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KX2 Safe Operating PA Temperature

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Steve Anness

KX2 Safe Operating PA Temperature

This question was posed last October by another on the reflector in regards
to the KX3 but does not look like there was a response. I had posed the
question once to Elecraft support and believe my email got lost in the
fray. When I posted the question to Elecraft support it was a month after
I received my KX2 and I was running 10 watts with it and it had gotten up
to 61C which is what prompted the question.

I have been running FT8 at around 5 watts recently and I see it getting up
to 51C.

At what point should I stop operating and let it cool down? I love my KX2
and don't want to damage it. I do know that these are used in fields by
many so perhaps I am just being paranoid.

73 de KJ5T
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jh3sif

Re: KX2 Safe Operating PA Temperature

I do not have KX2 but KX3.
KX3 internally set a PA temperature limit at which KX3 automatically reduces power output.
Assuming that KX2 and KX3 are very similar, unless your KX2 automatically reduces power output, the PA temperature is within the safe range.
I think running FT8 with 5W output is safe since I have made many FT8 QSOs with 5W.
You may attach any 3rd party heatsink if you want to feel safe.

73 de JH3SIF, Keith

> 2020/03/27 10:09、Steve Anness <[hidden email]>のメール:
>
> This question was posed last October by another on the reflector in regards
> to the KX3 but does not look like there was a response. I had posed the
> question once to Elecraft support and believe my email got lost in the
> fray. When I posted the question to Elecraft support it was a month after
> I received my KX2 and I was running 10 watts with it and it had gotten up
> to 61C which is what prompted the question.
>
> I have been running FT8 at around 5 watts recently and I see it getting up
> to 51C.
>
> At what point should I stop operating and let it cool down? I love my KX2
> and don't want to damage it. I do know that these are used in fields by
> many so perhaps I am just being paranoid.
>
> 73 de KJ5T
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

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Nr4c

Re: KX2 Safe Operating PA Temperature

In reply to this post by Steve Anness

I believe the radio might shut down somewhere above 80 C.

Sent from my iPhone
...nr4c. bill

> On Mar 26, 2020, at 9:11 PM, Steve Anness <[hidden email]> wrote:
>
> This question was posed last October by another on the reflector in regards
> to the KX3 but does not look like there was a response. I had posed the
> question once to Elecraft support and believe my email got lost in the
> fray. When I posted the question to Elecraft support it was a month after
> I received my KX2 and I was running 10 watts with it and it had gotten up
> to 61C which is what prompted the question.
>
> I have been running FT8 at around 5 watts recently and I see it getting up
> to 51C.
>
> At what point should I stop operating and let it cool down? I love my KX2
> and don't want to damage it. I do know that these are used in fields by
> many so perhaps I am just being paranoid.
>
> 73 de KJ5T
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Steve Anness

Re: KX2 Safe Operating PA Temperature

Thank you for the feedback. I have never seen the radio get that warm
during my operating. Someone did point out about the third party heatsinks
available so I may eventually purchase one. I primarily am doing very high
duty cycle modes such as RTTY and the JT modes with my KX2 so I want to
make sure that I am taking good care of it.

73 de KJ5T

On Thu, Mar 26, 2020 at 9:24 PM Nr4c <[hidden email]> wrote:

> I believe the radio might shut down somewhere above 80 C.
>
> Sent from my iPhone
> ...nr4c. bill
>
>
> > On Mar 26, 2020, at 9:11 PM, Steve Anness <[hidden email]> wrote:
> >
> > This question was posed last October by another on the reflector in
> regards
> > to the KX3 but does not look like there was a response. I had posed the
> > question once to Elecraft support and believe my email got lost in the
> > fray. When I posted the question to Elecraft support it was a month
> after
> > I received my KX2 and I was running 10 watts with it and it had gotten up
> > to 61C which is what prompted the question.
> >
> > I have been running FT8 at around 5 watts recently and I see it getting
> up
> > to 51C.
> >
> > At what point should I stop operating and let it cool down? I love my
> KX2
> > and don't want to damage it. I do know that these are used in fields by
> > many so perhaps I am just being paranoid.
> >
> > 73 de KJ5T
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
>

Elecraft mailing list

Re: KX2 Safe Operating PA Temperature

In reply to this post by Steve Anness

The KX2 will automatically fold back its power (responding to temperature) to prevent thermal runaway or damage to its finals

That being said, it is routinely recommended that when running any 100% duty cycle mode (e.g. typical digital text modes or FM Phone) one reduces RF output to 50% of rated output

73 de KX2CW
Joan

Darmok and Jalad at Tanagra, said Piglet.
Shaka, when the walls fell, said Pooh.

> On Mar 26, 2020, at 18:09, Steve Anness <[hidden email]> wrote:
>
> This question was posed last October by another on the reflector in regards
> to the KX3 but does not look like there was a response. I had posed the
> question once to Elecraft support and believe my email got lost in the
> fray. When I posted the question to Elecraft support it was a month after
> I received my KX2 and I was running 10 watts with it and it had gotten up
> to 61C which is what prompted the question.
>
> I have been running FT8 at around 5 watts recently and I see it getting up
> to 51C.
>
> At what point should I stop operating and let it cool down? I love my KX2
> and don't want to damage it. I do know that these are used in fields by
> many so perhaps I am just being paranoid.
>
> 73 de KJ5T
>

vk2rq

Re: KX2 Safe Operating PA Temperature

In reply to this post by Steve Anness

The other thing to watch is the frequency stability. When I used to
run digital modes on the KX3, the radio would drift a bit as it heated
up. I got one of the XG50 reference oscillators, and went through a
temperature compensation profiling procedure, and after that it worked
very well. I guess you already know with Elecraft radios that setting
the levels works differently to many other commercial radios -- often
you'll see procedures where you use the audio input drive to control
the transmitted power and saying to avoid ALC, but those procedures
and not appropriate for Elecraft -- there you need to set the input
level (on KX3 think it was something like 4 bars on the "ALC" meter)
then control the output power using the power output knob. Someone
else on this list probably has more current information than I which
pertains to the KX2.

73, Matt VK2RQ

On Fri, 27 Mar 2020 at 13:54, Steve Anness <[hidden email]> wrote:

>
> Thank you for the feedback. I have never seen the radio get that warm
> during my operating. Someone did point out about the third party heatsinks
> available so I may eventually purchase one. I primarily am doing very high
> duty cycle modes such as RTTY and the JT modes with my KX2 so I want to
> make sure that I am taking good care of it.
>
> 73 de KJ5T
>
> On Thu, Mar 26, 2020 at 9:24 PM Nr4c <[hidden email]> wrote:
>
> > I believe the radio might shut down somewhere above 80 C.
> >
> > Sent from my iPhone
> > ...nr4c. bill
> >
> >
> > > On Mar 26, 2020, at 9:11 PM, Steve Anness <[hidden email]> wrote:
> > >
> > > This question was posed last October by another on the reflector in
> > regards
> > > to the KX3 but does not look like there was a response. I had posed the
> > > question once to Elecraft support and believe my email got lost in the
> > > fray. When I posted the question to Elecraft support it was a month
> > after
> > > I received my KX2 and I was running 10 watts with it and it had gotten up
> > > to 61C which is what prompted the question.
> > >
> > > I have been running FT8 at around 5 watts recently and I see it getting
> > up
> > > to 51C.
> > >
> > > At what point should I stop operating and let it cool down? I love my
> > KX2
> > > and don't want to damage it. I do know that these are used in fields by
> > > many so perhaps I am just being paranoid.
> > >
> > > 73 de KJ5T
> > > ______________________________________________________________
> > > Elecraft mailing list
> > > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > > Help: http://mailman.qth.net/mmfaq.htm
> > > Post: mailto:[hidden email]
> > >
> > > This list hosted by: http://www.qsl.net
> > > Please help support this email list: http://www.qsl.net/donate.html
> > > Message delivered to [hidden email]
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Mooneer Salem

Re: KX2 Safe Operating PA Temperature

In reply to this post by Elecraft mailing list

FWIW, my KX3 handles 15 watts digital with no issues as far as I can tell.
I did the temperature compensation and have a third party heatsink, though.
I haven't looked too much at third party heatsinks for the KX2 but I
imagine I'd probably want to follow that 50% advice even with one installed
simply due to its physical size.

-Mooneer K6AQ

On Thu, Mar 26, 2020, 10:47 PM Joan via Elecraft <[hidden email]>
wrote:

> The KX2 will automatically fold back its power (responding to temperature)
> to prevent thermal runaway or damage to its finals
>
> That being said, it is routinely recommended that when running any 100%
> duty cycle mode (e.g. typical digital text modes or FM Phone) one reduces
> RF output to 50% of rated output
>
> 73 de KX2CW
> Joan
>
> Darmok and Jalad at Tanagra, said Piglet.
> Shaka, when the walls fell, said Pooh.
>
> > On Mar 26, 2020, at 18:09, Steve Anness <[hidden email]> wrote:
> >
> > This question was posed last October by another on the reflector in
> regards
> > to the KX3 but does not look like there was a response. I had posed the
> > question once to Elecraft support and believe my email got lost in the
> > fray. When I posted the question to Elecraft support it was a month
> after
> > I received my KX2 and I was running 10 watts with it and it had gotten up
> > to 61C which is what prompted the question.
> >
> > I have been running FT8 at around 5 watts recently and I see it getting
> up
> > to 51C.
> >
> > At what point should I stop operating and let it cool down? I love my
> KX2
> > and don't want to damage it. I do know that these are used in fields by
> > many so perhaps I am just being paranoid.
> >
> > 73 de KJ5T
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Steve Anness

Re: KX2 Safe Operating PA Temperature

It does sound like the KX2/KX3 are pretty tough little radios. I had heard
of some heatsink issues in earlier KX3s, not sure if that is true or not.
It sounds like 61C is fine. For the record the time that it got that hot
running 10 watts was SSB and I was doing a continual (recorded) CQ. I only
run digital modes at 5 watts or less. Again I appreciate all the feedback,
I have KX2 number 617, bought it in June 2016 but it sadly it gets
neglected at times, doing a bit more FT8/FT4 though now, especially since i
am stuck at my apartment.

73 de KJ5T

On Fri, Mar 27, 2020 at 1:05 AM Mooneer Salem <[hidden email]> wrote:

> FWIW, my KX3 handles 15 watts digital with no issues as far as I can tell.
> I did the temperature compensation and have a third party heatsink, though.
> I haven't looked too much at third party heatsinks for the KX2 but I
> imagine I'd probably want to follow that 50% advice even with one installed
> simply due to its physical size.
>
> -Mooneer K6AQ
>
> On Thu, Mar 26, 2020, 10:47 PM Joan via Elecraft <[hidden email]
> >
> wrote:
>
> > The KX2 will automatically fold back its power (responding to
> temperature)
> > to prevent thermal runaway or damage to its finals
> >
> > That being said, it is routinely recommended that when running any 100%
> > duty cycle mode (e.g. typical digital text modes or FM Phone) one reduces
> > RF output to 50% of rated output
> >
> > 73 de KX2CW
> > Joan
> >
> > Darmok and Jalad at Tanagra, said Piglet.
> > Shaka, when the walls fell, said Pooh.
> >
> > > On Mar 26, 2020, at 18:09, Steve Anness <[hidden email]> wrote:
> > >
> > > This question was posed last October by another on the reflector in
> > regards
> > > to the KX3 but does not look like there was a response. I had posed
> the
> > > question once to Elecraft support and believe my email got lost in the
> > > fray. When I posted the question to Elecraft support it was a month
> > after
> > > I received my KX2 and I was running 10 watts with it and it had gotten
> up
> > > to 61C which is what prompted the question.
> > >
> > > I have been running FT8 at around 5 watts recently and I see it getting
> > up
> > > to 51C.
> > >
> > > At what point should I stop operating and let it cool down? I love my
> > KX2
> > > and don't want to damage it. I do know that these are used in fields
> by
> > > many so perhaps I am just being paranoid.
> > >
> > > 73 de KJ5T
> > >
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
> >
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Elecraft mailing list

Re: KX2 Safe Operating PA Temperature

In reply to this post by Steve Anness

Hi,I have a KX3 in the 600 s/n range. There was a enlarged heatsink kit for radio's under 7500 s/n which doubled the time for the PA's to cut back. It's still listed on Elecraft's web site. Easy to install, no soldering.
73Jim HK7sss
In a message dated 3/27/2020 8:39:00 AM Pacific Standard Time, [hidden email] writes:

It does sound like the KX2/KX3 are pretty tough little radios. I had heard
of some heatsink issues in earlier KX3s, not sure if that is true or not.
It sounds like 61C is fine. For the record the time that it got that hot
running 10 watts was SSB and I was doing a continual (recorded) CQ. I only
run digital modes at 5 watts or less. Again I appreciate all the feedback,
I have KX2 number 617, bought it in June 2016 but it sadly it gets
neglected at times, doing a bit more FT8/FT4 though now, especially since i
am stuck at my apartment.

73 de KJ5T
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

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Tim McDonough N9PUZ

Re: KX2 Safe Operating PA Temperature

In reply to this post by Steve Anness

I'm curious, have people been seeing these high tempts indoors or
outdoors? I notice a significant temperature difference with my KX2 when
operating outdoors by just keeping it in the shade. I do have a third
party heatsink.

Tim N9PUZ
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Elecraft mailing list

Re: KX2 Safe Operating PA Temperature

Why use another heat sink ?

On Sunday, March 29, 2020, 11:16:31 AM EDT, Tim McDonough N9PUZ <[hidden email]> wrote:

I'm curious, have people been seeing these high tempts indoors or
outdoors? I notice a significant temperature difference with my KX2 when
operating outdoors by just keeping it in the shade. I do have a third
party heatsink.

Tim N9PUZ
______________________________________________________________
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______________________________________________________________
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