failing pin diode switch ? (not the PIN diode itself, but the 
semiconductor switching it)


73
Arie PA3A



Op 19-10-2015 om 14:20 schreef W4GRJ:

All of a sudden my KPA500 is misbehaving. It sounds like it is arcing inside
and smells the
classic something is burning smell. SWR LED's are dancing upwards as it
arcs.
KAT500 tuner has the SWR around 1.3:1

I will probably send it off to Elecraft but thought I would ask here for
suggestions to
look at before I send it off.

Thanks, Jack
W4GRJ



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