Re: [Elecraft] KPA1500 - temp reading drops 10C when under power
Elecraft has a fix for this.
73,
Scott K9MA
--
Scott Ellington
--- via iPad
> On Aug 18, 2018, at 1:55 PM, Paul Baldock wrote:
>
> I just checked mine on 40M and when on CW Temp is bouncing all over the
> place. Same into a dummy load as the antenna 300ft away. It also does it to a
> lesser extent on 80M and a little bounce on 17M and 10M.
>
> I suspect its in the amp and not related to common mode RF in the coax.
>
> Probably a cap in the right place would fix it.
>
> - Paul
>
>
> At 11:20 AM 8/18/2018, you wrote:
>> Some baluns offer good common mode current rejection while others offer
>> virtually no common mode rejection.  {See DJ0IP site and discussion on
>> baluns.}Â Since the feed line from the balun runs down the tower to the
>> point where the feedline runs underground, that segment of feedline is
>> exposed to radiation from the antenna. Certainly common mode current can
>> be a very realistic occurrence in this case. ..." it's some sort of
>> new hyper-super-ultra-infina-deluxe type never before discovered on earth."Â
>>  Nope, it is just basic physics regarding the properties of RF induced
>> currents.   Depending on band, a choking impedance of 300 to 5000 ohms
>> may be needed to resolve the issue.  Since it was disclosed as power
>> related, this supports the issues of common mode currents. Good luck in
>> finding and correcting the matter. 73 Bob, K4TAX On 8/18/2018 12:20 PM, Jeff
>> Blaine wrote: > Odds are not good there. The antennas have a balun at the
>> feedpoint, > are on a tower 500 feet from the shack and the hardline runs
>> under > ground. If there is common mode involved, it's some sort of new >
>> hyper-super-ultra-infina-deluxe type never before discovered on earth. > >
>> 73/jeff/ac0c > alpha-charlie-zero-charlie > www.ac0c.com > > On 18-Aug-18
>> 7:12 AM, Bob McGraw K4TAX wrote: >> I'd say a bit of common mode current on
>> the feed line.   I see that >> from time to time with my KPA500 on
>> certain bands/antennas. >> >> 73 >> >> Bob, K4TAX >> >> >> On 8/17/2018
>> 11:45 PM, Jeff Blaine wrote: >>> While running the KPA1500 in the SARTG
>> tonight, I noticed that the >>> temp reading drops about 10C when
>> transmitting. min fan speed 1. >>> >>> Seems to be related to power - at
>> 1500W it's pretty close to 10C. At >>> lower powers, it's less of a
>> difference. I don't recall seeing that >>> before. >>> >>> Normal? >>> >>>
>> 73/jeff/ac0c >>> alpha-charlie-zero-charlie >>> www.ac0c.com >>> >>>
>> __ >>> Elecraft
>> mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>
>> Help: http://mailman.qth.net/mmfaq.htm >>> Post:
>> mailto:Elecraft@mailman.qth.net >>> >>> This list hosted by:
>> http://www.qsl.net >>> Please help support this email list:
>> http://www.qsl.net/donate.html >>> Message delivered to rmcg...@blomand.net
>> >> >> >> __ >>
>> Elecraft mailing list >> Home:
>> http://mailman.qth.net/mailman/listinfo/elecraft >> Help:
>> http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >>
>> >> This list hosted by: http://www.qsl.net >> Please help support this email
>> list: http://www.qsl.net/donate.html >> Message delivered to
>> keepwalking...@ac0c.com > >
>> __ > Elecraft
>> mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft >
>> Help: http://mailman.qth.net/mmfaq.htm > Post:
>> mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net
>> > Please help support this email list: http://www.qsl.net/donate.html >
>> Message delivered to rmcg...@blomand.net
>> __ Elecraft
>> mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help:
>> http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This
>> list hosted by: http://www.qsl.net Please help support this email list:
>> http://www.qsl.net/donate.html Message delivered to p...@paulbaldock.com
>
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to k...@sdellington.us
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA1500 - temp reading drops 10C when under power
I just checked mine on 40M and when on CW Temp is
bouncing all over the place. Same into a dummy
load as the antenna 300ft away. It also does it
to a lesser extent on 80M and a little bounce on 17M and 10M.
I suspect its in the amp and not related to common mode RF in the coax.
Probably a cap in the right place would fix it.
- Paul
At 11:20 AM 8/18/2018, you wrote:
Some baluns offer good common mode current
rejection while others offer virtually no common
mode rejection.  {See DJ0IP site and
discussion on baluns.}Â Since the feed line
from the balun runs down the tower to the point
where the feedline runs underground, that
segment of feedline is exposed to radiation from
the antenna. Certainly common mode current can
be a very realistic occurrence in this case.
..." it's some sort of new
hyper-super-ultra-infina-deluxe type never
before discovered on earth."  Nope, it is
just basic physics regarding the properties of
RF induced currents.   Depending on band, a
choking impedance of 300 to 5000 ohms may be
needed to resolve the issue.  Since it was
disclosed as power related, this supports the
issues of common mode currents. Good luck in
finding and correcting the matter. 73 Bob, K4TAX
On 8/18/2018 12:20 PM, Jeff Blaine wrote: > Odds
are not good there. The antennas have a balun
at the feedpoint, > are on a tower 500 feet from
the shack and the hardline runs under >
ground. If there is common mode involved, it's
some sort of new >
hyper-super-ultra-infina-deluxe type never
before discovered on earth. > > 73/jeff/ac0c >
alpha-charlie-zero-charlie > www.ac0c.com > > On
18-Aug-18 7:12 AM, Bob McGraw K4TAX wrote: >>
I'd say a bit of common mode current on the feed
line.   I see that >> from time to time with
my KPA500 on certain bands/antennas. >> >>
73 >> >> Bob, K4TAX >> >> >> On 8/17/2018 11:45
PM, Jeff Blaine wrote: >>> While running the
KPA1500 in the SARTG tonight, I noticed that
the >>> temp reading drops about 10C when
transmitting. min fan speed 1. >>> >>> Seems
to be related to power - at 1500W it's pretty
close to 10C. At >>> lower powers, it's less of
a difference. I don't recall seeing that >>>
before. >>> >>> Normal? >>> >>> 73/jeff/ac0c >>>
alpha-charlie-zero-charlie >>>
www.ac0c.com >>> >>>
__
>>> Elecraft mailing list >>> Home:
http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm >>>
Post: mailto:Elecraft@mailman.qth.net >>> >>>
This list hosted by: http://www.qsl.net >>>
Please help support this email list:
http://www.qsl.net/donate.html >>> Message
delivered to rmcg...@blomand.net >> >> >>
__
>> Elecraft mailing list >> Home:
http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm >>
Post: mailto:Elecraft@mailman.qth.net >> >> This
list hosted by: http://www.qsl.net >> Please
help support this email list:
http://www.qsl.net/donate.html >> Message
delivered to keepwalking...@ac0c.com > >
__
> Elecraft mailing list > Home:
http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm >
Post: mailto:Elecraft@mailman.qth.net > > This
list hosted by: http://www.qsl.net > Please help
support this email list:
http://www.qsl.net/donate.html > Message
delivered to rmcg...@blomand.net
__
Elecraft mailing list Home:
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm Post:
mailto:Elecraft@mailman.qth.net This list hosted
by: http://www.qsl.net Please help support this
email list: http://www.qsl.net/donate.html
Message delivered to p...@paulbaldock.com
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA1500 - temp reading drops 10C when under power
Some baluns offer good common mode current rejection while others offer
virtually no common mode rejection. {See DJ0IP site and discussion on
baluns.} Since the feed line from the balun runs down the tower to the
point where the feedline runs underground, that segment of feedline is
exposed to radiation from the antenna. Certainly common mode current
can be a very realistic occurrence in this case.
..." it's some sort of new hyper-super-ultra-infina-deluxe type
never before discovered on earth." Nope, it is just basic physics
regarding the properties of RF induced currents. Depending on band, a
choking impedance of 300 to 5000 ohms may be needed to resolve the
issue. Since it was disclosed as power related, this supports the
issues of common mode currents.
Good luck in finding and correcting the matter.
73
Bob, K4TAX
On 8/18/2018 12:20 PM, Jeff Blaine wrote:
Odds are not good there. The antennas have a balun at the feedpoint,
are on a tower 500 feet from the shack and the hardline runs under
ground. If there is common mode involved, it's some sort of new
hyper-super-ultra-infina-deluxe type never before discovered on earth.
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
On 18-Aug-18 7:12 AM, Bob McGraw K4TAX wrote:
I'd say a bit of common mode current on the feed line. I see that
from time to time with my KPA500 on certain bands/antennas.
73
Bob, K4TAX
On 8/17/2018 11:45 PM, Jeff Blaine wrote:
While running the KPA1500 in the SARTG tonight, I noticed that the
temp reading drops about 10C when transmitting. min fan speed 1.
Seems to be related to power - at 1500W it's pretty close to 10C. At
lower powers, it's less of a difference. I don't recall seeing that
before.
Normal?
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to rmcg...@blomand.net
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to keepwalking...@ac0c.com
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to rmcg...@blomand.net
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA1500 - temp reading drops 10C when under power
Odds are not good there. The antennas have a balun at the feedpoint, are on a tower 500 feet from the shack and the hardline runs under ground. If there is common mode involved, it's some sort of new hyper-super-ultra-infina-deluxe type never before discovered on earth. 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com On 18-Aug-18 7:12 AM, Bob McGraw K4TAX wrote: I'd say a bit of common mode current on the feed line. I see that from time to time with my KPA500 on certain bands/antennas. 73 Bob, K4TAX On 8/17/2018 11:45 PM, Jeff Blaine wrote: While running the KPA1500 in the SARTG tonight, I noticed that the temp reading drops about 10C when transmitting. min fan speed 1. Seems to be related to power - at 1500W it's pretty close to 10C. At lower powers, it's less of a difference. I don't recall seeing that before. Normal? 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to keepwalking...@ac0c.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA1500 - temp reading drops 10C when under power
I'd say a bit of common mode current on the feed line. I see that from time to time with my KPA500 on certain bands/antennas. 73 Bob, K4TAX On 8/17/2018 11:45 PM, Jeff Blaine wrote: While running the KPA1500 in the SARTG tonight, I noticed that the temp reading drops about 10C when transmitting. min fan speed 1. Seems to be related to power - at 1500W it's pretty close to 10C. At lower powers, it's less of a difference. I don't recall seeing that before. Normal? 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA1500 - temp reading drops 10C when under power
Yea, I was on 40m also. So there's a second data point. Did not notice it before - but having watched it pretty consistently tonight, I will know what to look for on other bands. Tonight was the first night I had the chance to run it on RTTY and want to be sure the thing is ready for prime time given the CQ RTTY DX is coming up end of Sept. The good news is that the amp seemed to level off at 73C (or 63C?) and that means fan 2 was able to keep things under control. SWR is nearly 1:1 on that band and I don't know what it does on other bands but it was REALLY GREAT that fan speed 3+ was not needed. 1&2 are in a completely different sound category compared to the 3+ which sound like my company's computer server room. ha ha. 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com On 18-Aug-18 12:11 AM, Bill Stravinsky via Elecraft wrote: I noticed this problem shortly after getting my 1500 back in May. I only see this problem on 40 mtrs for some reason. I've never seen a 10 degree fluctuation but itis regularly 6 degrees and has approached 8 degrees. I only work cw for the most part. I see it all the time when the duty cycle goes up like when contesting and thatis when I start looking at the temp more often so that's how I noticed it to begin with.. I've learned to live with it, at least for the time being, for the following reason. I contacted Elecraft and talked with one of the engineers. Apparently this problem was addressed during early engineering but leave it to me to be the first one toexperience this. He explained that there might be a possible fix for it that would require installing a cap, most likely an SMD type. I would be more comfy with a discretecomponent, hi. But the jist of the conversation was that its just a touchy temp sending device. I downloaded some file from the utility program and I don't think thetrouble was exposed in the file for some reason after I sent it to them. Film at eleven. BillK3WJV. On Saturday, August 18, 2018, 12:49:55 AM EDT, Jeff Blaine wrote: While running the KPA1500 in the SARTG tonight, I noticed that the temp reading drops about 10C when transmitting. min fan speed 1. Seems to be related to power - at 1500W it's pretty close to 10C. At lower powers, it's less of a difference. I don't recall seeing that before. Normal? 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k3...@yahoo.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to keepwalking...@ac0c.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KPA1500 - temp reading drops 10C when under power
I noticed this problem shortly after getting my 1500 back in May. I only see this problem on 40 mtrs for some reason. I've never seen a 10 degree fluctuation but itis regularly 6 degrees and has approached 8 degrees. I only work cw for the most part. I see it all the time when the duty cycle goes up like when contesting and thatis when I start looking at the temp more often so that's how I noticed it to begin with.. I've learned to live with it, at least for the time being, for the following reason. I contacted Elecraft and talked with one of the engineers. Apparently this problem was addressed during early engineering but leave it to me to be the first one toexperience this. He explained that there might be a possible fix for it that would require installing a cap, most likely an SMD type. I would be more comfy with a discretecomponent, hi. But the jist of the conversation was that its just a touchy temp sending device. I downloaded some file from the utility program and I don't think thetrouble was exposed in the file for some reason after I sent it to them. Film at eleven. BillK3WJV. On Saturday, August 18, 2018, 12:49:55 AM EDT, Jeff Blaine wrote: While running the KPA1500 in the SARTG tonight, I noticed that the temp reading drops about 10C when transmitting. min fan speed 1. Seems to be related to power - at 1500W it's pretty close to 10C. At lower powers, it's less of a difference. I don't recall seeing that before. Normal? 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k3...@yahoo.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] KPA1500 - temp reading drops 10C when under power
While running the KPA1500 in the SARTG tonight, I noticed that the temp reading drops about 10C when transmitting. min fan speed 1. Seems to be related to power - at 1500W it's pretty close to 10C. At lower powers, it's less of a difference. I don't recall seeing that before. Normal? 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
