KX3 oscillator temperature

[on4iq]

I recently started extensive temperature testing on the KX3 to get more data on dissipation and stability.
For starters stability in RX. KX3 in original setup. Serial below #2000
I noticed that for a steady ambient temperature the oscillator temperature varies with frequency used.
Has anyone else similar observations? Temp taken after long (2h) warm up
For example:
50MHz: 39°C
28MHz: 37°C
 7MHz: 36°C

PA in RX remains 28°C
Any feedback is welcome.
73 Johan

[Fred Townsend-2]

Johan:
We know the higher the frequency the less efficient the amplifier /oscillator so what I think you are seeing is the effect of self heating. 3 degrees c seems like a reasonable number. I think you will see even more heating in transmit. That's why an oscillator with a low temperature coefficient is important.

73
Fred, AE6QL

-----Original Message-----

>From: on4iq <[hidden email]>
>Sent: Aug 20, 2014 11:50 AM
>To: [hidden email]
>Subject: [Elecraft] KX3 oscillator temperature
>
>I recently started extensive temperature testing on the KX3 to get more data
>on dissipation and stability.
>For starters stability in RX. KX3 in original setup. Serial below #2000
>I noticed that for a steady ambient temperature the oscillator temperature
>varies with frequency used.
>Has anyone else similar observations? Temp taken after long (2h) warm up
>For example:
>50MHz: 39°C
>28MHz: 37°C
> 7MHz: 36°C
>
>PA in RX remains 28°C
>Any feedback is welcome.
>73 Johan
>
>
>
>
>--
>View this message in context: http://elecraft.365791.n2.nabble.com/KX3-oscillator-temperature-tp7592410.html
>Sent from the Elecraft mailing list archive at Nabble.com.
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[wayne burdick]

The synthesizer I.C.'s current drain, and thus its operating temperature, vary in direct proportion to operating frequency.

73,
Wayne
N6KR

On Aug 20, 2014, at 11:50 AM, on4iq <[hidden email]> wrote:

> I recently started extensive temperature testing on the KX3 to get more data
> on dissipation and stability.
> For starters stability in RX. KX3 in original setup. Serial below #2000
> I noticed that for a steady ambient temperature the oscillator temperature
> varies with frequency used.
> Has anyone else similar observations? Temp taken after long (2h) warm up
> For example:
> 50MHz: 39°C
> 28MHz: 37°C
> 7MHz: 36°C
>
> PA in RX remains 28°C
> Any feedback is welcome.
> 73 Johan

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[Raymond Sills]

And, that makes a lot of sense, because the synthesizer's oscillations  
create more peaks per unit time (a definition of frequency), and  
therefore consume (or require) more power to do so than when the  
synthesizer is running at a lower frequency.  Think of a car's engine:  
it uses less fuel at idle than at high RPMs.  So more power being used  
in the synthesizer is going to make it hotter, since any electronic  
component is not 100% efficient and unused energy is spent as heat.

73 de Ray
K2ULR

On Aug 20, 2014, at 7:32 PM, Wayne Burdick wrote:

> The synthesizer I.C.'s current drain, and thus its operating  
> temperature, vary in direct proportion to operating frequency.
>
> 73,
> Wayne
> N6KR
>
> On Aug 20, 2014, at 11:50 AM, on4iq <[hidden email]> wrote:
>
>> I recently started extensive temperature testing on the KX3 to get  
>> more data
>> on dissipation and stability.
>> For starters stability in RX. KX3 in original setup. Serial below  
>> #2000
>> I noticed that for a steady ambient temperature the oscillator  
>> temperature
>> varies with frequency used.
>> Has anyone else similar observations? Temp taken after long (2h)  
>> warm up
>> For example:
>> 50MHz: 39°C
>> 28MHz: 37°C
>> 7MHz: 36°C
>>
>> PA in RX remains 28°C
>> Any feedback is welcome.
>> 73 Johan
>
>
>
> ______________________________________________________________
> 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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