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Max power for JT9 with K3S 100?

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Frank O'Donnell

Max power for JT9 with K3S 100?

I've been using JT9 mode on 630m this winter with my K3S outputting to
an external class D amp.

Now I'm interested in trying some JT9 QSOs with some people currently
operating on 160m. For me this would mean outputting directly from the
K3S (with internal tuner) to the antenna.

Given the 1-minute cycle time for JT9, are there recommendations
(official from Elecraft, or otherwise) on maximum power to use in a
situation like this? And/or, is the answer dependent on the SWR I can
achieve with the antenna?

Thanks and 73,

Frank K6FOD

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Bob McGraw - K4TAX

Re: Max power for JT9 with K3S 100?

Frank:

The duty cycle for the transmitter, as stated in the manual, is; CW and
SSB modes, 100% - 10 min, 100 W key-down at 25C ambient.   Do note that
6M has reduce power values of 85 watts {51 -52 MHz} or 70 watts {52 - 54
MHz}

The duty cycle for JT-9, 1 minute transmit, 1 minute receive would be
50%.   I frequently run 100 watts on WSJT-X FT-8 with no issues. Just
pay attention to PA temperature. It should be 60 C or less.   Also this
is with FANS in the automatic mode.

73

Bob, K4TAX

On 4/3/2020 4:18 PM, Frank O'Donnell wrote:

> I've been using JT9 mode on 630m this winter with my K3S outputting to
> an external class D amp.
>
> Now I'm interested in trying some JT9 QSOs with some people currently
> operating on 160m. For me this would mean outputting directly from the
> K3S (with internal tuner) to the antenna.
>
> Given the 1-minute cycle time for JT9, are there recommendations
> (official from Elecraft, or otherwise) on maximum power to use in a
> situation like this? And/or, is the answer dependent on the SWR I can
> achieve with the antenna?
>
> Thanks and 73,
>
> Frank K6FOD
>
>
> ______________________________________________________________
> Elecraft mailing list
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John Simmons

Re: Max power for JT9 with K3S 100?

Fred Cady's book:

"There are four fans speeds that turn on at different temperatures."
"If the temperature reaches 84 degrees C the KPA3 will be bypassed until
the temperature falls to stop any damage as a last-ditch backup measure
to protect your expensive power transistors from the excess heat."

-de John NI0K

Bob McGraw K4TAX wrote on 4/3/2020 6:39 PM:

> Frank:
>
> The duty cycle for the transmitter, as stated in the manual, is; CW
> and SSB modes, 100% - 10 min, 100 W key-down at 25C ambient.   Do note
> that 6M has reduce power values of 85 watts {51 -52 MHz} or 70 watts
> {52 - 54 MHz}
>
> The duty cycle for JT-9, 1 minute transmit, 1 minute receive would be
> 50%.   I frequently run 100 watts on WSJT-X FT-8 with no issues. Just
> pay attention to PA temperature. It should be 60 C or less.   Also
> this is with FANS in the automatic mode.
>
> 73
>
> Bob, K4TAX
>
>
> On 4/3/2020 4:18 PM, Frank O'Donnell wrote:
>> I've been using JT9 mode on 630m this winter with my K3S outputting
>> to an external class D amp.
>>
>> Now I'm interested in trying some JT9 QSOs with some people currently
>> operating on 160m. For me this would mean outputting directly from
>> the K3S (with internal tuner) to the antenna.
>>
>> Given the 1-minute cycle time for JT9, are there recommendations
>> (official from Elecraft, or otherwise) on maximum power to use in a
>> situation like this? And/or, is the answer dependent on the SWR I can
>> achieve with the antenna?
>>
>> Thanks and 73,
>>
>> Frank K6FOD
>>
>>
>> ______________________________________________________________
>> 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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Frank O'Donnell

Re: Max power for JT9 with K3S 100?

Thanks for the replies.

I've enabled the PA temp display (currently showing 22C right after
power-up but before transmitting), and will keep an eye on that.

Bob, I noticed that line in the K3S manual about the CW/SSB duty cycle.
Does "100% - 10 min, 100 W key-down" mean that if you key down without
stop in CW mode it can go 10 minutes at 100 watts? That seems like an
awful lot.

Where do the recommended TPO's for 6 meters, the 50% value for JT9, and
the 60C guideline for the PA temp come from?

Thanks again,

Frank K6FOD

On 4/4/20 6:22 AM, John Simmons wrote:

> Fred Cady's book:
>
> "There are four fans speeds that turn on at different temperatures."
> "If the temperature reaches 84 degrees C the KPA3 will be bypassed
> until the temperature falls to stop any damage as a last-ditch backup
> measure to protect your expensive power transistors from the excess
> heat."
>
> -de John NI0K
>
>
> Bob McGraw K4TAX wrote on 4/3/2020 6:39 PM:
>> Frank:
>>
>> The duty cycle for the transmitter, as stated in the manual, is; CW
>> and SSB modes, 100% - 10 min, 100 W key-down at 25C ambient.   Do
>> note that 6M has reduce power values of 85 watts {51 -52 MHz} or 70
>> watts {52 - 54 MHz}
>>
>> The duty cycle for JT-9, 1 minute transmit, 1 minute receive would be
>> 50%.   I frequently run 100 watts on WSJT-X FT-8 with no issues.
>> Just pay attention to PA temperature. It should be 60 C or less.
>> Also this is with FANS in the automatic mode.
>>
>> 73
>>
>> Bob, K4TAX
>>
>>
>> On 4/3/2020 4:18 PM, Frank O'Donnell wrote:
>>> I've been using JT9 mode on 630m this winter with my K3S outputting
>>> to an external class D amp.
>>>
>>> Now I'm interested in trying some JT9 QSOs with some people
>>> currently operating on 160m. For me this would mean outputting
>>> directly from the K3S (with internal tuner) to the antenna.
>>>
>>> Given the 1-minute cycle time for JT9, are there recommendations
>>> (official from Elecraft, or otherwise) on maximum power to use in a
>>> situation like this? And/or, is the answer dependent on the SWR I
>>> can achieve with the antenna?
>>>
>>> Thanks and 73,
>>>
>>> Frank K6FOD

ANDY DURBIN

Max power for JT9 with K3S 100?

In reply to this post by Frank O'Donnell

"Does "100% - 10 min, 100 W key-down" mean that if you key down without stop in CW mode it can go 10 minutes at 100 watts? That seems like an awful lot."

If you want to know what it actually means you'd probably have to run a test and record the PA temperature. Does it reach maximum value within that 10 minute period? If so, what is that maximum value and do you want to operate the finals at that temperature? If temperature does not reach a maximum then what is the rate of increase? At what time does the increasing temperature cross over the temperature at which you are willing to operate the finals?

I record KPA500 temperatures for every transmission. Unfortunately Kenwood does not provide finals temperature on the serial bus so I have to make do with recording my TS-590S rear chassis temperature.

Kenwood provided data shows TS-590S final temperature limited at about 85 deg C after 5 minutes and remained constant for remainder of the 2 hour 100 W key down test. (and no, I don't let mine get that hot)

73,
Andy, k3wyc

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NK7Z

Re: Max power for JT9 with K3S 100?

What is the recommended temp to run the KPA500 at?

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 4/4/20 3:01 PM, Andy Durbin wrote:

> "Does "100% - 10 min, 100 W key-down" mean that if you key down without stop in CW mode it can go 10 minutes at 100 watts? That seems like an awful lot."
>
> If you want to know what it actually means you'd probably have to run a test and record the PA temperature. Does it reach maximum value within that 10 minute period? If so, what is that maximum value and do you want to operate the finals at that temperature? If temperature does not reach a maximum then what is the rate of increase? At what time does the increasing temperature cross over the temperature at which you are willing to operate the finals?
>
> I record KPA500 temperatures for every transmission. Unfortunately Kenwood does not provide finals temperature on the serial bus so I have to make do with recording my TS-590S rear chassis temperature.
>
> Kenwood provided data shows TS-590S final temperature limited at about 85 deg C after 5 minutes and remained constant for remainder of the 2 hour 100 W key down test. (and no, I don't let mine get that hot)
>
> 73,
> Andy, k3wyc
>
>
>
>
>
>
>
> ______________________________________________________________
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>

iw2noy

(Too much..) RF back and through the RX ANT OUT for external receiver

Hello,

i ordered a Colibrì Nano USB SDR.
and i am thinkg to connect the Colibrì antenna through the RX ANT OT of
the K3s tu use the colibrì and his software like a panadapter for the
K3s.
The colibrì can't accept "IF OUT", so i will use RX ANT OUT from XV3B to
give antenna signal to the Colibrì.

But it seems, from some test i did with friends, that RX OUT is NOT well
or totally disconnected weh K3s goes in TX and some RF goes (or come
back) through the RX OUT.
I would like to know if someone knows how many "dbm" or watt could goes
through the RX OUT when the K3s is in TX with maximum power.
Too much RF can kill the the SDR receiver.

Anyone knows the answer ?

Maybe Wayne or Eric ? ;-)

Any help would be appreciated.

Thanks a lot, Graziano IW2NOY
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Bob McGraw - K4TAX

Re: Max power for JT9 with K3S 100?

In reply to this post by ANDY DURBIN

Andy et al;

Just quoted what is in the K3S manual. No interpretation provided. I
agree that 100 watts key down is a lot for a SSB amplifier running in CW
mode. To me that says 100 watts for 10 minutes and then RX for 10
minutes. Otherwise equal TX and RX times. Who does that?

I just pay attention to the PA temp when running digital modes. Likewise
for the KPA500.

73

Bob, K4TAX

On 4/4/2020 5:01 PM, Andy Durbin wrote:

Bob McGraw - K4TAX

Re: Max power for JT9 with K3S 100?

In reply to this post by NK7Z

Running FT-8 or PSK-31, I see 60 C from time to time. Some bands I see
the temp rise much faster indicating less efficiency.

73

Bob, K4TAX

On 4/4/2020 5:03 PM, Dave Cole wrote:

> What is the recommended temp to run the KPA500 at?
>
> 73, and thanks,
> Dave (NK7Z)
> https://www.nk7z.net
> ARRL Volunteer Examiner
> ARRL Technical Specialist
> ARRL Asst. Director, NW Division, Technical Resources
>
> On 4/4/20 3:01 PM, Andy Durbin wrote:
>> "Does "100% - 10 min, 100 W key-down" mean that if you key down
>> without stop in CW mode it can go 10 minutes at 100 watts? That seems
>> like an awful lot."
>>
>> If you want to know what it actually means you'd probably have to run
>> a test and record the PA temperature. Does it reach maximum value
>> within that 10 minute period? If so, what is that maximum value and
>> do you want to operate the finals at that temperature? If
>> temperature does not reach a maximum then what is the rate of
>> increase? At what time does the increasing temperature cross over
>> the temperature at which you are willing to operate the finals?
>>
>> I record KPA500 temperatures for every transmission. Unfortunately
>> Kenwood does not provide finals temperature on the serial bus so I
>> have to make do with recording my TS-590S rear chassis temperature.
>>
>> Kenwood provided data shows TS-590S final temperature limited at
>> about 85 deg C after 5 minutes and remained constant for remainder of
>> the 2 hour 100 W key down test. (and no, I don't let mine get that hot)
>>
>> 73,
>> Andy, k3wyc
>>
>>
>>
>>
>>
>>
>>
>> ______________________________________________________________
>> 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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Bob McGraw - K4TAX

Re: Max power for JT9 with K3S 100?

In reply to this post by Frank O'Donnell

Frank et al;

Just quoted what is in the K3S manual.   No interpretation provided.   I
agree that 100 watts key down is a lot for a SSB amplifier running in CW
mode. To me that says 100 watts for 10 minutes and then RX for 10
minutes.   Otherwise equal TX and RX times. Who does that?

And if one is running "100 watts" then running CW or SSB for 10 minutes
might be the limit. Just speculation.   On AM I might talk for 10
minutes but that is at 25% rated power output for carrier, yet it is 100
watts PEP.   The 60 C is MY guideline. The KPA3A will shut down about 85
C or so.

On 6M I run my KPA500 at about 300 to 400 watts. The K3S is running
about 25 to 30 watts on 6M.   At this point I'm watching the KPA500
temperature.

There is NO DX worth blowing a PA either in the K3S or the KPA500.
But I know guys that will blow things up, pushing things to the max and
beyond trying to work that DX station. I say bah humbug to that!

I just pay attention to the PA temp, specially when running digital
modes. Likewise for the KPA500.

73

Bob, K4TAX

On 4/4/2020 3:41 PM, Frank O'Donnell wrote:

> Thanks for the replies.
>
> I've enabled the PA temp display (currently showing 22C right after
> power-up but before transmitting), and will keep an eye on that.
>
> Bob, I noticed that line in the K3S manual about the CW/SSB duty
> cycle. Does "100% - 10 min, 100 W key-down" mean that if you key down
> without stop in CW mode it can go 10 minutes at 100 watts? That seems
> like an awful lot.
>
> Where do the recommended TPO's for 6 meters, the 50% value for JT9,
> and the 60C guideline for the PA temp come from?
>
> Thanks again,
>
> Frank K6FOD
>
>
> On 4/4/20 6:22 AM, John Simmons wrote:
>> Fred Cady's book:
>>
>> "There are four fans speeds that turn on at different temperatures."
>> "If the temperature reaches 84 degrees C the KPA3 will be bypassed
>> until the temperature falls to stop any damage as a last-ditch backup
>> measure to protect your expensive power transistors from the excess
>> heat."
>>
>> -de John NI0K
>>
>>
>> Bob McGraw K4TAX wrote on 4/3/2020 6:39 PM:
>>> Frank:
>>>
>>> The duty cycle for the transmitter, as stated in the manual, is; CW
>>> and SSB modes, 100% - 10 min, 100 W key-down at 25C ambient.   Do
>>> note that 6M has reduce power values of 85 watts {51 -52 MHz} or 70
>>> watts {52 - 54 MHz}
>>>
>>> The duty cycle for JT-9, 1 minute transmit, 1 minute receive would
>>> be 50%.   I frequently run 100 watts on WSJT-X FT-8 with no issues.
>>> Just pay attention to PA temperature. It should be 60 C or less.
>>> Also this is with FANS in the automatic mode.
>>>
>>> 73
>>>
>>> Bob, K4TAX
>>>
>>>
>>> On 4/3/2020 4:18 PM, Frank O'Donnell wrote:
>>>> I've been using JT9 mode on 630m this winter with my K3S outputting
>>>> to an external class D amp.
>>>>
>>>> Now I'm interested in trying some JT9 QSOs with some people
>>>> currently operating on 160m. For me this would mean outputting
>>>> directly from the K3S (with internal tuner) to the antenna.
>>>>
>>>> Given the 1-minute cycle time for JT9, are there recommendations
>>>> (official from Elecraft, or otherwise) on maximum power to use in a
>>>> situation like this? And/or, is the answer dependent on the SWR I
>>>> can achieve with the antenna?
>>>>
>>>> Thanks and 73,
>>>>
>>>> Frank K6FOD
>
> ______________________________________________________________
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ve3gmz

Re: Max power for JT9 with K3S 100?

This discussion fascinates me only in that I wonder why you are using so much power for weak signal modes? 5 or 10 watts should be plenty even with a compromised antenna and poor band conditions......or am I missing somthing.Brian VE3GMZ Sent from my Samsung Galaxy smartphone.
-------- Original message --------From: Bob McGraw K4TAX <[hidden email]> Date: 2020-04-04 8:19 p.m. (GMT-05:00) To: [hidden email] Subject: Re: [Elecraft] Max power for JT9 with K3S 100? Frank et al;Just quoted what is in the K3S manual. No interpretation provided. I agree that 100 watts key down is a lot for a SSB amplifier running in CW mode. To me that says 100 watts for 10 minutes and then RX for 10 minutes. Otherwise equal TX and RX times. Who does that?And if one is running "100 watts" then running CW or SSB for 10 minutes might be the limit. Just speculation. On AM I might talk for 10 minutes but that is at 25% rated power output for carrier, yet it is 100 watts PEP. The 60 C is MY guideline. The KPA3A will shut down about 85 C or so.On 6M I run my KPA500 at about 300 to 400 watts. The K3S is running about 25 to 30 watts on 6M. At this point I'm watching the KPA500 temperature.There is NO DX worth blowing a PA either in the K3S or the KPA500. But I know guys that will blow things up, pushing things to the max and beyond trying to work that DX station. I say bah humbug to that!I just pay attention to the PA temp, specially when running digital modes. Likewise for the KPA500.73Bob, K4TAXOn 4/4/2020 3:41 PM, Frank O'Donnell wrote:> Thanks for the replies.>> I've enabled the PA temp display (currently showing 22C right after > power-up but before transmitting), and will keep an eye on that.>> Bob, I noticed that line in the K3S manual about the CW/SSB duty > cycle. Does "100% - 10 min, 100 W key-down" mean that if you key down > without stop in CW mode it can go 10 minutes at 100 watts? That seems > like an awful lot.>> Where do the recommended TPO's for 6 meters, the 50% value for JT9, > and the 60C guideline for the PA temp come from?>> Thanks again,>> Frank K6FOD>>> On 4/4/20 6:22 AM, John Simmons wrote:>> Fred Cady's book:>>>> "There are four fans speeds that turn on at different temperatures.">> "If the temperature reaches 84 degrees C the KPA3 will be bypassed >> until the temperature falls to stop any damage as a last-ditch backup >> measure to protect your expensive power transistors from the excess >> heat.">>>> -de John NI0K>>>>>> Bob McGraw K4TAX wrote on 4/3/2020 6:39 PM:>>> Frank:>>>>>> The duty cycle for the transmitter, as stated in the manual, is; CW >>> and SSB modes, 100% - 10 min, 100 W key-down at 25C ambient. Do >>> note that 6M has reduce power values of 85 watts {51 -52 MHz} or 70 >>> watts {52 - 54 MHz}>>>>>> The duty cycle for JT-9, 1 minute transmit, 1 minute receive would >>> be 50%. I frequently run 100 watts on WSJT-X FT-8 with no issues. >>> Just pay attention to PA temperature. It should be 60 C or less. >>> Also this is with FANS in the automatic mode.>>>>>> 73>>>>>> Bob, K4TAX>>>>>>>>> On 4/3/2020 4:18 PM, Frank O'Donnell wrote:>>>> I've been using JT9 mode on 630m this winter with my K3S outputting >>>> to an external class D amp.>>>>>>>> Now I'm interested in trying some JT9 QSOs with some people >>>> currently operating on 160m. For me this would mean outputting >>>> directly from the K3S (with internal tuner) to the antenna.>>>>>>>> Given the 1-minute cycle time for JT9, are there recommendations >>>> (official from Elecraft, or otherwise) on maximum power to use in a >>>> situation like this? And/or, is the answer dependent on the SWR I >>>> can achieve with the antenna?>>>>>>>> Thanks and 73,>>>>>>>> Frank K6FOD>> ______________________________________________________________> 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 listHome: http://mailman.qth.net/mailman/listinfo/elecraftHelp: http://mailman.qth.net/mmfaq.htmPost: mailto:[hidden email] list hosted by: http://www.qsl.netPlease help support this email list: http://www.qsl.net/donate.htmlMessage delivered to [hidden email]
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Rick Bates, NK7I

Re: Max power for JT9 with K3S 100?

In reply to this post by Frank O'Donnell

Because it’s weak signal at the receiving end; you use what power it takes to succeed in making the contact, up to the legal limit.

On 160M, 1500 watts out is common.

Rick NK7I

Smell Czech corruptions are inevitable

> On Apr 4, 2020, at 9:02 PM, brianchapnick <[hidden email]> wrote:
>
> This discussion fascinates me only in that I wonder why you are using so much power for weak signal modes? 5 or 10 watts should be plenty even with a compromised antenna and poor band conditions......or am I missing somthing.Brian VE3GMZ Sent from my Samsung Galaxy smartphone.
> -------- Original message --------From: Bob McGraw K4TAX <[hidden email]> Date: 2020-04-04 8:19 p.m. (GMT-05:00) To: [hidden email] Subject: Re: [Elecraft] Max power for JT9 with K3S 100? Frank et al;Just quoted what is in the K3S manual. No interpretation provided. I agree that 100 watts key down is a lot for a SSB amplifier running in CW mode. To me that says 100 watts for 10 minutes and then RX for 10 minutes. Otherwise equal TX and RX times. Who does that?And if one is running "100 watts" then running CW or SSB for 10 minutes might be the limit. Just speculation. On AM I might talk for 10 minutes but that is at 25% rated power output for carrier, yet it is 100 watts PEP. The 60 C is MY guideline. The KPA3A will shut down about 85 C or so.On 6M I run my KPA500 at about 300 to 400 watts. The K3S is running about 25 to 30 watts on 6M. At this point I'm watching the KPA500 temperature.There is NO DX worth blowing a PA either in the K3S or the KPA500. But I know guys that will blow things up, pushing things to the max and beyond trying to work that DX station. I say bah humbug to that!I just pay attention to the PA temp, specially when running digital modes. Likewise for the KPA500.73Bob, K4TAXOn 4/4/2020 3:41 PM, Frank O'Donnell wrote:> Thanks for the replies.>> I've enabled the PA temp display (currently showing 22C right after > power-up but before transmitting), and will keep an eye on that.>> Bob, I noticed that line in the K3S manual about the CW/SSB duty > cycle. Does "100% - 10 min, 100 W key-down" mean that if you key down > without stop in CW mode it can go 10 minutes at 100 watts? That seems > like an awful lot.>> Where do the recommended TPO's for 6 meters, the 50% value for JT9, > and the 60C guideline for the PA temp come from?>> Thanks again,>> Frank K6FOD>>> On 4/4/20 6:22 AM, John Simmons wrote:>> Fred Cady's book:>>>> "There are four fans speeds that turn on at different temperatures.">> "If the temperature reaches 84 degrees C the KPA3 will be bypassed >> until the temperature falls to stop any damage as a last-ditch backup >> measure to protect your expensive power transistors from the excess >> heat.">>>> -de John NI0K>>>>>> Bob McGraw K4TAX wrote on 4/3/2020 6:39 PM:>>> Frank:>>>>>> The duty cycle for the transmitter, as stated in the manual, is; CW >>> and SSB modes, 100% - 10 min, 100 W key-down at 25C ambient. Do >>> note that 6M has reduce power values of 85 watts {51 -52 MHz} or 70 >>> watts {52 - 54 MHz}>>>>>> The duty cycle for JT-9, 1 minute transmit, 1 minute receive would >>> be 50%. I frequently run 100 watts on WSJT-X FT-8 with no issues. >>> Just pay attention to PA temperature. It should be 60 C or less. >>> Also this is with FANS in the automatic mode.>>>>>> 73>>>>>> Bob, K4TAX>>>>>>>>> On 4/3/2020 4:18 PM, Frank O'Donnell wrote:>>>> I've been using JT9 mode on 630m this winter with my K3S outputting >>>> to an external class D amp.>>>>>>>> Now I'm interested in trying some JT9 QSOs with some people >>>> currently operating on 160m. For me this would mean outputting >>>> directly from the K3S (with internal tuner) to the antenna.>>>>>>>> Given the 1-minute cycle time for JT9, are there recommendations >>>> (official from Elecraft, or otherwise) on maximum power to use in a >>>> situation like this? And/or, is the answer dependent on the SWR I >>>> can achieve with the antenna?>>>>>>>> Thanks and 73,>>>>>>>> Frank K6FOD>> ______________________________________________________________> 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 listHome: http://mailman.qth.net/mailman/listinfo/elecraftHelp: http://mailman.qth.net/mmfaq.htmPost: mailto:[hidden email] list hosted by: http://www.qsl.netPlease help support this email list: http://www.qsl.net/donate.htmlMessage delivered to [hidden email]
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Jim Brown-10

Re: Max power for JT9 with K3S 100?

In reply to this post by Frank O'Donnell

On 4/4/2020 9:01 PM, brianchapnick wrote:
> This discussion fascinates me only in that I wonder why you are using so much power for weak signal modes? 5 or 10 watts should be plenty even with a compromised antenna and poor band conditions......or am I missing somthing.

Yes. "Weak signal" does NOT mean low power. "Weak signal" is define by
the path, the frequency, noise levels on each end, and antennas. When
I'm trying to work EU on 160 and 80 from my QTH near San Francisco, I'm
running legal limit. When I'm working double-hop (or more hops) E-skip
on 6M, and meteor scatter on 6M, I'm running legal limit. And when I'm
running power like that, I almost never fill up the band with CQs.

Don't get me wrong -- I have >170 countries worked QRP, DXCC on 20 and
15 QRP, all CW or SSB. I rarely run FT8 on other bands, although I've
been doing it a bit on 60M and 30M, and I don't run much power there.
There is a time and place for everything. :)

73, Jim K9YC
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NK7Z

Re: Max power for JT9 with K3S 100?

In reply to this post by Frank O'Donnell

The moonbounce boys use a KW or more...

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist
ARRL Asst. Director, NW Division, Technical Resources

On 4/4/20 9:01 PM, brianchapnick wrote:

> This discussion fascinates me only in that I wonder why you are using so much power for weak signal modes? 5 or 10 watts should be plenty even with a compromised antenna and poor band conditions......or am I missing somthing.Brian VE3GMZ Sent from my Samsung Galaxy smartphone.
> -------- Original message --------From: Bob McGraw K4TAX <[hidden email]> Date: 2020-04-04 8:19 p.m. (GMT-05:00) To: [hidden email] Subject: Re: [Elecraft] Max power for JT9 with K3S 100? Frank et al;Just quoted what is in the K3S manual. No interpretation provided. I agree that 100 watts key down is a lot for a SSB amplifier running in CW mode. To me that says 100 watts for 10 minutes and then RX for 10 minutes. Otherwise equal TX and RX times. Who does that?And if one is running "100 watts" then running CW or SSB for 10 minutes might be the limit. Just speculation. On AM I might talk for 10 minutes but that is at 25% rated power output for carrier, yet it is 100 watts PEP. The 60 C is MY guideline. The KPA3A will shut down about 85 C or so.On 6M I run my KPA500 at about 300 to 400 watts. The K3S is running about 25 to 30 watts on 6M. At this point I'm watching the KPA500 temperature.There is NO DX worth blowing a PA either in the K3S or the KPA500. But I know guys that will blow things up, pushing things to the max and beyond trying to work that DX station. I say bah humbug to that!I just pay attention to the PA temp, specially when running digital modes. Likewise for the KPA500.73Bob, K4TAXOn 4/4/2020 3:41 PM, Frank O'Donnell wrote:> Thanks for the replies.>> I've enabled the PA temp display (currently showing 22C right after > power-up but before transmitting), and will keep an eye on that.>> Bob, I noticed that line in the K3S manual about the CW/SSB duty > cycle. Does "100% - 10 min, 100 W key-down" mean that if you key down > without stop in CW mode it can go 10 minutes at 100 watts? That seems > like an awful lot.>> Where do the recommended TPO's for 6 meters, the 50% value for JT9, > and the 60C guideline for the PA temp come from?>> Thanks again,>> Frank K6FOD>>> On 4/4/20 6:22 AM, John Simmons wrote:>> Fred Cady's book:>>>> "There are four fans speeds that turn on at different temperatures.">> "If the temperature reaches 84 degrees C the KPA3 will be bypassed >> until the temperature falls to stop any damage as a last-ditch backup >> measure to protect your expensive power transistors from the excess >> heat.">>>> -de John NI0K>>>>>> Bob McGraw K4TAX wrote on 4/3/2020 6:39 PM:>>> Frank:>>>>>> The duty cycle for the transmitter, as stated in the manual, is; CW >>> and SSB modes, 100% - 10 min, 100 W key-down at 25C ambient. Do >>> note that 6M has reduce power values of 85 watts {51 -52 MHz} or 70 >>> watts {52 - 54 MHz}>>>>>> The duty cycle for JT-9, 1 minute transmit, 1 minute receive would >>> be 50%. I frequently run 100 watts on WSJT-X FT-8 with no issues. >>> Just pay attention to PA temperature. It should be 60 C or less. >>> Also this is with FANS in the automatic mode.>>>>>> 73>>>>>> Bob, K4TAX>>>>>>>>> On 4/3/2020 4:18 PM, Frank O'Donnell wrote:>>>> I've been using JT9 mode on 630m this winter with my K3S outputting >>>> to an external class D amp.>>>>>>>> Now I'm interested in trying some JT9 QSOs with some people >>>> currently operating on 160m. For me this would mean outputting >>>> directly from the K3S (with internal tuner) to the antenna.>>>>>>>> Given the 1-minute cycle time for JT9, are there recommendations >>>> (official from Elecraft, or otherwise) on maximum power to use in a >>>> situation like this? And/or, is the answer dependent on the SWR I >>>> can achieve with the antenna?>>>>>>>> Thanks and 73,>>>>>>>> Frank K6FOD>> ______________________________________________________________> 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 listHome: http://mailman.qth.net/mailman/listinfo/elecraftHelp: http://mailman.qth.net/mmfaq.htmPost: mailto:[hidden email] list hosted by: http://www.qsl.netPlease help support this email list: http://www.qsl.net/donate.htmlMessage delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
> 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]
>

ve3gmz

Re: Max power for JT9 with K3S 100?

In reply to this post by Rick Bates, NK7I

My only rig is a kx3 so I have no experience at high power. With digital modes, does it matter at the receiving end whether the signal is -15db or 1db? Will not both signals be decoded the same way? With high power is it your practice to start with lower levels and work your way up or do you go for broke from the start? I understand the advantage of higher power with modes that you actually have to use your ears to make sense of things.

Brian VE3GMZ

Sent via BlackBerry Hub+ Inbox for Android

Original Message

From: [hidden email]
Sent: April 5, 2020 12:13 a.m.
To: [hidden email]
Cc: [hidden email]; [hidden email]
Subject: Re: [Elecraft] Max power for JT9 with K3S 100?

Because it’s weak signal at the receiving end; you use what power it takes to succeed in making the contact, up to the legal limit.

On 160M, 1500 watts out is common.

Rick NK7I

Smell Czech corruptions are inevitable

Bob McGraw - K4TAX

Re: Max power for JT9 with K3S 100?

In reply to this post by Frank O'Donnell

A weak signal mode does not imply a low power mode.

Bob, K4TAX

Sent from my iPhone

> On Apr 4, 2020, at 11:15 PM, brianchapnick <[hidden email]> wrote:
>
>
> This discussion fascinates me only in that I wonder why you are using so much power for weak signal modes? 5 or 10 watts should be plenty even with a compromised antenna and poor band conditions......or am I missing somthing.
>
> Brian VE3GMZ
>
>
>
>
>
> Sent from my Samsung Galaxy smartphone.
>
>
> -------- Original message --------
> From: Bob McGraw K4TAX <[hidden email]>
> Date: 2020-04-04 8:19 p.m. (GMT-05:00)
> To: [hidden email]
> Subject: Re: [Elecraft] Max power for JT9 with K3S 100?
>
> Frank et al;
>
>
> Just quoted what is in the K3S manual. No interpretation provided. I
> agree that 100 watts key down is a lot for a SSB amplifier running in CW
> mode. To me that says 100 watts for 10 minutes and then RX for 10
> minutes. Otherwise equal TX and RX times. Who does that?
>
> And if one is running "100 watts" then running CW or SSB for 10 minutes
> might be the limit. Just speculation. On AM I might talk for 10
> minutes but that is at 25% rated power output for carrier, yet it is 100
> watts PEP. The 60 C is MY guideline. The KPA3A will shut down about 85
> C or so.
>
> On 6M I run my KPA500 at about 300 to 400 watts. The K3S is running
> about 25 to 30 watts on 6M. At this point I'm watching the KPA500
> temperature.
>
> There is NO DX worth blowing a PA either in the K3S or the KPA500.
> But I know guys that will blow things up, pushing things to the max and
> beyond trying to work that DX station. I say bah humbug to that!
>
> I just pay attention to the PA temp, specially when running digital
> modes. Likewise for the KPA500.
>
> 73
>
> Bob, K4TAX
>
>
> On 4/4/2020 3:41 PM, Frank O'Donnell wrote:
> > Thanks for the replies.
> >
> > I've enabled the PA temp display (currently showing 22C right after
> > power-up but before transmitting), and will keep an eye on that.
> >
> > Bob, I noticed that line in the K3S manual about the CW/SSB duty
> > cycle. Does "100% - 10 min, 100 W key-down" mean that if you key down
> > without stop in CW mode it can go 10 minutes at 100 watts? That seems
> > like an awful lot.
> >
> > Where do the recommended TPO's for 6 meters, the 50% value for JT9,
> > and the 60C guideline for the PA temp come from?
> >
> > Thanks again,
> >
> > Frank K6FOD
> >
> >
> > On 4/4/20 6:22 AM, John Simmons wrote:
> >> Fred Cady's book:
> >>
> >> "There are four fans speeds that turn on at different temperatures."
> >> "If the temperature reaches 84 degrees C the KPA3 will be bypassed
> >> until the temperature falls to stop any damage as a last-ditch backup
> >> measure to protect your expensive power transistors from the excess
> >> heat."
> >>
> >> -de John NI0K
> >>
> >>
> >> Bob McGraw K4TAX wrote on 4/3/2020 6:39 PM:
> >>> Frank:
> >>>
> >>> The duty cycle for the transmitter, as stated in the manual, is; CW
> >>> and SSB modes, 100% - 10 min, 100 W key-down at 25C ambient. Do
> >>> note that 6M has reduce power values of 85 watts {51 -52 MHz} or 70
> >>> watts {52 - 54 MHz}
> >>>
> >>> The duty cycle for JT-9, 1 minute transmit, 1 minute receive would
> >>> be 50%. I frequently run 100 watts on WSJT-X FT-8 with no issues.
> >>> Just pay attention to PA temperature. It should be 60 C or less.
> >>> Also this is with FANS in the automatic mode.
> >>>
> >>> 73
> >>>
> >>> Bob, K4TAX
> >>>
> >>>
> >>> On 4/3/2020 4:18 PM, Frank O'Donnell wrote:
> >>>> I've been using JT9 mode on 630m this winter with my K3S outputting
> >>>> to an external class D amp.
> >>>>
> >>>> Now I'm interested in trying some JT9 QSOs with some people
> >>>> currently operating on 160m. For me this would mean outputting
> >>>> directly from the K3S (with internal tuner) to the antenna.
> >>>>
> >>>> Given the 1-minute cycle time for JT9, are there recommendations
> >>>> (official from Elecraft, or otherwise) on maximum power to use in a
> >>>> situation like this? And/or, is the answer dependent on the SWR I
> >>>> can achieve with the antenna?
> >>>>
> >>>> Thanks and 73,
> >>>>
> >>>> Frank K6FOD
> >
> > ______________________________________________________________
> > 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]

Rick Bates, NK7I

Re: Max power for JT9 with K3S 100?

In reply to this post by ve3gmz

Yes it matters. The short version is that your receiving ability may exceed that of the other stations noise floor.

Just because my noise floor is generally -130 or quieter doesn’t mean their noise is equally quiet. If they can’t reduce noise further, you need to present more signal.

With my quiet environment I base my output power on the signal I receive, if loud, low output; if weak, ramp it up.

Rick NK7I

Smell Czech corruptions are inevitable

> On Apr 5, 2020, at 6:09 AM, [hidden email] wrote:
>
> My only rig is a kx3 so I have no experience at high power. With digital modes, does it matter at the receiving end whether the signal is -15db or 1db? Will not both signals be decoded the same way? With high power is it your practice to start with lower levels and work your way up or do you go for broke from the start? I understand the advantage of higher power with modes that you actually have to use your ears to make sense of things.
>
> Brian VE3GMZ
>
>
>
> Sent via BlackBerry Hub+ Inbox for Android
______________________________________________________________
Elecraft mailing list
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Post: mailto:[hidden email]

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ANDY DURBIN

Max power for JT9 with K3S 100?

In reply to this post by Frank O'Donnell

"With high power is it your practice to start with lower levels and work your way up or do you go for broke from the start?"

For FT8 I make the initial call with the power that I think is required for the propagation path. If the station replies I may increase or reduce power based on their report. If the station does not reply I look at PSKReporter to find reports from the station I called or from others in the same area. If no one in the area reported my signal I may increase power.

My station controller automatically sets "FT8 power" on band change if that option is enabled. "FT8 power" is not max power on any band. It is set for each band based on antenna and experience of propagation conditions for that band. I can reduce power, or increase to band max power, whenever it is appropriate but I enjoy making QSO with the lowest power I can.

Some people think that WSJT-X modes require no skill but it's not just blast and log. Those who put some thought into operating technique may make the QSO where bigger stations fail.

I've been using WSJT-X since before version 1.0 was released but still have worked more DX using CW than any digital mode in the last 8 or so years.

Andy, k3wyc
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ve3gmz

Re: Max power for JT9 with K3S 100?

I'm glad I asked the question. Thanks for your thoughtful replies. I'm a very casual QRP operator. I have used many of the digital modes, cw, ssb and FM too, but certainly not with the sophistication you suggest. There appears to be a lot more to it than I thought. Certainly food for thought.
Again, thanks.

Brian VE3GMZ

Sent via BlackBerry Hub+ Inbox for Android

Original Message

From: [hidden email]
Sent: April 5, 2020 1:05 p.m.
To: [hidden email]
Subject: [Elecraft] Max power for JT9 with K3S 100?

"With high power is it your practice to start with lower levels and work your way up or do you go for broke from the start?"

For FT8 I make the initial call with the power that I think is required for the propagation path. If the station replies I may increase or reduce power based on their report. If the station does not reply I look at PSKReporter to find reports from the station I called or from others in the same area. If no one in the area reported my signal I may increase power.

My station controller automatically sets "FT8 power" on band change if that option is enabled. "FT8 power" is not max power on any band. It is set for each band based on antenna and experience of propagation conditions for that band. I can reduce power, or increase to band max power, whenever it is appropriate but I enjoy making QSO with the lowest power I can.

Some people think that WSJT-X modes require no skill but it's not just blast and log. Those who put some thought into operating technique may make the QSO where bigger stations fail.

I've been using WSJT-X since before version 1.0 was released but still have worked more DX using CW than any digital mode in the last 8 or so years.

Andy, k3wyc
______________________________________________________________
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Bob McGraw - K4TAX

Re: Max power for JT9 with K3S 100?

That is the nice thing about ham radio. There is a mode, frequency, means and group that usually fulfills ones desires within the hobby.

Bob, K4TAX

Sent from my iPhone

> On Apr 5, 2020, at 1:42 PM, [hidden email] wrote:
>
> I'm glad I asked the question. Thanks for your thoughtful replies. I'm a very casual QRP operator. I have used many of the digital modes, cw, ssb and FM too, but certainly not with the sophistication you suggest. There appears to be a lot more to it than I thought. Certainly food for thought.
> Again, thanks.
>
> Brian VE3GMZ
>
>
>
> Sent via BlackBerry Hub+ Inbox for Android
>
>
> Original Message
>
>
> From: [hidden email]
> Sent: April 5, 2020 1:05 p.m.
> To: [hidden email]
> Subject: [Elecraft] Max power for JT9 with K3S 100?
>
>
> "With high power is it your practice to start with lower levels and work your way up or do you go for broke from the start?"
>
> For FT8 I make the initial call with the power that I think is required for the propagation path. If the station replies I may increase or reduce power based on their report. If the station does not reply I look at PSKReporter to find reports from the station I called or from others in the same area. If no one in the area reported my signal I may increase power.
>
> My station controller automatically sets "FT8 power" on band change if that option is enabled. "FT8 power" is not max power on any band. It is set for each band based on antenna and experience of propagation conditions for that band. I can reduce power, or increase to band max power, whenever it is appropriate but I enjoy making QSO with the lowest power I can.
>
> Some people think that WSJT-X modes require no skill but it's not just blast and log. Those who put some thought into operating technique may make the QSO where bigger stations fail.
>
> I've been using WSJT-X since before version 1.0 was released but still have worked more DX using CW than any digital mode in the last 8 or so years.
>
> Andy, k3wyc
> ______________________________________________________________
> 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
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